1.41.2

• BUG FIX: Fix :hash REPL command to α-normalize input
• Add {From,To}Dhall instances for DayOfWeek
• Add {From,To}Dhall instances for ShortText
• Performance improvements
  • #2423
• Fixes and improvements to haddocks
  • #2396
• Fixes and improvements to test suite
  • #2342
  • #2394
• Build against newer dependencies
  • pretty-simple-4.1
  • aeson-2.1
  • vector-0.13
  • turtle-1.6

1.41.1

• BUG FIX: Don't escape ? path component when pretty-printing with expressions

1.41.0

• Support standard version 22.0.0
  • Allow with expressions to update Optional values using ?
  • Add showConstructor keyword
• BUG FIX: Fix pretty-printing of time zones
  • Timezones with a negative offset were previously being rendered with two leading minus signs instead of one
• BUG FIX: dhall freeze --cache to work with standard version 21.0.0
  • dhall freeze will now use missing sha256:… for the first import so that the latter import will be tried if the import is not in cache
  • The old behavior is incompatible with standard version 21.0.0 because the new behavior of the ? operator doesn't fall back on hash mismatches
• BUG FIX: Allow with expression to update a field named Some
  • This fixes a discrepancy between the Haskell implementation and the standard where the Haskell implementation would not permit { Some = 0 } with Some = 1
• Fix dhall {format,lint,freeze} to preserve leading shebangs
• Add FromDhall instances for Int{8,16,32,64}

1.40.2

• Supports standard version 21.1.0
  • The interpreter now supports customizing headers using a headers.dhall configuration file
  • Generalize grammar for certain annotations
  • Add support for a trailing line comment without a newline
• BUG FIX: dhall repl no longer ignores type annotations on :let commands
  • Before this fix, :let x : T = 3 would ignore the : T type annotation
• BUG FIX: Don't accept a bar after an empty union
  • Before this fix, the interpreter would accept something like <>|, which is not valid according to the standard grammar
• New FromDhall/ToDhall instances for Day/TimeOfDay/TimeZone #2294 #2300
  • These types correspond to the recent temporal literals added to the language
• New subExpressionsWith Traversal
• Add Template Haskell support for modifying field names in generated Haskell types
  • This adds a new makeHaskellTypesWith utility with takes a GenerateOptions function argument for customizing the code-generation logic
  • This comes in handy when Dhall fields have names are reserved keywords in Haskell code. You can now transform the Haskell field names to avoid collisions
• Support GHC 9.2
• Fixes and improvements to documentation
  • #2290
• Fixes and improvements to error messages
  • #2303

1.40.1

• BUG FIX: Fix equivalence check for Date / Time / TimeZone
  • This fixes a serious bug in the recently introduced support for temporal literals where they would fail to type-check when given a correct type annotation or when they were checked against an existing type
  • For example, 00:00:00 : Time was failing to type-check

1.40.0

• Almost supports version 20.2.0 of the standard
  • The main thing that is missing is support for the headers.dhall file
  • BREAKING CHANGE TO THE LANGUAGE: Add support for Date / Time / TimeZone
    • This is a breaking change because Date, Time, and TimeZone are now reserved identifiers
  • Improved fallback behavior for ?
• BREAKING CHANGE TO THE LANGUAGE: Require whitespace before with
  • The parser now requires whitespace before the with keyword, which brings the Haskell implementation into closer compliance with the standard
  • In practice this is a technically breaking change which will not affect most programs
• New FromDhall instances for Predicate, Equivalence, and Op
• dhall lint will now sort let bindings with imports
  • dhall lint now reorders let bindings to move imports to the top so long as doing so does not change the behavior of the program
• Fixes and improvements to code formatting
  • #2280
• Fixes and improvements to error messages
  • #2244
  • #2238

1.39.0

• Supports version 20.2.0 of the standard
  • Add support for Unix shebangs
• BREAKING CHANGE TO THE API: dhall {format,freeze,lint} now accept multiple files
  • The --inplace flag is no longer necessary and you can now specify multiple files to update in place on the command line, like dhall format foo.dhall bar.dhall
  • The --inplace flag is still accepted, but does nothing, and will emit a warning
  • This is a breaking change to the API for formatting/freezing/linting files because now you can specify multiple inputs instead of one input
• BREAKING CHANGE: Pre-6.0.0 hashes are no longer supported
  • The interpreter no longer provides backwards compatibility for integrity checks computed before standard version 6.0.0
  • This is a breaking change to the API of the Dhall.Binary module, where certain utilities are no longer parameterized on a StandardVersion
  • This is also a breaking change to any Dhall code that depended on these really old integrity checks
• BUG FIX: Formatting ≡ now correctly preserves the original character set
• BUG FIX: Don't panic on Text/replace ""
• Quasiquotation support for Dhall
  • You can now convert a Dhall expression to the corresponding syntax tree using a quasiquoter like this: [dhall| \x -> x + 2 ]
• New Dhall.Marshal.{Encode,Decode} modules
  • These modules split up the Dhall module into two smaller modules for encoding and decoding logic, respectively
  • The Dhall module still re-exports the same functionality as before, so this is not a breaking change
• Support GHC 9.0.1
• Fixes and improvements to code formatting
  • Improve pretty-printing of sha256

1.38.1

• Add INLINABLE annotations in more places
  • This may improve performance by enabling more specializations
• Fix hashable-related test failures
• Fix support for GHC 8.4.4
  • … by using GeneralizedNewtypeDeriving (with a z)
• Allow doctest-0.18
• Allow bytestring-0.11

1.38.0

• BREAKING CHANGE: Detect preferred character set from input
  • dhall format will now preserve the character set of the formatted file by default. In other words, if the file uses ASCII punctuation then dhall format will format the file using ASCII punctuation.
  • If the file contains both ASCII and Unicode punctuation it will prefer Unicode by default
  • This is a breaking change because the Lam / Pi / Combine / CombineTypes, and Prefer constructors now take an additional argument to record which character set was used
• BUG FIX: Fix CORS compliance check
  • Previous versions were not correctly enforcing CORS compliance
  • This implies that some imports that would have worked previously by accident will now fail; specifically: an import from one domain transitively importing something from another domain that has not opted into CORS
• Add ToDhall (Fix f) instance
• Fixes and improvements to error messages
  • #2130

1.37.1

• Fix performance regression for with expressions

1.37.0

• Supports version 20.0.0 of the standard
  • Implement revised Text/replace β-normalization
  • Allow Text/replace "" to support an abstract haystack
  • Support if expressions returning a type or kind
• BREAKING CHANGE TO THE API: Improve error message for duplicate projection label
  • This also makes the implementation more standards-compliant, by treating a duplicate label as a type error instead of a parse error
  • This is a breaking change since the Project constructor now stores a [Text] instead of Set Text
• Add --cache flag to dhall hash
  • This flag adds the hashed expression to the cache when enabled
• Deprecate Inject / Interpret
  • You should instead use ToDhall / FromDhall, respectively
• Fixes and improvements to the haddocks:
  • #2098
  • #2100
• Fixes and improvements to error messages:
  • #2082
  • #2095
• Fixes and improvements to the parser:
  • #2083
• Fixes and improvements to the pretty printer:
  • #2083
  • #2101

1.36.0

• Supports version 19.0.0 of the standard
  • BREAKING CHANGE TO THE API: Add Text/replace built-in
  • Implement with without syntactic sugar
• dhall lint will now add a .dhall extension to all Prelude imports
  • The old extension-free Prelude imports are deprecated
• Fix command-line completions for files
• Improve Template Haskell support for record constructors
• Fixes and improvements to code formatting
  • #2037
  • #2048
  • #2069

1.35.0

• Supports version 18.0.0 of the standard
  • Implement more efficient with desugaring
    • Chained with expressions will now be much more efficient
• BREAKING CHANGE TO THE API: Preserve whitespace for Lam constructor
  • This change extends the Lam constructor to preserve whitespace around the variable binding
  • The motivation for this change is to enable dhall-docs to support jumping to definitions
  • You can replace your existing Lam constructors with Dhall.Core.makeFunctionBinding
• BREAKING CHANGE TO THE API: Preserve whitespace for Field constructors
  • This change extends the Field constructor to preserve whitespace around the selected field
  • The motivation for this change is to enable dhall-docs to support jumping to definitions
  • You can use Dhall.Core.makeFieldSelection and Dhall.Core.fieldSelectionLabel to convert between the detailed and the simple representation of the selected field.
• Add FromDhall instances for {Int,Word}{,8,16,32,64}
• Add --output option for dhall text subcommand
• Add Dhall.Crypto.toString
• Make the HTTP Manager configurable
  • Several import-related functions now provide an alternative variants that allows the user to supply a custom Manager
  • You can use this to tweak HTTP request timeouts or use a different TLS manager (e.g. one from http-client-openssl)
• Fixes and improvements to code formatting

  • #2000

  • #2021

    The formatter now preserves comments for record fields (both record types and record literals)

• Fixes and improvements to documentation
  • #2011
  • #2013
  • #2014
• Fixes and improvements to test suite
  • #2020

1.34.0

• Supports version 17.1.0 of the standard
  • Add support for trailing commas
• BREAKING CHANGE to the API: Support prefix comments on record key-value pairs
  • The Dhall AST (i.e. Expr) now preserves some comments for record types and record literals
  • The impact of this change is that you will need to add Dhall.Syntax.makeRecordField or Dhall.Syntax.recordFieldValue in a few places wherever your Haskell assembles or disassembles record expressions
  • The motivation of this change is two-fold:
    • To eventually enable dhall-docs support for rendering record comments as documentation
    • To eventually enable support for preserving record-related comments when formatting Dhall code
• BUG FIX: Fix with expressions to permit functions on their left-hand side
  • This was a case of the Haskell implementation not being compliant with the standard grammar
• Drop support for GHC 8.2
• Add a new dhall rewrite-with-schemas command
  • You can now simplify a Dhall expression using a schema record (e.g. a ./schemas.dhall record that a package might provide)
  • This simplification replaces large anonymous records with an equivalent use of a record completion when possible
• Add --transitive flag to `dhall {format,lint,freeze}
  • This flag lets you format/lint/freeze a file and all of its transitive dependencies that are reachable via relative file imports
• Move man/dhall.1 to data-files
  • This ensures that Cabal will install dhall's man pages in the correct directory
• Performance improvements
  • #1879
• Standards compliance
  • #1953
  • #1954
  • #1956
  • #1957
  • #1958
• Fixes and improvements to haddocks
  • #1881
  • #1955

1.33.1

• Multi-line REPL / support repline-0.4.0.0
  • dhall repl supports a new :paste command that lets you input a command by pasting one or more lines

1.33.0

• Supports version 17.0.0 of the standard
  • BREAKING CHANGE: URLs no longer support quoted path components
  • BREAKING CHANGE: Optional/{fold,build} are no longer built-ins
  • Record fields now permit empty labels
• BREAKING CHANGE: Fail instead of hanging when deriving FromDhall for recursive types
  • This is a breaking change as now the expected type returns an Expector (Expr Src Void) (essentially an Either) instead of Expr Src Void
  • If you really don't want to handle the new error-related wrapper, you can get the old behavior using a partial pattern match (which will be partial, still an improvement over the previous behavior, which was hanging)
• Fix invalid cache entries
  • The interpreter will now correct cached expressions that are incorrect and warn you when this happens
  • Specifically, if there is a hash mismatch from the cached expression the interpreter will resolve the import again and fix the cache if the resolved import matches the expected hash
• Make encodeExpression polymorphic
  • encodeExpression now has a more general type, which means that you can use it to serialise expressions without imports (i.e. ones of type Expr Void Void)
• Add --quiet option for dhall decode
• Add --noted flag for dhall haskell-syntax-tree
• Performance improvements:
  • There were several performance improvements related to binary decoding, which should improve cache lookup speed
  • #1807
  • #1809
  • #1857
• Improvements to error messages
  • #1824
  • #1849
  • #1851
• Fixes to haddocks
  • #1815

1.32.0

• Supports version 16.0.0 of the standard
  • BREAKING CHANGE: Change the precedence of with and ===
    • The precedence change to with means that some old expressions that were valid now require explicit parentheses
  • BREAKING CHANGE: Use RFC7049bis encoding for Doubles
    • This is a breaking change because the hashes of expressions with small Double literals will change now
  • Add support for unions mixing terms and types
    • For example, < A : Bool | B : Type > is legal now
    • You can now write someRecord with a.b.c = x to update a nested fields
• DEPRECATION: Deprecate Dhall.Parser.exprA
  • Dhall.Parser module will eventually drop support for parsing custom import types
  • This is necessary in order to fix several parsing bugs and improve parsing error messages
• BUG FIX: GHC Generics instance for :+: now uses union
  • This fixes a few subtle bugs in how Dhall unions are marshalled into Haskell types, and also improves the error messages
• Formatting improvements
  • Change formatting of if expressions
  • Change formatting for functions and their types
  • Prefer puns when formatting record completions
• Convert union alternatives to directory tree
  • dhall to-directory-tree now supports unions which are automatically unwrapped
• Fix dhall freeze --cache to better handle protected imports
  • dhall freeze --cache will now also update imports that already have integrity checks
• Don't normalized partially saturated {List,Natural}/fold
  • The behavior now matches the standard. Previously, the Haskell implementation was not standards-compliant because it would normalize these partially saturated built-ins

1.31.1

• BUG FIX: Allow whitespace after record pun entry
  • The record pun feature introduced in the previous release did not correctly parse record puns with trailing whitespace, which this change fixes.
• Expose {default,}InputNormalizer
  • The previous version introduced a breaking change to the autoWith type that required access to the implementation of InputNormalizer, which was not exported. This change fixes that.
• Build against latest dependencies
  • QuickCheck-2.14
  • haskell-lsp-0.21
  • repline-0.3 / haskeline-0.8
  • template-haskell-2.16
• Prefer to format using record puns when possible
  • dhall format will now reformat code to use record puns when applicable
• Fixes and improvements to error messages:
  • #1721

1.31.0

• Supports version 15.0.0 of the standard
  • Implement with keyword
    • You can now write someRecord with a.b.c = x to update a nested fields
  • Add support for record puns
    • You can now write { x, y } as a shorthand for { x = x, y = y }
• BREAKING CHANGE TO THE API: Auto-derive Generic/FromDhall/ToDhall with Template Haskell
  • Now the Dhall.TH.makeHaskell* utilities will include these derived instances in the generated declarations
  • This is a breaking change since users were likely already generating these instances separately, which will now conflict with the included instances
• BREAKING CHANGE TO THE API: From/ToDhall no longer takes InterpretOptions argument
  • The types of the autoWith and injectWith methods have changed to take an InputNormalizer instead of an InterpretOptions
    • Note that InputNormalizer is a subset of InterpretOptions
  • This is a breaking change to how derived FromDhall / ToDhall instances are customized to more closely match how other Haskell packages customize derived instances (e.g. aeson with FromJSON / ToJSON)
    • Previously you would customize the behavior globally by passing in a top-level InterpretOptions record to autoWith
    • Now you can customize the behavior locally on a per-instance basis
  • This change enables the following change ...
• Add Dhall.Deriving module for deriving-via helpers
  • Now you can take advantage of the -XDerivingVia language extension to customize derived FromDhall/ToDhall instances, like this:
    • deriving (FromDhall, ToDhall) via Codec (SetSingletonConstructors Bare) Name
• BREAKING CHANGE TO THE LANGUAGE: Match standard with respect to using toMap
  • https://example.com using toMap customHeaders is now a parse error and needs to be explicitly parenthesized as https://example.com using (toMap customHeaders)
  • The language standard had always required the parentheses, but the Haskell implementation was not correctly matching the standard
• Fix formatting of indented comments containing empty lines
  • dhall format was previously not idempotent when formatting indented comments with empty lines
  • Specifically, the formatter kept indenting things further with each format, which this change fixes
• Fix pretty-printer to preserve original numeric literals
  • Now dhall format will preserve numeric literals exactly how you wrote them
  • For example, 0xFF will no longer be reformatted as 255
• Add dhall to-directory-tree support for Maps
  • Maps are now converted to directories (just like records)
• Add manpage
  • ... mainly for the benefit of people packaging Dhall for various distributions
• Group commands in CLI
  • The command-line --help output now groups commands into useful sections
• Fix numeric parsing for GHCJS
  • The GHCJS backend for Dhall was failing to parse numbers, which this change fixes
• Fixes and improvements to error messages:
  • #1656
  • #1698
  • #1702
• Fixes and improvements to the haddocks:
  • #1708
  • #1712

1.30.0

• Supports version 14.0.0 of the standard
• BREAKING CHANGE TO THE API: Add --check flag to dhall {lint,freeze}
  • You can now use the --check flag to verify that a file has already been linted or frozen
  • This is a breaking change to the types used by the Dhall.Format module
• BREAKING CHANGE TO THE LANGUAGE: Disallow Natural literals with leading zeros
  • Now a literal like 042 is no longer valid
  • See the changelog for standard version 14.0.0 for more details
• BUG FIX: Fix parsing of Double literal trailing whitespace
  • Certain expressions using Double literals would fail to parse, which this change fixes
• BUG FIX: Use DeriveLift instead of GHC Generics to derive Lift
  • This fixes a build failure on GHC 8.10
• Drop support for GHC 7.10.3
  • GHC 8.0.2 is now the earliest supported version
• Add support for dotted field syntax
  • { x.y.z = 1 } now legal syntax for nested fields
  • See the changelog for standard version 14.0.0 for more details
• Add support for duplicate record fields
  • This combines with the previous feature to let you write { x.y = 1, x.z = True }, which is equivalent to { x = { y = 1, z = True } }
  • See the changelog for standard version 14.0.0 for more details
• Add dhall lint support for deprecating Optional/{fold,build}
  • The Optional/{fold,build} built-ins are deprecated and can be implemented in terms of other language features
  • Optional/fold can be implemented in terms of merge (which now works on Optional values)
  • Optional/build could always be implemented using Some/None
  • dhall lint now transforms the deprecated built-ins to use their equivalent built-in-free versions
• Support Template Haskell for multiple datatypes
  • This extends the Template Haskell support added in the previous release to work for datatypes that refer to one another
• Add support for custom substitutions
  • You can now add custom substitutions, which are like let bindings that propagate to transitive imports
• Small formatting fixes

1.29.0

• Supports version 13.0.0 of the standard
• BREAKING CHANGE: Generate Haskell datatype declarations from Dhall types
  • You can now use the makeHaskellTypeFromUnion Template Haskell utility to generate a Haskell datatype declaration from a Dhall union type
  • This helps ensure that your Haskell types and Dhall types stay in sync, when you want the Dhall type to be the source of truth
  • This is a breaking change because the default InterpretOptions changed the default handling of singleton constructors from Wrapped to Smart
  • You can preserve the old behavior using: autoWith defaultInterpretOptions{ singletonConstructors = Wrapped }
• BUG FIX: Fix dhall freeze --cache and dhall lint to preserve let-related comments
  • Now they match the behavior of dhall format with regard to preserving these comments
• BUG FIX: Fix escaping of significant leading whitespace when formatting code
  • The formatter would sometimes unnecessarily escape significant leading whitespace for the final line of multiline string literals, which this change fixes
• BUG FIX: Fix dhall encode --json for Double values
• NEW FEATURE: dhall to-directory-tree command
  • You can now generate a directory tree from a Dhall expression
  • Specifically:
    • records are converted to directories
    • Text fields are converted to files named after the field
    • Optional values are omitted if None
    • Everything else is rejected
• NEW FEATURE: Hexadecimal literals
  • See the changelog for standard version 13.0.0 for more details
• NEW FEATURE: merge works on Optional values
  • See the changelog for standard version 13.0.0 for more details
• Improve formatter
  • dhall format will now render expressions nested inside record fields or alternatives more compactly, including:
    • Records
    • Record completion expressions
    • Expressions wrapped in Some
    • Lists
• Exclude the using ... suffix from imports listed by dhall resolve
  • Specifically when using the --{immediate,transitive}-dependencies flags

1.28.0

• Supports version 12.0.0 of the standard
• BREAKING CHANGE: Add Integer/{clamp,negate} built-ins
  • This is a technically breaking change API since this adds a new constructor to the Expr type
  • This is also a technically breaking change to the language. See the changelog for standard version 12.0.0 for more details
• BREAKING CHANGE: Remove support for fusion
  • This is also a technically breaking change to the language. See the changelog for standard version 12.0.0 for more details
• BREAKING CHANGE: Parse whitespace more precisely
  • The Haskell implementation now matches the official grammar much more closely, but as a result will now reject some programs that it used to accept
  • For example, 1:Natural used to be valid and now is no longer valid as the standard requires mandatory whitespace after the :
  • Consult the standard grammar if you run into a new parsing error as a result of this change
  • This is also a parsing performance regression (specifically for parsing comments), but should not be noticeable in practice. See #1512 for more details
• BREAKING CHANGE: Rename Type to Decoder and InputType to Encoder #1483 / #1489
• BUG FIX: Fix dhall format --check
  • Before this change dhall format --check would fail due to attempting to read all of standard input in twice
• BUG FIX: Fix dhall freeze to always re-freeze an import
  • Before this fix, dhall freeze would not attempt to refreeze an already frozen import
• Permit spaces around completion operator
  • See the changelog for standard version 12.0.0 for more details
• Make missing referentially transparent
  • missing can now be imported transitively via a remote import
  • Normally resolving missing would still still fail, except for missing as Location, which is now a valid transitive import
  • See the changelog for standard version 12.0.0 for more details
• Write cache files atomically
  • This is a resilience improvement so that the cache is not left in a corrupt state in the event of a power outage or exhausting disk/memory
• New Dhall.function utility
  • This is provides the same functionality as the Interpret instance for (->), except without the use of typeclasses
• New dhall haskell-syntax-tree command
  • This command displays the Haskell syntax tree of an expression (primarily for debugging purposes)
  • Note that this is highly-volatile and subject to change, so don't depend on this programmatically. We may break the output of this command without any notice.
• Add instance Show Ann
• Move normalization code from Dhall.Core to Dhall.Normalize
  • Note that this is not a breaking change. The relocated utilities are still re-exported from Dhall.Core
• Fix dhall resolve --transitive-dependencies to list dependencies in "post-order"
• Performance improvements
  • #1500
  • #1522
  • #1568
  • #1580
• Fixes and improvements to code formatting
  • #1460
  • #1466
  • #1508
  • #1527
  • #1422
  • #1552
  • #1543
  • #1554
  • #1569
• Fixes and improvements to code linting
  • #1518
  • #1531
• Fixes and improvements to error messages
  • #1443
  • #1448
  • #1482
  • #1519
  • #1556
  • #1528
• Fixes and improvements to the parser
  • #1473
  • #1549
  • #1563
  • #1584
• Fixes and improvements to diffs
  • #1585
• Fixes and improvements to the REPL
  • #1573
• Fixes and improvements to documentation
  • #1530

1.27.0

• Supports version 11.0.0 of the standard
• BREAKING CHANGE: Rename Inject/Interpret to ToDhall/FromDhall
  • This change ConstraintKinds to minimize disruption by keeping around Inject/Interpret as synonyms for ToDhall/FromDhall
  • In other words, constraints and derived instances using Inject or Interpret will still work
  • However, manual instances using Inject or Interpret won't work unless you rename them to ToDhall/FromDhall or enable the TypeSynonymInstances extension
• BREAKING CHANGE: Fix Eq instance for Exprs with special Doubles
  • This fixes the Eq instance for Exprs to match the standard regarding Double comparisons
  • Specifically: NaN == NaN and -0.0 /= 0.0
  • This is a breaking change because the DoubleLit constructor of Expr now stores a DhallDouble instead of a Double
• BREAKING CHANGE: Add --file option for dhall hash
  • This is a breaking change because it also removes the Dhall.Hash module, which wasn't really carrying its own weight
• Add support for leading separators
  • See the changelog for standard version 11.0.0 for more details
• Add record completion operator
  • See the changelog for standard version 11.0.0 for more details
• Add dhall tags subcommand
  • This generates an ETags file from an input file or directory
• Add dhall lint support for fixing malformed assertions
  • dhall lint now fixes let example = foo === bar to be let example = assert : foo === bar
• Normalize inferred types #1337
• New FromDhall/ToDhall (previously Interpret/Inject) instances for:
  • Void
  • Map #1391 / #1412
  • HashMap
  • Set and HashSet
  • ()
• Add --output option to dhall
• Move syntax things from Dhall.Core to a new Dhall.Syntax module
  • This is not a breaking change. Dhall.Core still re-exports the same API as before
• Performance improvements
  • #1362
  • #1366
  • #1368
  • #1397
  • #1401
• Fixes and improvements to code formatting
  • #1360
  • #1372
  • #1380
  • #1415

1.26.1

• TECHNICALLY BREAKING CHANGES: Simplify ⫽ within projection / Simplify nested record projections
  • These are technically breaking changes because you will need to update integrity checks that protect code simplified in this way
  • We're not bumping the major version since the likelihood that you're affected is quite low
• BUG FIX: Fix performance regression
  • This change fixes the performance regression introduced in the previous release (version 1.26.0)
• BUG FIX: Prevent REPL from inserting inferred Sorts into context
  • This protects the REPL from getting hosed if you define an expression using :let that has an inferred type of Sort
• NEW FEATURE: Improved Inject/Interpret support for 1-field constructors - (#1315 / #1321)
  • This adds a new singletonConstructors field to InterpretOptions that lets you control what Dhall type 1-field Haskell constructors correspond to
  • The default (Wrapped) is backwards compatible with the old behavior
  • The Smart option is probably what you want: it will strip the Haskell constructor from the Dhall type if the constructor has one anonymous field
  • The Bare option always strips 1-field Haskell constructors from the Dhall type
• NEW FEATURE: --censor flag that disables source code display (#1312 / #1329)
  • Use this flag when you don't want sensitive Text literals showing up in parsing or type-checking error messages
• Format record fields more compactly if they fit on 1 line
  • The formatter will now format record fields on a field-by-field basis to avoid unnecessary vertical sprawl of formatted records
  • Specifically, record fields that fit on one line will now be formatted on one line
• Add --quiet option to dhall type
  • This lets you use dhall type in "check only" mode (e.g. for CI for for development feedback)
• Improved GHCJS support - (#1311 / #1330)
• Fix all executables to accept --version
  • Note that the dhall version subcommand is still supported, too
• New Dhall.Version module
• Don't normalize inferred types
  • This fixes dhall type to more accurately follow the standard
• Initial changes for GHC 8.8 support
• Fix Haddock formatting for dhallFromJSON
• Improved Windows caching support
  • dhall will now prefer the %LOCALAPPDATA% directory for caching if it is available
• Warn about missing cache directories

1.26.0

• Supports version 10.0.0 of the standard
• BREAKING CHANGE TO THE LANGUAGE: Remove old union literal syntax
  • Union literals of the form < x = e | ... > are no longer valid
  • For more details, see: Migration: Deprecation of old union literal syntax
  • Also see the changelog for standard version 10.0.0 for more details
• BREAKING CHANGE TO THE API: Change X to be a type synonym for Data.Void
  • This is a breaking change if you were previously pattern matching on the X constructor. You can replace that with the use of Data.Void.absurd
• BREAKING CHANGE TO THE API: Treat multi-lets as syntactic sugar
  • This is a breaking change because the Let constructor now only stores one Binding instead of a NonEmpty list of Bindings
• PERFORMANCE REGRESSION & TECHNICALLY BREAKING CHANGE TO THE LANGUAGE: Dependent types
  • You can now write functions from terms to types
  • There is also now language support for tests of the form assert : x === y
  • This deteriorates the performance of large multi-let expressions (See: #1306)
  • Splitting large multi-let expressions into smaller files may mitigate the problem as a work-around for now
  • Follow #1129 for work to fix this performance regression
  • This is also a technically breaking change because assert is now a reserved keyword
  • See the changelog for standard version 10.0.0 for more details
• TECHNICALLY BREAKING CHANGE TO THE LANGUAGE: Add Natural/subtract built-in
  • The language now supports machine subtraction, which can be used to support several other high-performance operations (like Natural comparisons)
  • This is a technically breaking change if you used Natural/subtract as an identifier in your code
  • See the changelog for standard version 10.0.0 for more details
• TECHNICALLY BREAKING CHANGE TO THE LANGUAGE: More simplifications for field selection
  • Now the interpreter will more intelligently simplify certain field projections
  • For example: λ(x : { a : Bool, b : Bool }) → (x ⫽ { c = 0 }).{ a, c }.c will now simplify to λ(x : { a : Bool, b : Bool }) → 0
  • This is a technically breaking change because you will need to update integrity checks that protect code simplified in this way
  • See the changelog for standard version 10.0.0 for more details
• TECHNICALLY BREAKING CHANGE TO THE LANGUAGE: Simplify ⫽ when its arguments are equivalent
  • This is a technically breaking change for the same reason: this will perturb semantic integrity checks for affected code
  • See the changelog for standard version 10.0.0 for more details
• NEW FEATURE: Restore support for records containing both types and terms
  • In other words { foo = 1, bar = Bool } is now valid again
  • This means that you now can export a single package containing both types and terms
  • See the changelog for standard version 10.0.0 for more details
• dhall format now preserves let comments
  • dhall format will now preserve comments in the following locations of a let binding:
  • let {- HERE -} x {- HERE -} : {- HERE -} Bool = {- HERE -} True in x
  • This support handles both single-line and multi-line comments and also takes care of correctly indenting/dedenting them
  • Note that comments before the let keyword are still not preserved (unless it is the beginning of the file)
• Add API support for marshalling recursive types
  • You can now marshal recursive types from Dhall into Haskell using the newly-added utilities
  • See also: #1298
• New :help command for dhall repl
• New --no-cache flag #1290 / #1434 / #1436
  • You can now disable use of the cache with this flag
  • This comes in handy if you want to disable α-normalization for imports protected by a semantic integrity check
• Bug fixes
  • Fix isNormalized for field selections
  • Simplify Natural/subtract when its arguments are equivalent
  • Fix NaN to be judgmentally equivalent to itself
  • Fix Inject instance for lists
  • Fix typechecking of toMap
• Performance optimizations
  • Optimize a few Set instances
  • Remove some redundant sorting during normalization
• Improvements to error messages
  • Improve error reporting for failed remote imports
  • Improve HTTP errors
• Improvements to formatting
  • Indent function arguments when formatting
  • Prefer unquoted URLs
  • Strip leading whitespace
• Improvements to diffs
  • Fix diffs for lists
  • Improve diff for non-empty lists
  • Small fixes to dhall diff
• Improvements to documentation
  • Fix documentation for UnionInputType
  • Document support for caching protected imports
• Improvements to command-line interface
  • Improve description of dhall lint
  • Change dhall type to resolve imports

1.25.0

• Supports version 9.0.0 of the standard
  • See: https://github.com/dhall-lang/dhall-lang/releases/tag/v9.0.0
• BREAKING CHANGE: Remove support for old-style List-like Optional literals
  • List-like Optional Literals (i.e. [ 1 ] : Optional Natural) are no longer valid
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1002
• BREAKING CHANGE: Add support for semi-semantic caching
  • This change significantly improves the performance of imports
  • This change also automatically caches imports without an integrity check
  • This changes several types in Dhall.Import to support this new feature
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1113
• BREAKING CHANGE: Implement new Unicode braced escape sequence
  • Escape sequences encoding surrogate pairs are no longer valid
  • Instead, characters previously encoded as surrogate pairs can instead be encoded as a braced sequence
  • For example: "\uD834\uDD1E" must now be written as "\u{1D11E}"
  • See: https://github.com/dhall-lang/dhall-haskell/pull/987
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1104
• BREAKING CHANGE: Make the type of extract richer:
  • Dhall.extract can now return a detailed error instead of just a Maybe
  • This is a breaking chnage because the type of extract changed
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1011
• BREAKING CHANGE: Add support for importing expressions as Location
  • This is a breaking change because a new Location constructor was added to ImportMode
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1019
• BREAKING CHANGE: Switch Var to use an Int
  • This is a performance improvement, but also a breaking change since the Integer in the Var constructor was changed to an Int
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1044
• BREAKING CHANGE: Add new toMap keyword
  • This is a breaking change to the API because a new ToMap constructor was added to the Expr type
  • This is also a technically breaking change to the language because toMap is now a reserved keyword, although most code should be unaffected in practice
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1041
• BREAKING CHANGE: Sort the fields of a record projection during normalization
  • This is a technically breaking change to the language because any expressions with an uninterpreted record projection will have a different semantic integrity check. However, most could should be unaffected in practice
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1111
• BUG FIX: Fix substitution into record projection by type
  • An expression like this one was being incorrectly rejected: let e = { a = 10, b = "Text" } let s = { a : Natural } in e.(s), which this change fixes
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1012
• BUG FIX: Reject record projection when there is a field type mismatch
  • Record projection by type was previously not checking the expected field types, which this change fixes
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1027
• BUG FIX: Fix linting of unused let bindings
  • Certain let bindings were not correctly detected as unused, which this change fixes
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1001
• BUG FIX: Fix --file option
  • The --file option from the previous release did not work, due to not computing relative paths correctly, which this change fixes
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1004
• BUG FIX: Minor fix to dhall diff
  • dhall diff was incorrectly displaying spurious differences for identical lists that were function arguments, which this change fixes
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1006
• BUG FIX: Allow Sort as type annotation
  • This should have been implemented in the previous release as part of supporting version 8.0.0 of the standard, but was missed
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1024
• BUG FIX: Dhall.Map: Reflect original key ordering in Ord instance
  • Dhall.Map now considers key order when comparing Maps, which it should have done before, but didn't
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1050
• BUG FIX: Consistently format multi-line strings
  • The formatter now formats naked multi-line strings the same as nested multi-line strings
  • Specifically, naked multi-line strings can now be formatted on a single (just like nested multi-line strings)
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1056
• BUG FIX: Make isNormalized consistent with normalize
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1115
• BUG FIX: Make normalizeWithM consistent with normalize
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1126
• BUG FIX: Fix import alternatives to recover from type errors
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1152
• Feature: Semi-semantic caching
  • The Haskell implementation now implicitly caches all local imports, not just imports frozen by integrity checks, so that you don't have to freeze them when doing local development
  • These cached imports are still correctly invalidated if they or any of their dependencies change
  • This new implicit cache is stored underneath ~/.cache/dhall-haskell by default
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1154
• Feature: New dhall text subcommand
  • This new subcommand supersedes the old dhall-to-text executable
• Feature: Add instance Lift (Expr s a)
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1119
• Fixes and improvements to error messages:
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1030
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1137
• Fixes and improvements to tests:
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1155
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1159
• Performance improvements
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1036
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1051
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1048
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1057
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1065
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1066
  • See: https://github.com/dhall-lang/dhall-haskell/pull/1085

1.24.0

• Supports version 8.0.0 of the standard
  • See: https://github.com/dhall-lang/dhall-lang/releases/tag/v8.0.0
• BREAKING CHANGE: Allow tabs and blank lines in multi-line strings
  • Blank lines are now ignored for the purpose of dedenting multiline strings
  • Lines with leading tabs (or mixed tabs and spaces) are now dedented, too, so long as they all share the same prefix
  • This is technically a breaking change, but unlikely to affect programs in practice, especially if they were formatted with dhall format. This change mainly affects programs that were not indented correctly.
  • See the changelog for standard version 8.0.0 for more details
• BREAKING CHANGE: Simplify bare interpolations
  • Expressions like λ(x : Text) → "${x}" now simplify to λ(x : Text) → x
  • This is a technically breaking change because it changes how these sorts of expressions are serialized. This does not affect semantic integrity checks and the new simplified expressions are extensionally equivalent to their older counterpart expressions.
  • See the changelog for standard version 8.0.0 for more details
• BREAKING CHANGE: Encode integrity check as multihash
  • Semantic integrity checks are now encoded using the multihash spec
  • This is a technically breaking change that does not perturb the hash for user-facing semantic integrity checks. This only affects how expressions with unresolved imports are serialized, but semantic integrity checks are only computed for fully-resolved imports.
  • See the changelog for standard version 8.0.0 for more details
• BUG FIX: Fix type-checker to reject invalid record type annotations
  • e.g. { x = 1 } : { x : Text } was not properly rejected by the type checker
  • See: https://github.com/dhall-lang/dhall-haskell/pull/965
• BUG FIX: Custom header forwarding fixed
  • Forwarding custom headers could previously fail in various ways, such as:
    • Cyclic imports leading to endless network requests
    • Resolving a non-existent import for the custom headers
    • Resolving an existing but incorrect import for the custom headers
  • This change fixes that by forwarding custom headers by value instead of by reference
  • See: https://github.com/dhall-lang/dhall-haskell/pull/967
• BUG FIX: Fix GHCJS support
  • Natural/fold was broken in version 1.22, which this change fixes
  • Specifically, it would hang for Natural numbers greater than 1
  • See: https://github.com/dhall-lang/dhall-haskell/pull/985
• BUG FIX: dhall diff no longer double-prints key-value separators
  • See: https://github.com/dhall-lang/dhall-haskell/pull/952
• Feature: Record projection by expression
  • You can now project out a subset of record fields by the expected type
  • let t = { x : Natural } let p = { x = 1, y = 2 } in p.(t) = { x = 1 }
  • See the changelog for standard version 8.0.0 for more details
• Feature: Inline headers
  • You no longer need to specify custom headers in a separate import. You can now specify them inline within the same file.
  • e.g.: https://example.com/x using [ { header = "Foo", value = "Bar" } ]
  • See the changelog for standard version 8.0.0 for more details
• Feature: Allow Sort as a type annotation
  • An expression such as Kind → Kind : Sort will now type-check
  • Sort is still disallowed outside of a type annotation
  • See the changelog for standard version 8.0.0 for more details
• Feature: Allow self-describe-cbor when decoding
  • Dhall expressions serialized as CBOR can be tagged to describe themselves as CBOR without affecting decoding
  • See the changelog for standard version 8.0.0 for more details
• Feature: New --file option for dhall commands
  • In other words, instead of dhall <<< './some/file you can now use dhall --file some/file
  • See: https://github.com/dhall-lang/dhall-haskell/pull/949
• Feature: New --cache flag for dhall freeze command
  • This automates the idiom used by the Prelude to optimistically cache imports but gracefully degrade if the semantic integrity check fails
  • See: https://github.com/dhall-lang/dhall-haskell/pull/980
• Feature: Add :clear command to dhall repl
  • This deletes previous bindings from the history so that they can be garbage collected
  • See: https://github.com/dhall-lang/dhall-haskell/pull/966
• Feature: New chunkExprs Traversal added to Dhall.Core
  • See: https://github.com/dhall-lang/dhall-haskell/pull/954
• Feature: New Dhall.Optics module
  • This re-exports some convenient @lens@ utilities used internally for packages trying to avoid a @lens@ dependency
  • See: https://github.com/dhall-lang/dhall-haskell/pull/986
• More GHC 8.8 support
  • See: https://github.com/dhall-lang/dhall-haskell/pull/961

1.23.0

• BREAKING CHANGE: Fix marshaling union literals
  • 1.22.0 introduced two separate bugs in marshaling union literals between Dhall and Haskell, which this release fixes:
    • Dhall enums did not correctly map onto Haskell enums
    • New-style union literals (i.e. < A : T >.A x) were not correctly supported
  • See: https://github.com/dhall-lang/dhall-haskell/pull/918
  • See: https://github.com/dhall-lang/dhall-haskell/pull/927
  • See: https://github.com/dhall-lang/dhall-haskell/pull/936
• BUG FIX: Fix α-normalization
  • Version 1.22.0 introduced a new faster evaluation algorithm, but the new algorithm introduced two α-normalization regression, which this release fixes
  • The primary effect of this bug was that semantic integrity checks would fail for expressions that contain an if/then/else` expression in their normal form
  • See: https://github.com/dhall-lang/dhall-haskell/pull/931
  • See: https://github.com/dhall-lang/dhall-haskell/pull/938
• BUG FIX: Fix merging of sort-level record types
  • The language standard requires that { a : Kind } ⩓ { b : Kind } is valid, which this change fixes
  • See: https://github.com/dhall-lang/dhall-haskell/pull/891
• BUG FIX: dhall freeze respects the --ascii flag
  • See: https://github.com/dhall-lang/dhall-haskell/pull/934
• BUG FIX: Don't autocomplete fields for record types
  • This prevents the REPL from expanding { x : T }.<TAB> to { x : T }.x
  • See: https://github.com/dhall-lang/dhall-haskell/pull/937
• Support MonadFail-related changes in GHC 8.8
  • See: https://github.com/dhall-lang/dhall-haskell/pull/912
• Add cross flag to simplify cross-compilation
  • This allows the dhall package to be built without using TemplateHaskell
  • See: https://github.com/dhall-lang/dhall-haskell/pull/928
• Increase lines of context for error messages
  • Error messages now provide at least 20 lines of context instead of 3 before truncating large expressions
  • See: https://github.com/dhall-lang/dhall-haskell/pull/916
• Add line numbers to error messages
  • The bottom of every Dhall type error includes the original source code, which now has line numbers on the left margin
  • See: https://github.com/dhall-lang/dhall-haskell/pull/919
• Expand lower bounds on megaparsec/transformers-compat dependencies
  • This is to support dhall on Debian Sid
  • See: https://github.com/dhall-lang/dhall-haskell/pull/939

1.22.0

• Supports version 7.0.0 of the standard
  • See: https://github.com/dhall-lang/dhall-lang/releases/tag/v7.0.0
• BREAKING CHANGE: Add support for empty alternatives
  • The Union type now has an optional (Maybe) type for each alternative
  • See the changelog for standard version 7.0.0 for more details
  • See: https://github.com/dhall-lang/dhall-haskell/pull/863
• BREAKING CHANGE: Remove support for URL fragments
  • The URL type no longer has a field for a URL fragment since the language no longer supports fragments
  • See the changelog for standard version 7.0.0 for more details
  • See: https://github.com/dhall-lang/dhall-haskell/pull/851
• BREAKING CHANGE: Remove deprecated Path type synonym
  • See: https://github.com/dhall-lang/dhall-haskell/pull/858
• BUG FIX: Correctly parse identifiers beginning with http
  • i.e. httpPort was supposed to be a valid identifier name and now is
  • See: https://github.com/dhall-lang/dhall-haskell/pull/870
• BUG FIX: Fix dhall encode bug
  • dhall encode bug was generating binary expressions that were valid (i.e. they would decode correctly) but were non-standard (i.e. hashing them would not match the hash you would normally get from a semantic integrity check)
  • Semantic integrity checks were not affected by this bug since they used a slightly different code path that generated the correct binary input to the hash. Only the dhall decode subcommand was affected
  • See: https://github.com/dhall-lang/dhall-haskell/pull/859
• BUG FIX: Fix for Dhall.UnionType
  • This fixes some expressions that would previously fail to marshal into Haskell, specifically those were the marshalling logic was built using the UnionType utilities
  • See: https://github.com/dhall-lang/dhall-haskell/pull/857
• Feature: New --alpha flag to α-normalize command-line output
  • See: https://github.com/dhall-lang/dhall-haskell/pull/855
• Performance improvements
  • The normalizer is now much faster
  • See: https://github.com/dhall-lang/dhall-haskell/pull/876

1.21.0

• Supports version 6.0.0 of the language standard
  • See: https://github.com/dhall-lang/dhall-lang/releases/tag/v6.0.0
• BREAKING CHANGE: Remove the constructors keyword
  • ... as standardized in version 6.0.0 of the language standard
  • The deprecation cycle is over, so the keyword is no longer supported
  • For more details, see: https://github.com/dhall-lang/dhall-lang/wiki/Migration%3A-Deprecation-of-constructors-keyword
  • See: https://github.com/dhall-lang/dhall-haskell/pull/829
• BREAKING CHANGE: CBOR-encode only special Doubles as half-floats
  • ... as standardized in version 6.0.0 of the language standard
  • CBOR Doubles except Infinity/-Infinity/NaN/0.0 are now encoded in at least 32 bits
  • See: https://github.com/dhall-lang/dhall-haskell/pull/822
• BREAKING CHANGE: Sort record and union fields when CBOR-encoding
  • Fields and alternatives are now sorted when serialized
  • This does not affect semantic integrity checks, which already sorted these fields/alternatives before hashing expressions
  • This does affect the serialization of expressions that have not been normalized (e.g. uninterpreted expressions transmitted over the wire)
  • See: https://github.com/dhall-lang/dhall-haskell/pull/835
• BUG FIX: Fix non-exhaustive pattern match in dhall lint
  • This fixes: Irrefutable pattern failed for pattern Let (l' :| ls') d'
  • This bug would cause dhall lint to fail on some nested let/in expressions
  • See: https://github.com/dhall-lang/dhall-haskell/pull/780
  • See: https://github.com/dhall-lang/dhall-haskell/pull/784
• BUG FIX: Don't fail if $HOME environment variable is unset
  • The interpreter was incorrectly throwing an exception if HOME was unset
  • The standard requires that implementations should handle the HOME environment variable being missing
  • See: https://github.com/dhall-lang/dhall-haskell/pull/789
• Feature: Remove version tag from semantic integrity check
  • ... as standardized in version 6.0.0 of the language standard
  • This is not a breaking change because this change also includes backwards-compatible support for semantic integrity checks produced by older versions of the interpreter
• Feature: Support Unicode path components
  • ... as standardized in version 6.0.0 of the language standard
  • You can now use Unicode in path components if they are quoted
  • i.e. ./families/"禺.dhall" is now legal
• Feature: Add Text/show built-in
  • ... as standardized in version 6.0.0 of the language standard
  • You can now convert a Text literal to its equivalent Dhall source code (which is itself a Text literal)
  • This comes in handy when using Dhall code to generate JSON or Dhall code
  • See: https://github.com/dhall-lang/dhall-haskell/pull/811
• Feature: Add --immediate-dependencies/--transitive-dependencies flags for dhall resolve
  • You can now retrieve all of your immediate or transitive dependencies as a textual list
  • This simplifies integration with other command-line tools (such as file watchers)
  • See: https://github.com/dhall-lang/dhall-haskell/pull/795
  • See: https://github.com/dhall-lang/dhall-haskell/pull/803
• Feature: dhall freeze now only freezes remote imports by default
  • dhall freeze used to freeze all imports (including local imports and environment variables)
  • Now dhall freeze only freezes remote imports by default, which is what most users want
  • You can install freeze all imports using the --all flag
  • See: https://github.com/dhall-lang/dhall-haskell/pull/808
• Feature: :save and :load REPL state
  • :save with no arguments now saves the REPL state to a .dhall-repl-N file
  • The file format is a list of dhall repl commands
  • You can use :load to load the saved state back into the REPL
  • See: https://github.com/dhall-lang/dhall-haskell/pull/807
• Feature: Add :hash command to dhall repl
  • This lets you conveniently hash expressions within the dhall repl
  • See: https://github.com/dhall-lang/dhall-haskell/pull/806
• Feature: Add --check flag to dhall format
  • Use this to check if the input is already formatted
  • Useful for continuous integration when you want to ensure that all code under version control remains formatted
  • See: https://github.com/dhall-lang/dhall-haskell/pull/810
• Feature: Add UnionInputType builder for InputTypes
  • This is the union analog of RecordInputType, letting you build a record explicitly instead of deriving the instance using GHC generics
  • See: https://github.com/dhall-lang/dhall-haskell/pull/775
• Feature: Add :set/:unset commands to dhall repl
  • You can use these commands to set or unset command-line options
  • Currently only setting/unsetting --explain is supported
• Standards-compliance fixes:
  • See: https://github.com/dhall-lang/dhall-haskell/pull/779
  • See: https://github.com/dhall-lang/dhall-haskell/pull/804
  • See: https://github.com/dhall-lang/dhall-haskell/pull/833
• Documentation fixes:
  • See: https://github.com/dhall-lang/dhall-haskell/pull/792
  • See: https://github.com/dhall-lang/dhall-haskell/pull/825
• Test fixes:
  • See: https://github.com/dhall-lang/dhall-haskell/pull/782
  • See: https://github.com/dhall-lang/dhall-haskell/pull/836
• Improved error messages:
  • See: https://github.com/dhall-lang/dhall-haskell/pull/812
  • See: https://github.com/dhall-lang/dhall-haskell/pull/815
  • See: https://github.com/dhall-lang/dhall-haskell/pull/824
• Formatting fixes:
  • See: https://github.com/dhall-lang/dhall-haskell/pull/831
• REPL fixes:
  • See: https://github.com/dhall-lang/dhall-haskell/pull/837

1.20.1

• BUG FIX: Fix binary encoding to use correct standard version
  • This fixes computed hashes to correctly match standard version 5.0.0
  • This is not marked as a breaking change since it is a bug fix. The 1.20.0 release will be blacklisted on Hackage and users should upgrade from 1.19.* directly to 1.20.1
  • See: https://github.com/dhall-lang/dhall-haskell/pull/771

1.20.0

• Supports version 5.0.0 of the language standard
  • See: https://github.com/dhall-lang/dhall-lang/releases/tag/v5.0.0
• BREAKING CHANGE TO THE LANGUAGE: Implement standardized support for multi-line literals
  • This updates the multi-line support to match the standard
  • This is a breaking change because empty lines within the multi-line literal now require leading whitespace whereas previously they did not
  • This is also a breaking change because now a newline is required after the opening '' quotes whereas previously it was not required
  • If you use dhall format then your multi-line literals already have the necessary leading whitespace
• BREAKING CHANGE TO THE LANGUAGE: constructors x = x
  • Now the constructors keyword behaves like an identity function, since constructors can already be accessed as fields off the original union type.
  • This is a breaking change since any record of terms that contains a constructors field will now be a forbidden mixed record of types and terms.
  • This is also a breaking change if you annotated the type of what used to be a constructors record.
  • dhall lint will now remove the obsolete constructors keyword for you
  • See: https://github.com/dhall-lang/dhall-haskell/pull/693
  • See: https://github.com/dhall-lang/dhall-haskell/pull/701
• BREAKING CHANGE TO THE API: Restore Parent constructor for Local type
  • This more closely matches the standard and also enables dhall format to produce a leading ../ for imports instead of ./../
  • See: https://github.com/dhall-lang/dhall-haskell/pull/718
• BUG FIX: Fix type-checking bug for unions
  • The first fix was that the inferred type was wrong for unions where alternatives were types or kinds
  • The second fix was that unions that mixed terms/types/kinds were not properly rejected
  • See: https://github.com/dhall-lang/dhall-haskell/pull/763
• BUG FIX: Change how dhall repl handles prior definitions
  • This changes the REPL to handle previous bindings as if they were defined using a large let expression instead of adding them to the context
  • This fixes some type-checking false negatives
  • See: https://github.com/dhall-lang/dhall-haskell/pull/729
• Feature: Autocomplete for dhall repl
  • You can now auto-complete record fields, union constructors, and identifiers that are in scope
  • See: https://github.com/dhall-lang/dhall-haskell/pull/727
• Feature: GHCJS support
  • dhall can now be built using GHCJS, although some features are still not supported for GHCJS, such as:
    • Semantic integrity checks
    • Custom HTTP headers
  • Also, HTTP imports only work for URLs that support CORS
  • See: https://github.com/dhall-lang/dhall-haskell/pull/739
• Feature: Add support for records of records of types
  • You can now nest records of types
  • See: https://github.com/dhall-lang/dhall-haskell/pull/700
• Feature: Add :quit command for dhall repl
  • See: https://github.com/dhall-lang/dhall-haskell/pull/719
• Feature: Add --json flag for dhall {encode,decode}
  • You can now produce/consume CBOR expressions via JSON instead of binary
  • See: https://github.com/dhall-lang/dhall-haskell/pull/717
• Feature: Add decoding logic for as Text
  • You can now preserve the as Text qualifier on imports when serializing them
  • See: https://github.com/dhall-lang/dhall-haskell/pull/712
• Prenormalize substituted expressions
  • This is a performance improvement that reduces the time and memory consumption when normalizing expressions
  • See: https://github.com/dhall-lang/dhall-haskell/pull/765

1.19.1

• BUG FIX: Fix serious dhall lint bug
  • dhall lint would sometimes remove let expressions that were still in use
  • See: https://github.com/dhall-lang/dhall-haskell/pull/703
• BUG FIX: Fix import caching efficiency bug
  • Some imports were being wastefully fetched multiple times
  • See: https://github.com/dhall-lang/dhall-haskell/pull/702
• Feature: Generate dot graph to visualize import graph
  • Use the dhall resolve --dot command
  • See: https://github.com/dhall-lang/dhall-haskell/pull/698
  • See: https://github.com/dhall-lang/dhall-haskell/pull/713
• Improve HTTP error messages
  • See: https://github.com/dhall-lang/dhall-haskell/pull/710

1.19.0

• Supports version 4.0.0 of the language standard
  • See: https://github.com/dhall-lang/dhall-lang/releases/tag/v4.0.0
• BREAKING CHANGE TO THE LANGUAGE AND API: Prevent Hurkens' paradox
  • This fixes a type-checking soundness bug which permitted infinite loops
  • This is a breaking change because infinite loops are no longer possible
  • This is also a breaking change because a record of types is now treated as a kind instead of a type
  • See: https://github.com/dhall-lang/dhall-haskell/pull/680
• BREAKING CHANGE TO THE LANGUAGE AND API: Doubles are now double-precision floating point numbers
  • This restricts the range of Doubles to IEEE 754 double-precision floating point
  • This also implies that you can no longer convert Scientific values to Dhall expressions (i.e. no Inject instance for Scientific)
  • See: https://github.com/dhall-lang/dhall-haskell/pull/667
• BREAKING CHANGE TO THE API: Preserve field order for record projection
  • The API uses a new Dhall.Set.Set type instead of Data.Set.Set
  • See: https://github.com/dhall-lang/dhall-haskell/pull/670
• BREAKING CHANGE TO THE API: Add support for multi-let expressions
  • This changes the Let constructor to now support storing multiple bindings per let expression
  • See: https://github.com/dhall-lang/dhall-haskell/pull/675
• Access constructors as if they were fields of the union type
  • In other words: < Left : Bool | Right : Natural >.Left
  • See: https://github.com/dhall-lang/dhall-haskell/pull/657
• Support GHC 8.6
  • See: https://github.com/dhall-lang/dhall-haskell/pull/669
• Add support for quoted path components
  • i.e. /"foo"/bar/"baz qux" or https://example.com/foo/"bar?baz"?qux
  • See: https://github.com/dhall-lang/dhall-haskell/pull/690
• Fix parsing of //\\ operator
  • See: https://github.com/dhall-lang/dhall-haskell/commit/9d0fd42d95ab69fa64da4afd8b60d69aca8e65a6
• Preserve Unicode characters when formatting code
  • See: https://github.com/dhall-lang/dhall-haskell/pull/679
• Allow identifier names to begin with Some
  • See: https://github.com/dhall-lang/dhall-haskell/pull/658
• Add subExpressions Traversal
  • See: https://github.com/dhall-lang/dhall-haskell/pull/660
• Add normalizeWithM for monadic normalization
  • See: https://github.com/dhall-lang/dhall-haskell/pull/371
• Custom normalizers now take precedence over default normalization logic
  • This allows one to override the implementation of built-in operators
  • See: https://github.com/dhall-lang/dhall-haskell/pull/684

1.18.0

• Supports version 3.0.0 of the language standard:
  • See: https://github.com/dhall-lang/dhall-lang/releases/tag/v3.0.0
• BREAKING CHANGE TO THE LANGUAGE AND API: New Some/None constructors for Optional values
  • Example: [ Some 1, None Natural ]
  • This is a breaking change to the language because Some and None are now reserved keywords
  • This is a breaking change to the API because Some and None are new constructors for the Expr type
• BREAKING CHANGE TO THE LANGUAGE AND API: Support for kind polymorphism
  • This adds a new Sort constant above Kind in the hierarchy
  • i.e. Type : Kind : Sort
  • This is a breaking change to the language because Sort is now a reserved keyword
  • This is a breaking change to the API because Sort is a new constructor for the Expr type
• BREAKING CHANGE TO THE API: New Dhall.Map module
  • This replaces InsOrdHashMap in the API
  • The primary motivation is to improve performance and to remove the dependency on insert-ordered-containers
• BREAKING CHANGE TO THE API: Use standard version instead of protocol version
  • The binary protocol is now versioned alongside the standard
  • The ProtocolVersion type is renamed to StandardVersion and the
  • --protocol-version option is renamed to --standard-version
  • See: https://github.com/dhall-lang/dhall-haskell/pull/634
• BUG FIX: Fix import chaining for custom header imports
  • See: https://github.com/dhall-lang/dhall-haskell/pull/618
• BUG FIX: Fix import chaining for imports protected by semantic integrity checks
  • See: https://github.com/dhall-lang/dhall-haskell/pull/584
• BUG FIX: Record literals and types produced by ∧/⫽/⩓ are now sorted
  • This ensures that β-normalization is idempotent
  • See: https://github.com/dhall-lang/dhall-haskell/pull/572
• BUG FIX: dhall freeze now correctly handles the starting file being located outside the current working directory
  • See: https://github.com/dhall-lang/dhall-haskell/commit/a22aa79d1957be9ecf166ea066e2a9a5b309e1ae
• BUG FIX: Fix parsing of IPv4-mapped IPv6 addresses
  • See: https://github.com/dhall-lang/dhall-haskell/pull/632
• FEATURE: New --ascii flag for ASCII output
  • See: https://github.com/dhall-lang/dhall-haskell/pull/570
• FEATURE: New dhall encode and dhall decode subcommands
  • These allow you to transform Dhall source code to and from its binary representation
  • See: https://github.com/dhall-lang/dhall-haskell/pull/588
• LARGE parsing performance improvements
  • Parsing is about 10x-100x faster on most code
  • See: https://github.com/dhall-lang/dhall-haskell/pull/591
  • See: https://github.com/dhall-lang/dhall-haskell/pull/592
  • See: https://github.com/dhall-lang/dhall-haskell/pull/597
  • See: https://github.com/dhall-lang/dhall-haskell/pull/601
  • See: https://github.com/dhall-lang/dhall-haskell/pull/602
  • See: https://github.com/dhall-lang/dhall-haskell/pull/604
  • See: https://github.com/dhall-lang/dhall-haskell/pull/606
• Type-checking performance improvements:
  • See: https://github.com/dhall-lang/dhall-haskell/pull/566
• Normalization performance improvements:
  • See: https://github.com/dhall-lang/dhall-haskell/pull/610
• dhall freeze now caches the imports as it freezes them
  • See: https://github.com/dhall-lang/dhall-haskell/pull/587
• dhall freeze now refreezes imports with invalid semantic integrity checks
  • See: https://github.com/dhall-lang/dhall-haskell/pull/637
• dhall freeze now adds a trailing newline
  • See: https://github.com/dhall-lang/dhall-haskell/pull/629
• Build against megaparsec-7.0.*
  • See: https://github.com/dhall-lang/dhall-haskell/pull/565
• Support GHC 8.6
  • See: https://github.com/dhall-lang/dhall-haskell/pull/599
  • See: https://github.com/dhall-lang/dhall-haskell/pull/623
• Support GHC all the way back to 7.10.3
  • See: https://github.com/dhall-lang/dhall-haskell/pull/595
  • See: https://github.com/dhall-lang/dhall-haskell/pull/621
• Improvements to error messages:
  • See: https://github.com/dhall-lang/dhall-haskell/pull/563
  • See: https://github.com/dhall-lang/dhall-haskell/pull/576
  • See: https://github.com/dhall-lang/dhall-haskell/pull/583
  • See: https://github.com/dhall-lang/dhall-haskell/pull/589

1.17.0

• This release corresponds to version 2.0.0 of the language standard
• BREAKING CHANGE TO THE LANGUAGE AND API: Binary serialization support
  • This is a breaking change to the hash for all semantic integrity checks
  • The hash used by the semantic integrity check is now based on the binary representation instead of a text representation of the expression
  • You can pin the new hashes by supplying the --protocol-version 1.0 option on the command line until you need support for newer language features
  • This also includes a breaking change to ImportType in the API
• BREAKING CHANGE TO THE LANGUAGE: Disallow combining records of terms and types
  • This is mainly for consistency and to improve type errors that would have otherwise happened further downstream
  • This should not affect the vast majority of code
  • See: https://github.com/dhall-lang/dhall-haskell/pull/538
• BUG FIX: Semantic integrity checks now work for imported expression using the constructors keyword
  • See: https://github.com/dhall-lang/dhall-haskell/pull/554
• BUG FIX: Fix α-normalization of expressions with bound variables named _
  • See: https://github.com/dhall-lang/dhall-haskell/pull/524
• BUG FIX: Fix isNormalized to match normalize
  • See: https://github.com/dhall-lang/dhall-haskell/pull/522
• BUG FIX: dhall lint now correctly handles nested let expressions
  • See: https://github.com/dhall-lang/dhall-haskell/pull/555
• FEATURE: Imports protected by a semantic integrity check are now cached
  • See: https://github.com/dhall-lang/dhall-haskell/pull/533
• The default dhall command no longer outputs the type to stderr
  • You can add back the type as a type annotation using the --annotate switch
  • See: https://github.com/dhall-lang/dhall-haskell/pull/544
• New utilities for building InputTypes
  • See: https://github.com/dhall-lang/dhall-haskell/pull/530
• Improve parsing performance for long variable names
  • See: https://github.com/dhall-lang/dhall-haskell/pull/526
• More succinct type diffs for function types
  • See: https://github.com/dhall-lang/dhall-haskell/pull/540
• Identifier names can now begin with keywords
  • i.e. ifChanged and lettuce are now legal identifiers
  • See: https://github.com/dhall-lang/dhall-haskell/pull/551

1.16.1

• Fix test failure due to missing test data file

1.16.0

• BREAKING CHANGE: Consolidate input family of functions
  • These now take a record of options
  • This also _stack field of the Status type from [Import] to NonEmpty Import
• Permit $ in quoted variable names
  • See: https://github.com/dhall-lang/dhall-haskell/pull/510

1.15.1

• Fix infinite loop when formatting expressions containing ?
  • See: https://github.com/dhall-lang/dhall-haskell/pull/491

1.15.0

• BREAKING CHANGE TO THE API: Support alternative imports using new ? operator
  • This adds a new constructor which affects exhaustive pattern matches
  • See: https://github.com/dhall-lang/dhall-haskell/pull/473
• BREAKING CHANGE TO THE API: Add Integer/toDouble built-in function
  • This adds a new constructor which affects exhaustive pattern matches
  • See: https://github.com/dhall-lang/dhall-haskell/pull/434
• BREAKING CHANGE TO THE API: Use strict Text instead of lazy Text
  • See: https://github.com/dhall-lang/dhall-haskell/pull/455
• BREAKING CHANGE TO THE API: Remove Buildable in favor of Pretty
  • See: https://github.com/dhall-lang/dhall-haskell/pull/459
• BREAKING CHANGE TO THE API: Removed the Parent constructor from FilePrefix
  • Instead, use Here with a ".." prefix.
  • See: https://github.com/dhall-lang/dhall-haskell/pull/407
• BUG FIX: Disallow duplicate fields in records
  • See: https://github.com/dhall-lang/dhall-haskell/pull/430
• BUG FIX: Fix stripping of leading whitespace in multi-line strings
  • See: https://github.com/dhall-lang/dhall-haskell/pull/469
• BUG FIX: Fix formatting field access of an import
  • See: https://github.com/dhall-lang/dhall-haskell/pull/471
• Add dhall freeze command
  • See: https://github.com/dhall-lang/dhall-haskell/pull/486
• Add dhall diff command
  • See: https://github.com/dhall-lang/dhall-haskell/pull/442
• Add dhall lint command
  • See: https://github.com/dhall-lang/dhall-haskell/pull/484
• Change dhall-repl/dhall-hash/dhall-format to dhall subcommands
  • i.e. dhall repl/dhall hash/dhall format
  • See: https://github.com/dhall-lang/dhall-haskell/pull/435
  • See: https://github.com/dhall-lang/dhall-haskell/pull/452
• Add with-http cabal flag to disable support for remote imports
  • See: https://github.com/dhall-lang/dhall-haskell/pull/482
• Added inputFrom and inputFromWith
  • These allow naming the file that the expression is coming from for better error messages
  • See: https://github.com/dhall-lang/dhall-haskell/pull/464
• Performance improvements
  • See: https://github.com/dhall-lang/dhall-haskell/pull/420
• Tutorial recommends GitHub for Prelude instead of IPFS
  • See: https://github.com/dhall-lang/dhall-haskell/pull/479
• Pretty-print expressions in type errors
  • See: https://github.com/dhall-lang/dhall-haskell/pull/429
• Formatting improvements
  • See: https://github.com/dhall-lang/dhall-haskell/pull/398
  • See: https://github.com/dhall-lang/dhall-haskell/pull/458
• Diff improvements
  • See: https://github.com/dhall-lang/dhall-haskell/pull/455
  • See: https://github.com/dhall-lang/dhall-haskell/pull/470
  • See: https://github.com/dhall-lang/dhall-haskell/pull/478

1.14.0

• BREAKING CHANGE TO THE LANGUAGE: Switch grammar of Natural and Integer
  • Natural number literals are now unsigned and Integer literals always require a sign
  • This is a VERY disruptive change to most Dhall code in the wild but was unanimously agreed upon here: https://github.com/dhall-lang/dhall-lang/issues/138
  • See also: https://github.com/dhall-lang/dhall-haskell/pull/381
• BREAKING CHANGE TO THE LANGUAGE: Drop support for importing directories
  • Importing dir/ used to resolve to dir/@, which is no longer supported
  • See: https://github.com/dhall-lang/dhall-haskell/pull/384
• BREAKING CHANGE TO THE LANGUAGE: Change to the grammar for imports
  • File path components can no longer contain # or ? characters
  • URL imports must now contain at least one path component
  • URL path components must match the grammar for file path components
  • See: https://github.com/dhall-lang/dhall-haskell/pull/390
• BREAKING CHANGE TO THE API: Rename Path{,Mode,Hashed,Type} to Import{,Mode,Hashed,Type}
  • In practice this change is not breaking for the most common use cases since this also provides a Path type synonym for backwards compatibility
  • See: https://github.com/dhall-lang/dhall-haskell/pull/376
• BUG FIX: Fix α-equivalence bug when type-checking merge
  • merge expressions would sometimes reject valid code due to a type-checking bug
  • See: https://github.com/dhall-lang/dhall-haskell/pull/394
• Improve import caching
  • See: https://github.com/dhall-lang/dhall-haskell/pull/388
  • See: https://github.com/dhall-lang/dhall-haskell/pull/392
• Increase upper bound on tasty
  • See: https://github.com/dhall-lang/dhall-haskell/pull/382
• Fix lower bound on insert-ordered-containers
  • See: https://github.com/dhall-lang/dhall-haskell/pull/377

1.13.1

• Increase upper bound on ansi-terminal and megaparsec

1.13.0

• BUG FIX: Fix semantic integrity hashing support
  • Both parsing and pretty-printing semantic hashes were broken since version 1.11.0
  • See: https://github.com/dhall-lang/dhall-haskell/pull/345
• BUG FIX: Allow leading whitespace in interpolated expresssions
  • See: https://github.com/dhall-lang/dhall-haskell/pull/369
• BUG FIX: Fix deriving (Interpret) for sum types
  • The types of alternatives were not correctly included in the corresponding Dhall type
  • See: https://github.com/dhall-lang/dhall-haskell/pull/348
• BREAKING CHANGE TO LANGUAGE: Records cannot store both types and terms
  • Records can also not store type-level functions (like List)
    • Records might be allowed to store type-level functions again in the future
  • This fixes a potential soundness bug
  • The primarily practical consequence of this change is that if you are hosting a "package" then you will need to split terms and types from your package into different records for your users to import
  • This also implies removing the ./Monoid type-level function from the ./Prelude/package.dhall record
  • See: https://github.com/dhall-lang/dhall-haskell/pull/335
• BREAKING CHANGE TO THE API: Replace trifecta with megaparsec
  • This change the API to use the Parser type from megaparsec
  • This also slightly changes the type of exprFromText
  • If you program using the type classes provided by the parsers library then this is not a breaking change as that interface is preserved
  • See: https://github.com/dhall-lang/dhall-haskell/pull/268
• BREAKING CHANGE TO THE API: New ⩓ operator for merging record types
  • Example: { foo : Text } ⩓ { bar : Bool } = { foo : Text, bar : Bool }
  • This is breaking because it adds a new constructor to the Expr type
  • See: https://github.com/dhall-lang/dhall-haskell/pull/342
• BREAKING CHANGE TO THE API: New support for projecting a subset of fields
  • Example: { x = 1, y = 2, z = 3 }.{ x, y } = { x = 1, y = 2 }
  • This is breaking because it adds a new constructor to the Expr type
  • See: https://github.com/dhall-lang/dhall-haskell/pull/350
• API+UX feature: New support for pretty-printing diffs of Dhall expressions
  • Error messages also use this feature to simplify large type mismatches
  • There is also a new Dhall.Diff module
  • See: https://github.com/dhall-lang/dhall-haskell/pull/336
• Add version, resolve, type, and normalize sub-commands to interpreter
  • See: https://github.com/dhall-lang/dhall-haskell/pull/352
• Support GHC 7.10.3
  • See: https://github.com/dhall-lang/dhall-haskell/pull/340
• :type command in dhall-repl now only displays the type
  • Before it would also display the original expression
  • See: https://github.com/dhall-lang/dhall-haskell/pull/344
• Trim dependency tree
  • See: https://github.com/dhall-lang/dhall-haskell/pull/351
  • See: https://github.com/dhall-lang/dhall-haskell/pull/268
  • See: https://github.com/dhall-lang/dhall-haskell/pull/355

1.12.0

• Additional changes to support GHC 8.4
  • See: https://github.com/dhall-lang/dhall-haskell/pull/331
• BREAKING CHANGE TO API: Replace dependency on text-format with formatting
  • This replace the Data.Text.Buildable.Buildable instances with Formatting.Buildable.Buildable instances, which is why this is a breaking change
  • text-format is no longer maintained and blocking GHC 8.4 support
  • See: https://github.com/dhall-lang/dhall-haskell/pull/330

1.11.1

• Support GHC 8.4
  • See: https://github.com/dhall-lang/dhall-haskell/pull/321
• Fix α-normalization bug
  • Note that this is not a type-checking bug. This only affects users who were directly using the alphaNormalize function from the Haskell API because let expressions were not correctly α-normalized
  • See: https://github.com/dhall-lang/dhall-haskell/pull/319
• Slight tweak to syntax highlighting
  • See: https://github.com/dhall-lang/dhall-haskell/pull/324
• Increase upper bound on ansi-terminal and exceptions
  • See: https://github.com/dhall-lang/dhall-haskell/pull/322
  • See: https://github.com/dhall-lang/dhall-haskell/pull/325

1.11.0

• BREAKING CHANGE TO THE API: Fix {Natural,Optional,List}/build semantics to match standard
  • This is a breaking change because the OptionalLit and ListLit constructors changed their representations to efficiently support the standard semantics
  • ListLit now stores a Data.Sequence.Seq instead of a Data.Vector.Vector
  • OptionalLit now stores a Maybe instead of a Data.Vector.Vector
  • See: https://github.com/dhall-lang/dhall-haskell/pull/300
• BREAKING CHANGE TO THE COMMAND LINE: dhall executable always formats output
  • Previously you had to opt into formatting using --pretty
  • Now formatting is obligatory and the --pretty flag is gone
  • See: https://github.com/dhall-lang/dhall-haskell/pull/303
• Feature: New :save command for dhall-repl
  • Now you can save an expression to a file: ./yourFile = someExpression
  • See: https://github.com/dhall-lang/dhall-haskell/pull/309
• Improvement: Add new simplifications to match standard
  • See: https://github.com/dhall-lang/dhall-haskell/pull/312
  • See: https://github.com/dhall-lang/dhall-haskell/pull/316
• Improvement: Fix equivalence check to match standard
  • Practically this means that more corner cases of the language correctly type-check than before
• Improvement: New --plain flag to disable syntax highlighting
  • See: https://github.com/dhall-lang/dhall-haskell/pull/310
• Improvement: Prelude now provides an umbrella package.dhall import
  • This is primarily for convenience
  • See: https://github.com/dhall-lang/dhall-haskell/pull/298
• Improvement: Context is now normalized
  • See: https://github.com/dhall-lang/dhall-haskell/pull/302
• Replace cryptohash dependency with cryptonite
  • See: https://github.com/dhall-lang/dhall-haskell/commit/5d2012927a062ec8bdf2bbaba77150344f38db77
• Increase upper bound on exceptions
  • See: https://github.com/dhall-lang/dhall-haskell/pull/306
• Fix type error in tutorial
  • See: https://github.com/dhall-lang/dhall-haskell/commit/5a9126b2f684d3236fc1e8e20e206cfaf47d97db

1.10.0

• Feature: Records/unions can now have fields/alternatives that are types
  • i.e. { foo = Text, bar = List } is legal now
  • See: https://github.com/dhall-lang/dhall-haskell/pull/273
• Feature: New dhall-repl for interactively evaluating Dhall expressions
  • See: https://github.com/dhall-lang/dhall-haskell/pull/266
• Feature: Syntax highlighting
  • See: https://github.com/dhall-lang/dhall-haskell/pull/260
• Feature: BREAKING CHANGE TO THE API: dhall-format preserves field order
  • This changes the syntax tree to use an InsOrdHashMap instead of a Map
• BREAKING CHANGE TO THE API: Use Haskell's Scientific type
  • This is fixes the interpreter to correct handle really large/small numbers
  • This also allows marshaling into Haskell's Scientific type
  • See: https://github.com/dhall-lang/dhall-haskell/pull/256
• BREAKING CHANGE TO THE API: Remove system-filepath/system-fileio dependencies
  • Now the library uses Prelude.FilePath
  • See: https://github.com/dhall-lang/dhall-haskell/pull/248
• Feature: Labels can now begin with reserved names
  • i.e. List/map is now a legal label
  • See: https://github.com/dhall-lang/dhall-haskell/pull/255
• Fix: Rendered labels are now correctly escaped if they are numbers
  • See: https://github.com/dhall-lang/dhall-haskell/pull/252
• Add the instance Interpret String.
  • See: https://github.com/dhall-lang/dhall-haskell/pull/247
• Fix: Custom contexts passed to typeWith are now checked
  • This prevents a custom context from triggering an infinite loop
  • See: https://github.com/dhall-lang/dhall-haskell/pull/259

1.9.1

• dhall-format now emits single-quoted strings for multi-line strings
  • See: https://github.com/dhall-lang/dhall-haskell/pull/237
• Improved error messages for list elements with the wrong type
  • See: https://github.com/dhall-lang/dhall-haskell/pull/236
• Change lens dependency to lens-family-core
  • See: https://github.com/dhall-lang/dhall-haskell/pull/238

1.9.0

• Feature: BREAKING CHANGE TO LANGUAGE AND API: Add constructors keyword
  • This new keyword generates constructors from a union type
    • See the updated Haskell tutorial for more details
  • This means that constructors is now a reserved keyword
  • This adds a new Constructors constructor to the Expr type
  • See: https://github.com/dhall-lang/dhall-haskell/pull/199
• Feature: BREAKING CHANGE TO THE API: dhall-format preserves interpolation
  • This changes the TextLit constructor to represent an interpolated Text literal
  • See: https://github.com/dhall-lang/dhall-haskell/pull/220
• Feature: You can now define type synonyms using let
  • See: https://github.com/dhall-lang/dhall-haskell/pull/202
• Feature: Extend valid set of quoted labels
  • See: https://github.com/dhall-lang/dhall-lang/pull/65
  • See: https://github.com/dhall-lang/dhall-lang/pull/77
• Performance: Improve startup time when importing files, but not URLs
  • See: https://github.com/dhall-lang/dhall-haskell/pull/194
• Security: localhost/127.0.0.1 imports no longer count as local imports
  • Specifically: they cannot import environment variables or files
  • See: https://github.com/dhall-lang/dhall-haskell/pull/197
• Security: Fix potential type-checking bug
  • See: https://github.com/dhall-lang/dhall-haskell/pull/198
• Fix: BREAKING CHANGE TO API: Improve localization of error messages
  • This required fixing the type of normalize/shift/subst to preserve the first type parameter of Expr (i.e. they no longer delete Note constructors)
  • A new denote function was added for the explicit purpose of deleting Note constructors
  • See: https://github.com/dhall-lang/dhall-haskell/pull/218
• Expose MissingEnvironmentVariable exception type
  • See: https://github.com/dhall-lang/dhall-haskell/pull/196
• Add genericAuto
  • See: https://github.com/dhall-lang/dhall-haskell/pull/195
• Add inputWith
  • See: https://github.com/dhall-lang/dhall-haskell/pull/222
• AddloadWithContext
  • See: https://github.com/dhall-lang/dhall-haskell/pull/215
• Add pair/unit/string/list
  • See: https://github.com/dhall-lang/dhall-haskell/pull/227

1.8.2

• Add typeWithA for type-checking custom Embedded values
• Fix dhall{,-*} executables to ignore ambient locale and use UTF8
• Increase upper bound on tasty dependency

1.8.1

• dhall executable can now format output using --pretty
• Improved Unicode suppport on Windows

1.8.0

• BREAKING CHANGE TO LANGUAGE: Add support for import integrity checks
  • In practice, the likelihood of this breaking code in the wild is astronomically low
  • This would only break code of the form sha256:aaa...aaa (i.e. a variabled named sha256 with a type annotation for a type with a name 64 characters long drawn from the first 6 characters of the alphabet)
• BUG FIX: Fix parsing of single quotes in single-quoted strings
• BUG FIX: Fix superfluous parentheses introduced by dhall-format
• New dhall-hash executable
  • This goes hand-in-hand with the added support for integrity checks since the executable lets you compute the current hash of an import

1.7.0

• BREAKING CHANGE TO LANGUAGE: Update parser to match standardized grammar
  • Trailing commas and bars no longer supported for union and record literals
  • Paths no longer permit commas
  • URL grammar is now RFC-compliant
  • Environment variables can now be quoted to support full range of POSIX-compliant names
  • Text literals support full set of JSON escape sequences (such as \u2192)
• BREAKING CHANGE TO LANGUAGE: Single quoted strings strip leading newlines
• BUG FIX: Fixed type-checking infinite loops due to non-type-checked variables in context
• BUG FIX: Fixed type-checking bug due to missing context when type-checking certain expressions
• BUG FIX: Fixed type-checking bug due to off-by-one errors in name shadowing logic
• New dhall-format executable to automatically format code
• Performance optimizations to Natural/fold and List/fold
• Improved parsing performance (over 3x faster)
• Union literals can now specify the set value anywhere in the literal
  • i.e. < A : Integer | B = False | C : Text >
• New Inject instance for ()
• Several tutorial fixes and improvements

1.6.0

• BREAKING CHANGE TO THE API: Drop support for GHC 7.*
• BREAKING CHANGE TO THE API: Add support for customizing Dhall import
  • This is a breaking change because this changes the type of loadWith
• BREAKING CHANGE TO THE API: Add field to UnboundVariable error containing
• BUG FIX: Fix parsing single quotes in string literals the name of the unbound variable
• Add List/concatMap to the Prelude
• You can now derive Inject and Interpret for types with unlabeled fields
• Add new instances for Interpret:
  • []
  • (,)
• Add new instance for Inject
  • [], Data.Set.Set, Data.Sequence.Seq
  • (,)
  • Int, Word8, Word16, Word32, Word64
• Add Eq instance for Src

1.5.1

• Increase upper bound on vector and optparse-generic

1.5.0

• BREAKING CHANGE: Add list concatenation operator: (#)
  • This is a breaking change because it adds a new constructor to the Expr type which breaks exhaustive pattern matches
• BREAKING CHANGE: Add Interpret support for lazy Text
  • This is a breaking change because it renames text to strictText
• Add Interpret instance for decoding (a limited subset of) Dhall functions
• Dhall no longer requires Template Haskell to compile
  • This helps with cross-compilation
• Add rawInput utility for decoding a Haskell value from the Expr type
• Add loadWith/normalizeWith utilities for normalizing/importing modules with a custom context
• Export Type constructor

1.4.2

• Fix missing Prelude files in package archive uploaded to Hackage

1.4.1

• Fix missing tests/Tutorial.hs module in package archive uploaded to Hackage

1.4.0

• BREAKING CHANGE TO THE LANGUAGE AND API: You can now supply custom headers for URL imports with the new using keyword
  • This is a breaking change to the language because this adds a new reserved using keyword
  • This is a breaking change to the API because this adds a new field to the URL constructor to store optional custom headers
• BUG FIX: : is no longer a disallowed path character
  • This was breaking URL imports with a port
• BUG FIX: If you import a home-anchored path (i.e. ~/foo) and that imports a relative path (like ./bar), then the canonical path of the relative import should be home-anchored (i.e. ~/bar). However, there was a bug that made lose the home anchor (i.e. ./foo/bar), which this release fixes likely fail due to no longer being home-anchored (i.e. `./foob
• Add support for string interpolation
• merge no longer requires a type annotation if you are merging at least one alternative
• Expanded Prelude
  • ./Prelude/Optional/all
  • ./Prelude/Optional/any
  • ./Prelude/Optional/filter
  • ./Prelude/Optional/length
  • ./Prelude/Optional/null
  • ./Prelude/Text/concatMap
  • ./Prelude/Text/concatMapSep
  • ./Prelude/Text/concatSep
• Rearrange detailed error messages to put summary information at the bottom of the message

1.3.0

• BREAKING CHANGE TO THE API: Add support for new primitives, specifically:
  • (//) - Right-biased and shallow record merge
  • Optional/build (now a built-in in order to support build/fold fusion)
  • Natural/show
  • Integer/show
  • Double/show
  • Natural/toInteger
  • These all add new constructors to the Expr type, which would break exhaustive pattern matches
• BREAKING CHANGE TO THE LANGUAGE: Imported paths and URLs no longer support the characters: "()[]{}<>:"
  • This reduces the number of cases where you have to add a space after imports
  • Note that this does not exclude the : in the URL scheme (i.e. http://)
• Increase connection timeout for imports
• Variable names now allow the - character for all but the first character
• You can now escape identifiers with backticks
  • This lets you name identifiers so that they don't conflict with reserved key words
  • This is most useful when converting Dhall to other file formats (like JSON) where you might need to emit a field that conflicts with one of Dhall's reserved keywords
• New --version flag for the dhall executable

1.2.0

• BREAKING CHANGE: Add support for customizing derived Interpret instances
  • This is a breaking change to the Dhall library API since this changes the signature of the Interpret class by replacing the auto method with a more general autoWith method. This autoWith now takes an InterpretOptions argument that lets you customize derived field and constuctor names
  • In practice user programs that use the common path will be unaffected by this change
  • This is not a breaking change to the Dhall language
• BREAKING CHANGE: Type annotations now bind more tightly than lambda abstraction

  • This is a breaking change to the Dhall language. An expression like this:

    λ(x : A) → y : B
    

    ... used to parenthesized implicitly as:

    (λ(x : A) → y) : T
    

    ... but is now parenthesized implicitly as:

    λ(x : A) → (y : T)
    

    This is now consistent with Haskell's precedence and also consistent with the precedence of List and Optional type annotations

  • This change affects programs with an expression like this:

    -- Assuming that `y : B`
    λ(x : A) → y : A → B
    

    The above program would type-check before this change but not type-check after this change. You would you need to fix the above program by either changing the type signature to annotate just the type of y like this:

    λ(x : A) → y : B
    

    ... or by adding explicit parentheses like this:

    (λ(x : A) → y) : A → B
    

  • This is not a breaking change to the Dhall library API

• BREAKING CHANGE: Add support for importing a path's contents as raw Text by adding as Text after the import

  • This is a breaking change to the Dhall language

  • This is technically a breaking change, but is extremely unlikely to affect you program. This only changes the behavior of old programs that had an expression of the form:

    /some/imported/function as Text
    

    ... where /some/imported/function is an imported function being applied to two arguments, the first of which is a bound variable named as and the second of which is the type Text

  • This is not a breaking change to the Dhall library API

• BREAKING CHANGE: Add support for importing environment variables using env:VAR syntax

  • This is a breaking change to the Dhall library API since it adds a new Path constructor

  • This also technically a breaking change to the Dhall language but extremely unlikely to affect your program. This only changes the behavior of old programs that had an expression of the form:

    env:VAR
    

    ... where env was the name of a bound variable and :VAR was a type annotation without spaces around the type annotation operator

    After this change the program would be interpreted as an import of the contents for the environment variable named VAR

• BREAKING CHANGE: Support importing paths relative to home directory using ~/some/path syntax
  • This is a breaking change to the Dhall library API since it adds a new field to the File constructor indicating whether or not the imported path is relative to the home directory
  • This is not a breaking change to the Dhall language and the new syntax does not override any old syntax
• Permit trailing commas and bars in record/union syntax
• Improve location information for parsing errors

1.1.0

• BREAKING CHANGE: Non-empty lists no longer require a type annotation
  • This is a breaking change to the Haskell library, not the Dhall language
  • This change does not break existing Dhall programs
  • The Expr type was modified in a non-backwards-compatible way
• Add new exprA parser
• Add new InvalidType exception if input fails on an invalid Type
• Improve documentation and tutorial

1.0.2

• Add support for Nix-style "double single-quote" multi-line string literals
• Add isNormalized
• Improve documentation and tutorial
• Build against wider range of http-client versions

1.0.1

• Initial release

1.0.0

• Accidental premature upload to Hackage. This release was blacklisted