Changelog for zeolite-lang-0.12.0.0

Revision history for zeolite-lang

0.12.0.0 -- 2020-12-11

Language

[breaking] Several more fixes for named returns:
- [new] Allows initialization of named returns in if/elif/while predicates. Although setting a named return in a predicate has always been allowed, it previously did not count as an initialization for the purposes of checking usage in subsequent statements.
- [breaking] Fixes a bug where named returns used in if/elif/while predicates inside of cleanup blocks were not getting checked for initialization. This turns a potential runtime error into a compile-time error, which could break buggy code that was never going to be executed.
- [fix] Fixes a bug where a named return with a primitive type was not getting set in an explicit return statement. This only affected code that used primitive named returns inside of a cleanup block where the corresponding in block used an explicit return statement.
```
@type call () -> (Int)
call () (x) {
  cleanup {
    \ foo(x)     // x was not getting set for this call
  } in return 1  // 1 was still returned from the function as expected
}
```
  This did not affect non-primitive types such as String and user-defined concrete and interface categories.
[breaking] Updates associativity of infix operators:
- [breaking] Makes infix Bool operators && and || right-associative. For example, x && y && z used to be parsed as (x && y) && z, whereas now it is parsed as x && (y && z). This better reflects the intuition of side-effects happening in order, with respect to short-circuiting. (No other operators currently short-circuit.)
- [breaking] Makes comparison operators (e.g., <=) non-associative. This means that expressions such as x < y == true will no longer compile. This is because an equivalent-looking expression true == x < y might have a different interpretation. (Note that order operators such as < are not defined for Bool, so something like x < y < z would have already failed previously.)
All other infix operators (including infix function calls such as x `Math.pow` y) remain left-associative.

Libraries

[new] Adds Math.abs for Int absolute value to lib/math.

0.11.0.0 -- 2020-12-09

Compiler CLI

[breaking] Switches from parsec to megaparsec for parsing, to allow for better structuring of compile-time error messages. This should not affect syntax acceptance, but it has additional transitive dependencies that might prevent installation of zeolite.

Language

[breaking] Several cleanup fixes:
- [fix] Fixes a bug in cleanup that caused the scoped block to be prepended to it when it was inlined in the in block.
- [fix] Fixes a bug where cleanup might use an uninitialized named return when inlined at a break or continue statement in a while loop. Such situations will now cause a compilation error. Previously, this could have allowed an uninitialized value to be passed around, which would only be noticed with a Function called on null value failure at some point.
- [fix] Fixes inlining of cleanup blocks when continue is used inside of the in block. Previously, cleanup was skipped when continue was used inside of the respective in block.
- [breaking] Disallows explicit break and continue inside of cleanup blocks. Previously this was allowed (but return wasn't), which led to ambiguity when the in block contained a return.
- [new] Allows cleanup to refer to variables created at the top level of the in block.
```
cleanup {
  \ foo(bar)                    // bar is created below
} in Type bar <- Type.create()  // cleanup is inlined after this
```

0.10.0.0 -- 2020-12-05

Language

[breaking] Major changes to .0rt syntax:
- [breaking] Removes the expression argument from success and crash testcase types. Use one or more unittest (see next point) instead.
- [new] Adds unittest keyword to allow the user to define multiple tests within a single success testcase.
```
testcase "simple tests" {
  success
}

unittest checkInvariant1 {
  // this is a regular procedure with no return
}

unittest checkInvariant2 {
  // this is a regular procedure with no return
}
```
  This allows multiple tests to use the same setup, while still being able to track multiple test failures. error and crash testcase types are still available.
- [breaking] Allows testcase to statically set Argv (see lib/util) using the args keyword. By default, only the program name is set. Previously, Argv used whatever was passed to the test binary.
```
testcase "with static Argv" {
  success
  args "arg1" "arg2"
}

unittest test {
  // something that requires Argv.global()
}
```
  Note that this isn't a library change; this also affects C++ extensions that use Argv from base/logging.hpp.
- [new] Adds compiles mode for testcase. This is like success except nothing is executed. (success requires at least one unittest, whereas compiles will not execute anything even if unittest are present.)

Libraries

[new] Adds the lib/testing library with basic helpers for unit tests.

Compiler CLI

[new] Updates parsing of .zeolite-module to allow any ordering of the fields. Previously, the fields needed to be in a very specific order.
[fix] Adds compile-time protection against self-referential expression macros defined in expression_map: in .zeolite-module. Previously, the result was infinite recursion that could exhaust system resources.
[breaking] Adds an error when root/path in .zeolite-module differs from the location of the respective .zeolite-module. This is to catch both typos (e.g., copy-and-paste errors) and ambiguities.

0.9.0.0 -- 2020-11-23

Compiler CLI

[breaking] Major changes to C++ extensions:
- [breaking] Corrects hole in $ModuleOnly$ visibility in C++ extensions. Previously, C++ extensions could directly access categories defined in $ModuleOnly$ sources in dependencies.
- [breaking] Randomizes cache paths and namespaces for generated C++ code so that C++ extensions cannot use static #include paths to circumvent the visibility rules of a dependency.
- [breaking] Makes TypeInstances shared in generated C++ and in C++ extensions, to allow for better memory management of @types in the future.
- [breaking] Adds guards to C++ headers for $TestsOnly$ categories, to prevent them from being used in non- $TestsOnly$ C++ extensions.
[fix] Fixes regression where calling zeolite with -p would overwrite an existing .zeolite-module.

Language

[breaking] Syntax changes:
- [breaking] Changes the syntax for calling @category functions from $$ to :, e.g., Foo:create() instead of Foo$$create(). A new error message (to be removed later) will remind the user to stop using $$.
- [breaking] Changes the syntax for calling @type functions from $ to ., e.g., Foo.create() instead of Foo$create(). A new error message (to be removed later) will remind the user to stop using $.
[breaking] Changes to param usage:
- [breaking] Updates param inference to be more accurate. The new algorithm will infer a param type iff the best choice is unambiguous given the expected and actual function arguments.
- [breaking] Disallows bounding a single param both above and below, e.g., having both #x requires Foo and #x allows Bar. This is primarily to prevent cycles and contradictions in the type system.
  
  Previously, the best case for such restrictions was that there are extremely few choices for #x, and the worst case was that it implies Bar converts to Foo when it isn't true, thus making #x unusable. Having either of those requirements likely indicates a design flaw.
[breaking] Prohibits having a $TestsOnly$ definition for a non- $TestsOnly$ category. Previously, a concrete category declared in a non- $TestsOnly$ .0rp could be defined in a $TestsOnly$ .0rx, which creates a loophole that allows binaries to utilize $TestsOnly$ code.
[fix] Fixes a latent type-checking bug that could occur when attempting to assign a value with an intersection type to a variable with a union type, if one or both types has another nested type, e.g., [A&B]→[[A&B]|C] or [[A|B]&C]→[A|B]. This change shouldn't cause new type-checking failures.

Libraries

[fix] Implements subSequence for Argv in lib/util. This is required by ReadPosition but was forgotten. Calling it prior to this would cause a failure.

0.8.0.0 -- 2020-08-07

Language

[breaking] Makes the semantics of cleanup more consistent:
- [breaking] Disallows statements that modify return values within cleanup blocks, i.e., return with values and assigning named returns.
- [new] Allows cleanup to access named returns that are initialized within the corresponding in statement. Previously, access required initialization before the in statement.
- [new] An explicit positional return (e.g., return 1, 2) will assign the values to the respective named returns, if applicable. This will make the actual return values available within cleanup.
```
@type get () -> (Int)
get () (foo) {   // foo is the name of the return variable
  cleanup {
    \ bar(foo)   // foo has been initialized by the time this is called
  } in return 1  // 1 is assigned to foo here
}
```
- [fix] Adds unwinding of cleanup blocks when used with break and continue, respecting loop boundaries. Previously, cleanup was ignored.
[breaking] Skips compilation of unreachable statements. The target use-case is temporary changes to code that circumvent parts of a procedure, e.g., an early return for the purposes of debugging.
[breaking] Marks statements following break and continue as unreachable.

Compiler CLI

[behavior] Adds a compiler warning for public_deps that are not required by public .0rp sources within the same module, since they are potentially just cluttering the public namespace of the module.

0.7.1.0 -- 2020-07-13

Language

[new] Adds the $SourceContext$ macro, which inserts a String with info about source file and code location.
[fix] Adds context to error messages related to inherited functions that have not been overridden.

0.7.0.2 -- 2020-05-21

Language

[fix] Improves the likelihood of successful type inference when unions, intersections, or filters are combined with inheritance and type nesting.

0.7.0.1 -- 2020-05-20

Language

[fix] Fixes an edge-case where type-inference can be influenced by a param filter for a param with the same name in the scope that is calling the function. (For example, having #x requires Foo in scope while calling a function that also happens to have a param named #x.)
[fix] Fixes an edge-case where parameter substitution at the type level can clash with a type parameter scoped to a function. (Related to the above, but actually a separate issue discovered while solving the former.)
[behavior] Shows inferred-type assignments in error messages related to expressions containing inferred types.

0.7.0.0 -- 2020-05-19

Language

[new] Adds limited inference of type parameters in function calls. The new syntax is call<?,Int>(foo,bar), where ? designates that inference is requested for the first position.
[behavior] Reduces the memory cost of $TraceCreation$ by avoiding storing the entire trace text.

Compiler CLI

[behavior] Improves handling of I/O errors when calling zeolite, and allows compilation to continue in -r/-R modes if compilation of one module fails.

0.6.0.0 -- 2020-05-14

Compiler CLI

[behavior] Improves error messages for type mismatches and return-count mismatches.
[behavior] Improves the efficiency of loading metadata for dependencies.
[breaking] Fixes module-staleness check when running tests (-t).
[breaking] Prevents binaries from being created from main categories that are defined in $TestsOnly$ sources. (This was the original intention, but it was missed the first time around.)

Language

[new] Allows @category members in concrete categories to refer to each other during initialization.
[new] Adds the $ExprLookup[MACRO_NAME]$ pragma, which allows the user to define expression substitutions in .zeolite-module.
[new] Adds the $NoTrace$ pragma, which skips generating stack-trace information for specific functions. This is useful for deeply-recursive functions whose full trace would not be useful.
[new] Adds the $TraceCreation$ pragma, which appends a trace for the creation of a value when there is a crash in one of its functions. This is useful when the crash stems from value initialization.
[fix] Fixes parsing of the '"' Char-literal.

Libraries

[new] Adds the ErrorOr<#x> category to lib/util. This allows functions to return either the expected type or an error message.
[new] Adds the Void category to lib/util. This can be used to ignore type parameters when a value still needs to be instantiated.
[new] Adds the readAll function to TextReader (in lib/util) to support reading an entire file at once.
[breaking] Adds crashes when attempting to read RawFileReader or write RawFileWriter if there is a preexisting file error.

0.5.0.0 -- 2020-05-12

[new] Adds compiler support for pragmas, which will allow compiler features that aren't a part of the language:
- [new] $ModuleOnly$ pragma for .0rp files, which limits their visibility to the modules that own them.
- [new] $TestsOnly$ pragma for .0rp files, which limits their visibility to .0rt files, and .0rx files that also use $TestsOnly$ .
[new] Adds support for global seach paths for dependencies via a plain-text file at $(zeolite --get-path)/global-paths. This can be used to set up a separate directory for general-use Zeolite modules.
[breaking] Better handling of symbols from dependencies. This might break code that inavertently relied on broken visibility. In particular, .. in a dependency path precludes it from resolving to a system module.

0.4.1.0 -- 2020-05-05

[new] Adds a compiler mode (--show-deps) to display the symbolic dependencies of a module.
[new] Adds a compiler mode (--fast) to quickly compile a binary from a single source file without needing to create a module.
[new] Adds a compiler mode (-R) to recursively recompile modules.
[new] Improves thread-safety of internal code so that thread support can be safely added later. (Probably via a library.)
[new] Adds the Builder interface to make String concatenation more efficient.
[new] Adds support for basic mathematical Float operations, such as sin, exp, and sqrt.
[new] Adds support for bitwise Int operations.
[fix] Fixes broken --templates mode when builtin types are used.

0.4.0.0 -- 2020-05-05

[new] Allows modules to specify custom linker flags and private include paths in .zeolite-module. This lets categories written in C++ depend on external libraries written in other languages.
[behavior] Adds optimization of dependency inclusion for categories that are defined in C++ sources. This should eliminate linking in object files that are not needed by the binary.
[behavior] Adds checks to prevent a module from defining a category that was declared in another module.
[breaking] Updates the .zeolite-module format to require associating externally-defined categories with the source files that define them. This allows finer-grained linking of binaries and tests.

0.3.0.0 -- 2020-05-03

[breaking] Updates syntax for discarding all returns to use \ instead of ~. This will allow ~ to be used for bitwise-not later on. (Not to mention that ~ was kind of ugly in that context.)
[breaking] Cleans up multiple-return syntax by removing {}. This applies to both the return and the assignment.

0.2.0.0 -- 2020-05-03

[breaking] Requires that concrete categories defined in .cpp files be listed as external in .zeolite-module. This allows the compiler to ensure that all categories have a definition, which helps avoid linker errors.
[breaking] Gives .zeolite-module configs a proper file format.
[new] Adds version checking to cached module data.

0.1.3.0 -- 2020-05-01

[new] Adds support for more versions of GHC.

0.1.2.0 -- 2020-04-28

[fix] Fixes a parser issue with empty {} blocks following scoped.
[behavior] Updates cleanup procedures to allow setting named-return values. Previously, initializing a named return in cleanup was not sufficient.
[behavior] Updates zeolite-setup to unconditionally rebuild supporting libraries. Incidentally, this causes all existing user modules to be out of date.

0.1.1.0 -- 2020-04-27

[behavior] Set the default output path for binaries to the module's path rather than the current directory.
[new] Allows a base path (-p) with recompile mode (-r).

0.1.0.0 -- 2020-04-27

First version. Released on an unsuspecting world.