-- Hoogle documentation, generated by Haddock -- See Hoogle, http://www.haskell.org/hoogle/ -- | Source code suggestions -- -- HLint gives suggestions on how to improve your source code. @package hlint @version 1.9.21 -- | WARNING: This module represents the evolving second version of the -- HLint API. It will be deleted in favour of -- Language.Haskell.HLint3 in the next major version. -- -- This module provides a way to apply HLint hints. As an example of -- approximating the hlint experience: -- -- 
--   (flags, classify, hint) <- autoSettings
--   Right m <- parseModuleEx flags "MyFile.hs" Nothing
--   print $ applyHints classify hint [m]
--
module Language.Haskell.HLint2 -- | Given a way of classifying results, and a Hint, apply to a set -- of modules generating a list of Ideas. The Idea values -- will be ordered within a file. applyHints :: [Classify] -> Hint -> [(Module SrcSpanInfo, [Comment])] -> [Idea] -- | An idea suggest by a Hint. data Idea Idea :: String -> String -> Severity -> String -> SrcSpan -> String -> Maybe String -> [Note] -> Idea -- | The module the idea applies to, may be "" if the module -- cannot be determined or is a result of cross-module hints. ideaModule :: Idea -> String -- | The declaration the idea applies to, typically the function name, but -- may be a type name. ideaDecl :: Idea -> String -- | The severity of the idea, e.g. Warning. ideaSeverity :: Idea -> Severity -- | The name of the hint that generated the idea, e.g. "Use -- reverse". ideaHint :: Idea -> String -- | The source code the idea relates to. ideaSpan :: Idea -> SrcSpan -- | The contents of the source code the idea relates to. ideaFrom :: Idea -> String -- | The suggested replacement, or Nothing for no replacement (e.g. -- on parse errors). ideaTo :: Idea -> Maybe String -- | Notes about the effect of applying the replacement. ideaNote :: Idea -> [Note] -- | How severe an issue is. data Severity -- | The issue has been explicitly ignored and will usually be hidden (pass -- --show on the command line to see ignored ideas). Ignore :: Severity -- | Warnings are things that some people may consider improvements, but -- some may not. Warning :: Severity -- | Errors are suggestions that are nearly always a good idea to apply. Error :: Severity -- | A note describing the impact of the replacement. data Note -- | The replacement is increases laziness, for example replacing -- reverse (reverse x) with x makes the code lazier. IncreasesLaziness :: Note -- | The replacement is decreases laziness, for example replacing (fst -- x, snd x) with x makes the code stricter. DecreasesLaziness :: Note -- | The replacement removes errors, for example replacing foldr1 -- (+) with sum removes an error on [], and might -- contain the text "on []". RemovesError :: String -> Note -- | The replacement assumes standard type class lemmas, a hint with the -- note ValidInstance "Eq" "x" might only be valid if the -- x variable has a reflexive Eq instance. ValidInstance :: String -> String -> Note -- | An arbitrary note. Note :: String -> Note -- | How to classify an Idea. If any matching field is "" -- then it matches everything. data Classify Classify :: Severity -> String -> String -> String -> Classify -- | Severity to set the Idea to. classifySeverity :: Classify -> Severity -- | Match on Idea field ideaHint. classifyHint :: Classify -> String -- | Match on Idea field ideaModule. classifyModule :: Classify -> String -- | Match on Idea field ideaDecl. classifyDecl :: Classify -> String -- | Get the Cabal configured data directory of HLint getHLintDataDir :: IO FilePath -- | The function produces a tuple containg ParseFlags (for -- parseModuleEx), and Classify and Hint for -- applyHints. It approximates the normal HLint configuration -- steps, roughly: -- --
    --
  1. Use findSettings to find and load the HLint settings -- files.
    2. --
  2. Use readSettings to interpret the settings files, producing -- HintRule values (LHS ==> RHS replacements) and -- Classify values to assign Severity ratings to -- hints.
    3. --
  3. Use builtinHints and hintRules to generate a -- Hint value.
    4. --
  4. Take all fixities from the findSettings modules and put -- them in the ParseFlags.
    5. --
autoSettings :: IO (ParseFlags, [Classify], Hint) autoSettings' :: FilePath -> IO (ParseFlags, [Classify], Hint) -- | Given the data directory (where the hlint data files reside, -- see getHLintDataDir), and a filename to read, and optionally -- that file's contents, produce a pair containing: -- --
    --
  1. Builtin hints to use, e.g. List, which should be -- resolved using builtinHints.
    2. --
  2. A list of modules containing hints, suitable for processing with -- readSettings.
    3. --
-- -- Any parse failures will result in an exception. findSettings :: FilePath -> FilePath -> Maybe String -> IO ([String], [Module SrcSpanInfo]) -- | Given a module containing HLint settings information return the -- Classify rules and the HintRule expressions. Any fixity -- declarations will be discarded, but any other unrecognised elements -- will result in an exception. readSettings :: Module SrcSpanInfo -> ([Classify], [HintRule]) -- | Functions to generate hints, combined using the Monoid -- instance. data Hint Hint :: ([(Scope, Module SrcSpanInfo)] -> [Idea]) -> (Scope -> Module SrcSpanInfo -> [Idea]) -> (Scope -> Module SrcSpanInfo -> Decl SrcSpanInfo -> [Idea]) -> (Comment -> [Idea]) -> Hint -- | Given a list of modules (and their scope information) generate some -- Ideas. hintModules :: Hint -> [(Scope, Module SrcSpanInfo)] -> [Idea] -- | Given a single module and its scope information generate some -- Ideas. hintModule :: Hint -> Scope -> Module SrcSpanInfo -> [Idea] -- | Given a declaration (with a module and scope) generate some -- Ideas. This function will be partially applied with one -- module/scope, then used on multiple Decl values. hintDecl :: Hint -> Scope -> Module SrcSpanInfo -> Decl SrcSpanInfo -> [Idea] -- | Given a comment generate some Ideas. hintComment :: Hint -> Comment -> [Idea] -- | A list of builtin hints, currently including entries such as -- "List" and "Bracket". builtinHints :: [(String, Hint)] -- | A LHS ==> RHS style hint rule. data HintRule HintRule :: Severity -> String -> Scope -> Exp SrcSpanInfo -> Exp SrcSpanInfo -> Maybe (Exp SrcSpanInfo) -> [Note] -> HintRule -- | Default severity for the hint. hintRuleSeverity :: HintRule -> Severity -- | Name for the hint. hintRuleName :: HintRule -> String -- | Module scope in which the hint operates. hintRuleScope :: HintRule -> Scope -- | LHS hintRuleLHS :: HintRule -> Exp SrcSpanInfo -- | RHS hintRuleRHS :: HintRule -> Exp SrcSpanInfo -- | Side condition, typically specified with where _ = .... hintRuleSide :: HintRule -> Maybe (Exp SrcSpanInfo) -- | Notes about application of the hint. hintRuleNotes :: HintRule -> [Note] hintRules :: [HintRule] -> Hint -- | Data type representing the modules in scope within a module. Created -- with scopeCreate and queried with scopeMatch and -- scopeMove. Note that the mempty Scope is not -- equivalent to scopeCreate on an empty module, due to the -- implicit import of Prelude. data Scope -- | Create a Scope value from a module, based on the modules -- imports. scopeCreate :: Module SrcSpanInfo -> Scope -- | Given a two names in scopes, could they possibly refer to the same -- thing. This property is reflexive. scopeMatch :: (Scope, QName SrcSpanInfo) -> (Scope, QName SrcSpanInfo) -> Bool -- | Given a name in a scope, and a new scope, create a name for the new -- scope that will refer to the same thing. If the resulting name is -- ambiguous, it picks a plausible candidate. scopeMove :: (Scope, QName SrcSpanInfo) -> Scope -> QName SrcSpanInfo -- | Parse a Haskell module. Applies the C pre processor, and uses -- best-guess fixity resolution if there are ambiguities. The filename -- - is treated as stdin. Requires some flags (often -- defaultParseFlags), the filename, and optionally the contents -- of that file. parseModuleEx :: ParseFlags -> FilePath -> Maybe String -> IO (Either ParseError (Module SrcSpanInfo, [Comment])) -- | Default value for ParseFlags. defaultParseFlags :: ParseFlags -- | A parse error from parseModuleEx. data ParseError ParseError :: SrcLoc -> String -> String -> ParseError -- | Location of the error. parseErrorLocation :: ParseError -> SrcLoc -- | Message about the cause of the error. parseErrorMessage :: ParseError -> String -- | Snippet of several lines (typically 5) including a > -- character pointing at the faulty line. parseErrorContents :: ParseError -> String -- | Created with defaultParseFlags, used by parseModuleEx. data ParseFlags ParseFlags :: TextEncoding -> CppFlags -> ParseMode -> ParseFlags -- | How the file is read in (defaults to utf8). encoding :: ParseFlags -> TextEncoding -- | How the file is preprocessed (defaults to NoCpp). cppFlags :: ParseFlags -> CppFlags -- | How the file is parsed (defaults to all fixities in the base -- package and most non-conflicting extensions). hseFlags :: ParseFlags -> ParseMode -- | What C pre processor should be used. data CppFlags -- | No pre processing is done. NoCpp :: CppFlags -- | Lines prefixed with # are stripped. CppSimple :: CppFlags -- | The cpphs library is used. Cpphs :: CpphsOptions -> CppFlags -- | An Encoding represents how characters are stored in a file. -- Created with defaultEncoding or readEncoding and used -- with useEncoding. type Encoding = TextEncoding -- | The system default encoding. defaultEncoding :: Encoding -- | Create an encoding from a string, or throw an error if the encoding is -- not known. Accepts many encodings including locale, -- utf-8 and all those supported by the GHC -- mkTextEncoding function. readEncoding :: String -> IO Encoding -- | Apply an encoding to a Handle. useEncoding :: Handle -> Encoding -> IO () -- | WARNING: This module represents the evolving second version of the -- HLint API. It will be renamed to drop the "3" in the next major -- version. -- -- This module provides a way to apply HLint hints. As an example of -- approximating the hlint experience: -- -- 
--   (flags, classify, hint) <- autoSettings
--   Right m <- parseModuleEx flags "MyFile.hs" Nothing
--   print $ applyHints classify hint [m]
--
module Language.Haskell.HLint3 -- | Given a way of classifying results, and a Hint, apply to a set -- of modules generating a list of Ideas. The Idea values -- will be ordered within a file. applyHints :: [Classify] -> Hint -> [(Module SrcSpanInfo, [Comment])] -> [Idea] -- | An idea suggest by a Hint. data Idea Idea :: String -> String -> Severity -> String -> SrcSpan -> String -> Maybe String -> [Note] -> Idea -- | The module the idea applies to, may be "" if the module -- cannot be determined or is a result of cross-module hints. ideaModule :: Idea -> String -- | The declaration the idea applies to, typically the function name, but -- may be a type name. ideaDecl :: Idea -> String -- | The severity of the idea, e.g. Warning. ideaSeverity :: Idea -> Severity -- | The name of the hint that generated the idea, e.g. "Use -- reverse". ideaHint :: Idea -> String -- | The source code the idea relates to. ideaSpan :: Idea -> SrcSpan -- | The contents of the source code the idea relates to. ideaFrom :: Idea -> String -- | The suggested replacement, or Nothing for no replacement (e.g. -- on parse errors). ideaTo :: Idea -> Maybe String -- | Notes about the effect of applying the replacement. ideaNote :: Idea -> [Note] -- | How severe an issue is. data Severity -- | The issue has been explicitly ignored and will usually be hidden (pass -- --show on the command line to see ignored ideas). Ignore :: Severity -- | Warnings are things that some people may consider improvements, but -- some may not. Warning :: Severity -- | Errors are suggestions that are nearly always a good idea to apply. Error :: Severity -- | A note describing the impact of the replacement. data Note -- | The replacement is increases laziness, for example replacing -- reverse (reverse x) with x makes the code lazier. IncreasesLaziness :: Note -- | The replacement is decreases laziness, for example replacing (fst -- x, snd x) with x makes the code stricter. DecreasesLaziness :: Note -- | The replacement removes errors, for example replacing foldr1 -- (+) with sum removes an error on [], and might -- contain the text "on []". RemovesError :: String -> Note -- | The replacement assumes standard type class lemmas, a hint with the -- note ValidInstance "Eq" "x" might only be valid if the -- x variable has a reflexive Eq instance. ValidInstance :: String -> String -> Note -- | An arbitrary note. Note :: String -> Note -- | How to classify an Idea. If any matching field is "" -- then it matches everything. data Classify Classify :: Severity -> String -> String -> String -> Classify -- | Severity to set the Idea to. classifySeverity :: Classify -> Severity -- | Match on Idea field ideaHint. classifyHint :: Classify -> String -- | Match on Idea field ideaModule. classifyModule :: Classify -> String -- | Match on Idea field ideaDecl. classifyDecl :: Classify -> String -- | Get the Cabal configured data directory of HLint. getHLintDataDir :: IO FilePath -- | The function produces a tuple containg ParseFlags (for -- parseModuleEx), and Classify and Hint for -- applyHints. It approximates the normal HLint configuration -- steps, roughly: -- --
    --
  1. Use findSettings with readSettingsFile to find and -- load the HLint settings files.
    2. --
  2. Use parseFlagsAddFixities and resolveHints to -- transform the outputs of findSettings.
    3. --
-- -- If you want to do anything custom (e.g. using a different data -- directory, storing intermediate outputs, loading hints from a -- database) you are expected to copy and paste this function, then -- change it to your needs. autoSettings :: IO (ParseFlags, [Classify], Hint) -- | Given a function to load a module (typically readSettingsFile), -- and a module to start from (defaults to HLint.HLint) find the -- information from all settings files. findSettings :: (String -> IO (FilePath, Maybe String)) -> Maybe String -> IO ([Fixity], [Classify], [Either HintBuiltin HintRule]) -- | Given a directory (or Nothing to imply getHLintDataDir), -- and a mdoule name (e.g. HLint.Default), find the settings -- file associated with it, returning the name of the file, and -- (optionally) the contents. -- -- This function looks for all settings files starting with -- HLint. in the directory argument, and all other files -- relative to the current directory. readSettingsFile :: Maybe FilePath -> String -> IO (FilePath, Maybe String) -- | A list of the builtin hints wired into HLint. This list is likely to -- grow over time. data HintBuiltin HintList :: HintBuiltin HintListRec :: HintBuiltin HintMonad :: HintBuiltin HintLambda :: HintBuiltin HintBracket :: HintBuiltin HintNaming :: HintBuiltin HintStructure :: HintBuiltin HintImport :: HintBuiltin HintPragma :: HintBuiltin HintExtensions :: HintBuiltin HintUnsafe :: HintBuiltin HintDuplicate :: HintBuiltin HintComment :: HintBuiltin -- | A LHS ==> RHS style hint rule. data HintRule HintRule :: Severity -> String -> Scope -> Exp SrcSpanInfo -> Exp SrcSpanInfo -> Maybe (Exp SrcSpanInfo) -> [Note] -> HintRule -- | Default severity for the hint. hintRuleSeverity :: HintRule -> Severity -- | Name for the hint. hintRuleName :: HintRule -> String -- | Module scope in which the hint operates. hintRuleScope :: HintRule -> Scope -- | LHS hintRuleLHS :: HintRule -> Exp SrcSpanInfo -- | RHS hintRuleRHS :: HintRule -> Exp SrcSpanInfo -- | Side condition, typically specified with where _ = .... hintRuleSide :: HintRule -> Maybe (Exp SrcSpanInfo) -- | Notes about application of the hint. hintRuleNotes :: HintRule -> [Note] -- | Functions to generate hints, combined using the Monoid -- instance. data Hint Hint :: ([(Scope, Module SrcSpanInfo)] -> [Idea]) -> (Scope -> Module SrcSpanInfo -> [Idea]) -> (Scope -> Module SrcSpanInfo -> Decl SrcSpanInfo -> [Idea]) -> (Comment -> [Idea]) -> Hint -- | Given a list of modules (and their scope information) generate some -- Ideas. hintModules :: Hint -> [(Scope, Module SrcSpanInfo)] -> [Idea] -- | Given a single module and its scope information generate some -- Ideas. hintModule :: Hint -> Scope -> Module SrcSpanInfo -> [Idea] -- | Given a declaration (with a module and scope) generate some -- Ideas. This function will be partially applied with one -- module/scope, then used on multiple Decl values. hintDecl :: Hint -> Scope -> Module SrcSpanInfo -> Decl SrcSpanInfo -> [Idea] -- | Given a comment generate some Ideas. hintComment :: Hint -> Comment -> [Idea] -- | Transform a list of HintRule into a Hint. resolveHints :: [Either HintBuiltin HintRule] -> Hint -- | Data type representing the modules in scope within a module. Created -- with scopeCreate and queried with scopeMatch and -- scopeMove. Note that the mempty Scope is not -- equivalent to scopeCreate on an empty module, due to the -- implicit import of Prelude. data Scope -- | Create a Scope value from a module, based on the modules -- imports. scopeCreate :: Module SrcSpanInfo -> Scope -- | Given a two names in scopes, could they possibly refer to the same -- thing. This property is reflexive. scopeMatch :: (Scope, QName SrcSpanInfo) -> (Scope, QName SrcSpanInfo) -> Bool -- | Given a name in a scope, and a new scope, create a name for the new -- scope that will refer to the same thing. If the resulting name is -- ambiguous, it picks a plausible candidate. scopeMove :: (Scope, QName SrcSpanInfo) -> Scope -> QName SrcSpanInfo -- | Parse a Haskell module. Applies the C pre processor, and uses -- best-guess fixity resolution if there are ambiguities. The filename -- - is treated as stdin. Requires some flags (often -- defaultParseFlags), the filename, and optionally the contents -- of that file. parseModuleEx :: ParseFlags -> FilePath -> Maybe String -> IO (Either ParseError (Module SrcSpanInfo, [Comment])) -- | Default value for ParseFlags. defaultParseFlags :: ParseFlags parseFlagsAddFixities :: [Fixity] -> ParseFlags -> ParseFlags -- | A parse error from parseModuleEx. data ParseError ParseError :: SrcLoc -> String -> String -> ParseError -- | Location of the error. parseErrorLocation :: ParseError -> SrcLoc -- | Message about the cause of the error. parseErrorMessage :: ParseError -> String -- | Snippet of several lines (typically 5) including a > -- character pointing at the faulty line. parseErrorContents :: ParseError -> String -- | Created with defaultParseFlags, used by parseModuleEx. data ParseFlags ParseFlags :: TextEncoding -> CppFlags -> ParseMode -> ParseFlags -- | How the file is read in (defaults to utf8). encoding :: ParseFlags -> TextEncoding -- | How the file is preprocessed (defaults to NoCpp). cppFlags :: ParseFlags -> CppFlags -- | How the file is parsed (defaults to all fixities in the base -- package and most non-conflicting extensions). hseFlags :: ParseFlags -> ParseMode -- | What C pre processor should be used. data CppFlags -- | No pre processing is done. NoCpp :: CppFlags -- | Lines prefixed with # are stripped. CppSimple :: CppFlags -- | The cpphs library is used. Cpphs :: CpphsOptions -> CppFlags -- | WARNING: This module represents the old version of the HLint -- API. It will be deleted in favour of -- Language.Haskell.HLint3 in the next major version. -- -- This module provides a library interface to HLint, strongly modelled -- on the command line interface. module Language.Haskell.HLint -- | This function takes a list of command line arguments, and returns the -- given suggestions. To see a list of arguments type hlint -- --help at the console. This function writes to the stdout/stderr -- streams, unless --quiet is specified. -- -- As an example: -- -- 
--   do hints <- hlint ["src", "--ignore=Use map","--quiet"]
--      when (length hints > 3) $ error "Too many hints!"
--
hlint :: [String] -> IO [Suggestion] -- | A suggestion - the Show instance is of particular use. data Suggestion -- | From a suggestion, extract the file location it refers to. suggestionLocation :: Suggestion -> SrcLoc -- | From a suggestion, determine how severe it is. suggestionSeverity :: Suggestion -> Severity -- | How severe an issue is. data Severity -- | The issue has been explicitly ignored and will usually be hidden (pass -- --show on the command line to see ignored ideas). Ignore :: Severity -- | Warnings are things that some people may consider improvements, but -- some may not. Warning :: Severity -- | Errors are suggestions that are nearly always a good idea to apply. Error :: Severity