| Safe Haskell | Safe-Inferred |
|---|---|
| Language | Haskell2010 |
Language.Haskell.HLint
Description
This module provides a way to apply HLint hints. If you want to just run hlint in-process
and collect the results see hlint.
If you want to approximate the hlint experience with
a more structured API try:
(flags, classify, hint) <-autoSettingsRight m <-parseModuleExflags "MyFile.hs" Nothing print $applyHintsclassify hint [m]
Synopsis
- hlint :: [String] -> IO [Idea]
- applyHints :: [Classify] -> Hint -> [ModuleEx] -> [Idea]
- data Idea = Idea {
- ideaModule :: [String]
- ideaDecl :: [String]
- ideaSeverity :: Severity
- ideaHint :: String
- ideaSpan :: SrcSpan
- ideaFrom :: String
- ideaTo :: Maybe String
- ideaNote :: [Note]
- ideaRefactoring :: [Refactoring SrcSpan]
- data Severity
- = Ignore
- | Suggestion
- | Warning
- | Error
- data Note
- unpackSrcSpan :: SrcSpan -> Maybe (FilePath, (Int, Int), (Int, Int))
- showIdeaANSI :: Idea -> String
- data Classify = Classify {}
- getHLintDataDir :: IO FilePath
- autoSettings :: IO (ParseFlags, [Classify], Hint)
- argsSettings :: [String] -> IO (ParseFlags, [Classify], Hint)
- findSettings :: (String -> IO (FilePath, Maybe String)) -> Maybe String -> IO ([FixityInfo], [Classify], Hint)
- readSettingsFile :: Maybe FilePath -> String -> IO (FilePath, Maybe String)
- data Hint
- data ModuleEx
- parseModuleEx :: ParseFlags -> FilePath -> Maybe String -> IO (Either ParseError ModuleEx)
- createModuleEx :: Located HsModule -> ModuleEx
- createModuleExWithFixities :: [(String, Fixity)] -> Located HsModule -> ModuleEx
- data ParseError = ParseError {}
- defaultParseFlags :: ParseFlags
- data ParseFlags = ParseFlags {}
- data CppFlags
- type FixityInfo = (String, Associativity, Int)
- parseFlagsAddFixities :: [FixityInfo] -> ParseFlags -> ParseFlags
Generate hints
hlint :: [String] -> IO [Idea] Source #
This function takes a list of command line arguments, and returns the given hints.
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!"
Warning: The flags provided by HLint are relatively stable, but do not have the same API stability guarantees as the rest of the strongly-typed API. Do not run this function on your server with untrusted input.
applyHints :: [Classify] -> Hint -> [ModuleEx] -> [Idea] Source #
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.
Given a set of modules, it may be faster to pass each to applyHints in a singleton list.
When given multiple modules at once this function attempts to find hints between modules,
which is slower and often pointless (by default HLint passes modules singularly, using
--cross to pass all modules together).
Idea data type
An idea suggest by a Hint.
Constructors
| Idea | |
Fields
| |
How severe an issue is.
Constructors
| Ignore | The issue has been explicitly ignored and will usually be hidden (pass |
| Suggestion | Suggestions are things that some people may consider improvements, but some may not. |
| Warning | Warnings are suggestions that are nearly always a good idea to apply. |
| Error | Available as a setting for the user. Only parse errors have this setting by default. |
Instances
A note describing the impact of the replacement.
Constructors
| IncreasesLaziness | The replacement is increases laziness, for example replacing |
| DecreasesLaziness | The replacement is decreases laziness, for example replacing |
| RemovesError String | The replacement removes errors, for example replacing |
| ValidInstance String String | The replacement assumes standard type class lemmas, a hint with the note |
| RequiresExtension String | The replacement requires this extension to be available. |
| Note String | An arbitrary note. |
unpackSrcSpan :: SrcSpan -> Maybe (FilePath, (Int, Int), (Int, Int)) Source #
Unpack a SrcSpan value. Useful to allow using the Idea information without
adding a dependency on ghc or ghc-lib-parser. Unpacking gives:
(filename, (startLine, startCol), (endLine, endCol))
Following the GHC API, he end column is the column after the end of the error.
Lines and columns are 1-based. Returns Nothing if there is no helpful location information.
showIdeaANSI :: Idea -> String Source #
Show an Idea with ANSI color codes to give syntax coloring to the Haskell code.
Settings
How to classify an Idea. If any matching field is "" then it matches everything.
Constructors
| Classify | |
Fields
| |
getHLintDataDir :: IO FilePath Source #
Get the Cabal configured data directory of HLint.
autoSettings :: IO (ParseFlags, [Classify], Hint) Source #
The function produces a tuple containg ParseFlags (for parseModuleEx),
and Classify and Hint for applyHints.
It approximates the normal HLint configuration steps, roughly:
- Use
findSettingswithreadSettingsFileto find and load the HLint settings files. - Use
parseFlagsAddFixitiesandresolveHintsto transform the outputs offindSettings.
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.
argsSettings :: [String] -> IO (ParseFlags, [Classify], Hint) Source #
A version of autoSettings which respects some of the arguments supported by HLint.
If arguments unrecognised by HLint are used it will result in an error.
Arguments which have no representation in the return type are silently ignored.
findSettings :: (String -> IO (FilePath, Maybe String)) -> Maybe String -> IO ([FixityInfo], [Classify], Hint) Source #
Given a function to load a module (typically readSettingsFile), and a module to start from
(defaults to hlint.yaml) find the information from all settings files.
readSettingsFile :: Maybe FilePath -> String -> IO (FilePath, Maybe String) Source #
Given a directory (or Nothing to imply getHLintDataDir), and a module 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.
Hints
Functions to generate hints, combined using the Monoid instance.
Modules
Result of parseModuleEx, representing a parsed module.
parseModuleEx :: ParseFlags -> FilePath -> Maybe String -> IO (Either ParseError ModuleEx) Source #
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.
Note that certain programs, e.g. main = do successfully parse
with GHC, but then fail with an error in the renamer. These
programs will return a successful parse.
createModuleEx :: Located HsModule -> ModuleEx Source #
Create a ModuleEx from a GHC module. It is assumed the incoming
parsed module has not been adjusted to account for operator
fixities (it uses the HLint default fixities).
data ParseError Source #
A parse error.
Constructors
| ParseError | |
Fields
| |
Parse flags
defaultParseFlags :: ParseFlags Source #
Default value for ParseFlags.
data ParseFlags Source #
Created with defaultParseFlags, used by parseModuleEx.
Constructors
| ParseFlags | |
Fields
| |
What C pre processor should be used.
Constructors
| CppSimple | Lines prefixed with |
| Cpphs CpphsOptions | The |
type FixityInfo = (String, Associativity, Int) Source #
A Fixity definition, comprising the name the fixity applies to, the direction and the precedence. As an example, a source file containing:
infixr 3 `foo`
would create ("foo", RightAssociative, 3).
parseFlagsAddFixities :: [FixityInfo] -> ParseFlags -> ParseFlags Source #
Given some fixities, add them to the existing fixities in ParseFlags.