Changelog

Fourmolu 0.15.0.0

• Add single-deriving-parens configuration option to determine if deriving clauses of a single type should be parenthesized (#386)

• Fix the order in which the configurations are applied (#390)

Upstream changes:

Ormolu 0.7.4.0

• Don't error when the JavaScriptFFI language pragma is present. Issue 1087.

• Improve comment placement in if-then-else blocks. Issue 998.

• Now command line options for fixity overrides and module re-exports overwrite information from .ormolu files. Issue 1030.

• Respect newlines in data declarations in more cases. Issue 1077 and issue 947.

• The -d / --debug command line option now makes Ormolu print out debug information regarding operator fixity inference. Issue 1060.

Fourmolu 0.14.1.0

• Fix single-constraint-parens: never for nested quantified constraints (#374)

• Fix column-limit with BlockArguments (#377)

• Fixed an issue where re-exporting a module with Haddock comments + import-exports=leading was indented too far (#381)

Upstream changes:

Ormolu 0.7.3.0

• Switched to ghc-lib-parser-9.8, with the following new syntactic features:

  • ExtendedLiterals: 123#Int8 is a literal of type Int8#. (disabled by default)

  • TypeAbstractions: @k-binders in data type declarations (enabled by default)

  • GHC proposal #134: deprecating/warning about exports

  • GHC proposal #541: warning categories

Fourmolu 0.14.0.0

• Provide resolvePrinterOpts instead of fillMissingPrinterOpts

• Format configuration better in --debug output

Upstream changes:

Ormolu 0.7.2.0

• Preserve necessary braces for final function arguments. Issue 1044.

• Put "this" PackageImports at the end. Issue 1048.

• Format parenthesized operators starting with a # correctly in the presence of UnboxedSums. Issue 1062.

• Fix false positives in AST diffing related to empty Haddock comments in data declarations. Issue 1065.

Fourmolu 0.13.1.0

• Fix single-constraint-parens: never with QuantifiedConstraints (#340)

• Fix issue with single documented export + import-export-style: leading (#341)

• Fix reexports configuration not allowing repeated modules (#336)

Fourmolu 0.13.0.0

• Automatically ignore files in Cabal/Stack directories when recursively finding files to format.

Upstream changes:

Ormolu 0.7.1.0

• Include base fixity information when formatting a Haskell file that's not mentioned in an existing cabal file. Issue 1032

• Update displayException for OrmoluException to pretty print the exception. PR 1031.

• Ormolu is now aware of more common module re-exports by default.

• Support explicit mention of target package name in module re-exports. Even if the exported package is not specified as a direct dependency of the component being formatted it will still be taken into account correctly. Issue 1037.

• Ormolu no longer fails when CPP directly follows the import section (a regression introduced in 0.7.0.0). Issue 1040.

Ormolu 0.7.0.0

• Inference of operator fixity information is now more precise and takes into account the import section of the module being formatted. Issue 892 and issue 929.

• Ormolu can now be made aware of module re-exports through either special declarations in .ormolu files the reexports configuration option (see the readme for a description of the syntax), or on the command line with the --reexport/-r option. Issue 1017.

• Ormolu now looks for .ormolu files independently of .cabal files. This means that it is now possible to have one .ormolu file for multiple Cabal packages. Issue 1019.

• Consistently format do blocks/cases/MultiWayIfs with 4 spaces if and only if they occur as the applicand. Issue 1002 and issue 730.

• Support the (deprecated) DatatypeContexts extension to avoid surprises. Issue 1012.

• Don't let comments escape from empty export lists. Issue 906.

• Format \cases with multiple patterns across multiple lines correctly. Issue 1025.

Fourmolu 0.12.0.0

• Add single-constraint-parens option for controlling parenthesis around constraints in type signatures. See issue 288

• Add column-limit option to try to insert line breaks when lines exceed a certain length. May break idempotence in some particularly painful cases. See issue 71

• Add a new CLI flag --print-defaults which makes fourmolu print default options to stdout. This can be used to generate default config which can be further tweaked by user fourmolu --print-defaults > fourmolu.yaml. See issue 307

Upstream changes:

Ormolu 0.6.0.1

• Fix false positives in AST diffing related to UnicodeSyntax. PR 1009.

Ormolu 0.6.0.0

• Haddocks attached to arguments of a data constructor are now formatted in the pipe style (rather than the caret style), consistent with everything else. As a consequence, now Ormolu's output will be deemed invalid by the Haddock shipped with GHC <9.0. Issue 844 and issue 828.

• Insert space before char literals in ticked promoted constructs when necessary. Issue 1000.

• Switched to ghc-lib-parser-9.6:

  • Extended OverloadedLabels: #Foo, #3, #"Hello there".

    Also, it is now disabled by default, as it causes e.g. a#b to be parsed differently.

  • New extension: TypeData, enabled by default.

  • Parse errors now include error codes, cf. https://errors.haskell.org.

• Updated to Cabal-syntax-3.10.

• Now whenever Ormolu fails to parse a .cabal file it also explains why. PR 999.

Fourmolu 0.11.0.0

• Added the no-space value for the in-style option. See issue 291

Upstream changes:

Ormolu 0.5.2.0

• Eliminated the fixity-th Cabal flag because it caused issues on GHC 9.4 as well as on aarch64. See issue 941 and issue 927.

• Now operators without explicitly specified fixity default to left associativity and highest precedence. Issue 907.

Ormolu 0.5.3.0

• Stop making empty lets move comments. Issue 917.

• Now .ormolu fixity override files can use both LF and CRLF line endings. PR 969.

• Normalize parentheses around constraints. Issue 264.

• The ormolu function now consumes Text instead of String due to an internal refactoring.

• Exposed a more complete public API in the Ormolu module. The API is supposed to be stable and change according to PVP.

• Now warnings regarding Ormolu not being able to find .cabal files or finding such files but them not mentioning the source file in question are only displayed when --debug is used. Printing the warnings by default seems to have been confusing, see e.g. Issue 971 and issue 924.

Fourmolu 0.10.1.0

• Fix bug where using {- in a single-line comment would wrongfully escape it (#265)

• Fix idempotence bug with indented multiline comments (#273)

Fourmolu 0.10.0.0

New options:

• New leading-args option to function-arrows configuration that allows leading arrows only for function arguments (#233)

• Add haddock-style-module option (#135)

Improvements of existing options:

• Add unicode formatting for quasiquotes and arrow brackets (#261)

Bug fixes:

• Fix bug with let-style changing single-line let-in blocks in do blocks to multiline.

• Don't consider the first space after -- part of the comment (#255)

Upstream changes:

Ormolu 0.5.1.0

• Imports are now sorted by package qualifier, if one is present. Issue 905.

• Extension packs like GHC2021 and Haskell2010 are now bumped to the top of the list of language pragmas. Issue 922.

• Fix formatting of SCC pragmas in do blocks. Issue 925.

• Support type applications in patterns. Issue 930.

• Handle UnicodeSyntax variants more consistently. Issue 934.

• Fix an inconsistency in formatting of types in GADT declarations in certain cases. PR 932.

• Switched to ghc-lib-parser-9.4, which brings support for the following new syntactic features:

  • \cases via LambdaCase

  • OPAQUE pragmas

  • Unboxed sum type constructors like (# | #).

• Updated to Cabal-syntax-3.8, supporting cabal-version: 3.8.

Fourmolu 0.9.0.0

New configuration options:

• Add let-style and in-style configuration options (#229). The default is set to let-style: auto and in-style: right-align, which should not reformat already formatted files (with some exceptions depending on comment placement), but allows users to format with newline without additional configuration.

• Add unicode configuration (#206)

Bug fixes:

• Fix some edge cases with function arrows (#247)

• Fix formatting of module header + export lists when WARNING or DEPRECATED pragma is present (#244)

• Fixed a bug where an extra space was inserted before promoted types (e.g. foo @'True) (#211)

• When --respectful is enabled, a where keyword on the line after the export list will not be moved up to the end of the previous line. (#167)

Fourmolu 0.8.2.0

• Add multi-line-compact option to haddock-style that will output {-| for multiline haddocks instead of {- | (#130)

• Add function-arrows configuration option to style arrow placement in type signatures (#209)

Fourmolu 0.8.1.0

• Add emptyConfig (#221)

• Fixed CLI options not overriding config file options, broken in 0.7.0.0 (#225)

Fourmolu 0.8.0.0

• Consolidate import-export-comma-style and diff-friendly-import-export into a new option import-export-style (#201)

• Accept folders as input (#213)

Upstream changes:

Ormolu 0.5.0.1

• Fixed a bug in the diff printing functionality. Issue 886.

• Indent closing bracket for list comprehensions in do blocks. Issue 893.

• Fix hs-source-dirs: . resulting in failing to find a .cabal file for a Haskell source file. Issue 909.

• Comments in closed type family declarations are now indented correctly. Issue 913.

• Cache .cabal file parsing and processing when given multiple input files in the same project. This results in dramatic speedups on projects which have both huge .cabal files and a large number of individual modules. Issue 897.

Fourmolu 0.7.0.1

• Fix bad copy/paste where parsing errors for haddock-style would mention CommaStyle

• Include relevant test files in sdist bundle

Fourmolu 0.7.0.0

• Add --quiet flag to make the output quieter

• Removed --cabal-default-extensions flag; the behavior is now enabled by default

• Add fixities configuration to fourmolu.yaml

  • See the notes in the Ormolu changelog below, except instead of providing fixity information in a .ormolu file, it should be in a fixities config option in fourmolu.yaml, e.g.

  fixities:
    - 'infixr 8 .='
    - 'infixr 5 #'
  

• Fixed issue with import-export-comma-style for multiline import/export elements (#187)

• Multiline haddock comments with consecutive empty newlines will no longer report an "AST differs" error (#172)

Upstream changes:

Ormolu 0.5.0.0

• Changed the way operator fixities and precedences are inferred.

  • Ormolu now tries to locate .cabal files of source files by default and in addition to default extensions it also infers the list of dependencies.

  • Ormolu comes equipped with extensive knowledge of all packages on Hackage and operators that those packages define. Knowing the names of the dependencies it can select the right fixity and precedence info from its knowledge base.

  • You can ask Ormolu not to look for .cabal files by using the --no-cabal switch.

  • Dependencies can be selected manually by using the -p / --package option (can be repeated many times).

  • The default heuristic algorithm will still try to guess the right fixities and precedence.

  • Fixity overrides can be provided by the user in the familiar Haskell notation (e.g. infixr 9 ., one declaration per line). They are loaded by default from the .ormolu file that is expected to be in the same directory as the .cabal file of a given source file. However, if --no-cabal is supplied, the .ormolu file will not be looked for either. Fixity declarations can be also provided by using the -f / --fixity command line option, which see.

  • This resolves the following issues: Issue 826, Issue 785, Issue 690, Issue 825.

• Invalid haddock comments are formatted in a more consistent way. Leading haddock triggers (|, ^) in an invalid haddock comment block are now escaped with a backslash \. Issue 816.

• Type synonyms and families are now formatted correctly when the equals sign is preceded by a comment. Issue 829.

• Bidirectional pattern synonyms are formatted nicer in certain cases. Issue 843.

• Magic comments (like {- ORMOLU_DISABLED -}) now allow arbitrary succeeding text. This fixes use cases like Issue 856.

• Remove discrepancies between unboxed types and terms. Issue 856 .

  • Unboxed sum types are now formatted with a space before each |.

  • Unboxed unit tuples on type and value levels are formatted as (# #).

• Errors caused by AST differences now print before/after diffs. Issue 877.

• Improved formatting of data declarations in the case of single-constructor record with a Haddock. Issue 881.

Fourmolu 0.6.0.0

• Fixed regression in 0.5.0.0 with multiline tuples (#162)

• Fixed regression in 0.5.0.0 with multiline record types (#160)

• Fixed regression in 0.5.0.0 with indentation after a list comprehension (#149)

• Add import-export-comma-style configuration to allow leading commas in module import/export lists

Fourmolu 0.5.0.0

• Fixed issue with leading commas in guards (#123)

• Use trailing haddocks for record fields when using leading commas (#124)

Upstream changes:

Ormolu 0.4.0.0

• When a guard is located on its own line, the body associated with this guard is indented by one extra level, so that it can easily be distinguished from the guard predicate or pattern. Issue 806.

• Now a space is forced after -- in line comments. Issue 808.

• Allow formatting Backpack signature files (.hsig). The switch between regular module mode and signature mode is based on the file extension by default, but can be overridden with the -t / --source-type command line option. Issue 600.

• Blank Haddock comments are now eliminated. This also fixes issues with differing ASTs in some special cases. Issue 726.

• Rewrite rules that are never active are now formatted correctly. Issue 823.

• Promoted infix data constructors are now formatted correctly. Issue 768.

• Switched to ghc-lib-parser-9.2. Issue 794.

  • Support for the new syntax-related language extensions: OverloadedRecordDot and OverloadedRecordUpdate (disabled by default). Issue 709.

  • Removed support for record-dot-preprocessor. For the getter syntax, consider using OverloadedRecordDot instead. Issue 659. Issue 705.

  • Support for the GHC2021 language.

Ormolu 0.3.1.0

• Allow check mode when working with stdin input. Issue 634.

• Now guards are printed on a new line if at least one guard is multiline or if all guards together occupy more than one line. The body of each guard is also indented one level deeper in that case. Issue 712.

• Invalid Haddock comments are no longer silently deleted, but rather converted into regular comments. Issue 474.

Fourmolu 0.4.0.0

• Write "Loaded config from" message to stderr instead of stdout (#42)

• Fixed issue with multiline haddocks in indented contexts (#64)

• Avoid renaming magic comments (#90)

Upstream changes:

Ormolu 0.3.0.1

• Improvements to .cabal file handling:

  • When looking for a .cabal file, directories were previously erroneously also considered. Issue 781.

  • We now print a note if Ormolu was told to consider .cabal files, but no suitable one could be found.

  • Handle an empty hs-source-dirs correctly.

  • Also consider modules which are only conditionally listed in the .cabal file.

• The special handling of CPP is now only applied if CPP is actually enabled. Issue 782.

• The left hand side of the : operator now uses braces if necessary. Issue 780.

Ormolu 0.3.0.0

• Data declarations with multiline kind signatures are now formatted correctly. Issue 749.

• Infix arrow command formations are formatted like usual operators. This fixes Issue 748.

• do arrow commands are formatted more flexibly. Fixes Issue 753.

• Source code is always read and written using UTF8 and ignoring the native line ending conventions. Issue 717.

• Opt-in support to respect default-extensions and default-language from .cabal files. Issue 517.

• Empty case expressions are now rendered with braces. Issue 765.

• Omit braces on repeated application of do blocks. Issue 735.

• Improved handling of disabled regions. PR 773.

  • Disabled regions are now exactly preserved, in particular empty lines and trailing spaces. Issue 673.

  • Strings like -} can now be present in disabled regions. Issue 708.

  This means that using CPP or magic comments in certain ways which were only supported as a side effect previously (like in Issue 601) will now result in formatting failures. Also see Issue 774.

Ormolu 0.2.0.0

• Now standalone kind signatures are grouped with type synonyms. Issue 683.

• TemplateHaskell is not enabled by default anymore. Issue 699.

• Made record dot pre-processor rendering idempotent in certain specific cases. Issue 701.

• Added support for arrow command application. Issue 716.

• Switched to ghc-lib-parser-9.0.1. PR 722.

  • Support for the new language extensions:

    • LexicalNegation, LinearTypes: disabled by default

    • QualifiedDo: enabled by default

  • Due to upstream changes in whitespace sensitity, TypeApplications is now enabled by default. Issue 452.

  • Haddocks on declarations in files without a module header are no longer deleted. Issue 480.

  • Due to a change in Haddock parsing, empty Haddock comments on function arguments now get deleted.

• CTYPE pragmas are now preserved. Issue 689.

• TypeApplications in data/type family instances are now supported. Issue 698.

• Formatting infix arrow command formations now preserves the AST. Issue 718.

• Surround code in brackets with spaces if it contains a StarIsType * to prevent unparseable output. Issue 704.

• Formatting applied multiline constructs in do blocks now preserves the AST. Issue 707.

  This will sometimes result in odd indentations, e.g. this snippet is a fixed point:

  foo = do
    do
      (+1)
     1
  

• GHC options passed in via the CLI can now be overridden in local files. Previously, if an extension was disabled via the CLI, it could not be re-enabled per file.

• NegativeLiterals is no longer enabled by default. Also, spaces after negation via - are removed where possible. Issue 694.

• Minus signs in literal patterns are now preserved in all cases. Issue 733.

• Added support for left-to-right arrow application. Issue 737.

• Now --mode check fails on missing trailing blank lines. Issue 743.

• Fixed indentation of arrow forms in do blocks. Issue 739.

Ormolu 0.1.4.1

• Added command line option --color to control how diffs are printed. Standardized the way errors are printed.

Ormolu 0.1.4.0

• Added support for monad comprehensions. Issue 665.

• Fixed a bug when a space was inserted in front of promoted types even when it wasn't strictly necessary. Issue 668.

• Now the checking mode displays diffs per file when unformatted files are found. The rendering of the diffs is also improved. Issue 656.

Ormolu 0.1.3.1

• Fixed a problem with multiline record updates using the record dot preprocessor. Issue 658.

Fourmolu 0.3.0.0

• New config option newlines-between-decls, to choose the number of blank lines between top-level declarations.

• Minor CLI improvements. In particular, the set of valid values for each option is communicated more consistently.

Fourmolu 0.2.0.0

• More consistent indentation. Previously, with indentation set to n, some constructs such as nested lists and tuples would use an ugly mix of n-space and 2-space indentation.

• New configuration options (see README or Hackage docs for details):

  • comma-style

  • record-brace-space

  • indent-wheres

  • diff-friendly-import-export

  • respectful

  • haddock-style

Upstream changes:

Ormolu 0.1.3.0:

• Ormolu no longer overwrites already formatted files. PR 649.

• Now a space is guaranteed before ticked promoted types. Issue 631.

• Made formatting of single-line explicitly bidirectional pattern synonyms idempotent. Issue 630.

Ormolu 0.1.2.0:

• Fixed the bug when comments in different styles got glued together after formatting. Issue 589.

• Added -i as a shortcut for --mode inplace. Issue 467.

• Improved grouping of top-level declarations. Issue 466.

Fourmolu 0.1.1.0

Upstream changes:

Ormolu 0.1.1.0:

• Imports in a import lists are now normalized: duplicate imports are combined/eliminated intelligently.

• Import declarations that can be merged are now automatically merged. Issue 414.

• The magic comments for disabling and enabling Ormolu now can encompass any fragment of code provided that the remaining code after exclusion of the disabled part is still syntactically correct. Issue 601.

• Improved sorting of operators in imports. Issue 602.

• Fixed a bug related to trailing space in multiline comments in certain cases. Issue 603.

• Added support for formatting linked lists with (:) as line terminator. Issue 478.

• Fixed rendering of function arguments in multiline layout. Issue 609.

• Blank lines between definitions in let and while bindings are now preserved. Issue 554.

• Fixed the bug when type applications stuck to the $ of TH splices that followed them. Issue 613.

• Improved region formatting so that indented fragments—such as definitions inside of where clauses—can be formatted. Issue 572.

• Fixed the bug related to the de-association of pragma comments. Issue 619.

Fourmolu 0.1.0.0

• Allow configuration of indentation size via fourmolu.yaml config files.

• An operator on a new line is no longer indented when its left operand is a do-block. This prevents the AST from potentially changing when indenting by more than two spaces.

Upstream changes:

Ormolu 0.1.0.0:

• Fixed rendering of type signatures concerning several identifiers. Issue 566.

• Fixed an idempotence issue with inline comments in tuples and parentheses. Issue 450.

• Fixed an idempotence issue when certain comments were picked up as “continuation” of a series of comments Issue 449.

• Fixed an idempotence issue related to different indentation levels in a comment series. Issue 512.

• Fixed an idempotence issue related to comments which may happen to be separated from the elements they are attached to by the equality sign. Issue 340.

• Fixed an idempotence issue with type synonym and data declarations where the type has a Haddock. Issue 578.

• Fix the false positive about AST differences in presence of comments with multiple blank lines in a row. Issue 518.

• Fixed rendering of comments around if expressions. Issue 458.

• Unnamed fields of data constructors are now documented using the -- ^ syntax. Issue 445 and Issue 428.

• Fixed non-idempotent transformation of partly documented data definition. Issue 590.

• Fixed an idempotence issue related to operators. Issue 522.

• Renamed the --check-idempotency flag to --check-idempotence. Apparently only the latter is correct.

Fourmolu 0.0.6.0

• The project was fourked to provide four space indent.

Ormolu 0.0.5.0

• Grouping of statements in do-blocks is now preserved. Issue 74.

• Grouping of TH splices is now preserved. Issue 507.

• Comments on pragmas are now preserved. Issue 216.

• Ormolu can now be enabled and disabled via special comments. Issue 435.

• Added experimental support for simple CPP. Issue 415.

• Added two new options --start-line and --end-line that allow us to select a region to format. Issue 516.

• Fixed rendering of module headers in the presence of preceding comments or Haddocks. Issue 561.

Ormolu 0.0.4.0

• When given several files to format, Ormolu does not stop on the first failure, but tries to format all the files. Issue 502.

• Made rendering of pattern matches involving operators consistent with other cases of rendering of operators. Issue 500.

• More compact rendering of type family injectivity constraints. Issue 482.

• Improved rendering of the keyword where in class, data, and type family declarations. When headers of these declarations are multi-line where is now put on its own line. Issue 509.

• Fixed the bug pertaining to rendering of arrow notation with multiline expressions. Issue 513.

• Made rendering of data type definitions, value-level applications, and application of types use the same style. Moreover, existential now doesn't cause the data constructor be unconditionally rendered in multiline layout. Issue 427.

• Records with a single data constructor are now formatted more compactly. Issue 425.

• Switched to ghc-lib-parser-8.10.1.

• Implemented support for the new language extensions ImportQualifiedPost and StandaloneKindSignatures.

Ormolu 0.0.3.1

• Fixed rendering of record updates with the record dot preprocessor syntax Issue 498.

Ormolu 0.0.3.0

• Fixed an issue related to unnecessary use of curly braces. Issue 473.

• Fixed the issue with formatting multi-way if when it happens to be a function applied to arguments Issue 488. This changed the way multi-line if is formatted in general.

• Added support for record dot pre-processor when used via the plugin. Issue 486.

• Stopped hanging record constructors and improved placing potentially-hanging consturctions in the presence of comments. Issue 447.

• Fixed indentation in presence of type applications. Issue 493.

• Class and instance declarations now do not have a blank line after where. Grouping of methods from the original input is also preserved with some normalizations. Issue 431.

Ormolu 0.0.2.0

• Switched to ghc-lib-parser instead of depending on the ghc package directly. This should allow us to use newest features of GHC while not necessarily depending on the newest version of the compiler. In addition to that Ormolu is now GHCJS-compatible.

• Now unrecognized GHC options passed with --ghc-opt cause Ormolu to fail (exit code 7).

• Fixed formatting of result type in closed type families. See issue 420.

• Fixed a minor inconsistency between formatting of normal and foreign type signatures. See issue 408.

• Fixed a bug when comment before module header with Haddock was moved inside the export list. See issue 430.

• Empty foralls are now correctly preserved. See issue 429.

• Fixed issue 446, which involved braces and operators.

• When there are comments between preceding Haddock (pipe-style) and its corresponding declaration they are preserved like this in the output instead of being shifted. To be clear, this is not a very good idea to have comments in that position because the Haddock will end up not being associated with the declarations. Issues 440 and 448.

• Implemented correct handling of shebangs. Issue 377.

• Implemented correct handling of stack headers. Issue 393.

• Sorting language pragmas cannot not change meaning of the input program anymore. Issue 404.

• Fixed formatting of applications where function is a complex expression. Issue 444.

Ormolu 0.0.1.0

• Initial release.