.stylish-haskell.yaml

# stylish-haskell configuration file
# ==================================

# The stylish-haskell tool is mainly configured by specifying steps. These steps
# are a list, so they have an order, and one specific step may appear more than
# once (if needed). Each file is processed by these steps in the given order.
steps:
  # Convert some ASCII sequences to their Unicode equivalents. This is disabled
  # by default.
  # - unicode_syntax:
  #     # In order to make this work, we also need to insert the UnicodeSyntax
  #     # language pragma. If this flag is set to true, we insert it when it's
  #     # not already present. You may want to disable it if you configure
  #     # language extensions using some other method than pragmas. Default:
  #     # true.
  #     add_language_pragma: true

  # Format module header
  #
  # Currently, this option is not configurable and will format all exports and
  # module declarations to minimize diffs
  #
  # - module_header:
  #     # How many spaces use for indentation in the module header.
  #     indent: 4
  #
  #     # Should export lists be sorted?  Sorting is only performed within the
  #     # export section, as delineated by Haddock comments.
  #     sort: true
  #
  #     # See `separate_lists` for the `imports` step.
  #     separate_lists: true
  #
  #     # When to break the "where".
  #     # Possible values:
  #     # - exports: only break when there is an explicit export list.
  #     # - single: only break when the export list counts more than one export.
  #     # - inline: only break when the export list is too long. This is
  #     #   determined by the `columns` setting. Not applicable when the export
  #     #   list contains comments as newlines will be required.
  #     # - always: always break before the "where".
  #     break_where: exports
  #
  #     # Where to put open bracket
  #     # Possible values:
  #     # - same_line: put open bracket on the same line as the module name, before the
  #     #              comment of the module
  #     # - next_line: put open bracket on the next line, after module comment
  #     open_bracket: next_line

  # Format record definitions. This is disabled by default.
  #
  # You can control the layout of record fields. The only rules that can't be configured
  # are these:
  #
  # - "|" is always aligned with "="
  # - "," in fields is always aligned with "{"
  # - "}" is likewise always aligned with "{"
  #
  - records:
      # How to format equals sign between type constructor and data constructor.
      # Possible values:
      # - "same_line" -- leave "=" AND data constructor on the same line as the type constructor.
      # - "indent N" -- insert a new line and N spaces from the beginning of the next line.
      equals: "indent 2"

      # How to format first field of each record constructor.
      # Possible values:
      # - "same_line" -- "{" and first field goes on the same line as the data constructor.
      # - "indent N" -- insert a new line and N spaces from the beginning of the data constructor
      first_field: "indent 2"

      # How many spaces to insert between the column with "," and the beginning of the comment in the next line.
      field_comment: 2

      # How many spaces to insert before "deriving" clause. Deriving clauses are always on separate lines.
      deriving: 2

      # How many spaces to insert before "via" clause counted from indentation of deriving clause
      # Possible values:
      # - "same_line" -- "via" part goes on the same line as "deriving" keyword.
      # - "indent N" -- insert a new line and N spaces from the beginning of "deriving" keyword.
      via: "indent 2"

      # Sort typeclass names in the "deriving" list alphabetically.
      sort_deriving: true

      # Whether or not to break enums onto several lines
      #
      # Default: false
      break_enums: false

      # Whether or not to break single constructor data types before `=` sign
      #
      # Default: true
      break_single_constructors: false

      # Whether or not to curry constraints on function.
      #
      # E.g: @allValues :: Enum a => Bounded a => Proxy a -> [a]@
      #
      # Instead of @allValues :: (Enum a, Bounded a) => Proxy a -> [a]@
      #
      # Default: false
      curried_context: false

  # Align the right hand side of some elements.  This is quite conservative
  # and only applies to statements where each element occupies a single
  # line.
  # Possible values:
  # - always - Always align statements.
  # - adjacent - Align statements that are on adjacent lines in groups.
  # - never - Never align statements.
  # All default to always.
  - simple_align:
      cases: always
      top_level_patterns: always
      records: always
      multi_way_if: always

  # Import cleanup
  - imports:
      # There are different ways we can align names and lists.
      #
      # - global: Align the import names and import list throughout the entire
      #   file.
      #
      # - file: Like global, but don't add padding when there are no qualified
      #   imports in the file.
      #
      # - group: Only align the imports per group (a group is formed by adjacent
      #   import lines).
      #
      # - none: Do not perform any alignment.
      #
      # Default: global.
      align: global

      # The following options affect only import list alignment.
      #
      # List align has following options:
      #
      # - after_alias: Import list is aligned with end of import including
      #   'as' and 'hiding' keywords.
      #
      #   > import qualified Data.List      as List (concat, foldl, foldr, head,
      #   >                                          init, last, length)
      #
      # - with_alias: Import list is aligned with start of alias or hiding.
      #
      #   > import qualified Data.List      as List (concat, foldl, foldr, head,
      #   >                                 init, last, length)
      #
      # - with_module_name: Import list is aligned `list_padding` spaces after
      #   the module name.
      #
      #   > import qualified Data.List      as List (concat, foldl, foldr, head,
      #                          init, last, length)
      #
      #   This is mainly intended for use with `pad_module_names: false`.
      #
      #   > import qualified Data.List as List (concat, foldl, foldr, head,
      #                          init, last, length, scanl, scanr, take, drop,
      #                          sort, nub)
      #
      # - new_line: Import list starts always on new line.
      #
      #   > import qualified Data.List      as List
      #   >     (concat, foldl, foldr, head, init, last, length)
      #
      # - repeat: Repeat the module name to align the import list.
      #
      #   > import qualified Data.List      as List (concat, foldl, foldr, head)
      #   > import qualified Data.List      as List (init, last, length)
      #
      # Default: after_alias
      list_align: after_alias

      # Right-pad the module names to align imports in a group:
      #
      # - true: a little more readable
      #
      #   > import qualified Data.List       as List (concat, foldl, foldr,
      #   >                                           init, last, length)
      #   > import qualified Data.List.Extra as List (concat, foldl, foldr,
      #   >                                           init, last, length)
      #
      # - false: diff-safe
      #
      #   > import qualified Data.List as List (concat, foldl, foldr, init,
      #   >                                     last, length)
      #   > import qualified Data.List.Extra as List (concat, foldl, foldr,
      #   >                                           init, last, length)
      #
      # Default: true
      pad_module_names: false

      # Long list align style takes effect when import is too long. This is
      # determined by 'columns' setting.
      #
      # - inline: This option will put as much specs on same line as possible.
      #
      # - new_line: Import list will start on new line.
      #
      # - new_line_multiline: Import list will start on new line when it's
      #   short enough to fit to single line. Otherwise it'll be multiline.
      #
      # - multiline: One line per import list entry.
      #   Type with constructor list acts like single import.
      #
      #   > import qualified Data.Map as M
      #   >     ( empty
      #   >     , singleton
      #   >     , ...
      #   >     , delete
      #   >     )
      #
      # Default: inline
      long_list_align: inline

      # Align empty list (importing instances)
      #
      # Empty list align has following options
      #
      # - inherit: inherit list_align setting
      #
      # - right_after: () is right after the module name:
      #
      #   > import Vector.Instances ()
      #
      # Default: inherit
      empty_list_align: right_after

      # List padding determines indentation of import list on lines after import.
      # This option affects 'long_list_align'.
      #
      # - <integer>: constant value
      #
      # - module_name: align under start of module name.
      #   Useful for 'file' and 'group' align settings.
      #
      # Default: 4
      list_padding: 4

      # Separate lists option affects formatting of import list for type
      # or class. The only difference is single space between type and list
      # of constructors, selectors and class functions.
      #
      # - true: There is single space between Foldable type and list of it's
      #   functions.
      #
      #   > import Data.Foldable (Foldable (fold, foldl, foldMap))
      #
      # - false: There is no space between Foldable type and list of it's
      #   functions.
      #
      #   > import Data.Foldable (Foldable(fold, foldl, foldMap))
      #
      # Default: true
      separate_lists: true

      # Space surround option affects formatting of import lists on a single
      # line. The only difference is single space after the initial
      # parenthesis and a single space before the terminal parenthesis.
      #
      # - true: There is single space associated with the enclosing
      #   parenthesis.
      #
      #   > import Data.Foo ( foo )
      #
      # - false: There is no space associated with the enclosing parenthesis
      #
      #   > import Data.Foo (foo)
      #
      # Default: false
      space_surround: false

      # Post qualify option moves any qualifies found in import declarations
      # to the end of the declaration. This also adjust padding for any
      # unqualified import declarations.
      #
      # - true: Qualified as <module name> is moved to the end of the
      #   declaration.
      #
      #   > import Data.Bar
      #   > import Data.Foo qualified as F
      #
      # - false: Qualified remains in the default location and unqualified
      #   imports are padded to align with qualified imports.
      #
      #   > import           Data.Bar
      #   > import qualified Data.Foo as F
      #
      # Default: false
      post_qualify: false

      # Automatically group imports based on their module names, with
      # a blank line separating each group. Groups are ordered in
      # alphabetical order.
      #
      # By default, this groups by the first part of each module's
      # name (Control.* will be grouped together, Data.*... etc), but
      # this can be configured with the group_patterns setting.
      #
      # When enabled, this rewrites existing blank lines and groups.
      #
      # - true: Group imports by the first part of the module name.
      #
      #   > import Control.Applicative
      #   > import Control.Monad
      #   > import Control.Monad.MonadError
      #   >
      #   > import Data.Functor
      #
      # - false: Keep import groups as-is (still sorting and
      #   formatting the imports within each group)
      #
      #   > import Control.Monad
      #   > import Data.Functor
      #   >
      #   > import Control.Applicative
      #   > import Control.Monad.MonadError
      #
      # Default: false
      group_imports: false

      # A list of rules specifying how to group modules and how to
      # order the groups.
      #
      # Each rule has a match field; the rule only applies to module
      # names matched by this pattern. Patterns are POSIX extended
      # regular expressions; see the documentation of Text.Regex.TDFA
      # for details:
      # https://hackage.haskell.org/package/regex-tdfa-1.3.1.2/docs/Text-Regex-TDFA.html
      #
      # Rules are processed in order, so only the *first* rule that
      # matches a specific module will apply. Any module names that do
      # not match a single rule will be put into a single group at the
      # end of the import block.
      #
      # Example: group MyApp modules first, with everything else in
      # one group at the end.
      #
      #  group_rules:
      #    - match: "^MyApp\\>"
      #
      #  > import MyApp
      #  > import MyApp.Foo
      #  >
      #  > import Control.Monad
      #  > import MyApps
      #  > import Test.MyApp
      #
      # A rule can also optionally have a sub_group pattern. Imports
      # that match the rule will be broken up into further groups by
      # the part of the module name matched by the sub_group pattern.
      #
      # Example: group MyApp modules first, then everything else
      # sub-grouped by the first part of the module name.
      #
      #  group_rules:
      #    - match: "^MyApp\\>"
      #    - match: "."
      #      sub_group: "^[^.]+"
      #
      #  > import MyApp
      #  > import MyApp.Foo
      #  >
      #  > import Control.Applicative
      #  > import Control.Monad
      #  >
      #  > import Data.Map
      #
      # A pattern only needs to match part of the module name, which
      # could be in the middle. You can use ^pattern to anchor to the
      # beginning of the module name, pattern$ to anchor to the end
      # and ^pattern$ to force a full match. Example:
      #
      #  - "Test\\." would match "Test.Foo" and "Foo.Test.Lib"
      #  - "^Test\\." would match "Test.Foo" but not "Foo.Test.Lib"
      #  - "\\.Test$" would match "Foo.Test" but not "Foo.Test.Lib"
      #  - "^Test$" would *only* match "Test"
      #
      # You can use \\< and \\> to anchor against the beginning and
      # end of words, respectively. For example:
      #
      #  - "^Test\\." would match "Test.Foo" but not "Test" or "Tests"
      #  - "^Test\\>" would match "Test.Foo" and "Test", but not
      #    "Tests"
      #
      # The default is a single rule that matches everything and
      # sub-groups based on the first component of the module name.
      #
      # Default: [{ "match" : ".*", "sub_group": "^[^.]+" }]
      group_rules:
        - match: ".*"
          sub_group: "^[^.]+"

  # Language pragmas
  - language_pragmas:
      # We can generate different styles of language pragma lists.
      #
      # - vertical: Vertical-spaced language pragmas, one per line.
      #
      # - compact: A more compact style.
      #
      # - compact_line: Similar to compact, but wrap each line with
      #   `{-# LANGUAGE #-}'.
      #
      # - vertical_compact: Similar to vertical, but use only one language pragma.
      #
      # Default: vertical.
      style: vertical

      # Align affects alignment of closing pragma brackets.
      #
      # - true: Brackets are aligned in same column.
      #
      # - false: Brackets are not aligned together. There is only one space
      #   between actual import and closing bracket.
      #
      # Default: true
      align: true

      # stylish-haskell can detect redundancy of some language pragmas. If this
      # is set to true, it will remove those redundant pragmas. Default: true.
      remove_redundant: true

      # Language prefix to be used for pragma declaration, this allows you to
      # use other options non case-sensitive like "language" or "Language".
      # If a non correct String is provided, it will default to: LANGUAGE.
      language_prefix: LANGUAGE

  # Replace tabs by spaces. This is disabled by default.
  # - tabs:
  #     # Number of spaces to use for each tab. Default: 8, as specified by the
  #     # Haskell report.
  #     spaces: 8

  # Remove trailing whitespace
  - trailing_whitespace: {}

  # Squash multiple spaces between the left and right hand sides of some
  # elements into single spaces. Basically, this undoes the effect of
  # simple_align but is a bit less conservative.
  # - squash: {}

# A common setting is the number of columns (parts of) code will be wrapped
# to. Different steps take this into account.
#
# Set this to null to disable all line wrapping.
#
# Default: 80.
columns: 80

# By default, line endings are converted according to the OS. You can override
# preferred format here.
#
# - native: Native newline format. CRLF on Windows, LF on other OSes.
#
# - lf: Convert to LF ("\n").
#
# - crlf: Convert to CRLF ("\r\n").
#
# Default: native.
newline: native

# Sometimes, language extensions are specified in a cabal file or from the
# command line instead of using language pragmas in the file. stylish-haskell
# needs to be aware of these, so it can parse the file correctly.
#
# No language extensions are enabled by default.
# language_extensions:
  # - TemplateHaskell
  # - QuasiQuotes

# Attempt to find the cabal file in ancestors of the current directory, and
# parse options (currently only language extensions) from that.
#
# Default: true
cabal: true