.hlint.yaml

# HLint configuration file
# https://github.com/ndmitchell/hlint
##########################

# This file contains a template configuration file, which is typically
# placed as .hlint.yaml in the root of your project


# Specify additional command line arguments
#
# - arguments: [--color, --cpp-simple, -XQuasiQuotes]


# Control which extensions/flags/modules/functions can be used
#
# - extensions:
#   - default: false # all extension are banned by default
#   - name: [PatternGuards, ViewPatterns] # only these listed extensions can be used
#   - {name: CPP, within: CrossPlatform} # CPP can only be used in a given module
#
# - flags:
#   - {name: -w, within: []} # -w is allowed nowhere
#
# - modules:
#   - {name: [Data.Set, Data.HashSet], as: Set} # if you import Data.Set qualified, it must be as 'Set'
#   - {name: Control.Arrow, within: []} # Certain modules are banned entirely
#
# - functions:
#   - {name: unsafePerformIO, within: []} # unsafePerformIO can only appear in no modules

- modules:
  # Enforce some common qualified imports aliases across the codebase
  - {name: [Data.Aeson, Data.Aeson.Types], as: Json}
  - {name: [Data.ByteArray], as: BA}
  - {name: [Data.ByteString.Base16], as: B16}
  - {name: [Data.ByteString.Char8], as: B8}
  - {name: [Data.ByteString.Lazy], as: BL}
  - {name: [Data.ByteString], as: BS}
  - {name: [Data.Foldable], as: F}
  - {name: [Data.List.NonEmpty], as: NE}
  - {name: [Data.List], as: L}
  - {name: [Data.Map.Strict], as: Map}
  - {name: [Data.Sequence], as: Seq}
  - {name: [Data.Set, Data.HashSet], as: Set}
  - {name: [Data.Text, Data.Text.Encoding], as: T}
  - {name: [Data.Vector], as: V}

# Ignore some build-in rules
- ignore: {name: "Reduce duplication"} # This is a decision left to developers and reviewers
- ignore: {name: "Redundant bracket"} # Not everyone knows precedences of every operators in Haskell. Brackets help readability.
- ignore: {name: "Redundant do"} # Just an annoying hlint built-in, GHC may remove redundant do if he wants
- ignore: {name: "Monoid law, left identity"} # Using 'mempty' can be useful to vertically-align elements
- ignore: {name: "Use ?~"} # It's actually much clearer to do (.~ Just ...) than having to load yet-another-lens-operator
- ignore: {name: "Use newtype instead of data"} # The semantic is slightly different, sometimes
- ignore: {name: "Use newTMVarIO"}
- ignore: {name: "Use newEmptyTMVarIO"}
- ignore: {name: "Use newTVarIO"}
- ignore: {name: "Use catMaybes"}
- ignore: {name: "Use head"}

# Add custom hints for this project
#
# Will suggest replacing "wibbleMany [myvar]" with "wibbleOne myvar"
# - error: {lhs: "wibbleMany [x]", rhs: wibbleOne x}


# Turn on hints that are off by default
#
# Ban "module X(module X) where", to require a real export list
# - warn: {name: Use explicit module export list}
#
# Replace a $ b $ c with a . b $ c
# - group: {name: dollar, enabled: true}
#
# Generalise map to fmap, ++ to <>
# - group: {name: generalise, enabled: true}


# Ignore some builtin hints
# - ignore: {name: Use let}
# - ignore: {name: Use const, within: SpecialModule} # Only within certain modules


# Define some custom infix operators
# - fixity: infixr 3 ~^#^~


# To generate a suitable file for HLint do:
# $ hlint --default > .hlint.yaml