CurryInfo: stylechecker-2.0.0 / Check.AST.Pattern.EqualsTrue

Check.AST.Pattern.EqualsTrue

checkApplyEqualsTrue checkEqualsTrue checkInfixEqualsTrue warnEqualsTrue

module Check.AST.Pattern.EqualsTrue where

import Curry.SpanInfo
import Curry.Span
import Curry.Position
import Curry.Types
import Curry.Ident
import Text.Pretty

import Types

-- Calls actual checks on correct patterns:
--   1. a == b
--   2. (==) a b
checkEqualsTrue :: Expression a -> Int -> CSM ()
checkEqualsTrue e _ =
  case e of
    (InfixApply
      _
      _
      (InfixOp _
        (QualIdent _ _
          (Ident _ _ _)))
      _)
      -> checkInfixEqualsTrue e
    (Apply _
      (Apply _
        (Variable _ _
          (QualIdent _ _
            (Ident _ _ _)
          )
        )
        _)
      _)
      -> checkApplyEqualsTrue e
    _ -> return ()

-- For each `True`, `False` and `==`, `/=` combination with a bool, just using
-- the bool is recommended.
checkInfixEqualsTrue :: Expression a -> CSM ()
checkInfixEqualsTrue e = case checkInfixCompare e of
  (sI, (Constructor _ _ (QualIdent _ _ (Ident _ "True" _))), "==", _)   -> warnEqualsTrue sI "True == a"     "a"
  (sI, (Constructor _ _ (QualIdent _ _ (Ident _ "False" _))) , "==", _) -> warnEqualsTrue sI "False == a"    "not a"
  (sI, (Constructor _ _ (QualIdent _ _ (Ident _ "True" _))) , "/=", _)  -> warnEqualsTrue sI "True /= a"     "not a"
  (sI, (Constructor _ _ (QualIdent _ _ (Ident _ "False" _))) , "/=", _) -> warnEqualsTrue sI "False /= a"    "a"
  (sI, _ , "==", (Constructor _ _ (QualIdent _ _ (Ident _ "True" _))))  -> warnEqualsTrue sI "a == True"     "a"
  (sI, _ , "==", (Constructor _ _ (QualIdent _ _ (Ident _ "False" _)))) -> warnEqualsTrue sI "a == False"    "not a"
  (sI, _ , "/=", (Constructor _ _ (QualIdent _ _ (Ident _ "True" _))))  -> warnEqualsTrue sI "a /= True"     "not a"
  (sI, _ , "/=", (Constructor _ _ (QualIdent _ _ (Ident _ "False" _)))) -> warnEqualsTrue sI "a /= False"    "a"
  _                                                                     -> return ()

checkApplyEqualsTrue :: Expression a -> CSM ()
checkApplyEqualsTrue e = case checkApplyCompare e of
  (sI, "==", (Constructor _ _ (QualIdent _ _ (Ident _ "True" _))), _)   -> warnEqualsTrue sI "(==) True a"   "a"
  (sI, "==", (Constructor _ _ (QualIdent _ _ (Ident _ "False" _))), _)  -> warnEqualsTrue sI "(==) False a"  "not a"
  (sI, "/=", (Constructor _ _ (QualIdent _ _ (Ident _ "True" _))), _)   -> warnEqualsTrue sI "(/=) True a"   "not a"
  (sI, "/=", (Constructor _ _ (QualIdent _ _ (Ident _ "False" _))), _)  -> warnEqualsTrue sI "(/=) False a"  "a"
  (sI, "==", _ , (Constructor _ _ (QualIdent _ _ (Ident _ "True" _))))  -> warnEqualsTrue sI "(==) a True"   "a"
  (sI, "==", _ , (Constructor _ _ (QualIdent _ _ (Ident _ "False" _)))) -> warnEqualsTrue sI "(==) a False"  "not a"
  (sI, "/=", _ , (Constructor _ _ (QualIdent _ _ (Ident _ "True" _))))  -> warnEqualsTrue sI "(/=) a True"   "not a"
  (sI, "/=", _ , (Constructor _ _ (QualIdent _ _ (Ident _ "False" _)))) -> warnEqualsTrue sI "(/=) a False"  "a"
  _                                                                     -> return ()

-- Reports a superfluous code warning.
warnEqualsTrue :: SpanInfo -> String -> String -> CSM ()
warnEqualsTrue sI dn d =
  do
    report (Message
             (getSpan sI)
             (text "superflous code")
             (text "Instead of"
             <+> colorizeKey dn
             <+> text "use"
             <+> colorizeKey d))

safe