{-# OPTIONS_GHC -fno-warn-missing-signatures #-}

Prevents warnings of top level functions which have no type signature.
NOTE: For better readability, sometimes it makes sense not to declate the type of top level functions and letting the compiler to infer the type.

expample:

...
 
import Parser
 
...
 
synMain = SynSeq [synNumber, synComment, synNumber, SynEOI]
synComment = SynSeq [ synCommentBegin, synNotCommentEnds, synCommentEnd]
synCommentBegin = SynSeq [SynChar '{', SynChar '-']
synCommentEnd = SynSeq [SynChar '-', SynChar '}']
synNotCommentEnds = SynRep synNotCommentEnd
synNotCommentEnd = SynAbs synCommentEnd
synNumber = SynSel [synNumberZero,synNonZeroNumber]
synNumberZero = SynChar '0'
synNonZeroNumber = SynSeq [synNonZeroDigit, SynRep synDigit]
synNonZeroDigit = SynSel (map SynChar ['1'..'9'])
synDigit = SynSel (map SynChar ['0'..'9'])

compiler warning, when using -Wall:

app\Main.hs:59:1: warning: [-Wmissing-signatures]
    Top-level binding with no type signature: synMain :: Syntax
   |
59 | synMain = SynSeq [synNumber, synComment, synNumber, SynEOI]
   | ^^^^^^^

expample:

{-# OPTIONS_GHC -fno-warn-missing-signatures #-}
 
...
 
import Parser
 
...
 
synMain = SynSeq [synNumber, synComment, synNumber, SynEOI]
synComment = SynSeq [ synCommentBegin, synNotCommentEnds, synCommentEnd]
synCommentBegin = SynSeq [SynChar '{', SynChar '-']
synCommentEnd = SynSeq [SynChar '-', SynChar '}']
synNotCommentEnds = SynRep synNotCommentEnd
synNotCommentEnd = SynAbs synCommentEnd
synNumber = SynSel [synNumberZero,synNonZeroNumber]
synNumberZero = SynChar '0'
synNonZeroNumber = SynSeq [synNonZeroDigit, SynRep synDigit]
synNonZeroDigit = SynSel (map SynChar ['1'..'9'])
synDigit = SynSel (map SynChar ['0'..'9'])

compiles, error and warning free, with compiler: GHC 9.0.2, using compiler option -Wall

✎

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