copilot-theorem: Remove unused function Copilot.Theorem.Misc.SExpr.parseSExpr. Refs #661.

The function `copilot-theorem:Copilot.Theorem.Misc.SExpr.parseSExpr` is
not used anywhere in the implementation. The module is internal and not
exposed to the user, so that function does not have and cannot have any
users.

This commit removes the function, as well as another definition in the
module only used by `parseSExpr`, and an import only used by those two
functions.

Author: ivanperez-keera

copilot-theorem/src/Copilot/Theorem/Misc/SExpr.hs

@@ -2,10 +2,9 @@
 {-# LANGUAGE Safe              #-}
 
 -- | A representation for structured expression trees, with support for pretty
--- printing and for parsing.
+-- printing.
 module Copilot.Theorem.Misc.SExpr where
 
-import Text.ParserCombinators.Parsec
 import Text.PrettyPrint.HughesPJ as PP hiding (char, Str)
 
 import Control.Monad
@@ -70,37 +69,3 @@ toDoc shouldIndent printAtom expr = case expr of
         doc $$ indent (toDoc shouldIndent printAtom s)
       | otherwise =
         doc <+> toDoc shouldIndent printAtom s
-
--- | Parser for strings of characters separated by spaces into a structured
--- tree.
---
--- Parentheses are interpreted as grouping elements, that is, defining a
--- 'List', which may be empty.
-parser :: GenParser Char st (SExpr String)
-parser =
-  choice [try unitP, nodeP, leafP]
-
-  where
-    symbol     = oneOf "!#$%&|*+-/:<=>?@^_~."
-    lonelyStr  = many1 (alphaNum <|> symbol)
-
-    unitP      = string "()" >> return unit
-
-    leafP      = atom <$> lonelyStr
-
-    nodeP      = do void $ char '('
-                    spaces
-                    st <- sepBy parser spaces
-                    spaces
-                    void $ char ')'
-                    return $ List st
-
--- | Parser for strings of characters separated by spaces into a structured
--- tree.
---
--- Parentheses are interpreted as grouping elements, that is, defining a
--- 'List', which may be empty.
-parseSExpr :: String -> Maybe (SExpr String)
-parseSExpr str = case parse parser "" str of
-  Left s -> error (show s) -- Nothing
-  Right t -> Just t