Re: [Haskell-cafe] Multiple statements with Where

18 Dec 2007

      insertjokehere wrote:
...
Hi all, I am having problems adding multiple definitions with where for
example in my code
--A parser for recognising binary operations
parseBinaryOp :: String -> String -> [(Expr, Expr, String)]
parseBinaryOp op str
  | (elem op binops) && (notElem '(' (snd bm)) && (notElem ')' (snd bm)) &&
(elem nstr!!1 binops) = [(EInt 1, EInt 1, "HERE!")]
  | otherwise = []
      where bm = bracketMatch str
      	  nstr = words (snd (bracketMatch str))
alignment. Where clauses are layout.

Here is how I suggest you layit out:

--A parser for recognising binary operations
parseBinaryOp :: String -> String -> [(Expr, Expr, String)]
parseBinaryOp op str
     | (elem op binops) &&
       (notElem '(' (snd bm)) &&
       (notElem ')' (snd bm)) &&
       (elem nstr!!1 binops) = [(EInt 1, EInt 1, "HERE!")]
     | otherwise = []
   where bm = bracketMatch str
         nstr = words (snd (bracketMatch str))

Note that the where clause comes to the left of the |, because where 
clauses scope over all the guards

It may be a good idea not to use 'hard' tabs.

Jules

Re: [Haskell-cafe] Multiple statements with Where

Jules Bean