starlitcanopy/simple-sql-parser
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refactor the symbol lexer a little

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Jake Wheat 2016-02-22 23:20:11 +02:00
parent 3f7e0123a2
commit a3178ad249
1 changed files with 9 additions and 22 deletions
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31
Language/SQL/SimpleSQL/Lex.lhs
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@ -416,43 +416,30 @@ which allows the last character of a multi character symbol to be + or
> <*> option [] opMoreChars
> ]
> symbol d | diSyntaxFlavour d == SQLServer =
> Symbol <$> choice (otherSymbol ++ regularOp)
> symbol d = Symbol <$> choice (otherSymbol ++ regularOp)
> where
> otherSymbol = many1 (char '.') :
> (map (string . (:[])) ",;():?"
> (map (string . (:[])) otherSymbolChars
> ++ if allowOdbc d
> then [string "{", string "}"]
> else [])
> otherSymbolChars =
> case diSyntaxFlavour d of
> SQLServer -> ",;():?"
> _ -> "[],;():?"
try is used because most of the first characters of the two character
symbols can also be part of a single character symbol
> regularOp = map (try . string) [">=","<=","!=","<>"]
> ++ map (string . (:[])) "+-^*/%~&<>="
> -- what about using many1 (char '|'), then it will
> -- fail in the parser? Not sure exactly how
> -- standalone the lexer should be
> ++ [char '|' *>
> choice ["||" <$ char '|' <* notFollowedBy (char '|')
> ,return "|"]]
> symbol d =
> Symbol <$> choice (otherSymbol ++ regularOp)
> where
> otherSymbol = many1 (char '.') :
> (map (string . (:[])) "[],;():?"
> ++ if allowOdbc d
> then [string "{", string "}"]
> else [])
try is used because most of the first characters of the two character
symbols can also be part of a single character symbol
> regularOp = map (try . string) [">=","<=","!=","<>"]
> ++ map (string . (:[])) "+-^*/%~&<>=[]"
> ++ [char '|' *>
> choice ["||" <$ char '|' <* notFollowedBy (char '|')
> ,return "|"]]
> sqlWhitespace :: Dialect -> Parser Token
> sqlWhitespace _ = Whitespace <$> many1 (satisfy isSpace)