This isn't quite what you're asking for, but by using the applicative interface to parsers, you need do little more than spell out what your AST looks like:<div><br></div><div>import Control.Applicative</div><div>import Control.Applicative.Infix</div>
<div><br></div><div>data Equation = String :=: Expression</div><div>data Expression = EApp fun arg | EInt Int | EId String</div><div><br></div><div>parseEquation :: Parser Equation</div><div>parseEquation = parseIdentifier <^(:=:)^> parseExpression</div>
<div><br></div><div>parseExpression :: Parser Expression</div><div>parseExpression =</div><div> (EApp <$> parseExpression <*> parseExpression)</div><div> <|> (EInt <$> parseInt)</div><div> <|> (EId <$> parseIdentifier)</div>
<div><br></div><div>parseIdentifier :: Parser String</div><div>parseIdentifier = parseLowercaseChar <^(:)^> parseString</div><div><br></div><div>etc</div><div><br></div><div>Bob</div><div><br><div class="gmail_quote">
On Sun, Dec 27, 2009 at 10:18 AM, CK Kashyap <span dir="ltr"><<a href="mailto:ck_kashyap@yahoo.com">ck_kashyap@yahoo.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Hi All,<br>
I recently came across the paper titled "Monadic Parser Combinators" - After going through it a few times, I think I am beginning to understand monads.<br>
However, the parser developed in the paper does not generate an AST - I feel, I'd grasp the whole thing a lot better if I could go over a sample that generates an AST from a simple expression (or even a standard language such as C or Java) ... Can someone please point me to a sample that generates AST - preferably with the simple parser combinator given in the paper.<br>
Regards,<br>
<font color="#888888">Kashyap<br>
</font><div><div></div><div class="h5"><br>
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