[Haskell-cafe] Parsec and (then?) type-check
skynare at gmail.com
Fri Dec 12 20:27:28 EST 2008
I use my type checking monad, which is separate from Parsec's monad.
So, I can't think of a way to type check during parsing in Parsec's monad.
Anyways, this is what I did:
data Expr = ... | At SourcePos Expr
SourcePos is from Parsec.
Basically, my parse actions will return (At pos e).
And I pass At pos e to typeCheck action.
typeCheck (At pos e) = do
-- typeCheck is in State monad.
-- in case of error, I'll pos <- get and report source position.
typeCheck (Variable a) = do
check out this:
On Fri, Dec 12, 2008 at 5:06 PM, Greg Fitzgerald <garious at gmail.com> wrote:
> Parser gurus,
> When you write a parser with a library like Parsec, do you typically
> type-check while parsing, or afterward in a separate pass? The latter
> is more modular, but it means labeling every element in the AST with
> the parser position so that you can give good error messages. Do you
> find the added modularity worth the hassle or just pack type-checking
> into the parser pass?
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