This is what hint does, isn't it? However, this still leaves it to me to infer what type [|a|] in [| reverse (a:b:[]) = (b:a:[]) |] is.
Thanks a lot anyway. Martin On Thu, 2009-03-12 at 12:59 -0200, Daniel Gorín wrote: > would using ghc-as-a-library to type (strings with) haskell > expressions at runtime help? > > On Mar 12, 2009, at 12:37 PM, Martin Hofmann wrote: > > > I am doing meta-programming at runtime. So my program gets a full > > Haskell declaration in expression quotation ([d|...|]) modifies it and > > returns the modified expression. Therefore, I need type information of > > this expression, and any subexpression, at _runtime_ ! For example: > > > > [d| reverse x1 = y1 |] > > > > - rewrites_to -> > > > > [d| reverse x2:xs = y2:ys |] > > > > - rewrites_to -> > > > > [d| reverse x:xs = reverse xs ++ [x] |] > > > > reverse :: [a] -> [a] implies > > x2,y2 :: a > > x1,y1,xs,ys :: [a] > > > > TH.reify is not applicable, because I need the information at runtime > > and I am in IO. I suppose Data.Dynamic does not work either, because > > [| > > xs|] :: ExpQ and not [a]. > > > > So it looks like I need my own type checker and inference and tag each > > subexpression with its type. If so, I can even omit TH and use my own > > data type for the abstract syntax tree. This annoys me a bit, because > > for me it seems that all I need is already there. > > > > Did anybody have similar problems, because I shouldn't be the only one > > doing dynamic typing in a static language? Is there a Haskell > > implementation of the paper "Typing Dynamic Typing" by Baars and > > Swierstra (http://people.cs.uu.nl/arthurb/dynamic.html ), so I can try > > out if this helps me? > > > > Any help, comments, and how-to-suggestions are highly welcome. > > > > Thanks a lot, > > > > Martin > > > > > > > > _______________________________________________ > > Haskell-Cafe mailing list > > Haskell-Cafe@haskell.org > > http://www.haskell.org/mailman/listinfo/haskell-cafe _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
