On 07/04/10 10:50, Stephen Tetley wrote:

You don't need HDirect for this.

I've attached an early revision of Wolfram Kahl's code that I download years ago - this is a plain Haskell version rather than a literate file you should find it easier to use.

The file itself seems to have disappeared from the web, though maybe it is findable through the Wayback machine.

Thanks Stephen; however, when I tried with your interpret.hs, I got the same error I got with: http://www.cas.mcmaster.ca/~kahl/FP/2003/Interpreter.lhs that is: ={============ cut here ============== ~/prog_dev/haskell/modular-interpreter $ hugs -98 +o Interpreter.hs __ __ __ __ ____ ___ _________________________________________ || || || || || || ||__ Hugs 98: Based on the Haskell 98 standard ||___|| ||__|| ||__|| __|| Copyright (c) 1994-2005 ||---|| ___|| World Wide Web: http://haskell.org/hugs || || Bugs: http://hackage.haskell.org/trac/hugs || || Version: September 2006 _________________________________________ Hugs mode: Restart with command line option +98 for Haskell 98 mode ERROR "Interpreter.hs" - Can't find imported module "FiniteMaps" Hugs> =}============ cut here ============== The only reason I though hdirect was needed was because it has a FiniteMaps module. Hmm...I looked more closely and it has a FiniteMap module. Where do can I get this FiniteMaps module? TIA. -Larry

On 07/04/10 11:19, Stephen Tetley wrote:

Hi Larry

Hugs comes with a library - FiniteMap. Maybe FiniteMaps is a spelling mistake or maybe it it a module the Wolfram Kahl didn't distribute.

Thanks Stephen, I changed the name; however, then 2 other names needed changing: lookupDftFM -> lookupWithDefaultFM zeroFM -> emptyFM However, even after those changes, I got several errors: ~/prog_dev/haskell/modular-interpreter $ ghc -fallow-overlapping-instances -fallow-undecidable-instances -fglasgow-exts -o Int Interpreter.hs Interpreter.hs:155:39: Couldn't match expected type `FiniteMap Name (InterpM Value)' against inferred type `Name' In the first argument of `addToFM', namely `n' In the first argument of `Env', namely `(addToFM n v e)' In the expression: Env (addToFM n v e) Interpreter.hs:203:14: Overlapping instances for StateMonad s (StateT Store (EnvT Env (ContT Answer (StateT [String] (ErrorT []))))) arising from a use of `liftSTFun' at Interpreter.hs:203:14-38 Matching instances: instance [overlap ok] (StateMonad s m, MonadT t m) => StateMonad s (t m) -- Defined at Interpreter.hs:(391,0)-(392,23) instance [overlap ok] (Monad m) => StateMonad s (StateT s m) -- Defined at Interpreter.hs:(301,0)-(302,43) (The choice depends on the instantiation of `s' To pick the first instance above, use -fallow-incoherent-instances when compiling the other instance declarations) In the expression: liftSTFun (updateStore p) In the definition of `updateLoc': updateLoc p = liftSTFun (updateStore p) Interpreter.hs:211:56: Couldn't match expected type `InterpM Value' against inferred type `FiniteMap Integer (InterpM Value)' In the third argument of `addToFM', namely `fm' In the second argument of `Store', namely `(addToFM i v fm)' In the expression: Store n (addToFM i v fm) Interpreter.hs:427:9: The scoped type variables `env' and `r' are bound to the same type (variable) Distinct scoped type variables must be distinct In the pattern: r :: env In the definition of `inEnv': inEnv (r :: env) (ContT c) = ContT (\ k -> do o <- rdEnv inEnv r (c (inEnv (o :: env) . k))) In the definition for method `inEnv' ~/prog_dev/haskell/modular-interpreter $ Any suggestions for workarounds would be appreciated. -regards, Larry

On 07/05/10 02:08, Stephen Tetley wrote:

Hi Larry

I'll take a look at getting the code to work later today.

Thanks very much.

Which system - GHCi or Hugs - would you prefer to use?

GHCi, because I tried: cabal install --hugs after download & unzip & untar: http://hackage.haskell.org/packages/archive/hdirect/0.21.0/hdirect-0.21.0.ta... but, apparently, the hugs compiler I've got cannot correctly parse some of the .lhs files downloaded :(

If you prefer GHCi, I'll replace the whole FiniteMap module with Data.Map as FiniteMap has been made obsolete by Data.Map.

That sounds best.

Best wishes

Stephen

Thank you Stephen. -regards, Larry

On 07/05/10 08:12, Stephen Tetley wrote:

Hi Larry

Here is the working code.

[snip] Thanks very much Stephen. I just added: {-# LANGUAGE PatternSignatures #-} to get it to compile with ghci: ~/prog_dev/haskell/modular-interpreter $ ghci Interpreter.hs GHCi, version 6.8.3: http://www.haskell.org/ghc/ :? for help Loading package base ... linking ... done. [1 of 1] Compiling Interpreter ( Interpreter.hs, interpreted ) Ok, modules loaded: Interpreter. *Interpreter>