This is a work in progress, but usable as it is now.
Some memory leaks and segfaults to be expected. 


The files are 

CRuntimeFFI.hsc  -- user-friendly functions, almost the same as in the real Haskell PGF library.
Gu.hsc           -- mindlessly copypasted functions from various files in gu/
PgfLow.hs        -- mindlessly copypasted functions from various files in pgf/

The first two files (.hsc) use some special constructions for accessing C objects from Haskell.
See the syntax here: http://www.haskell.org/ghc/docs/7.2.1/html/users_guide/hsc2hs.html

HOW TO COMPILE:

hsc2hs Gu.hsc CRuntimeFFI.hsc -v --cflag="-std=c99" && ghc -lpgf -lgu --make CRuntimeFFI 

HOW TO USE:

- Symlink or copy the files in this directory to the directory you're working with; these files are not included in any makefiles
- Import CRuntimeFFI to a Haskell program you're writing

  module Main where
  import CRuntimeFFI

- Use the functions in your program

  main = do
    pgf <- readPGF "Foo.pgf"
    let english = getConcr pgf (mkCId ("FooEng"))

I haven't managed to make it work in ghci, get errors about unknown symbols (low level C functions).
