loadConcr, unloadConcr and addLiteral modify the Concr structure as a side
effect. This means that other functions with a Concr argument (e.g. parse
and linearize) are no longer pure.
Possible solutions:
1. Don't try to hide the imperative nature of the C run-time system: remove
all uses of unsafePerformIO and let all functions operate in the IO monad.
2. Don't export functions with side effects. Perhaps the desired functionality
of loadConcr, unloadConcr and addLiteral can be folded into readPGF.
The Concr structures can then treaded as immutable after after the
readPGF function returns...
(1) introduces the module GF.Infra.Concurreny with lifted concurrency
operators (to reduce uses of liftIO) and some additional concurrency
utilities, e.g. a function for sequential logging that is used in
both GF.CompileInParallel and GFServer.
(2) avoids leaving broken .gfo files behind if compilation is aborted.
* httpd-shed-0.4 does not specify an upper bound on network, but it fails
to build against network>=2.6. This is fixed in httpd-shed-0.4.0.2.
* With network-2.6, the Network.URI modules is moved to a separate package,
so for the time being GF requires network>=2.3 && <2.6. This is compatible
with the four most recent versions of the Haskell Platform.
* Introducing the module CGI, re-exporting a subset of the cgi package. It
might complete replace the cgi package in the future.
* Introducing the module CGIUtils, containing functions from FastCGIUtils that
have nothing to do with fastcgi.
Some low level hackery with unsafePerformIO and global variables was left
in FastCGIUtils, but it is actually not used, neither for gf -server nor
exec/pgf-fcgi.hs.
On my laptop these changes speed up the full build of the RGL and example
grammars with 'cabal build' from ~95s to ~43s and the zero build from ~18s
to ~5s.
The main change is the introduction of the module GF.CompileInParallel that
replaces GF.Compile and the function GF.Compile.ReadFiles.getAllFiles. At
present, it is activated with the new -j flag, and it is only used when
combined with --make or --batch. In addition, to get parallel computations,
you need to add GHC run-time flags, e.g., +RTS -N -A20M -RTS, to the command
line.
The Setup.hs script has been modified to pass the appropriate flags to GF
for parallel compilation when compiling the RGL and example grammars, but you
need a recent version of Cabal for this to work (probably >=1.20).
Some additonal refactoring were made during this work. A new monad is used to
avoid warnings/error messages from different modules to be intertwined when
compiling in parallel, so some functios that were hardiwred to the IO or IOE
monads have been lifted to work in arbitrary monads that are instances in
the appropriate classes.
I prefer small functions with descriptive names over large monilithic chunks
of code, so I grouped the compiler passes called from compileSourceModule
into funcitons named frontend, middle and backend. This also makes decisions
about which passes to run clearly visible up front.
Also made some small changes in GF.Compile.
In particular, the function compileOne has been moved to the new module
GF.CompileOne and its type has been changed from
compileOne :: ... -> CompileEnv -> FilePath -> IOE CompileEnv
to
compileOne :: ... -> SourceGrammar -> FilePath -> IOE OneCompiledModule
making it more suitable for use in a parallel compiler.
The def rules are now compiled to byte code by the compiler and then to
native code by the JIT compiler in the runtime. Not all constructions
are implemented yet. The partial implementation is now in the repository
but it is not activated by default since this requires changes in the
PGF format. I will enable it only after it is complete.
