Because the prompt included the name of the abstract syntax, the loading
of the PGF was forced even if -retain was used. Even worse,
if an error occured while loading the PGF, it was repeated and caught
every time the prompt was printed, creating an infite loop. The solution
is to not print the name of the abstract syntax when the grammar is
imported with -retain, which is the way things were before anyway.
The commands available in the shell after import -retain are now a superset
of the commands available after import without -retain.
The PGF is created lazily, so there should be no performance penalty if
the PGF isn't needed. If there are errors, they won't be reported until a
command that uses the PGF is entered.
Included renamings:
SourceGrammar -> Grammar
SourceModule -> Module
SourceModInfo -> ModuleInfo
emptySourceGrammar -> emptyGrammar
Also introduces a type synonym (which might be good to turn into a newtype):
type ModuleName = Ident
The reason is to make types like the following more self documenting:
type Module = (ModuleName,ModuleInfo)
type QIdent = (ModuleName,Ident)
* The following modules are no longer used and have been removed completely:
GF.Compile.Compute.ConcreteLazy
GF.Compile.Compute.ConcreteStrict
GF.Compile.Refresh
* The STM monad has been commented out. It was only used in
GF.Compile.SubExpOpt, where could be replaced with a plain State monad,
since no error handling was needed. One of the functions was hardwired to
the Err monad, but did in fact not use error handling, so it was turned
into a pure function.
* The function errVal has been renamed to fromErr (since it is analogous to
fromMaybe).
* Replaced 'fail' with 'raise' and 'return ()' with 'done' in a few places.
* Some additional old code that was already commented out has been removed.
