The print_history command was among the commands implemented in an ad-hoc
way instead of being handled by the command line interpreter, which means
it could not be used in a pipe, as in the example in the help info.
The refactoring in the previous patch made this old bug easy to fix.
Also fixed a bug in the "empty" command, introduced when moving the PGF from
CommandEnv to GFEnv.
TODO: fix the undocumented eh command. A comment in the help info for
print_history, and some commented out old code, suggest that eh means
"execute_history", but at present it does nothing...
+ Generalize the CommandInfo type by parameterizing it on the monad
instead of just the environment.
+ Generalize the commands defined in
GF.Command.{Commands,Commands2,CommonCommands,SourceCommands,HelpCommand}
to work in any monad that supports the needed operations.
+ Liberate GF.Command.Interpreter from the IO monad.
Also, move the current PGF from CommandEnv to GFEnv in
GF.Interactive, making the command interpreter even more generic.
+ Use a state monad to maintain the state of the interpreter in
GF.{Interactive,Interactive2}.
These commands are now implemented as regular commands (i.e. using the
CommandInfo data type) in the new module GF.Command.SourceCommands.
The list of commands exported from GF.Command.Commmands now called pgfCommands
instead of allCommands.
The list allCommands of all commands is now assembled
from sourceCommands, pgfCommands, commonCommands and helpCommand in
GF.Interactive.
+ Move type CommandInfo from GF.Command.Commands to a new module
GF.Commands.CommandInfo and make it independent of the PGF type.
+ Make the module GF.Command.Interpreter independent of the PGF type and
eliminate the import of GF.Command.Commands.
+ Move the implementation of the "help" command to its own module
GF.Command.Help
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.
