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}.
Some C run-time functionality is now available in the GF shell, by starting
GF with 'gf -cshell' or 'gf -crun'. Only limited functionality is available
when running the shell in these modes:
- You can only import .pgf files, not source files.
- The -retain flag can not be used and the commands that require it to work
are not available.
- Only 18 of the 40 commands available in the usual shell have been
implemented. The 'linearize' and 'parse' commands are the only ones
that call the C run-time system, and they support only a limited set of
options and flags. Use the 'help' commmands for details.
- A new command 'generate_all', that calls PGF2.generateAll, has been added.
Unfortuntaly, using it causes 'segmentation fault'.
This is implemented by adding two new modules: GF.Command.Commands2 and
GF.Interactive2. They are copied and modified versions of GF.Command.Commands
and GF.Interactive, respectively. Code for unimplemented commands and other
code that has not been adapted to the C run-time system has been left in
place, but commented out, pending further work.
