- See also
- -
library(optparse) for comprehensive option parsing.
- library(prolog_stack) to force backtraces in case of an
uncaught exception.
- XPCE users should have a look at library(pce_main), which
starts the GUI and processes events until all windows have gone.
This library is intended for supporting PrologScript on Unix using
the
#! magic sequence for scripts using commandline options.
The entry point main/0 calls
the user-supplied predicate main/1 passing
a list of commandline options. Below is a simle echo
implementation in Prolog.
#!/usr/bin/env swipl
:- initialization(main, main).
main(Argv) :-
echo(Argv).
echo([]) :- nl.
echo([Last]) :- !,
write(Last), nl.
echo([H|T]) :-
write(H), write(' '),
echo(T).
- main
- Call main/1 using the passed command-line
arguments. Before calling
main/1 this predicate installs a signal
handler for
SIGINT (Control-C) that terminates the process
with status 1.
- [det]argv_options(+Argv,
-RestArgv, -Options)
- Generic transformation of long commandline arguments to options. Each
--Name=Value is mapped to Name(Value). Each plain name is mapped to
Name(true), unless Name starts with
no-, in which case the
option is mapped to Name(false). Numeric option values are mapped to
Prolog numbers.
- See also
library(optparse) provides a more involved option library,
providing both short and long options, help and error handling. This
predicate is more for quick-and-dirty scripts.
- [det]cli_parse_debug_options(+OptionsIn,
-Options)
- Parse certain commandline options for debugging and development
purposes. Options processed are below. Note that the option
argument is an atom such that these options may be activated as e.g.,
--debug='http(_)'.
- debug(Topic)
- Call
debug(Topic). See debug/1
and debug/3.
- spy(Predicate)
- Place a spy-point on Predicate.
- gspy(Predicate)
- As spy using the graphical debugger. See tspy/1.
- interactive(true)
- Start the Prolog toplevel after main/1
completes.
- cli_enable_development_system
- Re-enable the development environment. Currently re-enables xpce if this
was loaded, but not initialised and causes the interactive toplevel to
be re-enabled.
This predicate may be called from main/1
to enter the Prolog toplevel rather than terminating the application
after main/1 completes.
0 
