/ 
Language-Lisp-ECLs-0.25
River stage zero No dependents
/ Language::Lisp::ECLs

NAME

Language::Lisp::ECLs - Perl extension for ECL lisp

SYNOPSIS

use Language::Lisp::ECLs;
my $cl = new Language::Lisp::ECLs;
my $r = $cl->eval_string("(format nil \"[~S]\" 'qwerty)");
my $lam = $cl->eval_string("(lambda (x y) (+ x y))");
$lam->funcall(5,9); # results 14

DESCRIPTION

Language::Lisp::ECLs is a bit easier to use than Language::Lisp because of embeddable nature of ECLs. Language::Lisp uses different approach because they are other way down: Lisp calls Perl and not vice versa.

new()

The new method used to create Language::Lisp::ECLs object which is used to talk with underlying lisp. This object looks like an interpreter instance, although there is actually no interpreter instance created. Instead, this object is used to create a handy way of invoking API: given that you have $cl object you can execute:

my $res = $cl->eval_string("(format nil \"~A\" (expt 2 1000))");

which is equivalent to

my $res = Language::Lisp::ECLs::eval_string(undef, "....");

but is much better to use.

Passing parameters to ECL and getting results from ECL

Required Perl objects converted to Lisp objects and vice versa. Compatible types are converted as-is (e.g. ECL type t_integer becomes SvIV), all other types are blessed into some package, for example into Language::Lisp::ECLs::Symbol

This is done behind the scenes and user should not bother about this.

This makes following code to work:

my $lam = $cl->eval_string("(lambda (x y) (+ x y))");
print $lam->funcall(40,2);     # prints 42
print $cl->funcall($lam,40,2); # ... another way to say the same

If you have a list object in Lisp, it will be automatically blessed into the Language::Lisp::ECLs::List package, which could be tied as array with a tie perl funciton:

tie my @arr, "Language::Lisp::ECLs::List", $list;

Even simplier, $list have _tie method to return tied array reference:

my $arr = $list->_tie;

Fetching items from this array works, storing them currently do not work.

$cl->eval_string(string)

runs string within ECLs interpreter and returns whatever lisp returns to us. Internally this transforms to the call si_safe_eval(...);

$cl->eval(lisp_object)

same as eval_string but takes lisp object instead of string as argument.

$lispobj->funcall(...)

given lisp object blessed to package Language::Lisp::ECLs::Code calls the procedure.

AUTOLOADing

$cl->someFunctionName(args) get transformed into function call to "some-function-name"

This is done by finding lisp object for evaluating arguments, and blessing it into Language::Lisp::ECLs::Code package

$cl->prin1("qwerty");
TODO

EXPORT

None. No namespace pollution, the greens are happy.

BUGS

  • ECL uses Boehm GC, and at the moment of writing it did not had reliable interface on returning memory to GC, so the leaks of memory are unavoidable.

  • funcall can not take more than 10 args - this should be fixed.

SEE ALSO

Language::Lisp

See ecls.sf.net to read about ECL lisp project.

AUTHOR

Vadim Konovalov, <vkon@cpan.org>

COPYRIGHT AND LICENSE

Copyright (C) 2008 by VKON

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.004 or, at your option, any later version of Perl 5 you may have available.