Invoking method with a block in C extension

[Dmitry V. Sabanin]

Hi.
I'm converting some of my ruby code to C extension for better perfomance.
I ran into problems with executing methods that take blocks.
I.e. in ruby i have
string.gsub!(/regexp/) { |subst| ... }
and i can't find the way to translate it to C. I tried to search through
ruby-talk archives, but I couldn't find anything usefull.
As far as I was looking at problem, I found rb_iterate, rb_yield, but I
couldn't clearly understand what's their purpose, and how to get them all
together to achieve what I want.
Could somebody please explain me how can I implement this ruby code in C?
I'd really appreciate any help. Thanks in advance!
--
sdmitry -=- Dmitry V. Sabanin
MuraveyLabs.

[ts]

>>>>> "D" == Dmitry V Sabanin <sdmitry@lrn.ru> writes:

D> As far as I was looking at problem, I found rb_iterate, rb_yield, but I
D> couldn't clearly understand what's their purpose, and how to get them all
D> together to achieve what I want.

Look in enum.c in the distribution of ruby, you have examples for call to
rb_iterate



Guy Decoux

[Mauricio Fernández]

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On Sat, Nov 22, 2003 at 10:34:27PM +0900, Dmitry V. Sabanin wrote:

> Hi.
> I'm converting some of my ruby code to C extension for better perfomance.
> I ran into problems with executing methods that take blocks.
> I.e. in ruby i have
> string.gsub!(/regexp/) { |subst| ... }
> and i can't find the way to translate it to C. I tried to search through
> ruby-talk archives, but I couldn't find anything usefull.
> As far as I was looking at problem, I found rb_iterate, rb_yield, but I
> couldn't clearly understand what's their purpose, and how to get them all
> together to achieve what I want.
> Could somebody please explain me how can I implement this ruby code in C?
> I'd really appreciate any help. Thanks in advance!

I was surprised to see that rb_funcall propagates the block passed with
rb_iterate, so there's 2 solutions (attached).

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require "mkmf"

create_makefile("gsub_example")


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#include <ruby.h>
#include <stdio.h>

VALUE mCTest;

static
VALUE
block(VALUE args)
{
VALUE str = rb_ary_entry(args, 0);
Check_Type(str, T_STRING);
printf("Inside block, with string: %s.\n", RSTRING(str)->ptr);
return rb_funcall(str, rb_intern("upcase"), 0);
}

static
VALUE
block2(VALUE str)
{
Check_Type(str, T_STRING);
printf("Inside block, with string: %s.\n", RSTRING(str)->ptr);
return rb_funcall(str, rb_intern("upcase"), 0);
}

static
VALUE
foo(VALUE self, VALUE str, VALUE re)
{
VALUE proc;

proc = rb_proc_new(block, Qnil);
return rb_funcall(str, rb_intern("_gsub!"), 2, re, proc);
}

static
VALUE
call_gsub(VALUE args)
{
VALUE str, re;
str = rb_ary_entry(args, 0);
re = rb_ary_entry(args, 1);

return rb_funcall(str, rb_intern("gsub!"), 1, re);
}

static
VALUE
foo2(VALUE self, VALUE str, VALUE re)
{
VALUE args;
args = rb_ary_new();
rb_ary_push(args, str);
rb_ary_push(args, re);

return rb_iterate(call_gsub, args, block2, str);
}

void
Init_gsub_example()
{
mCTest = rb_define_module("CTest");
rb_define_singleton_method(mCTest, "foo", foo, 2);
rb_define_singleton_method(mCTest, "foo2", foo2, 2);

rb_eval_string("class String; def _gsub!(re,block); gsub!(re,&block) end end");
}


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require "gsub_example"

a = "hello, world!"
CTest.foo(a, /[ehl]/)
p a

b = "hello, world!"
CTest.foo2(b, /[ehl]/)
p b

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[Dmitry V. Sabanin]

On Saturday 22 November 2003 21:55, Mauricio Fernández wrote:

> On Sat, Nov 22, 2003 at 10:34:27PM +0900, Dmitry V. Sabanin wrote:

> > Hi.
> > I'm converting some of my ruby code to C extension for better perfomance.
> > I ran into problems with executing methods that take blocks.
> > I.e. in ruby i have
> > string.gsub!(/regexp/) { |subst| ... }
> > and i can't find the way to translate it to C. I tried to search through
> > ruby-talk archives, but I couldn't find anything usefull.
> > As far as I was looking at problem, I found rb_iterate, rb_yield, but I
> > couldn't clearly understand what's their purpose, and how to get them all
> > together to achieve what I want.
> > Could somebody please explain me how can I implement this ruby code in C?
> > I'd really appreciate any help. Thanks in advance!

>
> I was surprised to see that rb_funcall propagates the block passed with
> rb_iterate, so there's 2 solutions (attached).

Thank you very much, that code saved me :)

--
sdmitry -=- Dmitry V. Sabanin
MuraveyLabs.