Redefining rb_str_init()

ruby-talk
1

Hi all,

I'm just messing around with a custom String class, so I did this to
string.c:

static VALUE rb_str_init(int argc, VALUE* argv, VALUE v_str){
   VALUE v_orig;

   rb_scan_args(argc, argv, "01", &v_orig);

   if(RTEST(v_orig))
      rb_str_replace(v_str, v_orig);

   printf("Hello!\n");

   return v_str;
}

I rebuilt Ruby and installed it without issue. But, the "Hello" only
prints if you use the long form of the constructor:

s1 = String.new('test') # "Hello!"
s2 = "test" # Nothing printed

What do I need to change to make the constructor shortcut work as
expected?

Thanks,

Dan

2

Hi,

···

In message "Re: Redefining rb_str_init()" on Mon, 4 Dec 2006 08:55:08 +0900, "Daniel Berger" <djberg96@gmail.com> writes:

What do I need to change to make the constructor shortcut work as
expected?

I don't think it's a good idea to invoke function for every string
allocation. But if you really want to do, modify str_alloc() in
string.c.

In general, #initialize is not called for literals.

              matz.

3

Yukihiro Matsumoto wrote:

Hi,

>What do I need to change to make the constructor shortcut work as
>expected?

I don't think it's a good idea to invoke function for every string
allocation. But if you really want to do, modify str_alloc() in
string.c.

Well, I'm just tinkering around for now. However, I did realize something interesting. I put a printf in the str_alloc() function as you mentioned and ran an empty Ruby program. Even an empty Ruby program appears to invoke the str_alloc function 107 times!

I take it there's a bunch of setup happening within the interpreter that makes a lot of calls to str_alloc() before the interpeter ever runs? That, or I've messed something up.

In general, #initialize is not called for literals.

              matz.

Good to know, thanks,

- Dan

···

In message "Re: Redefining rb_str_init()" > on Mon, 4 Dec 2006 08:55:08 +0900, "Daniel Berger" <djberg96@gmail.com> writes:

4

Daniel Berger wrote:
...

I take it there's a bunch of setup happening within the interpreter that makes a lot of calls to str_alloc() before the interpeter ever runs? That, or I've messed something up.

Strings like this...

$ RUBYLIB='' RUBYOPT='' ruby -e 'a=;ObjectSpace.each_object(String) {|s| a<<s}; puts a'
a=;ObjectSpace.each_object(String) {|s| a<<s}; puts a
.
/usr/local/lib/ruby/1.8/i686-linux
/usr/local/lib/ruby/1.8
/usr/local/lib/ruby/site_ruby
/usr/local/lib/ruby/site_ruby/1.8/i686-linux
/usr/local/lib/ruby/site_ruby/1.8

-e
a=;ObjectSpace.each_object(String) {|s| a<<s}; puts a
ruby
i686-linux
2005-12-24
1.8.4
failed to allocate memory
stack level too deep
exception reentered
Process::Sys
.
. (snip)
.
Errno::ESRCH
Errno::ENOENT
Errno::EPERM
Errno
NameError::message
NameError

···

--
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407