From: Rolando Abarca <funkaster@...>
Date: 2008-12-19T04:34:22+09:00
Subject: [ruby-core:20665] best way to handle $: when embedding ruby

Hi all,
I'm trying to embed ruby in an iPhone App, and so, I have to follow  
apple rules: I can't just install it in /usr, it has to live inside my  
app bundle (the app home). I have successfully included ruby, libruby- 
static.a and a simple script works just fine.
I'm concerned on how the $: global variable will be filled though,  
because AFAIK it is created with compile-time static strings that will  
not reflect the real directories in my app. So far, this is what I'm  
doing:

void init_ruby_stuff() {
	ruby_init();

	NSString *rubydir = [[NSBundle mainBundle] pathForResource:@"lib"  
ofType:nil inDirectory:@"ruby"];
	// clean $:
	VALUE libdirs = rb_gv_get("$:");
	rb_funcall(libdirs, rb_intern("clear"), 0);
	// set $: to the lib structure inside $APP/ruby
	rb_funcall(libdirs, rb_intern("push"), 1, rb_str_new2([[NSString  
stringWithFormat:@"%@/ruby/1.8", rubydir]  
cStringUsingEncoding:NSUTF8StringEncoding]));
	rb_funcall(libdirs, rb_intern("push"), 1, rb_str_new2([[NSString  
stringWithFormat:@"%@/ruby/site_ruby/1.8/arm-darwin9", rubydir]  
cStringUsingEncoding:NSUTF8StringEncoding]));
	rb_funcall(libdirs, rb_intern("push"), 1, rb_str_new2([[NSString  
stringWithFormat:@"%@/ruby/vendor_ruby/1.8/arm-darwin9", rubydir]  
cStringUsingEncoding:NSUTF8StringEncoding]));
	
	ruby_init_loadpath();
	ruby_script("embedded");
}

Basically: clearing the content of $: and then pushing some  
directories, so far so good, but I'm not feeling ok modifying the  
content of $: in this way... How should I recreate the directory  
structure? I can't just set it to a fix location, since the  
application base directory is placed in a sandbox (when developing),  
with a different prefix each time.
NOTE: the ruby directory is a stripped down version of what lies after  
a make install. The prefix (when configuring) was set to a "ruby"  
directory inside my app project, that's the reason of the line in the  
code above to look for the directory "lib" inside "ruby".

-- 
Rolando Abarca M.