From: nobu.nokada@...
Date: 2003-01-26T21:57:18+09:00
Subject: Re: datafiles as Ruby source musings

Hi,

At Sun, 26 Jan 2003 06:18:09 +0900,
Wilbert Berendsen wrote:
> module Data
> 	load "datafile"
> end

Kernel#load code in the file into toplevel context if (omitted)
second argument is false, or an anonymous module.

If it were return that anonymous module, you can write as:

  module Data
    include load("datafile", true)
  end

or even

  Data = load("datafile", true)

> 2.
> 
> Other files which my app will need, must contain Makefile-like structures.
> I would rather just "load" the file, and having the Ruby interpreter take care 
> of the parsing (example:)
> 
> ALSA && (
> 	depend "audio/alsa-driver" { |p| p.version >= 0.9 }
> 	configure << "--enable-alsa"
> )
> 
> where 'depend' and 'configure' are just methods in the current instance, and 
> 'ALSA' a constant defined in a module that got included. But again using 
> 'obj.instance_eval File.new("file").read' is the only thing I can think of.

To do it, Kernel#load would need to accept a Module as second
argument, like as:

  load("depend", Data)


Although I don't guess this modification rarely breaks existing
code, but not sure it's a good thing.


Index: eval.c
===================================================================
RCS file: /cvs/ruby/src/ruby/eval.c,v
retrieving revision 1.389
diff -u -2 -p -r1.389 eval.c
--- eval.c	23 Jan 2003 08:27:05 -0000	1.389
+++ eval.c	26 Jan 2003 12:44:42 -0000
@@ -5398,8 +5398,7 @@ rb_mod_module_eval(argc, argv, mod)
 VALUE rb_load_path;
 
-void
+VALUE
 rb_load(fname, wrap)
-    VALUE fname;
-    int wrap;
+    VALUE fname, wrap;
 {
     VALUE tmp;
@@ -5411,5 +5410,5 @@ rb_load(fname, wrap)
     TMP_PROTECT;
 
-    if (wrap && ruby_safe_level >= 4) {
+    if (RTEST(wrap) && ruby_safe_level >= 4) {
 	StringValue(fname);
     }
@@ -5428,5 +5427,6 @@ rb_load(fname, wrap)
     wrapper = ruby_wrapper;
     ruby_cref = top_cref;
-    if (!wrap) {
+    if (!RTEST(wrap)) {
+	wrap = Qnil;
 	rb_secure(4);		/* should alter global state */
 	ruby_class = rb_cObject;
@@ -5434,6 +5434,9 @@ rb_load(fname, wrap)
     }
     else {
-	/* load in anonymous module as toplevel */
-	ruby_class = ruby_wrapper = rb_module_new();
+	if (TYPE(wrap) != T_MODULE) {
+	    /* load in anonymous module as toplevel */
+	    wrap = rb_module_new();
+	}
+	ruby_class = ruby_wrapper = wrap;
 	self = rb_obj_clone(ruby_top_self);
 	rb_extend_object(self, ruby_class);
@@ -5485,10 +5488,11 @@ rb_load(fname, wrap)
     if (!NIL_P(ruby_errinfo))	/* exception during load */
 	rb_exc_raise(ruby_errinfo);
+    return wrap;
 }
 
-void
+VALUE
 rb_load_protect(fname, wrap, state)
     VALUE fname;
-    int wrap;
+    VALUE wrap;
     int *state;
 {
@@ -5497,8 +5501,9 @@ rb_load_protect(fname, wrap, state)
     PUSH_TAG(PROT_NONE);
     if ((status = EXEC_TAG()) == 0) {
-	rb_load(fname, wrap);
+	wrap = rb_load(fname, wrap);
     }
     POP_TAG();
     if (state) *state = status;
+    return wrap;
 }
 
@@ -5511,6 +5516,5 @@ rb_f_load(argc, argv)
 
     rb_scan_args(argc, argv, "11", &fname, &wrap);
-    rb_load(fname, RTEST(wrap));
-    return Qtrue;
+    return rb_load(fname, wrap);
 }
 
Index: intern.h
===================================================================
RCS file: /cvs/ruby/src/ruby/intern.h,v
retrieving revision 1.109
diff -u -2 -p -r1.109 intern.h
--- intern.h	16 Jan 2003 07:34:01 -0000	1.109
+++ intern.h	26 Jan 2003 12:39:37 -0000
@@ -168,6 +168,6 @@ ID rb_frame_last_func _((void));
 VALUE rb_obj_instance_eval _((int, VALUE*, VALUE));
 VALUE rb_mod_module_eval _((int, VALUE*, VALUE));
-void rb_load _((VALUE, int));
-void rb_load_protect _((VALUE, int, int*));
+VALUE rb_load _((VALUE, VALUE));
+VALUE rb_load_protect _((VALUE, VALUE, int*));
 NORETURN(void rb_jump_tag _((int)));
 int rb_provided _((const char*));


-- 
Nobu Nakada