From: Elias Athanasopoulos <elathan@...>
Date: 2004-04-19T19:32:07+09:00
Subject: Re: proposal Hash eql? , ==, ===

> I agree with both Hash#== and Hash#eql?  But I'm not very positive 
 
elathan@testbed:~/hacking/ruby> cat ../test.rb 
 
h1 = Hash.new(42) 
h1["a"] = 1 
h1["b"] = 2 
 
h2 = { "a" => 1, "b" => 2 } 
 
puts h1 == h2 
puts h1.eql?(h2) 
elathan@testbed:~/hacking/ruby> ./ruby ../test.rb 
true 
false 
 
 
--- hash.c.orig 2004-04-19 12:08:24.000000000 +0300 
+++ hash.c      2004-04-19 12:21:06.000000000 +0300 
@@ -1425,6 +1425,48 @@ 
     } 
     if (RHASH(hash1)->tbl->num_entries != RHASH(hash2)->tbl->num_entries) 
        return Qfalse; 
+ 
+    data.tbl = RHASH(hash2)->tbl; 
+    data.result = Qtrue; 
+    st_foreach(RHASH(hash1)->tbl, equal_i, (st_data_t)&data); 
+ 
+    return data.result; 
+} 
+ 
+/* 
+ *  call-seq: 
+ *     hsh.eql? other_hash    => true or false 
+ * 
+ *  Strict Equality---Two hashes are strictly equal if they each contain  
+ *  the same number of keys and if each key-value pair is equal to (according to 
+ *  <code>Object#==</code>) the corresponding elements in the other 
+ *  hash. Both hashes must have equal default values/procs. 
+ *      
+ *     h1 = { "a" => 1, "c" => 2 } 
+ *     h2 = { 7 => 35, "c" => 2, "a" => 1 } 
+ *     h3 = { "a" => 1, "c" => 2, 7 => 35 } 
+ *     h4 = { "a" => 1, "d" => 2, "f" => 35 } 
+ *     h1.eql? h2   #=> false 
+ *     h2.eql? h3   #=> true 
+ *     h3.eql? h4   #=> false 
+ *      
+ */ 
+ 
+static VALUE 
+rb_hash_strict_equal(hash1, hash2) 
+    VALUE hash1, hash2; 
+{ 
+    struct equal_data data; 
+ 
+    if (hash1 == hash2) return Qtrue; 
+    if (TYPE(hash2) != T_HASH) { 
+       if (!rb_respond_to(hash2, rb_intern("to_hash"))) { 
+           return Qfalse; 
+       } 
+       return rb_equal(hash2, hash1); 
+    } 
+    if (RHASH(hash1)->tbl->num_entries != RHASH(hash2)->tbl->num_entries) 
+       return Qfalse; 
     if (!(rb_equal(RHASH(hash1)->ifnone, RHASH(hash2)->ifnone) && 
          FL_TEST(hash1, HASH_PROC_DEFAULT) == FL_TEST(hash2, 
HASH_PROC_DEFAULT))) 
        return Qfalse; 
@@ -2365,6 +2407,8 @@ 
     rb_define_method(rb_cHash,"inspect", rb_hash_inspect, 0); 
  
     rb_define_method(rb_cHash,"==", rb_hash_equal, 1); 
+    rb_define_method(rb_cHash,"eql?", rb_hash_strict_equal, 1); 
+    rb_define_method(rb_cHash,"==", rb_hash_equal, 1); 
     rb_define_method(rb_cHash,"[]", rb_hash_aref, 1); 
     rb_define_method(rb_cHash,"fetch", rb_hash_fetch, -1); 
     rb_define_method(rb_cHash,"[]=", rb_hash_aset, 2);