diff --git a/ChangeLog b/ChangeLog
index 341570161d..a3c0530f75 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,19 @@
+Wed Oct 17 05:07:18 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* encoding.c (rb_primary_encoding): added Encoding.primary_encoding.
+
+	* parse.y (rb_parser_encoding): added.
+
+	* ruby.c (proc_options): added -E and --encoding options.
+
+	* ruby.c (process_options): set primary encoding from command line
+	  option if set, or source encoding.
+
+	* include/ruby/encoding.h (rb_enc_from_encoding,
+	  rb_get_primary_encoding, rb_set_primary_encoding): prototypes.
+
+	* include/ruby/node.h (rb_parser_encoding): prototype.
+
 Wed Oct 17 03:37:07 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* re.c (rb_reg_desc): set encoding.
diff --git a/encoding.c b/encoding.c
index 93c3eca48c..ff62a3f083 100644
--- a/encoding.c
+++ b/encoding.c
@@ -43,8 +43,8 @@ enc_new(rb_encoding *encoding)
     return enc;
 }
 
-static VALUE
-enc_from_encoding(rb_encoding *enc)
+VALUE
+rb_enc_from_encoding(rb_encoding *enc)
 {
     return enc_initialized_p(enc) ? ENC_FROM_ENCODING(enc) : enc_new(enc);
 }
@@ -384,7 +384,7 @@ rb_obj_encoding(VALUE obj)
     if (!enc) {
 	rb_raise(rb_eTypeError, "unknown encoding");
     }
-    return enc_from_encoding(enc);
+    return rb_enc_from_encoding(enc);
 }
 
 
@@ -482,7 +482,7 @@ enc_list(VALUE klass)
     for (i = 0; i < enc_table_size; ++i) {
 	rb_encoding *enc = enc_table[i].enc;
 	if (enc) {
-	    rb_ary_push(ary, enc_from_encoding(enc));
+	    rb_ary_push(ary, rb_enc_from_encoding(enc));
 	}
     }
     return ary;
@@ -495,7 +495,7 @@ enc_find(VALUE klass, VALUE enc)
     if (idx < 0) {
 	rb_raise(rb_eArgError, "unknown encoding name - %s", RSTRING_PTR(enc));
     }
-    return enc_from_encoding(rb_enc_from_index(idx));
+    return rb_enc_from_encoding(rb_enc_from_index(idx));
 }
 
 /* :nodoc: */
@@ -513,6 +513,34 @@ enc_load(VALUE klass, VALUE str)
     return enc_find(klass, str);
 }
 
+static VALUE rb_primary_encoding;
+
+VALUE
+rb_get_primary_encoding(void)
+{
+    return rb_primary_encoding;
+}
+
+static VALUE
+get_primary_encoding(VALUE klass)
+{
+    return rb_get_primary_encoding();
+}
+
+void
+rb_set_primary_encoding(VALUE encoding)
+{
+    rb_to_encoding(encoding);
+    rb_primary_encoding = encoding;
+}
+
+static VALUE
+set_primary_encoding(VALUE klass, VALUE enc)
+{
+    rb_set_primary_encoding(enc);
+    return rb_primary_encoding;
+}
+
 void
 Init_Encoding(void)
 {
@@ -526,4 +554,8 @@ Init_Encoding(void)
 
     rb_define_method(rb_cEncoding, "_dump", enc_dump, -1);
     rb_define_singleton_method(rb_cEncoding, "_load", enc_load, 1);
+
+    rb_primary_encoding = rb_enc_from_encoding(rb_enc_from_index(0));
+    rb_define_singleton_method(rb_cEncoding, "primary_encoding", get_primary_encoding, 0);
+    rb_define_singleton_method(rb_cEncoding, "primary_encoding=", set_primary_encoding, 1);
 }
diff --git a/include/ruby/encoding.h b/include/ruby/encoding.h
index 6645a1e29d..08371cc141 100644
--- a/include/ruby/encoding.h
+++ b/include/ruby/encoding.h
@@ -99,5 +99,8 @@ int rb_enc_tolower(int c, rb_encoding *enc);
 ID rb_intern3(const char*, long, rb_encoding*);
 int rb_enc_symname_p(const char*, rb_encoding*);
 int rb_enc_str_coderange(VALUE);
+VALUE rb_enc_from_encoding(rb_encoding *enc);
+VALUE rb_get_primary_encoding(void);
+void rb_set_primary_encoding(VALUE encoding);
 
 #endif /* RUBY_ENCODING_H */
diff --git a/include/ruby/node.h b/include/ruby/node.h
index 51268061e0..eeea3cea99 100644
--- a/include/ruby/node.h
+++ b/include/ruby/node.h
@@ -481,6 +481,7 @@ typedef struct RNode {
 
 VALUE rb_parser_new(void);
 VALUE rb_parser_end_seen_p(VALUE);
+VALUE rb_parser_encoding(VALUE);
 
 NODE *rb_parser_compile_cstr(volatile VALUE, const char*, const char*, int, int);
 NODE *rb_parser_compile_string(volatile VALUE, const char*, VALUE, int);
diff --git a/parse.y b/parse.y
index 2708415446..a6e8637f8e 100644
--- a/parse.y
+++ b/parse.y
@@ -8895,6 +8895,21 @@ rb_parser_end_seen_p(VALUE vparser)
     return ruby__end__seen ? Qtrue : Qfalse;
 }
 
+/*
+ *  call-seq:
+ *    ripper#encoding   -> encoding
+ *
+ *  Return encoding of the source.
+ */
+VALUE
+rb_parser_encoding(VALUE vparser)
+{
+    struct parser_params *parser;
+
+    Data_Get_Struct(vparser, struct parser_params, parser);
+    return rb_enc_from_encoding(parser->enc);
+}
+
 #ifdef YYMALLOC
 #define HEAPCNT(n, size) ((n) * (size) / sizeof(YYSTYPE))
 #define NEWHEAP() rb_node_newnode(NODE_ALLOCA, 0, (VALUE)parser->heap, 0)
@@ -9415,6 +9430,7 @@ Init_ripper(void)
     rb_define_method(Ripper, "column", ripper_column, 0);
     rb_define_method(Ripper, "lineno", ripper_lineno, 0);
     rb_define_method(Ripper, "end_seen?", rb_parser_end_seen_p, 0);
+    rb_define_method(Ripper, "encoding", rb_parser_encoding, 0);
 #ifdef RIPPER_DEBUG
     rb_define_method(rb_mKernel, "assert_Qundef", ripper_assert_Qundef, 2);
     rb_define_method(rb_mKernel, "rawVALUE", ripper_value, 1);
diff --git a/ruby.c b/ruby.c
index a5f20adf6e..653944b61d 100644
--- a/ruby.c
+++ b/ruby.c
@@ -687,10 +687,15 @@ proc_options(int argc, char **argv, struct cmdline_options *opt)
 	    }
 	    break;
 
+	  case 'E':
+	    if (!*++s) {
+		rb_raise(rb_eRuntimeError, "missing argument for -E");
+	    }
+	    goto encoding;
+
 	  case 'K':
 	    if (*++s) {
 		rb_encoding *enc = 0;
-		if ((opt->enc_index = rb_enc_find_index(s)) >= 0) break;
 		switch (*s) {
 		  case 'E': case 'e':
 		    enc = ONIG_ENCODING_EUC_JP;
@@ -705,10 +710,9 @@ proc_options(int argc, char **argv, struct cmdline_options *opt)
 		    enc = ONIG_ENCODING_ASCII;
 		    break;
 		}
-		if (!enc) {
-		    rb_raise(rb_eRuntimeError, "unknown encoding name - %s", s);
+		if (enc) {
+		    opt->enc_index = rb_enc_find_index(rb_enc_name(enc));
 		}
-		opt->enc_index = rb_enc_find_index(rb_enc_name(enc));
 		s++;
 	    }
 	    goto reswitch;
@@ -770,6 +774,20 @@ proc_options(int argc, char **argv, struct cmdline_options *opt)
 		ruby_debug = Qtrue;
                 ruby_verbose = Qtrue;
             }
+	    else if (strcmp("encoding", s) == 0) {
+		if (!--argc || !(s = *++argv)) {
+		  noencoding:
+		    rb_raise(rb_eRuntimeError, "missing argument for --encoding");
+		}
+	      encoding:
+		if ((opt->enc_index = rb_enc_find_index(s)) < 0) {
+		    rb_raise(rb_eRuntimeError, "unknown encoding name - %s", s);
+		}
+	    }
+	    else if (strncmp("encoding=", s, 9) == 0) {
+		if (*(s += 9)) goto noencoding;
+		goto encoding;
+	    }
 	    else if (strcmp("version", s) == 0)
 		opt->version = 1;
 	    else if (strcmp("verbose", s) == 0) {
@@ -824,6 +842,7 @@ process_options(VALUE arg)
     char **argv = opt->argv;
     NODE *tree = 0;
     VALUE parser;
+    VALUE encoding;
     const char *s;
     int i = proc_options(argc, argv, opt);
 
@@ -920,7 +939,8 @@ process_options(VALUE arg)
     ruby_init_loadpath();
     parser = rb_parser_new();
     if (opt->e_script) {
-	rb_enc_associate_index(opt->e_script, opt->enc_index);
+	if (opt->enc_index >= 0)
+	    rb_enc_associate_index(opt->e_script, opt->enc_index);
 	require_libraries();
 	tree = rb_parser_compile_string(parser, opt->script, opt->e_script, 1);
     }
@@ -950,6 +970,14 @@ process_options(VALUE arg)
 	}
     }
 
+    if (opt->enc_index >= 0) {
+	encoding = rb_enc_from_encoding(rb_enc_from_index(opt->enc_index));
+    }
+    else {
+	encoding = rb_parser_encoding(parser);
+    }
+    rb_set_primary_encoding(encoding);
+
     return (VALUE)tree;
 }
 
@@ -1068,7 +1096,7 @@ load_file(VALUE parser, const char *fname, int script, struct cmdline_options *o
 	}
 	require_libraries();	/* Why here? unnatural */
     }
-    rb_enc_associate_index(f, opt->enc_index);
+    if (opt->enc_index >= 0) rb_enc_associate_index(f, opt->enc_index);
     parser = rb_parser_new();
     tree = (NODE *)rb_parser_compile_file(parser, fname, f, line_start);
     if (script && rb_parser_end_seen_p(parser)) {
@@ -1312,6 +1340,7 @@ ruby_process_options(int argc, char **argv)
     rb_argv0 = rb_progname;
     opt.argc = argc;
     opt.argv = argv;
+    opt.enc_index = -1;
     tree = (NODE *)rb_vm_call_cfunc(rb_vm_top_self(),
 				    process_options, (VALUE)&opt,
 				    0, rb_progname);