1 files changed, 78 insertions, 6 deletions

diff --git a/spec/ruby/language/regexp/escapes_spec.rb b/spec/ruby/language/regexp/escapes_spec.rb
index 2e5fe5ad2e..16a4d8c23b 100644
--- a/spec/ruby/language/regexp/escapes_spec.rb
+++ b/spec/ruby/language/regexp/escapes_spec.rb
@@ -2,8 +2,10 @@
 require_relative '../../spec_helper'
 require_relative '../fixtures/classes'
 
+# TODO: synchronize with spec/core/regexp/new_spec.rb -
+#       escaping is also tested there
 describe "Regexps with escape characters" do
-  it "they're supported" do
+  it "supports escape sequences" do
     /\t/.match("\t").to_a.should == ["\t"] # horizontal tab
     /\v/.match("\v").to_a.should == ["\v"] # vertical tab
     /\n/.match("\n").to_a.should == ["\n"] # newline
@@ -15,9 +17,7 @@ describe "Regexps with escape characters" do
     # \nnn         octal char            (encoded byte value)
   end
 
-  it "support quoting meta-characters via escape sequence" do
-    /\\/.match("\\").to_a.should == ["\\"]
-    /\//.match("/").to_a.should == ["/"]
+  it "supports quoting meta-characters via escape sequence" do
     # parenthesis, etc
     /\(/.match("(").to_a.should == ["("]
     /\)/.match(")").to_a.should == [")"]
@@ -25,6 +25,8 @@ describe "Regexps with escape characters" do
     /\]/.match("]").to_a.should == ["]"]
     /\{/.match("{").to_a.should == ["{"]
     /\}/.match("}").to_a.should == ["}"]
+    /\</.match("<").to_a.should == ["<"]
+    /\>/.match(">").to_a.should == [">"]
     # alternation separator
     /\|/.match("|").to_a.should == ["|"]
     # quantifiers
@@ -37,11 +39,81 @@ describe "Regexps with escape characters" do
     /\$/.match("$").to_a.should == ["$"]
   end
 
+  it "supports quoting meta-characters via escape sequence when used as a terminator" do
+    # parenthesis, etc
+    # %r[[, %r((, etc literals - are forbidden
+    %r(\().match("(").to_a.should == ["("]
+    %r(\)).match(")").to_a.should == [")"]
+    %r)\().match("(").to_a.should == ["("]
+    %r)\)).match(")").to_a.should == [")"]
+
+    %r[\[].match("[").to_a.should == ["["]
+    %r[\]].match("]").to_a.should == ["]"]
+    %r]\[].match("[").to_a.should == ["["]
+    %r]\]].match("]").to_a.should == ["]"]
+
+    %r{\{}.match("{").to_a.should == ["{"]
+    %r{\}}.match("}").to_a.should == ["}"]
+    %r}\{}.match("{").to_a.should == ["{"]
+    %r}\}}.match("}").to_a.should == ["}"]
+
+    %r<\<>.match("<").to_a.should == ["<"]
+    %r<\>>.match(">").to_a.should == [">"]
+    %r>\<>.match("<").to_a.should == ["<"]
+    %r>\>>.match(">").to_a.should == [">"]
+
+    # alternation separator
+    %r|\||.match("|").to_a.should == ["|"]
+    # quantifiers
+    %r?\??.match("?").to_a.should == ["?"]
+    %r.\...match(".").to_a.should == ["."]
+    %r*\**.match("*").to_a.should == ["*"]
+    %r+\++.match("+").to_a.should == ["+"]
+    # line anchors
+    %r^\^^.match("^").to_a.should == ["^"]
+    %r$\$$.match("$").to_a.should == ["$"]
+  end
+
+  it "supports quoting non-meta-characters via escape sequence when used as a terminator" do
+    non_meta_character_terminators = [
+      '!', '"', '#', '%', '&', "'", ',', '-', ':', ';', '@', '_', '`', '/', '=', '~'
+    ]
+
+    non_meta_character_terminators.each do |c|
+      pattern = eval("%r" + c + "\\" + c + c)
+      pattern.match(c).to_a.should == [c]
+    end
+  end
+
+  it "does not change semantics of escaped non-meta-character when used as a terminator" do
+    all_terminators = [*("!".."/"), *(":".."@"), *("[".."`"), *("{".."~")]
+    meta_character_terminators = ["$", "^", "*", "+", ".", "?", "|", "}", ")", ">", "]"]
+    special_cases = ['(', '{', '[', '<', '\\']
+
+    # it should be equivalent to
+    #   [ '!', '"', '#', '%', '&', "'", ',', '-', ':', ';', '@', '_', '`', '/', '=', '~' ]
+    non_meta_character_terminators = all_terminators - meta_character_terminators - special_cases
+
+    non_meta_character_terminators.each do |c|
+      pattern = eval("%r" + c + "\\" + c + c)
+      pattern.should == /#{c}/
+    end
+  end
+
+  it "does not change semantics of escaped meta-character when used as a terminator" do
+    meta_character_terminators = ["$", "^", "*", "+", ".", "?", "|", "}", ")", ">", "]"]
+
+    meta_character_terminators.each do |c|
+      pattern = eval("%r" + c + "\\" + c + c)
+      pattern.should == eval("/\\#{c}/")
+    end
+  end
+
   it "allows any character to be escaped" do
     /\y/.match("y").to_a.should == ["y"]
   end
 
-  it "support \\x (hex characters)" do
+  it "supports \\x (hex characters)" do
     /\xA/.match("\nxyz").to_a.should == ["\n"]
     /\x0A/.match("\n").to_a.should == ["\n"]
     /\xAA/.match("\nA").should be_nil
@@ -53,7 +125,7 @@ describe "Regexps with escape characters" do
     # \x{7HHHHHHH} wide hexadecimal char (character code point value)
   end
 
-  it "support \\c (control characters)" do
+  it "supports \\c (control characters)" do
     #/\c \c@\c`/.match("\00\00\00").to_a.should == ["\00\00\00"]
     /\c#\cc\cC/.match("\03\03\03").to_a.should == ["\03\03\03"]
     /\c'\cG\cg/.match("\a\a\a").to_a.should == ["\a\a\a"]