franckverrot · May 26, 2016 17:19 · May 26, 2016
diff --git a/0001-parse.y-Replace-squotes-with-dquotes.patch b/0001-parse.y-Replace-squotes-with-dquotes.patch
@@ -0,0 +1,42 @@
+From 739265f2f2c54d8be56ad58d7c863193f0ce472d Mon Sep 17 00:00:00 2001
+From: Franck Verrot <franck@verrot.fr>
+Date: Thu, 26 May 2016 10:12:29 -0700
+Subject: [PATCH] * parse.y : Replace squotes with dquotes
+
+---
+ parse.y | 6 +++---
+ 1 file changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/parse.y b/parse.y
+index 005e926..1752d3b 100644
+--- a/parse.y
++++ b/parse.y
+@@ -6560,7 +6560,7 @@ parser_heredoc_identifier(struct parser_params *parser)
+     }
+     switch (c) {
+       case '\'':
+-	func |= str_squote; goto quoted;
++	func |= str_dquote; goto quoted;
+       case '"':
+ 	func |= str_dquote; goto quoted;
+       case '`':
+@@ -7739,7 +7739,7 @@ parse_percent(struct parser_params *parser, const int space_seen, const enum lex
+ 	    return tSTRING_BEG;
+
+ 	  case 'q':
+-	    lex_strterm = NEW_STRTERM(str_squote, term, paren);
++	    lex_strterm = NEW_STRTERM(str_dquote, term, paren);
+ 	    return tSTRING_BEG;
+
+ 	  case 'W':
+@@ -8411,7 +8411,7 @@ parser_yylex(struct parser_params *parser)
+
+       case '\'':
+ 	label = (IS_LABEL_POSSIBLE() ? str_label : 0);
+-	lex_strterm = NEW_STRTERM(str_squote | label, '\'', 0);
++	lex_strterm = NEW_STRTERM(str_dquote | label, '\'', 0);
+ 	return tSTRING_BEG;
+
+       case '?':
+-- 
+2.7.3
diff --git a/concatenation.rb b/concatenation.rb
@@ -0,0 +1,35 @@
+# courtesy of https://github.com/JuanitoFatas/fast-ruby/blob/master/code/string/concatenation.rb
+require 'benchmark/ips'
+
+# 2 + 1 = 3 object
+def slow_plus
+  'foo' + 'bar'
+end
+
+# 2 + 1 = 3 object
+def slow_concat
+  'foo'.concat 'bar'
+end
+
+# 2 + 1 = 3 object
+def slow_append
+  'foo' << 'bar'
+end
+
+# 1 object
+def fast
+  'foo' 'bar'
+end
+
+def fast_interpolation
+  "#{'foo'}#{'bar'}"
+end
+
+Benchmark.ips do |x|
+  x.report('String#+')                 { slow_plus }
+  x.report('String#concat')            { slow_concat }
+  x.report('String#append')            { slow_append }
+  x.report('"foo" "bar"')              { fast }
+  x.report('"#{\'foo\'}#{\'bar\'}"')   { fast_interpolation }
+  x.compare!
+end
diff --git a/with-patch.log b/with-patch.log
@@ -0,0 +1,20 @@
+λ ruby concatenation.rb
+Warming up --------------------------------------
+            String#+    58.167k i/100ms
+       String#concat    59.549k i/100ms
+       String#append    60.170k i/100ms
+         "foo" "bar"    79.179k i/100ms
+  "#{'foo'}#{'bar'}"    81.362k i/100ms
+Calculating -------------------------------------
+            String#+    999.051k (± 3.8%) i/s -      5.002M in   5.014765s
+       String#concat      1.082M (± 4.8%) i/s -      5.419M in   5.022983s
+       String#append      1.140M (± 4.3%) i/s -      5.716M in   5.022578s
+         "foo" "bar"      1.826M (± 4.8%) i/s -      9.106M in   4.999979s
+  "#{'foo'}#{'bar'}"      1.789M (± 7.7%) i/s -      8.950M in   5.038771s
+
+Comparison:
+         "foo" "bar":  1825544.4 i/s
+  "#{'foo'}#{'bar'}":  1788974.3 i/s - same-ish: difference falls within error
+       String#append:  1140399.8 i/s - 1.60x slower
+       String#concat:  1081619.8 i/s - 1.69x slower
+            String#+:   999051.2 i/s - 1.83x slower
diff --git a/without-patch.log b/without-patch.log
@@ -0,0 +1,20 @@
+~  [○] λ ruby /tmp/concatenation.rb
+Warming up --------------------------------------
+            String#+    56.174k i/100ms
+       String#concat    59.173k i/100ms
+       String#append    62.512k i/100ms
+         "foo" "bar"    81.058k i/100ms
+  "#{'foo'}#{'bar'}"    81.225k i/100ms
+Calculating -------------------------------------
+            String#+    964.524k (± 4.5%) i/s -      4.831M in   5.019469s
+       String#concat      1.060M (± 4.6%) i/s -      5.326M in   5.036661s
+       String#append      1.129M (± 4.1%) i/s -      5.689M in   5.048866s
+         "foo" "bar"      1.825M (± 4.5%) i/s -      9.160M in   5.030873s
+  "#{'foo'}#{'bar'}"      1.818M (± 4.9%) i/s -      9.097M in   5.018021s
+
+Comparison:
+         "foo" "bar":  1824600.9 i/s
+  "#{'foo'}#{'bar'}":  1817629.8 i/s - same-ish: difference falls within error
+       String#append:  1128802.6 i/s - 1.62x slower
+       String#concat:  1059964.0 i/s - 1.72x slower
+            String#+:   964524.3 i/s - 1.89x slower