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From 6255dd5f7263624e36295d21b0180fc88c599621 Mon Sep 17 00:00:00 2001
From: Joshua Miller <josh@joshinharrisburg.com>
Date: Thu, 19 May 2011 19:13:28 -0700
Subject: [PATCH] Add #<=> and #casecmp to Symbol
---
kernel/common/symbol.rb | 19 +++++++++++++++++++
1 files changed, 19 insertions(+), 0 deletions(-)
diff --git a/kernel/common/symbol.rb b/kernel/common/symbol.rb
index 42369bd..a01d3f7 100644
--- a/kernel/common/symbol.rb
+++ b/kernel/common/symbol.rb
@@ -38,6 +38,25 @@ class Symbol
alias_method :intern, :to_sym
alias_method :id2name, :to_s
+
+ ##
+ # Comparison --- Returns -1 if <i>other</i> is less than, 0 if
+ # <i>other</i> is equal, and +1 if <i>other</i> is greater than
+ # <i>self</i>. Comparison is provided by <code>String#<=></code>.
+ def <=>(other)
+ return unless other.respond_to?(:to_sym) && other.respond_to?(:<=>)
+ self.to_s <=> other.to_sym.to_s
+ end
+
+ ##
+ # Case-insensitive version of <code>Symbol#<=></code>. Similarly
+ # relies on <code>String#casecmp</code> using string representations
+ # of <i>self</i> and <i>other</i>
+ def casecmp(other)
+ return unless other.respond_to?(:to_sym) && other.respond_to?(:<=>)
+ self.to_s.casecmp(other.to_sym.to_s)
+ end
+
# Returns a Proc object which respond to the given method by sym.
def to_proc
# Put sym in the outer enclosure so that this proc can be instance_eval'd.
--
1.7.0.4
@brixen
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brixen commented May 25, 2011

Why is there a check for '&& other.respond_to?(:<=>)' in #<=> ? self.to_s is sent #<=>

Also, why is there '&& other.respond_to?(:<=>)' in #casecmp ?

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