Words

.rvmrc

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-rvm --create use ruby-1.9.2@rpncalc
+rvm --create use ruby-1.9.2@rpn

Readme.md

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+#Reverse Polish Notation calculator
+
+A simple implementation of a RPN (also known as _postfix_ notation) calculator.
+
+In a nutshell, this notation consists of operands followed by their operators.
+As opposed to express an operation like this...
+
+    (3 + 4) * 7 - 1
+
+...in reverse Polish notation it would look like this:
+
+    7 3 4 + * 1 -
+
+It basically works like a stack in which you push operands until you find an
+operator; given an arity _n_, you evaluate this operator with _n_ numbers from
+the stack, and substitute them for their result. Check out the [Wikipedia
+article](http://en.wikipedia.org/wiki/Reverse_Polish_notation) to learn more about this notation.
+
+##Install
+
+    gem install rpn
+
+##Usage
+
+Just require it in your Gemfile:
+
+    gem 'rpn'
+
+Note: If you are not using Bundler, you should `require 'rpn'` manually.
+
+Now you have to initialize a calculator. You can provide a custom _n_ arity 
+(the number of operands that will get evaluated by each operator). Default
+arity is 2. You can also provide the delimiter the parser will use (will be ' '
+by default).
+
+    my_rpn = RPN::Calculator.new # => will use the defaults
+    my_rpn.solve "7 3 4 + * 1 -"
+    # => 48
+
+For now, it supports the following operators:
+
+    + - * / ^
+
+##Contribute!
+
+* Fork the project.
+* Make your feature addition or bug fix.
+* Add specs for it. This is important so I don't break it in a future
+  version unintentionally.
+* Commit, do not mess with rakefile, version, or history.
+  If you want to have your own version, that is fine but bump version
+  in a commit by itself I can ignore when I pull.
+* Send me a pull request. Bonus points for topic branches.
+
+## Copyright
+
+Copyright (c) 2011 Josep M. Bach. See LICENSE for details.