post_in_fix

PostInFix

Parse an expression in infix format using the Infix class, and obtain a stack based notation from it (RPN). The stack output can also be converted into a Postfix object, for further translation into other forms.

The only use so far for this has been to convert infix notated Solr boost expressions into a form Solr can understand. Therefor to_solr() is the only output of the Postfix class.

Installation

Add this line to your application's Gemfile:

gem 'post_in_fix'

And then execute:

$ bundle

Or install it yourself as:

$ gem install post_in_fix

Usage

Stack from a simple expression:

infix = PostInFix::Infix.new("1+2")
infix.to_stack  # => [1, 2, OP<+>]

OP<+> here is an object of the class PostInFix::Operator

Stack from a slightly more complex expression:

infix = PostInFix::Infix.new("(33.73+9.2)*7")
infix.to_stack  # => [33.73, 9.2, OP<+>, 7, OP<*>]

Stack from an expression where variables (non-values) are included:

infix = PostInFix::Infix.new("foo/(3.2*(bar-baz))")
infix.to_stack  # => ["foo", 3.2, "bar", "baz", OP<->, OP<*>, OP</>]

Output a Solr compatible expression from that last expression:

infix = PostInFix::Infix.new("foo/(3.2*(bar-baz))")
infix.to_postfix.to_solr  # => "div(foo,product(3.2,sub(bar,baz)))"

Contributing

• Fork it ( https://github.com/stefanberndtsson/post_in_fix/fork )
• Create your feature branch (git checkout -b my-new-feature)
• Commit your changes (git commit -am 'Add some feature')
• Push to the branch (git push origin my-new-feature)
• Create a new Pull Request