Calculus is utility library which allow to parse some subset of latex equations and store them in postfix notation It also allows translate it to abstract syntax tree and calculate (implemented for simple expressions).
gem install calculus
001:0> require 'calculus'
true
002:0> exp = Calculus::Expression.new("2 + 3 * x")
#<Expression:f46e77a9377ed2d5a9da768496a7e1c20be51bfe postfix_notation=[2, 3, "x", :mul, :plus] variables={"x"=>nil}>
003:0> exp.postfix_notation
[2, 3, "x", :mul, :plus]
004:0> exp.abstract_syntax_tree
[:plus, 2, [:mul, 3, "x"]]
005:0> exp.variables
["x"]
006:0> exp.unbound_variables
["x"]
007:0> exp["x"] = 5
5
008:0> exp.unbound_variables
[]
009:0> exp.calculate
17
You can also render expression to PNG image if you have latex and dvipng installed.
010:0> Calculus::Expression.new("2 + 3 \\cdot x").to_png
"/tmp/d20110512-16457-dhxt71/f46e77a9377ed2d5a9da768496a7e1c20be51bfe.png"
Also you can skip parser if you need only png generation
011:0> Calculus::Expression.new("\\hat{f}(\\xi) = \\int_{-\\infty}^{\\infty} f(x)\\ e^{- 2\\pi i x \\xi}\\,dx", :parse => false).to_png
Don’t forget to cleanup file after using.
Just fork and pull request.
You can download this project in either zip or tar formats.
You can also clone the project with Git by running:
$ git clone git://github.com/avsej/calculus