re = /^((-?\d+(?:\.\d+)?)(?:[*+\/^eE-]| (?:to the power of|plus|add|minus|subtract|divided?|times|multipl(?:y|ied))(?: by)?)(?: )?)(?1)*(?2)$/m
str = '2*2
2+2
2/2
2-2
2^2-2
2^2
2e10^4
2^2^2^2+4
2+2+2+2
2 times 2
2 multiplied by 2
2 multiply 2
2 divide 2
2 divided by 2
2 add 2
2 plus 2
2 minus 2
2 subtract 2
2 to the power of 2 divided by 10
2 multiplied by 10 times 3
2.09187 times 9
-3 times 9
2+-6
2 multiplied by'
# Print the match result
str.scan(re) do |match|
puts match.to_s
end
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Ruby, please visit: http://ruby-doc.org/core-2.2.0/Regexp.html