Contents

module Unitwise
  module Expression
    class Parser < Parslet::Parser
      attr_reader :key
      def initialize(key=:primary_code)
        @key = key
      end

      root :expression

      rule (:atom) { Matcher.atom(key).as(:atom_code) }
      rule (:metric_atom) { Matcher.metric_atom(key).as(:atom_code) }
      rule (:prefix) { Matcher.prefix(key).as(:prefix_code) }

      rule (:simpleton) do
        (prefix.as(:prefix) >> metric_atom.as(:atom) | atom.as(:atom))
      end

      rule (:annotation) do
        str('{') >> match['^}'].repeat.as(:annotation) >> str('}')
      end

      rule (:digits) { match['0-9'].repeat(1) }

      rule (:integer) { (str('-').maybe >> digits).as(:integer) }

      rule (:fixnum) do
        (str('-').maybe >> digits >> str('.') >> digits).as(:fixnum)
      end

      rule (:number) { fixnum | integer }

      rule (:exponent) { number.as(:exponent) }

      rule (:factor) { number.as(:factor) }

      rule (:operator) { (str('.') | str('/')).as(:operator) }

      rule (:term) do
        ((simpleton | factor) >> exponent.maybe >> annotation.maybe).as(:term)
      end

      rule (:group) do
        (str('(') >> expression.as(:nested) >> str(')') >> exponent.maybe).as(:group)
      end

      rule (:expression) do
        ((group | term).as(:left)).maybe >> (operator >> expression.as(:right)).maybe
      end

    end
  end
end

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
unitwise-0.3.0	lib/unitwise/expression/parser.rb
unitwise-0.2.2	lib/unitwise/expression/parser.rb