Class: Spectre::Operators::Union

Inherits:
Object
  • Object
show all
Includes:
Op
Defined in:
lib/spectre/base/operators.rb

Overview

Matches either the first or the second Node it receives as parameters Union.new p1, p2 is equal to p1 | p2. This operator applies the tactics of short-circuiting, i.e. if p1 matches, p2 will not be tried at all.

Instance Attribute Summary

Attributes included from Parser

#node

Instance Method Summary collapse

Methods included from Op

#pre_skip?

Methods included from Parser

#backtrack, #create_match, from_POD, #pre_skip?, #to_p

Instance Method Details

#inspect ⇒ Object 



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# File 'lib/spectre/base/operators.rb', line 122

def inspect
    '(' + @node.left.inspect + ' | ' + @node.right.inspect + ')'
end

#scan(iter) ⇒ Object 



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# File 'lib/spectre/base/operators.rb', line 87

def scan iter
    first = @node.left.parse iter

    if @node.policy[:union] == :normal
        if first
            create_match iter, first
        else
            backtrack iter
            create_match iter, @node.right.parse(iter)
        end
    else
        fiter = iter.dup
        backtrack iter
        second = @node.right.parse iter
        siter = iter.dup
        backtrack iter

        if first and second
            mm = [[first,fiter], [second,siter]].minmax_by { |x| x[0].length }
            winner = @node.policy[:union] == :longest ? mm[1] : mm[0]

            iter.to winner[1].pos
            create_match iter, winner[0]
        elsif first
            iter.to fiter.pos
            create_match iter, first
        elsif second
            iter.to siter.pos
            create_match iter, second
        else
            nil
        end
    end
end