Methods
public class
public instance
Attributes
| extension | [R] | The module this rule uses to extend new matches. |
| grammar | [RW] | The grammar this rule belongs to, if any. |
| label | [R] | A label for this rule. If a rule has a label, all matches that it creates will be accessible as named captures from the scope of their parent match using that label. |
| name | [R] | The name of this rule. |
Public class methods
Returns a new Rule object depending on the type of object given.
# File lib/citrus.rb, line 589 589: def self.for(obj) 590: case obj 591: when Rule then obj 592: when Symbol then Alias.new(obj) 593: when String then StringTerminal.new(obj) 594: when Regexp then Terminal.new(obj) 595: when Array then Sequence.new(obj) 596: when Range then Choice.new(obj.to_a) 597: when Numeric then StringTerminal.new(obj.to_s) 598: else 599: raise ArgumentError, "Invalid rule object: #{obj.inspect}" 600: end 601: end
Public instance methods
# File lib/citrus.rb, line 732 732: def ==(other) 733: case other 734: when Rule 735: to_s == other.to_s 736: else 737: super 738: end 739: end
Tests the given obj for case equality with this rule.
# File lib/citrus.rb, line 685 685: def ===(obj) 686: !test(obj).nil? 687: end
Returns true if this rule should extend a match but should not appear in its event stream.
# File lib/citrus.rb, line 696 696: def elide? 697: false 698: end
Specifies a module that will be used to extend all Match objects that result from this rule. If mod is a Proc, it is used to create an anonymous module with a value method.
# File lib/citrus.rb, line 627 627: def extension=(mod) 628: if Proc === mod 629: mod = Module.new { define_method(:value, &mod) } 630: end 631: 632: raise ArgumentError, "Extension must be a Module" unless Module === mod 633: 634: @extension = mod 635: end
Sets the label of this rule.
# File lib/citrus.rb, line 615 615: def label=(label) 616: @label = label.to_sym 617: end
Sets the name of this rule.
# File lib/citrus.rb, line 607 607: def name=(name) 608: @name = name.to_sym 609: end
Attempts to parse the given string and return a Match if any can be made. options may contain any of the following keys:
| consume: | If this is true a ParseError will be raised unless the entire input string is consumed. Defaults to true. |
| memoize: | If this is true the matches generated during a parse are memoized. See MemoizedInput for more information. Defaults to false. |
| offset: | The offset in string at which to start parsing. Defaults to 0. |
# File lib/citrus.rb, line 658 658: def parse(source, options={}) 659: opts = default_options.merge(options) 660: 661: input = (opts[:memoize] ? MemoizedInput : Input).new(source) 662: string = input.string 663: input.pos = opts[:offset] if opts[:offset] > 0 664: 665: events = input.exec(self) 666: length = events[-1] 667: 668: if !length || (opts[:consume] && length < (string.length - opts[:offset])) 669: raise ParseError, input 670: end 671: 672: Match.new(input, events, opts[:offset]) 673: end
Returns true if this rule is a Terminal.
# File lib/citrus.rb, line 690 690: def terminal? 691: false 692: end
Tests whether or not this rule matches on the given string. Returns the length of the match if any can be made, nil otherwise. Accepts the same options as parse.
# File lib/citrus.rb, line 678 678: def test(string, options={}) 679: parse(string, options).length 680: rescue ParseError 681: nil 682: end
Returns the Citrus notation of this rule as a string.
# File lib/citrus.rb, line 707 707: def to_s 708: if label 709: "#{label}:" + (needs_paren? ? "(#{to_citrus})" : to_citrus) 710: else 711: to_citrus 712: end 713: end