Class: LookAroundPattern

Inherits:
PatternBase show all
Defined in:
lib/ruby_grammar_builder/pattern_extensions/lookaround_pattern.rb

Overview

Implements lookarounds for some pattern p this is equivalent to one of /(?=p)/, /(?!p)/, /(?<p)/, /(?<!p)/ depending on the type

Instance Attribute Summary

Attributes inherited from PatternBase

#arguments, #match, #next_pattern, #original_arguments

Instance Method Summary collapse

Methods inherited from PatternBase

#==, #__deep_clone__, #__deep_clone_self__, #collect_group_attributes, #convert_group_attributes_to_captures, #convert_includes_to_patterns, #do_collect_self_groups, #each, #eql?, #evaluate, #evaluate_operator, #fixup_regex_references, #groupless, #groupless?, #hash, #initialize, #insert, #insert!, #inspect, #lookAheadFor, #lookAheadToAvoid, #lookAround, #lookBehindFor, #lookBehindToAvoid, #map, #map!, #map_includes!, #matchResultOf, #maybe, #name, #needs_to_capture?, #oneOf, #oneOrMoreOf, #optimize_outer_group?, #or, #placeholder, #raise_if_regex_has_capture_group, #reTag, #recursivelyMatch, #resolve, #run_self_tests, #run_tests, #self_scramble_references, #start_pattern, #then, #to_r, #to_s, #to_tag, #transform_includes, #transform_tag_as, #zeroOrMoreOf

Constructor Details

This class inherits a constructor from PatternBase

Instance Method Details

#do_add_attributes(indent) ⇒ String

return a string of any additional attributes that need to be added to the #to_s output indent is a string with the amount of space the parent block is indented, attributes are indented 2 more spaces called by #to_s

Parameters:

  • indent (String) —

    the spaces to indent with

Returns:

  • (String) —

    the attributes to add



34
35
36
 
# File 'lib/ruby_grammar_builder/pattern_extensions/lookaround_pattern.rb', line 34

def do_add_attributes(indent)
    ",\n#{indent}  type: :#{@arguments[:type]}"
end

#do_evaluate_self(groups) ⇒ String

Note:

optionally override when inheriting

Note:

by default this optionally adds a capture group

evaluates @match

Parameters:

  • groups (Hash) —

    group attributes

Returns:

  • (String) —

    the result of evaluating @match



10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
 
# File 'lib/ruby_grammar_builder/pattern_extensions/lookaround_pattern.rb', line 10

def do_evaluate_self(groups)
    self_regex = @match
    self_regex = @match.evaluate(groups) if @match.is_a? PatternBase

    case @arguments[:type]
    when :lookAheadFor      then self_regex = "(?=#{self_regex})"
    when :lookAheadToAvoid  then self_regex = "(?!#{self_regex})"
    when :lookBehindFor     then self_regex = "(?<=#{self_regex})"
    when :lookBehindToAvoid then self_regex = "(?<!#{self_regex})"
    end

    if needs_to_capture?
        raise "You cannot capture a lookAround\nconsider capturing the pattern inside"
    end

    self_regex
end

#do_get_to_s_name(top_level) ⇒ String

What is the name of the method that the user would call top_level is if a freestanding or chaining function is called called by #to_s

Parameters:

  • top_level (Boolean) —

    is this top_level or chained

Returns:

  • (String) —

    the name of the method



29
30
31
 
# File 'lib/ruby_grammar_builder/pattern_extensions/lookaround_pattern.rb', line 29

def do_get_to_s_name(top_level)
    top_level ? "lookAround(" : ".lookAround("
end

#single_entity? ⇒ true

Returns:

  • (true) 


40
41
42
 
# File 'lib/ruby_grammar_builder/pattern_extensions/lookaround_pattern.rb', line 40

def single_entity?
    true
end