require 'regexp_parser/expression'
class Regexp::Parser
include Regexp::Expression
include Regexp::Syntax
class ParserError < StandardError; end
class UnknownTokenTypeError < ParserError
def initialize(type, token)
super "Unknown token type #{type} #{token.inspect}"
end
end
class UnknownTokenError < ParserError
def initialize(type, token)
super "Unknown #{type} token #{token.token}"
end
end
def self.parse(input, syntax = "ruby/#{RUBY_VERSION}", options: nil, &block)
new.parse(input, syntax, options: options, &block)
end
def parse(input, syntax = "ruby/#{RUBY_VERSION}", options: nil, &block)
root = Root.build(extract_options(input, options))
self.root = root
self.node = root
self.nesting = [root]
self.options_stack = [root.options]
self.switching_options = false
self.conditional_nesting = []
self.captured_group_counts = Hash.new(0)
Regexp::Lexer.scan(input, syntax, options: options) do |token|
parse_token(token)
end
assign_referenced_expressions
if block_given?
block.call(root)
else
root
end
end
private
attr_accessor :root, :node, :nesting,
:options_stack, :switching_options, :conditional_nesting,
:captured_group_counts
def extract_options(input, options)
if options && !input.is_a?(String)
raise ArgumentError, 'options cannot be supplied unless parsing a String'
end
options = input.options if input.is_a?(::Regexp)
return {} unless options
enabled_options = {}
enabled_options[:i] = true if options & ::Regexp::IGNORECASE != 0
enabled_options[:m] = true if options & ::Regexp::MULTILINE != 0
enabled_options[:x] = true if options & ::Regexp::EXTENDED != 0
enabled_options
end
def nest(exp)
nesting.push(exp)
node << exp
update_transplanted_subtree(exp, node)
self.node = exp
end
# subtrees are transplanted to build Alternations, Intersections, Ranges
def update_transplanted_subtree(exp, new_parent)
exp.nesting_level = new_parent.nesting_level + 1
exp.respond_to?(:each) &&
exp.each { |subexp| update_transplanted_subtree(subexp, exp) }
end
def decrease_nesting
while nesting.last.is_a?(SequenceOperation)
nesting.pop
self.node = nesting.last
end
nesting.pop
yield(node) if block_given?
self.node = nesting.last
self.node = node.last if node.last.is_a?(SequenceOperation)
end
def nest_conditional(exp)
conditional_nesting.push(exp)
nest(exp)
end
def parse_token(token)
close_completed_character_set_range
case token.type
when :meta; meta(token)
when :quantifier; quantifier(token)
when :anchor; anchor(token)
when :escape; escape(token)
when :group; group(token)
when :assertion; group(token)
when :set; set(token)
when :type; type(token)
when :backref; backref(token)
when :conditional; conditional(token)
when :keep; keep(token)
when :posixclass, :nonposixclass
posixclass(token)
when :property, :nonproperty
property(token)
when :literal
node << Literal.new(token, active_opts)
when :free_space
free_space(token)
else
raise UnknownTokenTypeError.new(token.type, token)
end
end
def set(token)
case token.token
when :open
open_set(token)
when :close
close_set
when :negate
negate_set
when :range
range(token)
when :intersection
intersection(token)
when :collation, :equivalent
node << Literal.new(token, active_opts)
else
raise UnknownTokenError.new('CharacterSet', token)
end
end
def meta(token)
case token.token
when :dot
node << CharacterType::Any.new(token, active_opts)
when :alternation
sequence_operation(Alternation, token)
else
raise UnknownTokenError.new('Meta', token)
end
end
def backref(token)
case token.token
when :name_ref
node << Backreference::Name.new(token, active_opts)
when :name_recursion_ref
node << Backreference::NameRecursionLevel.new(token, active_opts)
when :name_call
node << Backreference::NameCall.new(token, active_opts)
when :number, :number_ref
node << Backreference::Number.new(token, active_opts)
when :number_recursion_ref
node << Backreference::NumberRecursionLevel.new(token, active_opts)
when :number_call
node << Backreference::NumberCall.new(token, active_opts)
when :number_rel_ref
node << Backreference::NumberRelative.new(token, active_opts).tap do |exp|
assign_effective_number(exp)
end
when :number_rel_call
node << Backreference::NumberCallRelative.new(token, active_opts).tap do |exp|
assign_effective_number(exp)
end
else
raise UnknownTokenError.new('Backreference', token)
end
end
def type(token)
case token.token
when :digit
node << CharacterType::Digit.new(token, active_opts)
when :nondigit
node << CharacterType::NonDigit.new(token, active_opts)
when :hex
node << CharacterType::Hex.new(token, active_opts)
when :nonhex
node << CharacterType::NonHex.new(token, active_opts)
when :space
node << CharacterType::Space.new(token, active_opts)
when :nonspace
node << CharacterType::NonSpace.new(token, active_opts)
when :word
node << CharacterType::Word.new(token, active_opts)
when :nonword
node << CharacterType::NonWord.new(token, active_opts)
when :linebreak
node << CharacterType::Linebreak.new(token, active_opts)
when :xgrapheme
node << CharacterType::ExtendedGrapheme.new(token, active_opts)
else
raise UnknownTokenError.new('CharacterType', token)
end
end
def conditional(token)
case token.token
when :open
nest_conditional(Conditional::Expression.new(token, active_opts))
when :condition
conditional_nesting.last.condition = Conditional::Condition.new(token, active_opts)
conditional_nesting.last.add_sequence(active_opts)
when :separator
conditional_nesting.last.add_sequence(active_opts)
self.node = conditional_nesting.last.branches.last
when :close
conditional_nesting.pop
decrease_nesting
self.node =
if conditional_nesting.empty?
nesting.last
else
conditional_nesting.last
end
else
raise UnknownTokenError.new('Conditional', token)
end
end
def posixclass(token)
node << PosixClass.new(token, active_opts)
end
include Regexp::Expression::UnicodeProperty
def property(token)
case token.token
when :alnum; node << Alnum.new(token, active_opts)
when :alpha; node << Alpha.new(token, active_opts)
when :ascii; node << Ascii.new(token, active_opts)
when :blank; node << Blank.new(token, active_opts)
when :cntrl; node << Cntrl.new(token, active_opts)
when :digit; node << Digit.new(token, active_opts)
when :graph; node << Graph.new(token, active_opts)
when :lower; node << Lower.new(token, active_opts)
when :print; node << Print.new(token, active_opts)
when :punct; node << Punct.new(token, active_opts)
when :space; node << Space.new(token, active_opts)
when :upper; node << Upper.new(token, active_opts)
when :word; node << Word.new(token, active_opts)
when :xdigit; node << Xdigit.new(token, active_opts)
when :xposixpunct; node << XPosixPunct.new(token, active_opts)
# only in Oniguruma (old rubies)
when :newline; node << Newline.new(token, active_opts)
when :any; node << Any.new(token, active_opts)
when :assigned; node << Assigned.new(token, active_opts)
when :letter; node << Letter::Any.new(token, active_opts)
when :cased_letter; node << Letter::Cased.new(token, active_opts)
when :uppercase_letter; node << Letter::Uppercase.new(token, active_opts)
when :lowercase_letter; node << Letter::Lowercase.new(token, active_opts)
when :titlecase_letter; node << Letter::Titlecase.new(token, active_opts)
when :modifier_letter; node << Letter::Modifier.new(token, active_opts)
when :other_letter; node << Letter::Other.new(token, active_opts)
when :mark; node << Mark::Any.new(token, active_opts)
when :combining_mark; node << Mark::Combining.new(token, active_opts)
when :nonspacing_mark; node << Mark::Nonspacing.new(token, active_opts)
when :spacing_mark; node << Mark::Spacing.new(token, active_opts)
when :enclosing_mark; node << Mark::Enclosing.new(token, active_opts)
when :number; node << Number::Any.new(token, active_opts)
when :decimal_number; node << Number::Decimal.new(token, active_opts)
when :letter_number; node << Number::Letter.new(token, active_opts)
when :other_number; node << Number::Other.new(token, active_opts)
when :punctuation; node << Punctuation::Any.new(token, active_opts)
when :connector_punctuation; node << Punctuation::Connector.new(token, active_opts)
when :dash_punctuation; node << Punctuation::Dash.new(token, active_opts)
when :open_punctuation; node << Punctuation::Open.new(token, active_opts)
when :close_punctuation; node << Punctuation::Close.new(token, active_opts)
when :initial_punctuation; node << Punctuation::Initial.new(token, active_opts)
when :final_punctuation; node << Punctuation::Final.new(token, active_opts)
when :other_punctuation; node << Punctuation::Other.new(token, active_opts)
when :separator; node << Separator::Any.new(token, active_opts)
when :space_separator; node << Separator::Space.new(token, active_opts)
when :line_separator; node << Separator::Line.new(token, active_opts)
when :paragraph_separator; node << Separator::Paragraph.new(token, active_opts)
when :symbol; node << Symbol::Any.new(token, active_opts)
when :math_symbol; node << Symbol::Math.new(token, active_opts)
when :currency_symbol; node << Symbol::Currency.new(token, active_opts)
when :modifier_symbol; node << Symbol::Modifier.new(token, active_opts)
when :other_symbol; node << Symbol::Other.new(token, active_opts)
when :other; node << Codepoint::Any.new(token, active_opts)
when :control; node << Codepoint::Control.new(token, active_opts)
when :format; node << Codepoint::Format.new(token, active_opts)
when :surrogate; node << Codepoint::Surrogate.new(token, active_opts)
when :private_use; node << Codepoint::PrivateUse.new(token, active_opts)
when :unassigned; node << Codepoint::Unassigned.new(token, active_opts)
when *Token::UnicodeProperty::Age
node << Age.new(token, active_opts)
when *Token::UnicodeProperty::Derived
node << Derived.new(token, active_opts)
when *Token::UnicodeProperty::Emoji
node << Emoji.new(token, active_opts)
when *Token::UnicodeProperty::Script
node << Script.new(token, active_opts)
when *Token::UnicodeProperty::UnicodeBlock
node << Block.new(token, active_opts)
else
raise UnknownTokenError.new('UnicodeProperty', token)
end
end
def anchor(token)
case token.token
when :bol
node << Anchor::BeginningOfLine.new(token, active_opts)
when :eol
node << Anchor::EndOfLine.new(token, active_opts)
when :bos
node << Anchor::BOS.new(token, active_opts)
when :eos
node << Anchor::EOS.new(token, active_opts)
when :eos_ob_eol
node << Anchor::EOSobEOL.new(token, active_opts)
when :word_boundary
node << Anchor::WordBoundary.new(token, active_opts)
when :nonword_boundary
node << Anchor::NonWordBoundary.new(token, active_opts)
when :match_start
node << Anchor::MatchStart.new(token, active_opts)
else
raise UnknownTokenError.new('Anchor', token)
end
end
def escape(token)
case token.token
when :backspace
node << EscapeSequence::Backspace.new(token, active_opts)
when :escape
node << EscapeSequence::AsciiEscape.new(token, active_opts)
when :bell
node << EscapeSequence::Bell.new(token, active_opts)
when :form_feed
node << EscapeSequence::FormFeed.new(token, active_opts)
when :newline
node << EscapeSequence::Newline.new(token, active_opts)
when :carriage
node << EscapeSequence::Return.new(token, active_opts)
when :tab
node << EscapeSequence::Tab.new(token, active_opts)
when :vertical_tab
node << EscapeSequence::VerticalTab.new(token, active_opts)
when :hex
node << EscapeSequence::Hex.new(token, active_opts)
when :octal
node << EscapeSequence::Octal.new(token, active_opts)
when :codepoint
node << EscapeSequence::Codepoint.new(token, active_opts)
when :codepoint_list
node << EscapeSequence::CodepointList.new(token, active_opts)
when :control
if token.text =~ /\A(?:\\C-\\M|\\c\\M)/
node << EscapeSequence::MetaControl.new(token, active_opts)
else
node << EscapeSequence::Control.new(token, active_opts)
end
when :meta_sequence
if token.text =~ /\A\\M-\\[Cc]/
node << EscapeSequence::MetaControl.new(token, active_opts)
else
node << EscapeSequence::Meta.new(token, active_opts)
end
else
# treating everything else as a literal
node << EscapeSequence::Literal.new(token, active_opts)
end
end
def keep(token)
node << Keep::Mark.new(token, active_opts)
end
def free_space(token)
case token.token
when :comment
node << Comment.new(token, active_opts)
when :whitespace
if node.last.is_a?(WhiteSpace)
node.last.merge(WhiteSpace.new(token, active_opts))
else
node << WhiteSpace.new(token, active_opts)
end
else
raise UnknownTokenError.new('FreeSpace', token)
end
end
def quantifier(token)
offset = -1
target_node = node.expressions[offset]
while target_node.is_a?(FreeSpace)
target_node = node.expressions[offset -= 1]
end
target_node || raise(ArgumentError, 'No valid target found for '\
"'#{token.text}' ")
# in case of chained quantifiers, wrap target in an implicit passive group
# description of the problem: https://github.com/ammar/regexp_parser/issues/3
# rationale for this solution: https://github.com/ammar/regexp_parser/pull/69
if target_node.quantified?
new_token = Regexp::Token.new(
:group,
:passive,
'', # text
target_node.ts,
nil, # te (unused)
target_node.level,
target_node.set_level,
target_node.conditional_level
)
new_group = Group::Passive.new(new_token, active_opts)
new_group.implicit = true
new_group << target_node
increase_level(target_node)
node.expressions[offset] = new_group
target_node = new_group
end
case token.token
when :zero_or_one
target_node.quantify(:zero_or_one, token.text, 0, 1, :greedy)
when :zero_or_one_reluctant
target_node.quantify(:zero_or_one, token.text, 0, 1, :reluctant)
when :zero_or_one_possessive
target_node.quantify(:zero_or_one, token.text, 0, 1, :possessive)
when :zero_or_more
target_node.quantify(:zero_or_more, token.text, 0, -1, :greedy)
when :zero_or_more_reluctant
target_node.quantify(:zero_or_more, token.text, 0, -1, :reluctant)
when :zero_or_more_possessive
target_node.quantify(:zero_or_more, token.text, 0, -1, :possessive)
when :one_or_more
target_node.quantify(:one_or_more, token.text, 1, -1, :greedy)
when :one_or_more_reluctant
target_node.quantify(:one_or_more, token.text, 1, -1, :reluctant)
when :one_or_more_possessive
target_node.quantify(:one_or_more, token.text, 1, -1, :possessive)
when :interval
interval(target_node, token)
else
raise UnknownTokenError.new('Quantifier', token)
end
end
def increase_level(exp)
exp.level += 1
exp.respond_to?(:each) && exp.each { |subexp| increase_level(subexp) }
end
def interval(target_node, token)
text = token.text
mchr = text[text.length-1].chr =~ /[?+]/ ? text[text.length-1].chr : nil
case mchr
when '?'
range_text = text[0...-1]
mode = :reluctant
when '+'
range_text = text[0...-1]
mode = :possessive
else
range_text = text
mode = :greedy
end
range = range_text.gsub(/\{|\}/, '').split(',', 2)
min = range[0].empty? ? 0 : range[0]
max = range[1] ? (range[1].empty? ? -1 : range[1]) : min
target_node.quantify(:interval, text, min.to_i, max.to_i, mode)
end
def group(token)
case token.token
when :options, :options_switch
options_group(token)
when :close
close_group
when :comment
node << Group::Comment.new(token, active_opts)
else
open_group(token)
end
end
MOD_FLAGS = %w[i m x].map(&:to_sym)
ENC_FLAGS = %w[a d u].map(&:to_sym)
def options_group(token)
positive, negative = token.text.split('-', 2)
negative ||= ''
self.switching_options = token.token.equal?(:options_switch)
opt_changes = {}
new_active_opts = active_opts.dup
MOD_FLAGS.each do |flag|
if positive.include?(flag.to_s)
opt_changes[flag] = new_active_opts[flag] = true
end
if negative.include?(flag.to_s)
opt_changes[flag] = false
new_active_opts.delete(flag)
end
end
if (enc_flag = positive.reverse[/[adu]/])
enc_flag = enc_flag.to_sym
(ENC_FLAGS - [enc_flag]).each do |other|
opt_changes[other] = false if new_active_opts[other]
new_active_opts.delete(other)
end
opt_changes[enc_flag] = new_active_opts[enc_flag] = true
end
options_stack << new_active_opts
options_group = Group::Options.new(token, active_opts)
options_group.option_changes = opt_changes
nest(options_group)
end
def open_group(token)
case token.token
when :passive
exp = Group::Passive.new(token, active_opts)
when :atomic
exp = Group::Atomic.new(token, active_opts)
when :named
exp = Group::Named.new(token, active_opts)
when :capture
exp = Group::Capture.new(token, active_opts)
when :absence
exp = Group::Absence.new(token, active_opts)
when :lookahead
exp = Assertion::Lookahead.new(token, active_opts)
when :nlookahead
exp = Assertion::NegativeLookahead.new(token, active_opts)
when :lookbehind
exp = Assertion::Lookbehind.new(token, active_opts)
when :nlookbehind
exp = Assertion::NegativeLookbehind.new(token, active_opts)
else
raise UnknownTokenError.new('Group type open', token)
end
if exp.capturing?
exp.number = total_captured_group_count + 1
exp.number_at_level = captured_group_count_at_level + 1
count_captured_group
end
# Push the active options to the stack again. This way we can simply pop the
# stack for any group we close, no matter if it had its own options or not.
options_stack << active_opts
nest(exp)
end
def close_group
options_stack.pop unless switching_options
self.switching_options = false
decrease_nesting
end
def open_set(token)
token.token = :character
nest(CharacterSet.new(token, active_opts))
end
def negate_set
node.negate
end
def close_set
decrease_nesting(&:close)
end
def range(token)
exp = CharacterSet::Range.new(token, active_opts)
scope = node.last.is_a?(CharacterSet::IntersectedSequence) ? node.last : node
exp << scope.expressions.pop
nest(exp)
end
def close_completed_character_set_range
decrease_nesting if node.is_a?(CharacterSet::Range) && node.complete?
end
def intersection(token)
sequence_operation(CharacterSet::Intersection, token)
end
def sequence_operation(klass, token)
unless node.is_a?(klass)
operator = klass.new(token, active_opts)
sequence = operator.add_sequence(active_opts)
sequence.expressions = node.expressions
node.expressions = []
nest(operator)
end
node.add_sequence(active_opts)
end
def active_opts
options_stack.last
end
def total_captured_group_count
captured_group_counts.values.reduce(0, :+)
end
def captured_group_count_at_level
captured_group_counts[node.level]
end
def count_captured_group
captured_group_counts[node.level] += 1
end
def assign_effective_number(exp)
exp.effective_number =
exp.number + total_captured_group_count + (exp.number < 0 ? 1 : 0)
end
def assign_referenced_expressions
targets = {}
root.each_expression do |exp|
exp.is_a?(Group::Capture) && targets[exp.identifier] = exp
end
root.each_expression do |exp|
exp.respond_to?(:reference) &&
exp.referenced_expression = targets[exp.reference]
end
end
end # module Regexp::Parser