Module: Regexp::Lexer
- Defined in:
- lib/regexp_parser/lexer.rb
Overview
A very thin wrapper around the scanner that breaks quantified literal runs, collects emitted tokens into an array, calculates their nesting depth, and normalizes tokens for the parser, and checks if they are implemented by the given syntax flavor.
Constant Summary collapse
- OPENING_TOKENS =
[:capture, :options, :passive, :atomic, :named, :lookahead, :nlookahead, :lookbehind, :nlookbehind ].freeze
- CLOSING_TOKENS =
[:close].freeze
Class Method Summary collapse
- .ascend(type, token) ⇒ Object
-
.break_literal(token) ⇒ Object
called by scan to break a literal run that is longer than one character into two separate tokens when it is followed by a quantifier.
- .descend(type, token) ⇒ Object
-
.merge_literal(current) ⇒ Object
called by scan to merge two consecutive literals.
- .scan(input, syntax = "ruby/#{RUBY_VERSION}", &block) ⇒ Object
Class Method Details
.ascend(type, token) ⇒ Object
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# File 'lib/regexp_parser/lexer.rb', line 51 def self.ascend(type, token) if type == :group or type == :assertion @nesting -= 1 if CLOSING_TOKENS.include?(token) end if type == :set or type == :subset @set_nesting -= 1 if token == :close end end |
.break_literal(token) ⇒ Object
called by scan to break a literal run that is longer than one character into two separate tokens when it is followed by a quantifier
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# File 'lib/regexp_parser/lexer.rb', line 73 def self.break_literal(token) text = token.text if text.scan(/./mu).length > 1 lead = text.sub(/.\z/mu, "") last = text[/.\z/mu] || '' if RUBY_VERSION >= '1.9' lead_length = lead.bytesize last_length = last.bytesize else lead_length = lead.length last_length = last.length end @tokens.pop @tokens << Regexp::Token.new(:literal, :literal, lead, token.ts, (token.te - last_length), @nesting, @set_nesting) @tokens << Regexp::Token.new(:literal, :literal, last, (token.ts + lead_length), token.te, @nesting, @set_nesting) end end |
.descend(type, token) ⇒ Object
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# File 'lib/regexp_parser/lexer.rb', line 61 def self.descend(type, token) if type == :group or type == :assertion @nesting += 1 if OPENING_TOKENS.include?(token) end if type == :set or type == :subset @set_nesting += 1 if token == :open end end |
.merge_literal(current) ⇒ Object
called by scan to merge two consecutive literals. this happens when tokens get normalized (as in the case of posix/bre) and end up becoming literals.
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# File 'lib/regexp_parser/lexer.rb', line 99 def self.merge_literal(current) last = @tokens.pop replace = Regexp::Token.new(:literal, :literal, last.text + current.text, last.ts, current.te, @nesting, @set_nesting) end |
.scan(input, syntax = "ruby/#{RUBY_VERSION}", &block) ⇒ Object
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# File 'lib/regexp_parser/lexer.rb', line 13 def self.scan(input, syntax = "ruby/#{RUBY_VERSION}", &block) syntax = Regexp::Syntax.new(syntax) @tokens = [] @nesting, @set_nesting = 0, 0 last = nil Regexp::Scanner.scan(input) do |type, token, text, ts, te| type, token = *syntax.normalize(type, token) syntax.check! type, token ascend(type, token) break_literal(last) if type == :quantifier and last and last.type == :literal current = Regexp::Token.new(type, token, text, ts, te, @nesting, @set_nesting) current = merge_literal(current) if type == :literal and last and last.type == :literal last.next(current) if last current.previous(last) if last @tokens << current last = current descend(type, token) end if block_given? @tokens.each {|t| block.call(t)} else @tokens end end |