class Racc::GrammarFileScanner - Documentation for Ruby 3.2

# class Racc::GrammarFileScanner

### Constants

CACHE
LEFT_TO_RIGHT
ReservedWord

### Attributes

debug[RW]
epilogue[R]

### Public Class Methods

new(str, filename = '-') click to toggle source

    # File lib/racc/grammarfileparser.rb, line 298
    def initialize(str, filename = '-')
      @lines  = str.b.split(/\n|\r\n|\r/)
      @filename = filename
      @lineno = -1
      @line_head   = true
      @in_rule_blk = false
      @in_conv_blk = false
      @in_block = nil
      @epilogue = ''
      @debug = false
      next_line
    end

### Public Instance Methods

lineno() click to toggle source

    # File lib/racc/grammarfileparser.rb, line 313
    def lineno
      @lineno + 1
    end

yylex() { |sym, tok| ... } click to toggle source

    # File lib/racc/grammarfileparser.rb, line 319
    def yylex(&block)
      unless @debug
        yylex0(&block)
      else
        yylex0 do |sym, tok|
          $stderr.printf "%7d %-10s %s\n", lineno(), sym.inspect, tok.inspect
          yield [sym, tok]
        end
      end
    end

### Private Instance Methods

atom_symbol(token) click to toggle source

    # File lib/racc/grammarfileparser.rb, line 399
    def atom_symbol(token)
      if token == 'end'
        symbol = :END
        @in_conv_blk = false
        @in_rule_blk = false
      else
        if @line_head and not @in_conv_blk and not @in_rule_blk
          symbol = ReservedWord[token] || :SYMBOL
        else
          symbol = :SYMBOL
        end
        case symbol
        when :RULE then @in_rule_blk = true
        when :CONV then @in_conv_blk = true
        end
      end
      @line_head = false
      symbol
    end

get_quoted_re(left) click to toggle source

    # File lib/racc/grammarfileparser.rb, line 550
    def get_quoted_re(left)
      term = Regexp.quote(LEFT_TO_RIGHT[left] || left)
      CACHE[left] ||= /\A[^#{term}\\]*(?:\\.[^\\#{term}]*)*#{term}/
    end

literal_head?(pre, post) click to toggle source

    # File lib/racc/grammarfileparser.rb, line 506
    def literal_head?(pre, post)
      (!pre || /[a-zA-Z_0-9]/n !~ pre[-1,1]) &&
          !post.empty? && /\A[\s\=]/n !~ post
    end

next_line() click to toggle source

    # File lib/racc/grammarfileparser.rb, line 364
    def next_line
      @lineno += 1
      @line = @lines[@lineno]
      if not @line or /\A----/ =~ @line
        @epilogue = @lines.join("\n")
        @lines.clear
        @line = nil
        if @in_block
          @lineno -= 1
          scan_error! sprintf('unterminated %s', @in_block)
        end
        false
      else
        @line.sub!(/(?:\n|\r\n|\r)\z/, '')
        @line_head = true
        true
      end
    end

read(len) click to toggle source

    # File lib/racc/grammarfileparser.rb, line 511
    def read(len)
      s = @line[0, len]
      @line = @line[len .. -1]
      s
    end

reads(re) click to toggle source

    # File lib/racc/grammarfileparser.rb, line 517
    def reads(re)
      m = re.match(@line) or return nil
      @line = m.post_match
      m[0]
    end

scan_action() click to toggle source

    # File lib/racc/grammarfileparser.rb, line 430
    def scan_action
      buf = String.new
      nest = 1
      pre = nil
      @in_block = 'action'
      begin
        pre = nil
        if s = reads(/\A\s+/)
          # does not set 'pre'
          buf << s
        end
        until @line.empty?
          if s = reads(/\A[^'"`{}%#\/\$]+/)
            buf << (pre = s)
            next
          end
          case ch = read(1)
          when '{'
            nest += 1
            buf << (pre = ch)
          when '}'
            nest -= 1
            if nest == 0
              @in_block = nil
              buf.sub!(/[ \t\f]+\z/, '')
              return buf
            end
            buf << (pre = ch)
          when '#'   # comment
            buf << ch << @line
            break
          when "'", '"', '`'
            buf << (pre = scan_quoted(ch))
          when '%'
            if literal_head? pre, @line
              # % string, regexp, array
              buf << ch
              case ch = read(1)
              when /[qQx]/n
                buf << ch << (pre = scan_quoted(read(1), '%string'))
              when /wW/n
                buf << ch << (pre = scan_quoted(read(1), '%array'))
              when /s/n
                buf << ch << (pre = scan_quoted(read(1), '%symbol'))
              when /r/n
                buf << ch << (pre = scan_quoted(read(1), '%regexp'))
              when /[a-zA-Z0-9= ]/n   # does not include "_"
                scan_error! "unknown type of % literal '%#{ch}'"
              else
                buf << (pre = scan_quoted(ch, '%string'))
              end
            else
              # operator
              buf << '||op->' if $raccs_print_type
              buf << (pre = ch)
            end
          when '/'
            if literal_head? pre, @line
              # regexp
              buf << (pre = scan_quoted(ch, 'regexp'))
            else
              # operator
              buf << '||op->' if $raccs_print_type
              buf << (pre = ch)
            end
          when '$'   # gvar
            buf << ch << (pre = read(1))
          else
            raise 'racc: fatal: must not happen'
          end
        end
        buf << "\n"
      end while next_line()
      raise 'racc: fatal: scan finished before parser finished'
    end

scan_error!(msg) click to toggle source

    # File lib/racc/grammarfileparser.rb, line 555
    def scan_error!(msg)
      raise CompileError, "#{lineno()}: #{msg}"
    end

scan_quoted(left, tag = 'string') click to toggle source

    # File lib/racc/grammarfileparser.rb, line 523
    def scan_quoted(left, tag = 'string')
      buf = left.dup
      buf = "||#{tag}->" + buf if $raccs_print_type
      re = get_quoted_re(left)
      sv, @in_block = @in_block, tag
      begin
        if s = reads(re)
          buf << s
          break
        else
          buf << @line
        end
      end while next_line()
      @in_block = sv
      buf << "<-#{tag}||" if $raccs_print_type
      buf
    end

skip_comment() click to toggle source

    # File lib/racc/grammarfileparser.rb, line 419
    def skip_comment
      @in_block = 'comment'
      until m = /\*\//.match(@line)
        next_line
      end
      @line = m.post_match
      @in_block = nil
    end

yylex0() { |atom_symbol(s), intern| ... } click to toggle source

    # File lib/racc/grammarfileparser.rb, line 332
    def yylex0
      begin
        until @line.empty?
          @line.sub!(/\A\s+/, '')
          if /\A\#/ =~ @line
            break
          elsif /\A\/\*/ =~ @line
            skip_comment
          elsif s = reads(/\A[a-zA-Z_]\w*/)
            yield [atom_symbol(s), s.intern]
          elsif s = reads(/\A\d+/)
            yield [:DIGIT, s.to_i]
          elsif ch = reads(/\A./)
            case ch
            when '"', "'"
              yield [:STRING, eval(scan_quoted(ch))]
            when '{'
              lineno = lineno()
              yield [:ACTION, SourceText.new(scan_action(), @filename, lineno)]
            else
              if ch == '|'
                @line_head = false
              end
              yield [ch, ch]
            end
          else
          end
        end
      end while next_line()
      yield nil
    end