Class: ShellOpts::Lexer

Inherits:
Object
  • Object
show all
Defined in:
lib/shellopts/lexer.rb

Constant Summary collapse

COMMAND_RE = 
/[a-z][a-z._-]*!/
DECL_RE = 
/^(?:-|--|\+|\+\+|(?:@(?:\s|$))|(?:[^\\!]\S*!(?:\s|$)))/
SPEC_RE =

Match ArgSpec argument words. TODO

/^[^a-z]{2,}$/
DESCR_RE =

Match ArgDescr words (should be at least two characters long)

/^[^a-z]{2,}$/
SECTIONS = 
%w(DESCRIPTION OPTION OPTIONS COMMAND COMMANDS)

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, source, oneline) ⇒ Lexer

Returns a new instance of Lexer.



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# File 'lib/shellopts/lexer.rb', line 58

def initialize(name, source, oneline)
  @name = name
  @source = source
  @oneline = oneline
  @source += "\n" if @source[-1] != "\n" # Always terminate source with a newline
end

Instance Attribute Details

#name ⇒ Object (readonly)

Name of program



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# File 'lib/shellopts/lexer.rb', line 52

def name
  @name
end

#source ⇒ Object (readonly)

Returns the value of attribute source.



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# File 'lib/shellopts/lexer.rb', line 53

def source
  @source
end

#tokens ⇒ Object (readonly)

Returns the value of attribute tokens.



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# File 'lib/shellopts/lexer.rb', line 54

def tokens
  @tokens
end

Class Method Details

.lex(name, source, oneline, lineno = 1, charno = 1) ⇒ Object 



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# File 'lib/shellopts/lexer.rb', line 168

def self.lex(name, source, oneline, lineno = 1, charno = 1)
  Lexer.new(name, source, oneline).lex(lineno, charno)
end

Instance Method Details

#lex(lineno = 1, charno = 1) ⇒ Object 



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# File 'lib/shellopts/lexer.rb', line 65

def lex(lineno = 1, charno = 1)
  # Split source into lines and tag them with lineno and charno. Only the
  # first line can have charno != 1
  lines = source[0..-2].split("\n").map.with_index { |line,i|
    l = Line.new(i + lineno, charno, line)
    charno = 1
    l
  }

  # Skip initial comments and blank lines and compute indent level
  lines.shift_while { |line| line.text == "" || line.text.start_with?("#") && line.charno == 1 }
  initial_indent = lines.first&.charno

  # Create program token. The source is the program name
  @tokens = [Token.new(:program, 0, 0, name)]

  # Used to detect code blocks
  last_nonblank = @tokens.first

  # Process lines
  while line = lines.shift
    # Pass-trough blank lines
    if line.to_s == ""
      @tokens << Token.new(:blank, line.lineno, line.charno, "")
      next
    end
      
    # Ignore meta comments
    if line.charno < initial_indent
      next if line =~ /^#/
      error_token = Token.new(:text, line.lineno, 0, "")
      lexer_error error_token, "Illegal indentation"
    end

    # Line without escape sequences
    source = line.text[(line.text =~ /^\\/ ? 1 : 0)..-1]

    # Code lines
    if last_nonblank.kind == :text && line.charno > last_nonblank.charno && line !~ DECL_RE
      @tokens << Token.new(:text, line.lineno, line.charno, source)
      lines.shift_while { |line| line.blank? || line.charno > last_nonblank.charno }.each { |line|
        kind = (line.blank? ? :blank : :text)
        @tokens << Token.new(kind, line.lineno, line.charno, line.text)
      }

    # Sections
    elsif SECTIONS.include?(line.text)
      @tokens << Token.new(:section, line.lineno, line.charno, line.text.sub(/S$/, ""))

    # Options, commands, usage, arguments, and briefs
    elsif line =~ DECL_RE
      words = line.words
      while (charno, word = words.shift)
        case word
          when "@"
            if words.empty?
              error_token = Token.new(:text, line.lineno, charno, "@")
              lexer_error error_token, "Empty '@' declaration"
            end
            source = words.shift_while { true }.map(&:last).join(" ")
            @tokens << Token.new(:brief, line.lineno, charno, source)
          when "--" # FIXME Rename argdescr
            @tokens << Token.new(:usage, line.lineno, charno, "--")
            source = words.shift_while { |_,w| w =~ DESCR_RE }.map(&:last).join(" ")
            @tokens << Token.new(:usage_string, line.lineno, charno, source)
          when "++" # FIXME Rename argspec
            @tokens << Token.new(:spec, line.lineno, charno, "++")
            words.shift_while { |c,w| 
              w =~ SPEC_RE and @tokens << Token.new(:argument, line.lineno, c, w) 
            }
          when /^-|\+/
            @tokens << Token.new(:option, line.lineno, charno, word)
          when /!$/
            @tokens << Token.new(:command, line.lineno, charno, word)
        else
          source = [word, words.shift_while { |_,w| w !~ DECL_RE }.map(&:last)].flatten.join(" ")
          @tokens << Token.new(:brief, line.lineno, charno, source)
        end
      end

      # TODO: Move to parser and remove @oneline from Lexer
      (token = @tokens.last).kind != :brief || !oneline? or 
          lexer_error token, "Briefs are only allowed in multi-line specifications"

    # Paragraph lines
    else
      @tokens << Token.new(:text, line.lineno, line.charno, source)
    end
    # FIXME Not sure about this
#       last_nonblank = @tokens.last 
    last_nonblank = @tokens.last if ![:blank, :usage_string, :argument].include? @tokens.last.kind 
  end

  # Move arguments and briefs before first command if one-line source
#     if oneline? && cmd_index = @tokens.index { |token| token.kind == :command }
#       @tokens = 
#           @tokens[0...cmd_index] +
#           @tokens[cmd_index..-1].partition { |token| ![:command, :option].include?(token.kind) }.flatten
#     end

  @tokens
end

#lexer_error(token, message) ⇒ Object

Raises:



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# File 'lib/shellopts/lexer.rb', line 172

def lexer_error(token, message) raise LexerError.new(token), message end

#oneline? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/shellopts/lexer.rb', line 56

def oneline?() @oneline end