Class: CodeRay::Tokens

Inherits:
Array
  • Object
show all
Defined in:
lib/coderay/tokens.rb

Overview

The Tokens class represents a list of tokens returned from a Scanner. It’s actually just an Array with a few helper methods.

A token itself is not a special object, just two elements in an Array:

  • the token text (the original source of the token in a String) or a token action (begin_group, end_group, begin_line, end_line)

  • the token kind (a Symbol representing the type of the token)

It looks like this:

..., '# It looks like this', :comment, ...
..., '3.1415926', :float, ...
..., '$^', :error, ...

Some scanners also yield sub-tokens, represented by special token actions, for example :begin_group and :end_group.

The Ruby scanner, for example, splits “a string” into:

[
 :begin_group, :string,
 '"',          :delimiter,
 'a string',   :content,
 '"',          :delimiter,
 :end_group,   :string
]

Tokens can be used to save the output of a Scanners in a simple Ruby object that can be send to an Encoder later:

tokens = CodeRay.scan('price = 2.59', :ruby).tokens
tokens.encode(:html)
tokens.html
CodeRay.encoder(:html).encode_tokens(tokens)

Tokens gives you the power to handle pre-scanned code very easily: You can serialize it to a JSON string and store it in a database, pass it around to encode it more than once, send it to other algorithms…

Instance Attribute Summary collapse

Instance Method Summary collapse

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(meth, options = {}) ⇒ Object

Redirects unknown methods to encoder calls.

For example, if you call tokens.html, the HTML encoder is used to highlight the tokens.



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# File 'lib/coderay/tokens.rb', line 67

def method_missing meth, options = {}
  encode meth, options
rescue PluginHost::PluginNotFound
  super
end

Instance Attribute Details

#scanner ⇒ Object

The Scanner instance that created the tokens.



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# File 'lib/coderay/tokens.rb', line 44

def scanner
  @scanner
end

Instance Method Details

#begin_group(kind) ⇒ Object 



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# File 'lib/coderay/tokens.rb', line 153

def begin_group kind; push :begin_group, kind end

#begin_line(kind) ⇒ Object 



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# File 'lib/coderay/tokens.rb', line 155

def begin_line kind; push :begin_line, kind end

#count ⇒ Object

Return the actual number of tokens.



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# File 'lib/coderay/tokens.rb', line 148

def count
  size / 2
end

#encode(encoder, options = {}) ⇒ Object

Encode the tokens using encoder.

encoder can be

  • a plugin name like :html oder ‘statistic’

  • an Encoder object

options are passed to the encoder.



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# File 'lib/coderay/tokens.rb', line 53

def encode encoder, options = {}
  encoder = Encoders[encoder].new options if encoder.respond_to? :to_sym
  encoder.encode_tokens self, options
end

#end_group(kind) ⇒ Object 



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# File 'lib/coderay/tokens.rb', line 154

def end_group kind; push :end_group, kind end

#end_line(kind) ⇒ Object 



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# File 'lib/coderay/tokens.rb', line 156

def end_line kind; push :end_line, kind end

#split_into_parts(*sizes) ⇒ Object

Split the tokens into parts of the given sizes.

The result will be an Array of Tokens objects. The parts have the text size specified by the parameter. In addition, each part closes all opened tokens. This is useful to insert tokens betweem them.

This method is used by @Scanner#tokenize@ when called with an Array of source strings. The Diff encoder uses it for inline highlighting.



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# File 'lib/coderay/tokens.rb', line 82

def split_into_parts *sizes
  return Array.new(sizes.size) { Tokens.new } if size == 2 && first == ''
  parts = []
  opened = []
  content = nil
  part = Tokens.new
  part_size = 0
  size = sizes.first
  i = 0
  for item in self
    case content
    when nil
      content = item
    when String
      if size && part_size + content.size > size  # token must be cut
        if part_size < size  # some part of the token goes into this part
          content = content.dup  # content may no be safe to change
          part << content.slice!(0, size - part_size) << item
        end
        # close all open groups and lines...
        closing = opened.reverse.flatten.map do |content_or_kind|
          case content_or_kind
          when :begin_group
            :end_group
          when :begin_line
            :end_line
          else
            content_or_kind
          end
        end
        part.concat closing
        begin
          parts << part
          part = Tokens.new
          size = sizes[i += 1]
        end until size.nil? || size > 0
        # ...and open them again.
        part.concat opened.flatten
        part_size = 0
        redo unless content.empty?
      else
        part << content << item
        part_size += content.size
      end
      content = nil
    when Symbol
      case content
      when :begin_group, :begin_line
        opened << [content, item]
      when :end_group, :end_line
        opened.pop
      else
        raise ArgumentError, 'Unknown token action: %p, kind = %p' % [content, item]
      end
      part << content << item
      content = nil
    else
      raise ArgumentError, 'Token input junk: %p, kind = %p' % [content, item]
    end
  end
  parts << part
  parts << Tokens.new while parts.size < sizes.size
  parts
end

#to_s ⇒ Object

Turn tokens into a string by concatenating them.



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# File 'lib/coderay/tokens.rb', line 59

def to_s
  encode CodeRay::Encoders::Encoder.new
end