Class: CodeRay::Scanners::Scanner

Inherits:
StringScanner
  • Object
show all
Extended by:
Plugin
Includes:
Enumerable
Defined in:
lib/coderay/scanner.rb

Overview

Scanner

The base class for all Scanners.

It is a subclass of Ruby’s great StringScanner, which makes it easy to access the scanning methods inside.

It is also Enumerable, so you can use it like an Array of Tokens:

require 'coderay'

c_scanner = CodeRay::Scanners[:c].new "if (*p == '{') nest++;"

for text, kind in c_scanner
  puts text if kind == :operator
end

# prints: (*==)++;

OK, this is a very simple example :) You can also use map, any?, find and even sort_by, if you want.

Constant Summary collapse

ScanError =

Raised if a Scanner fails while scanning

Class.new(Exception)
DEFAULT_OPTIONS =

The default options for all scanner classes.

Define @default_options for subclasses.

{ :stream => false }

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Plugin

helper, included, plugin_host, plugin_id, register_for, title

Constructor Details

#initialize(code = '', options = {}, &block) ⇒ Scanner

Create a new Scanner.

  • code is the input String and is handled by the superclass StringScanner.

  • options is a Hash with Symbols as keys. It is merged with the default options of the class (you can overwrite default options here.)

  • block is the callback for streamed highlighting.

If you set :stream to true in the options, the Scanner uses a TokenStream with the block as callback to handle the tokens.

Else, a Tokens object is used.



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# File 'lib/coderay/scanner.rb', line 113

def initialize code='', options = {}, &block
  @options = self.class::DEFAULT_OPTIONS.merge options
  raise "I am only the basic Scanner class. I can't scan "\
    "anything. :( Use my subclasses." if self.class == Scanner

  super Scanner.normify(code)

  @tokens = options[:tokens]
  if @options[:stream]
    warn "warning in CodeRay::Scanner.new: :stream is set, "\
      "but no block was given" unless block_given?
    raise NotStreamableError, self unless kind_of? Streamable
    @tokens ||= TokenStream.new(&block)
  else
    warn "warning in CodeRay::Scanner.new: Block given, "\
      "but :stream is #{@options[:stream]}" if block_given?
    @tokens ||= Tokens.new
  end

  setup
end

Class Method Details

.file_extension(extension = nil) ⇒ Object 



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# File 'lib/coderay/scanner.rb', line 79

def file_extension extension = nil
  if extension
    @file_extension = extension.to_s
  else
    @file_extension ||= plugin_id.to_s
  end
end

.normify(code) ⇒ Object 



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# File 'lib/coderay/scanner.rb', line 66

def normify code
  code = code.to_s
  if code.respond_to? :force_encoding
    begin
      code.force_encoding 'utf-8'
      code[/\z/]  # raises an ArgumentError when code contains a non-UTF-8 char
    rescue ArgumentError
      code.force_encoding 'binary'
    end
  end
  code.to_unix
end

.streamable? ⇒ Boolean

Returns if the Scanner can be used in streaming mode.

Returns:

  • (Boolean) 


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# File 'lib/coderay/scanner.rb', line 62

def streamable?
  is_a? Streamable
end

Instance Method Details

#column(pos = self.pos) ⇒ Object 



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# File 'lib/coderay/scanner.rb', line 189

def column pos = self.pos
  return 0 if pos <= 0
  string = string()
  if string.respond_to?(:bytesize) && (defined?(@bin_string) || string.bytesize != string.size)
    @bin_string ||= string.dup.force_encoding(:binary)
    string = @bin_string
  end
  pos - (string.rindex(?\n, pos) || 0)
end

#each(&block) ⇒ Object

Traverses the tokens.

Raises:

  • (ArgumentError) 


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# File 'lib/coderay/scanner.rb', line 174

def each &block
  raise ArgumentError,
    'Cannot traverse TokenStream.' if @options[:stream]
  tokens.each(&block)
end

#line ⇒ Object

The current line position of the scanner.

Beware, this is implemented inefficiently. It should be used for debugging only.



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# File 'lib/coderay/scanner.rb', line 185

def line
  string[0..pos].count("\n") + 1
end

#reset ⇒ Object 



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# File 'lib/coderay/scanner.rb', line 135

def reset
  super
  reset_instance
end

#streaming? ⇒ Boolean

Whether the scanner is in streaming mode.

Returns:

  • (Boolean) 


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# File 'lib/coderay/scanner.rb', line 169

def streaming?
  !!@options[:stream]
end

#string=(code) ⇒ Object Also known as: code= 



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# File 'lib/coderay/scanner.rb', line 140

def string= code
  code = Scanner.normify(code)
  super code
  reset_instance
end

#tokenize(new_string = nil, options = {}) ⇒ Object

Scans the code and returns all tokens in a Tokens object.



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# File 'lib/coderay/scanner.rb', line 151

def tokenize new_string=nil, options = {}
  options = @options.merge(options)
  self.string = new_string if new_string
  @cached_tokens =
    if @options[:stream]  # :stream must have been set already
      reset unless new_string
      scan_tokens @tokens, options
      @tokens
    else
      scan_tokens @tokens, options
    end
end

#tokens ⇒ Object 



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# File 'lib/coderay/scanner.rb', line 164

def tokens
  @cached_tokens ||= tokenize
end