Class: Parslet::Source

Inherits:
Object
  • Object
show all
Defined in:
lib/parslet/source.rb,
lib/parslet/source/line_cache.rb

Overview

Wraps the input string for parslet.

Defined Under Namespace

Modules: RangeSearch Classes: LineCache

Instance Method Summary collapse

Constructor Details

#initialize(str) ⇒ Source

Returns a new instance of Source.

Raises:

  • (ArgumentError) 


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# File 'lib/parslet/source.rb', line 12

def initialize(str)
  raise(
    ArgumentError, 
    "Must construct Source with a string like object."
  ) unless str.respond_to?(:to_str)

  @str = StringScanner.new(str)

  # maps 1 => /./m, 2 => /../m, etc...
  @re_cache = Hash.new { |h,k| 
    h[k] = /(.|$){#{k}}/m }

  @line_cache = LineCache.new
  @line_cache.scan_for_line_endings(0, str)
end

Instance Method Details

#bytepos ⇒ Object 



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# File 'lib/parslet/source.rb', line 77

def bytepos
  @str.pos
end

#bytepos=(n) ⇒ Object

Note:

Please be aware of encodings at this point.



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# File 'lib/parslet/source.rb', line 83

def bytepos=(n)
  @str.pos = n
rescue RangeError
end

#chars_left ⇒ Object

Returns how many chars remain in the input.



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# File 'lib/parslet/source.rb', line 54

def chars_left
  @str.rest_size
end

#chars_until(str) ⇒ Fixnum

Returns how many chars there are between current position and the string given. If the string given doesn’t occur in the source, then the remaining chars (#chars_left) are returned.

Returns:

  • (Fixnum) —

    count of chars until str or #chars_left



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# File 'lib/parslet/source.rb', line 64

def chars_until str
  slice_str = @str.check_until(Regexp.new(Regexp.escape(str)))
  return chars_left unless slice_str
  return slice_str.size - str.size
end

#consume(n) ⇒ Object

Consumes n characters from the input, returning them as a slice of the input.



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# File 'lib/parslet/source.rb', line 41

def consume(n)
  position = self.pos
  slice_str = @str.scan(@re_cache[n])
  slice = Parslet::Slice.new(
    position, 
    slice_str,
    @line_cache)

  return slice
end

#line_and_column(position = nil) ⇒ Object

Returns a <line, column> tuple for the given position. If no position is given, line/column information is returned for the current position given by #pos.



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# File 'lib/parslet/source.rb', line 92

def line_and_column(position=nil)
  @line_cache.line_and_column(position || self.bytepos)
end

#matches?(pattern) ⇒ Boolean Also known as: match

Checks if the given pattern matches at the current input position.

Parameters:

  • pattern (Regexp) —

    pattern to check for

Returns:

  • (Boolean) —

    true if the pattern matches at #pos



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# File 'lib/parslet/source.rb', line 33

def matches?(pattern)
  @str.match?(pattern)
end

#pos ⇒ Object

Note:

Please be aware of encodings at this point.

Position of the parse as a character offset into the original string.



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# File 'lib/parslet/source.rb', line 74

def pos
  Position.new(@str.string, @str.pos)
end