Class: Citrus::Input

Inherits:
StringScanner
  • Object
show all
Defined in:
lib/citrus.rb

Overview

An Input is a scanner that is responsible for executing rules at different positions in the input string and persisting event streams.

Direct Known Subclasses

MemoizedInput

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(source) ⇒ Input 



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# File 'lib/citrus.rb', line 173

def initialize(source)
  super(source_text(source))
  @source = source
  @max_offset = 0
end

Instance Attribute Details

#max_offset ⇒ Object (readonly)

The maximum offset in the input that was successfully parsed.



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# File 'lib/citrus.rb', line 180

def max_offset
  @max_offset
end

#source ⇒ Object (readonly)

The initial source passed at construction. Typically a String or a Pathname.



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# File 'lib/citrus.rb', line 184

def source
  @source
end

Instance Method Details

#exec(rule, events = []) ⇒ Object

Returns an array of events for the given rule at the current pointer position. Objects in this array may be one of three types: a Rule, Citrus::CLOSE, or a length (integer).



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# File 'lib/citrus.rb', line 246

def exec(rule, events=[])
  position = pos
  index = events.size

  if apply_rule(rule, position, events).size > index
    @max_offset = pos if pos > @max_offset
  else
    self.pos = position
  end

  events
end

#line(pos = pos()) ⇒ Object

Returns the text of the line that contains the character at the given pos. pos defaults to the current pointer position.



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# File 'lib/citrus.rb', line 234

def line(pos=pos())
  lines[line_index(pos)]
end

#line_index(pos = pos()) ⇒ Object

Returns the 0-based number of the line that contains the character at the given pos. pos defaults to the current pointer position.



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# File 'lib/citrus.rb', line 214

def line_index(pos=pos())
  p = n = 0
  string.each_line do |line|
    p += line.length
    return n if p >= pos
    n += 1
  end
  0
end

#line_number(pos = pos()) ⇒ Object Also known as: lineno

Returns the 1-based number of the line that contains the character at the given pos. pos defaults to the current pointer position.



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# File 'lib/citrus.rb', line 226

def line_number(pos=pos())
  line_index(pos) + 1
end

#line_offset(pos = pos()) ⇒ Object

Returns the 0-based offset of the given pos in the input on the line on which it is found. pos defaults to the current pointer position.



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# File 'lib/citrus.rb', line 202

def line_offset(pos=pos())
  p = 0
  string.each_line do |line|
    len = line.length
    return (pos - p) if p + len >= pos
    p += len
  end
  0
end

#lines ⇒ Object

Returns an array containing the lines of text in the input.



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# File 'lib/citrus.rb', line 192

def lines
  if string.respond_to?(:lines)
    string.lines.to_a
  else
    string.to_a
  end
end

#memoized? ⇒ Boolean

Returns true when using memoization to cache match results.



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# File 'lib/citrus.rb', line 239

def memoized?
  false
end

#reset ⇒ Object

:nodoc:



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# File 'lib/citrus.rb', line 186

def reset # :nodoc:
  @max_offset = 0
  super
end

#test(rule) ⇒ Object

Returns the length of a match for the given rule at the current pointer position, nil if none can be made.



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# File 'lib/citrus.rb', line 261

def test(rule)
  position = pos
  events = apply_rule(rule, position, [])
  self.pos = position
  events[-1]
end