Module: QDA::Coding

Included in:
Code, Fragment
Defined in:
lib/weft/coding.rb

Overview

Classes mixing-in should implement the offset, length, [x, y], and << methods

Instance Method Summary collapse

Instance Method Details

#<=>(other) ⇒ Object

note that no-argument version of Array#sort does not call this method



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# File 'lib/weft/coding.rb', line 33

def <=>(other)
  self.offset == other.offset ?

  self.end <=> other.end :
    self.offset <=> other.offset
end

#end ⇒ Object 



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# File 'lib/weft/coding.rb', line 5

def end()
  offset + length
end

#exclude(other) ⇒ Object Also known as: -

returns a QDA::CodeSet created by removing the characters coded by other from self. The returned CodeSet may be 0, 1 or 2 elements long. The diagram below shows how 2 results may be returned.

-----+++++++++++++++++------ # self
-
-----------++++++++--------- # exclude
=
-----++++++--------+++------ # result



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# File 'lib/weft/coding.rb', line 81

def exclude(other)
     this, other = prepare_args(other)
     results = QDA::CodeSet[]
     if offset < other.offset
       if this.end < other.offset
         results.add( this )
       else
         results.add( this[offset, other.offset - offset] )
       end
     end
     if this.end > other.end
       if this.offset > other.end
         results.add(this)
       else
         results.add( this[other.end, this.end - other.end] )
       end
     end
     return results
end

#include?(point) ⇒ Boolean Also known as: contains?

Returns:

  • (Boolean) 


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# File 'lib/weft/coding.rb', line 9

def include?(point)
  if point.nil?
    raise ArgumentError, 
    "Point should be an integer, got #{point.inspect}"
  end
  point >= self.offset && point < self.end()
end

#intersect(other) ⇒ Object Also known as: %

returns the code representing the intersection of self and other returns nil if there is no overlap



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# File 'lib/weft/coding.rb', line 58

def intersect(other)
  # this represents self, possibly coerced into a different class

  this, other = prepare_args(other)
  unless this.overlap?(other)
    return nil
  end
  sorted = QDA::CodeSet[ this, other ].sort
  this_start = [ other.offset, this.offset ].max
  this_end = [other.end, this.end ].min
  fragment = sorted[0][this_start, this_end - this_start ]
end

#overlap?(other) ⇒ Boolean

Returns true if self and other overlap at any point - ie there is at least one character that is coded by both items

Returns:

  • (Boolean) 


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# File 'lib/weft/coding.rb', line 20

def overlap?(other)
  first, second = [self, other].sort_by { | x | x.offset }
  first.end > second.offset ? true : false
end

#prepare_args(other) ⇒ Object 



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# File 'lib/weft/coding.rb', line 40

def prepare_args(other)
  # it should be a type that implements these methods

  unless other.kind_of?(Coding)
    raise ArgumentError,
    "Cannot combine with #{other.inspect}, should implement Coding"
  end
  
  # if it's not the same class, we need to determine what kind of

  # thing to return by combining the classes

  if other.is_a?(self.class)
    return self, other
  else
    return self.coerce(other), other.coerce(self)
  end
end

#touch?(other) ⇒ Boolean

Returns true if self and other overlap or are contiguous

Returns:

  • (Boolean) 


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# File 'lib/weft/coding.rb', line 26

def touch?(other)
  first, second = [self, other].sort_by { | x | x.offset }
  first.end >= second.offset ? true : false
end

#union(other) ⇒ Object Also known as: +

Returns the code produced by merging self with other. If the two codes do not touch each other, then an CodeSet of the two codes is returned.



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# File 'lib/weft/coding.rb', line 105

def union(other)
  this, other = prepare_args(other)
  return this if this == other
  return QDA::CodeSet[ self, other ].sort unless touch?(other)

  # if they overlap or touch, a single coding will be returned

  first, second = QDA::CodeSet[ this, other ].sort
  fragment = first.dup()
  if second.end > first.end
    fragment << second[first.end, second.end - first.end]  
  end
  return fragment
end