Class: Pyper::PostfixMachine::ArgumentSource

Inherits:
Struct
  • Object
show all
Defined in:
lib/pyper/postfix_machine/argument_source.rb

Overview

Compile-time argument source stack. To explain, the default source of arguments in compiled Pyper methods is ‘args’ local variable, containing all the arguments supplied to the method (as in method(*args) call). However, this default argument source can be changed to something else. For this purpose, compil-time argument source stack is maintained, showing where the next argument will come from. It is implemented as a struct with two arrays: source and grab_method. The source shows where the argument comes from, and grab method shows how is it obtained. There are 3 possible ways to obtain an argument from a source:

  • :ref – by reference (ie. by simply taking it)

  • :dup – by duplication (calling #dup method on the source)

  • :shift – by shifting (calling #shift method on the source)

As for the sources, there may be the following ones in a compiled method:

  • :args – whole argument array

  • :args_counted – args referenced with compile time counter – default

  • :alpha – primary pipeline

  • :beta – secondary pipeline

  • :delta – in-block pipeline

  • :epsilon – block argument 0

  • :zeta – block argument 1

  • :psi – penultimate element in the args array; penultimate argument

  • :omega – last element in the args array; last argument

We can se that :args_counted source comes as if with its own special grabbing method. At compile time, PostfixMachine maintains @args_count attribute, an index to the args array, and increments it each time an argument is taken. Other argument sources do not have counters and if they contain arrays, they can only be grabbed by the standard three methods.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#grab_method ⇒ Object

Returns the value of attribute grab_method

Returns:

  • (Object) —

    the current value of grab_method



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 35

def grab_method
  @grab_method
end

#source ⇒ Object

Returns the value of attribute source

Returns:

  • (Object) —

    the current value of source



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 35

def source
  @source
end

Class Method Details

.new ⇒ Object

Initially, argument stack has a single layer with :args_counted as the source, and :ref as grab method.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 40

def new
  self[ [:args_counted], [:ref] ]
end

Instance Method Details

#alpha ⇒ Object

Pushes :alpha source and :ref grab method on the stack.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 116

def alpha
  var :alpha
end

#alpha! ⇒ Object

Modifies the topmost source on the stack to :alpha, leaving the grab method unchanged.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 123

def alpha!
  var! :alpha
end

#args ⇒ Object

Pushes :args source and :shift grab method on the stack.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 86

def args
  source.push :args
  grab_method.push :shift
end

#args! ⇒ Object

Modifies the topmost source on the stack to :args, and grab method to :shift.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 94

def args!
  source[-1] = :args
  shift!
end

#args_counted ⇒ Object

Pushes :args_counted source and :ref grab method on the stack.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 72

def args_counted
  source.push :args_counted
  grab_method.push :ref
end

#args_counted! ⇒ Object

Modifies the topmost source on the stack to :args_counted, leaving grab method unchanged.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 80

def args_counted!
  source[-1] = :args_counted
end

#beta ⇒ Object

Pushes :beta source and :ref grab method on the stack.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 129

def beta
  var :beta
end

#beta! ⇒ Object

Modifies the topmost source on the stack to :beta, leaving the grab method unchanged.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 136

def beta!
  var! :beta
end

#delta ⇒ Object

Pushes :delta source and :ref grab method on the stack.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 142

def delta
  var :delta
end

#delta! ⇒ Object

Modifies the topmost source on the stack to :delta, leaving the grab method unchanged.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 149

def delta!
  var! :delta
end

#dup! ⇒ Object

Modifies the topmost grab method on the stack to :dup.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 66

def dup!
  grab_method[-1] = :dup
end

#epsilon ⇒ Object

Pushes :epsilon source and :ref grab method on the stack.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 155

def epsilon
  var :epsilon
end

#epsilon! ⇒ Object

Modifies the topmost source on the stack to :epsilon, leaving the grab method unchanged.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 162

def epsilon!
  var! :epsilon
end

#omega ⇒ Object

Pushes :omega source and :ref grab method on the stack.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 194

def omega
  var :omega
end

#omega! ⇒ Object

Modifies the topmost source on the stack to :omega, leaving the grab method unchanged.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 201

def omega!
  var! :omega
end

#psi ⇒ Object

Pushes :psi source and :ref grab method on the stack.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 181

def psi
  var :psi
end

#psi! ⇒ Object

Modifies the topmost source on the stack to :psi, leaving the grab method unchanged.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 188

def psi!
  var! :psi
end

#ref! ⇒ Object

Modifies the topmost grab method on the stack to :ref.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 60

def ref!
  grab_method[-1] = :ref
end

#shift! ⇒ Object

Modifies the topmost grab method on the stack to :shift.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 54

def shift!
  grab_method[-1] = :shift
end

#std! ⇒ Object

Resets the stack back to the initial condition.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 47

def std!
  self.source = [:args_counted]
  self.grab_method = [:ref]
end

#var(variable) ⇒ Object

Pushes on the stack a given variable name as the source, and :ref as the grab method.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 102

def var variable
  source.push variable
  grab_method.push :ref
end

#var!(variable) ⇒ Object

Modifies the topmost source on the stack to the given variable name, leaving the grab method unchanged.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 110

def var! variable
  source[-1] = variable
end

#zeta ⇒ Object

Pushes :zeta source and :ref grab method on the stack.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 168

def zeta
  var :zeta
end

#zeta! ⇒ Object

Modifies the topmost source on the stack to :zeta, leaving the grab method unchanged.



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# File 'lib/pyper/postfix_machine/argument_source.rb', line 175

def zeta!
  var! :zeta
end