Class: CheapBlock

• Inheritance
• Description
• Related information
• Class protocol
  • queries
• Instance protocol
  • accessing
  • conversion
  • printing & storing
  • testing

Inheritance:

   Object
   |
   +--ExecutableFunction
      |
      +--CompiledCode
         |
         +--Block
            |
            +--CheapBlock
               |
               +--VarArgCheapBlock

Package:

stx:libbasic

Category:

Kernel-Methods

Version:

rev: 1.26 date: 2017/06/23 08:59:10

user: stefan

file: CheapBlock.st directory: libbasic

module: stx stc-classLibrary: libbasic

Author:

Claus Gittinger

Description:

CheapBlocks are blocks which do not need their home-context
(i.e. blocks that do not access any method arguments 
 or method locals).

CheapBlocks are never created explicitely; the only creation
is done by the compilers, when some sourceCode is compiled to either
machine or byteCode, and the generated block is found to neither access
any variables from its homeContext nor does a method-return.
CheapBlocks create less overhead to the runtime system, in that they
do not keep the creating context from being reclaimed (but, don't expect
too much of a difference ;-)

Since they have no reference to the home, they must store their
creating method explicitely - otherwise, the system had no 
chance of finding the source-position of the block.

[Instance variables:]

  selfValue   <Object>          copied self value
                                (if it's a copying block)

  method      <Method>          method where block was created 

NOTICE: layout known by runtime system and compiler - do not change

Related information:

    Block
    Context
    Method
    [contexts, stacks & unwinding]

Class protocol:

 isBuiltInClass

return true if this class is known by the run-time-system.
Here, true is returned for myself, false for subclasses.

Instance protocol:

 homeMethod

return the receiver's home method.
That's the method where the block was created.

 selfValue

return the copied self

 setMethod: aMethod

set the receiver's home method.
This is a private entry for the compiler

 asVarArgBlock

convert myself into a varArg block;
this one has 1 formal argument, which gets the list
of actual arguments when evaluated.

 printOn: aStream

append a a printed representation of the block to aStream

 isCheapBlock