IEEE 200X Fast Track Change Proposal

ID:	  FT-

Proposer:     John Ries
email:        johnr@model.com

Status:       Open
Proposed:     04/20/04
Analyzed:     Date
Resolved:     Date

Enhancement Summary:  Allow aggregates, array operands, and array operators
to be locally static.   
Related issues:          
Relevant LRM section:    

Enhancement Detail:
----------------------------

Currently the only locally static non-scalars are bit string literals
and string literals.  As a result aggregates, concatenation, slices,
or functions returning composites cannot be used in places that
require locally static expression such as choices for cases.

This enhancement is to modify the statement

An expression is said to be locally static if and only if every operator in the
expression denotes an implicitly defined operator whose operands and result are 
scalar and if every primary in the expression is a locally static primary, where
locally static primary is defined to be one of the following:

To

An expression is said to be locally static if and only if every operator in the
expression denotes an implicitly defined operator whose operands and if every 
primary in the expression is a locally static primary, where locally static
 primary is defined to be one of the following:

Addition items defining a locally static primary would be added

k) An array aggregate, if and only if

   1) All expression in its element associations are locally static expressions, and
   2) All ranges in its element associations are locally static ranges

l) A record aggregate, if and only if all expressions in its element associations are 
   locally static expressions

m) A subelement or a slice of a locally static primary, provided that any index
  expressions are locally static expressions and any discrete ranges used in slice
  names are locally static discrete ranges 

A locally static range is either a range of the second form (see 3.1) whose
bounds are locally static expressions, or a range of the first form whose prefix 
denotes either a locally static subtype or and object that is of a locally static 
subtype. A locally static range constraint is a range constraint whose range is
locally static.

n) A select name, whose prefix denotes a locally static primary.

These changes allow better use of existing language construct at the
expense of compiler complexity.  Specifically the inability to use
& in constants that are then used as case choices currently is illegal
and causes users problems.  


Analysis:
----------------------------
[To be performed by the 200X Fast Track Working Group]


Resolution:
----------------------------
[To be performed by the 200X Fast Track Working Group]