IEEE 200X Fast Track Change Proposal

ID:	  FT-20

Proposer:     Jim Lewis 
email:        Jim@SynthWorks.com

Status:       Analyzed
Proposed:     1/04
Analyzed:     1/04
Resolved:     Date

Enhancement Summary:     Permit concatenation on LHS of an expression
Related issues:          
Relevant LRM section:    

Enhancement Detail:
----------------------------
Allow concatenation on the LHS of an assignment
CarryOut & Result <= ('0'&A) + ('0'&B) ;


Analysis:
----------------------------
Modifications to 1076-2002

Modify target defintion in clause 8.4 to: 
target ::=
   name 
   | aggregate
   | name {& name}
   | (name {& name})

Add paragraph in clause 8.4 addressing concatentation on LHS:

If the target of the signal assignment statement is in the form of 
concatenation, each name in the target must a signal.
Each name in the target must be a subtype or a one-dimensional 
array whose element type is the same subtype. 
The base type of the value component of each transaction produced
by a waveform element on the right-hand side must be the same as the 
base type of the concatenation of signals on the left-hand side. 
This form of signal assignment assigns slices or elements of the 
right-hand side values to the drivers associated with the signals 
named in the concatenation on the left-hand side.


Add paragraph in clause 8.5 addressing concatentation on LHS:

If the target of the variable assignment statement is in the form of 
concatenation, each name in the target must a variable.
Each name in the target must be a subtype or a one-dimensional 
array whose element type is the same subtype. 
The base type of the value component of each transaction produced
by a waveform element on the right-hand side must be the same as the 
base type of the concatenation of variables on the left-hand side. 
This form of variable assignment assigns slices or elements of the 
right-hand side values to the variables named in the concatenation 
on the left-hand side.



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