(r28) LCS2016_007 < P1076

P1076 Web>VHDL2017>LCS2016_007 (revision 28) (raw view)~~EditAttach~~
---+ Language Change Specification for Sequential Declaration Regions

---++ 

| <sticky><b>LCS Number:</b></sticky> | LCS-2016-007 |
| <sticky><b>Version:</b>   </sticky> | 3  |
| <sticky><b>Date:</b>      </sticky> | 11-Mar-2017  |
| <sticky><b>Status:</b>    </sticky> | Voting  |
| <sticky><b>Author:</b>    </sticky> | Jim Lewis |
| <sticky><b>Email:</b>     </sticky> | [[Main.JimLewis]] |
| <sticky><b>Source Doc:</b></sticky> | [[LCS_2016_007_Examples][Examples]]      [[LCS_2016_007_History][History]]     [[SequentialDeclare][Proposal]] |
| <sticky><b>Summary:</b>   </sticky> |  Sequential Declaration Regions  |


---+++ Style Notes

Changes are shown in %RED%red font%ENDCOLOR%.  
Deletions are %RED%<del>crossed out</del>%ENDCOLOR%.
Editing notes in %GREEN%green font%ENDCOLOR%.

---+++ Reviewing Notes

sequential_block_declarative_part is defined in terms of process_declarative_item.
Need a term for sequential_declarative_item and it should be used by here,
process, and subprogram_declarative_item

---+++ Details of Language Change

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<sticky>
 
---+++ Section 10.1 General
---++++ 007.1:  Production for Sequential_statement p145 (and ) 
<pre>  sequential_statement ::=
            wait_statement
          | assertion_statement
          | report_statement
          | signal_assignment_statement
          | variable_assignment_statement
          | procedure_call_statement
          | if_statement
          | case_statement
          | loop_statement
          | next_statement
          | exit_statement
          | return_statement
          | null_statement
%RED%          | sequential_block_statement%ENDCOLOR%</pre>


---+++ 007.2:  New Section 10.15
<font color="red">A sequential block statement encloses a sequence of sequential statements.
Block statements may be nested.

<pre>sequential_block_statement ::=
    [ sequential_block_label : ] block  [ is ]
        sequential_block_declarative_part
    begin
        sequential_block_statement_part
    end [ block ] [ block_label ] ;
    
  sequential_block_declarative_part ::=
      {process_declarative_item}

  sequential_block_statement_part ::= 
      {sequential_statement}
</pre>
If a label appears at the end of an sequential statement, 
it shall repeat the sequential block label.

The execution of a sequential block statement consists of the elaboration of the  
sequential block declarative part followed by the execution of the statements in the
sequential block statement part. 
    
It is an error if a variable declaration in a process declarative part declares a shared variable.
</font>

---+++ 12. Scope and visibility
---++++ 12.1 Declarative region
---++++ 007.3:  List following paragraph 1 of section 12.1 on page 185
<font color="green">[Add new list item and reorder the ones that follow it.]</font>
h) A process statement<br>
<font color="red">i) A sequential block statement</font>
<font color="red">j<strike> i</strike></font>) A loop statement
<font color="red">k<strike> j</strike></font>) A block configuration
<font color="red">l<strike> k</strike></font>) A component configuration
<font color="red">m<strike> l</strike></font>) A generate statement
<font color="red">n<strike> m</strike></font>) A protected type declaration, together with the corresponding body

---+++ 14.6 Dynamic elaboration
---++++ 007.4:  paragraph 2 of section 14.6 on page 213
There are
<font color="red"> four <strike> three </strike></font> 
particular instances in which elaboration occurs dynamically during simulation. These are as
follows:
---++++ 007.5:  New list item d in section 14.6 on page 214
<font color="red">d) Execution of a sequential block statement involves the 
elaboration of the sequential block declarative part followed by the execution 
of the statements in the sequential block statement part.</font>
---++++ 007.6:  Note 1 at end of section 14.6 on page 214
<font color="red"><strike>NOTE 1-It is a consequence of these rules that declarative 
items appearing within the declarative part of a subprogram
body are elaborated each time the corresponding subprogram is called; 
thus, successive elaborations of a given declarative item appearing in 
such a place may create items with different characteristics. 
For example, successive elaborations of the same subtype declaration 
appearing in a subprogram body may create subtypes with different constraints.</strike>

NOTE 1-Each time a subprogram is called or a sequential block statement 
is executed, the corresponding declarative region is elaborated.   
As a result, a given declarative item in these constructs may have 
different characteristics, such as subtype constraints, on successive 
executions of the same construct.</font>

---+++ 16.2.5 Predefined attributes of named entities
---++++ 007.7:  Production for full_path_instance_element on page 249

<pre>full_path_instance_element ::=
    %GREEN%[other BNF unmodified]%ENDCOLOR%
    | process_label
%RED%    | sequential_block_label%ENDCOLOR%
    | loop_label

%RED%sequential_block_label ::= [ <i>sequential_block_</i>label ]
%ENDCOLOR%</pre>

---++++ 007.8:  Page 249 3rd paragraph from bottom.

A process statement with no label is denoted by an empty process label. 
Similarly, a loop statement with no label is denoted by an empty loop label.
%RED%A sequential block statement with no label is denoted by an empty 
sequential block label.%ENDCOLOR% 

---++++ 007.9:  Production for path_instance_element on page 251

<pre>path_instance_element ::=
    %GREEN%[other BNF unmodified]%ENDCOLOR%
    | process_label
%RED%    | sequential_block_label%ENDCOLOR%
    | loop_label
</pre>

---+++ Annex C
-- Update sequential statements per above
-- Add sequential block statement syntax
---++++ 007.10  BNF

<br>
<br>
---++ Comments


%COMMENT%</sticky>

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Topic revision: r1 - 2017-07-16 - 18:26:01 - TWikiGuest
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