(r11) LCS2016_018 < P1076

P1076 Web>VHDL_2017>LCS2016_018 (revision 11) (raw view)~~EditAttach~~
---+ Language Change Specification for Attributes for Enumerated Types
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| <sticky><b>LCS Number:</b></sticky> | LCS-2016-018 |
| <sticky><b>Version:</b>   </sticky> | 2 |
| <sticky><b>Date:</b>      </sticky> | 11-Jan-2017  |
| <sticky><b>Status:</b>    </sticky> | Approved |
| <sticky><b>Author:</b>    </sticky> | [[Main.PatrickLehmann][Patrick Lehmann]] |
| <sticky><b>%RED%<del>Source Doc:</del>%ENDCOLOR%</b></sticky> | <del> [[EnumAttributes][Attributes for Enumerated Types]] </del> |
| <sticky><b>More:</b></sticky> | [[LCS2016_018.Proposal][Proposal]] %BR% [[LCS2016_018_Examples][Examples]] %BR% [[LCS2016_018_History][LCS History]] |
| <sticky><b>Summary:</b>   </sticky> | Adds new attributes for enumerated types. |

%TOC%


---++ Style Notes
Changes are shown in %RED%red font%ENDCOLOR%.%BR%
Deletions are %RED%<del>crossed out</del>%ENDCOLOR%.%BR%
Editing or reviewing notes in %GREEN%green font%ENDCOLOR%.
 
---++ Reviewing Notes
The original proposal requested special attributes for enumerated types. This LCS lifts the demand and adds the demanded attributes %BR%
for scalar types in general. See also the related LCS' LCS-2016-018a and LCS-2016-018b for further related improvements, but not covered %BR%
by the original proposal.

This LCS also adds a prefix description to all sub-section because the prefix is not properly defined in the current LRM text. It also %BR%
splits section 16.2.2 into two parts to distinguish types and objects. This distinction is a) a clean-up and b) needed by other LCS' like %BR%
LCS-2016-018b.

NOTE 1 in sub-section 16.2.2 is going to be remove or should be moved to 5.2.1 where it belongs?


---++ Details of Language Change
---+++ 16.2.2 Predefined attributes of types and objects

| %GREEN%[Reviewer note: Extended existing attributes for use with objects.]%ENDCOLOR% |||
| %RED%P<del>T</del>%ENDCOLOR%'BASE \
  | Kind:         | Type |
| | Prefix:       | %RED%<del>Any type or subtype T.</del> %BR% \
                    Any prefix P that is appropriate for an object with type or subtype T, or an alias thereof, or that %BR% \
                    denotes any type or subtype T.%ENDCOLOR% |
| | Result:       | The base type of T. |
| | Restrictions: | This attribute is allowed only as the prefix of the name of another attribute; %BR% \
                    for example, P'BASE'LEFT. |
| |||
| %RED%P<del>T</del>%ENDCOLOR%'LEFT \
  | Kind:         | Value |
| | Prefix:       | %RED%<del>Any scalar type or subtype T.</del> %BR% \
                    Any prefix P that is appropriate for an object with a scalar type or subtype T, or an alias thereof, %BR% \
                    or that denotes any scalar type or subtype T.%ENDCOLOR% |
| | Result type:  | Same type as T. |
| | Result:       | The left bound of T. |
| |||
| %RED%P<del>T</del>%ENDCOLOR%'RIGHT \
  | Kind:         | Value |
| | Prefix:       | %RED%<del>Any scalar type or subtype T.</del> %BR% \
                    Any prefix P that is appropriate for an object with a scalar type or subtype T, or an alias thereof, %BR% \
                    or that denotes any scalar type or subtype T.%ENDCOLOR% |
| | Result type:  | Same type as T. |
| | Result:       | The right bound of T. |
| |||
| %RED%P<del>T</del>%ENDCOLOR%'HIGH \
  | Kind:         | Value |
| | Prefix:       | %RED%<del>Any scalar type or subtype T.</del> %BR% \
                    Any prefix P that is appropriate for an object with a scalar type or subtype T, or an alias thereof, %BR% \
                    or that denotes any scalar type or subtype T.%ENDCOLOR% |
| | Result type:  | Same type as T. |
| | Result:       | The upper bound of T. |
| |||
| %RED%P<del>T</del>%ENDCOLOR%'LOW \
  | Kind:         | Value |
| | Prefix:       | %RED%<del>Any scalar type or subtype T.</del> %BR% \
                    Any prefix P that is appropriate for an object with a scalar type or subtype T, or an alias thereof, %BR% \
                    or that denotes any scalar type or subtype T.%ENDCOLOR% |
| | Result type:  | Same type as T. |
| | Result:       | The lower bound of T. |
| |||
| %RED%P<del>T</del>%ENDCOLOR%'ASCENDING \
  | Kind:         | Value |
| | Prefix:       | %RED%<del>Any scalar type or subtype T.</del> %BR% \
                    Any prefix P that is appropriate for an object with a scalar type or subtype T, or an alias thereof, %BR% \
                    or that denotes any scalar type or subtype T.%ENDCOLOR% |
| | Result type:  | Type BOOLEAN. |
| | Result:       | It is TRUE if T is defined with an ascending range; FALSE otherwise. |
| %GREEN%[Reviewer note: New attributes.]%ENDCOLOR% |||
| %RED%P'LENGTH%ENDCOLOR% \
  | %RED%Kind:%ENDCOLOR%        | %RED%Pure function%ENDCOLOR% |
| | %RED%Prefix:%ENDCOLOR%      | %RED%Any prefix P that is appropriate for an object with a discrete or physical type or subtype T, %BR% \
                                  or an alias thereof, or that denotes any discrete or physical type or subtype T.%ENDCOLOR% |
| | %RED%Result type:%ENDCOLOR% | %RED%<i>universal_integer</i>%ENDCOLOR% |
| | %RED%Result:%ENDCOLOR%      | %RED%T'LENGTH = maximum(0, T'POS(T'HIGH) - T'POS(T'LOW) + 1)%ENDCOLOR% |
| |||
| %RED%P'RANGE%ENDCOLOR% \
  | %RED%Kind:%ENDCOLOR%        | %RED%Range%ENDCOLOR% |
| | %RED%Prefix:%ENDCOLOR%      | %RED%Any prefix P that is appropriate for an object with a scalar type or subtype T, %BR% \
                                  or an alias thereof, or that denotes any scalar type or subtype T.%ENDCOLOR% |
| | %RED%Result type:%ENDCOLOR% | %RED%The type of T.%ENDCOLOR% |
| | %RED%Result:%ENDCOLOR%      | %RED%The range T'LEFT to T'RIGHT if the range of T is ascending, or the range %BR% \
                                  T'LEFT downto T'RIGHT if the range of T is descending.%ENDCOLOR% |
| |||
| %RED%P'REVERSE_RANGE%ENDCOLOR% \
  | %RED%Kind:%ENDCOLOR%        | %RED%Range%ENDCOLOR% |
| | %RED%Prefix:%ENDCOLOR%      | %RED%Any prefix P that is appropriate for an object with a scalar type or subtype T, %BR% \
                                  or an alias thereof, or that denotes any scalar type or subtype T.%ENDCOLOR% |
| | %RED%Result type:%ENDCOLOR% | %RED%The type of T.%ENDCOLOR% |
| | %RED%Result:%ENDCOLOR%      | %RED%The range T'RIGHT downto T'LEFT if the range of T is ascending, or the range %BR% \
                                  T'RIGHT to T'LEFT if the range of T is descending.%ENDCOLOR% |
| |||
| T'IMAGE(X)   | %GREEN%[Not modified]%ENDCOLOR% ||
| T'VALUE(X)   | %GREEN%[Not modified]%ENDCOLOR% ||
| T'POS(X)     | %GREEN%[Not modified]%ENDCOLOR% ||
| T'VAL(X)     | %GREEN%[Not modified]%ENDCOLOR% ||
| T'SUCC(X)    | %GREEN%[Not modified]%ENDCOLOR% ||
| T'PRED(X)    | %GREEN%[Not modified]%ENDCOLOR% ||
| T'LEFTOF(X)  | %GREEN%[Not modified]%ENDCOLOR% ||
| T'RIGHTOF(X) | %GREEN%[Not modified]%ENDCOLOR% ||
| O'SUBTYPE    | %GREEN%[Not modified]%ENDCOLOR% ||
| %GREEN%[Reviewer note: new attributes for objects as a shorthand to existing attributes on types.]%ENDCOLOR% |||
| %RED%O'IMAGE%ENDCOLOR% \
  | %RED%Kind:%ENDCOLOR%          | %RED%Pure function%ENDCOLOR% |
| | %RED%Prefix:%ENDCOLOR%        | %RED%Any prefix O that is appropriate for an object with a scalar type or subtype, or an alias thereof.%ENDCOLOR% |
| | %RED%Shorthand for:%ENDCOLOR% | %RED%O'SUBTYPE'IMAGE(O)%ENDCOLOR% |
| |||
| %RED%O'POS%ENDCOLOR% \
  | %RED%Kind:%ENDCOLOR%          | %RED%Pure function%ENDCOLOR% |
| | %RED%Prefix:%ENDCOLOR%        | %RED%Any prefix O that is appropriate for an object with a  discrete or physical type or subtype, or an alias thereof.%ENDCOLOR% |
| | %RED%Shorthand for:%ENDCOLOR% | %RED%O'SUBTYPE'POS(O)%ENDCOLOR% |
| |||
| %RED%O'SUCC%ENDCOLOR% \
  | %RED%Kind:%ENDCOLOR%          | %RED%Pure function%ENDCOLOR% |
| | %RED%Prefix:%ENDCOLOR%        | %RED%Any prefix O that is appropriate for an object with a  discrete or physical type or subtype, or an alias thereof.%ENDCOLOR% |
| | %RED%Shorthand for:%ENDCOLOR% | %RED%O'SUBTYPE'SUCC(O)%ENDCOLOR% |
| |||
| %RED%O'PRED%ENDCOLOR% \
  | %RED%Kind:%ENDCOLOR%          | %RED%Pure function%ENDCOLOR% |
| | %RED%Prefix:%ENDCOLOR%        | %RED%Any prefix O that is appropriate for an object with a  discrete or physical type or subtype, or an alias thereof.%ENDCOLOR% |
| | %RED%Shorthand for:%ENDCOLOR% | %RED%O'SUBTYPE'PRED(O)%ENDCOLOR% |
| |||
| %RED%O'LEFTOF%ENDCOLOR% \
  | %RED%Kind:%ENDCOLOR%          | %RED%Pure function%ENDCOLOR% |
| | %RED%Prefix:%ENDCOLOR%        | %RED%Any prefix O that is appropriate for an object with a  discrete or physical type or subtype, or an alias thereof.%ENDCOLOR% |
| | %RED%Shorthand for:%ENDCOLOR% | %RED%O'SUBTYPE'LEFTOF(O)%ENDCOLOR% |
| |||
| %RED%O'RIGHTOF%ENDCOLOR% \
  | %RED%Kind:%ENDCOLOR%          | %RED%Pure function%ENDCOLOR% |
| | %RED%Prefix:%ENDCOLOR%        | %RED%Any prefix O that is appropriate for an object with a  discrete or physical type or subtype, or an alias thereof.%ENDCOLOR% |
| | %RED%Shorthand for:%ENDCOLOR% | %RED%O'SUBTYPE'RIGHTOF(O)%ENDCOLOR% |


NOTE 1 - The relationship between the values of the LEFT, RIGHT, LOW, and HIGH attributes is expressed as follows:

|                                    |   | <b>Ascending range</b>            | <b>Descending range</b>           |
| %RED%P<del>T</del>%ENDCOLOR%'LEFT  | = | %RED%P<del>T</del>%ENDCOLOR%'LOW  | %RED%P<del>T</del>%ENDCOLOR%'HIGH |
| %RED%P<del>T</del>%ENDCOLOR%'RIGHT | = | %RED%P<del>T</del>%ENDCOLOR%'HIGH | %RED%P<del>T</del>%ENDCOLOR%'LOW  |


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Topic revision: r1 - 2017-04-02 - 12:19:45 - TWikiGuest
P1076