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Datatypes R2 Issue 67
Revision as of 18:00, 14 September 2006 by GrahameGrieve (talk | contribs)
Need to document what the acceptable substitution rules are for datatypes.
This table summarizes the allowable datatype substitutions in designs.
There are two circumstances when one would constrain datatypes:
- Modelling-time: as part of the HDF, done by committee or affilliate
- Run time: as part of the on the wire format (uses xsi:type) as a constraint of a datatype as used in the serialized model (mostly: the message type)
Relationship to Conformance
Conformance discusses constraints, this is about specialisation. Constraints may be applied without specialisation. to complete this section and discuss with Conformance.
Run-time dataype substitution
- ANY can be substitutioned as below
- GTS
- I've got an R-MIM that has GTS in it (see the ActReference R-MIMs in shared messages) since they reference (are an extract of, a summary of) any random act. This requires run-time subtitution. According to Grahame GTS should not be in the above list, in which case I'd have to change the models to use ANY for effectiveTime and constrain the runtime substitution somehow. I dont really want to do that. Rene spronk 06:45, 14 September 2006 (CDT)
- Right. That's an interesting issue. Why does it require run time substitution - what are you thinking this will achieve? And you can't change to ANY
- At modelling time I won't know what specilaization of GTS has been used in Acts that I'll be referencing. As such I have to allow for all GTS specializations. The acts I'm referencing are based on various R-MIMs, each may have used a different GTS speclilization at modelling-time. Rene spronk 07:37, 14 September 2006 (CDT)
Modelling time datatype substitution
Note that regards to collections, COLL<X> can by substitution to COLL<Y> where Y is a valid constraint on X. Note also the committees can introduce Mixins (UVL, and NPPD) in the models to any attribute (if thy make sense)
The second table is those proposed by Lloyd, but they have no formal basis in the abstract datatypes:
Source | Allowed |
ANY | anything (including mixins?) |
BL | nothing |
BN | nothing |
ED | ST |
ST | UID |
CD | CE, CV, CO |
CE | CV, CO |
CV | CO |
CO | nothing |
CS | nothing |
CR | nothing |
SC | nothing |
II | nothing |
TEL | nothing |
AD | nothing |
EN | PN, ON, TN |
PN | nothing |
TN | nothing |
ON | nothing |
QTY | TS, MO, REAL, INT, TS, RTO<QTY, QTY>, PQ |
INT | nothing |
REAL | INT |
RTO | nothing |
PQ | REAL, INT |
PQR | nothing |
MO | nothing |
TS | nothing |
SET<T> | T |
LIST<T> | T |
GLIST<T> | T |
SLIST<T> | T |
BAG<T> | T |
IVL<T> | T |
HIST<T> | HXIT<T>, T |
UVP<T> | T |
NPPD<T> | T |
PIVL<T> | nothing |
EIVL<T> | nothing |
GTS<T> | SET<PIVL<TS>>, SET<EIVL<TS>> |
PPD<T> | ? |
Source | Allowed |
SC | ST |
PN | TN |
ON | TN |
BAG | SET, LIST |
PIVL<T> | IVL<TS> |