Re: Some thoughts on dicts in SWIPL 7

2014-02-18 11:48 GMT+01:00 Jan Wielemaker <[email protected]>:

> On 02/18/2014 11:27 AM, Carlo Capelli wrote:
> >
> > I forgot: a pattern that could be handy could be a member_dict/2, to
> > avoid this kind of code
> >
> > (member(F, T.foreignKeys), F >:< _{pkCol:PkCol, fkTable:FkTable,
> > fkCol:FkCol})
>
> I think I'm missing something:
>
> 16 ?- A is _{a:1, b:2}.Key.
> A = 1,
> Key = a ;
> A = 2,
> Key = b.
>
> What am I missing?
>

What I meant: porting older code, that was like

table(T, ..., ForeignKeys),
member(foreignKey(PkCol,FkTable,FkCol), ForeignKeys)

I initially wrote

member(_{pkCol:PkCol, fkTable:FkTable,fkCol:FkCol}, T.foreignKeys),

and that worked. Then I realized that if I add a field to foreignKeys, it
will fail...
Still learning, of course...

>
>         Cheers --- Jan
>
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