Re: compiler types: records / collections interaction

[siiky]

Hi Al,

> What combination of
>
> * define-record-type (srfi-9, srfi-99, chicken define-record, whatever) and
>
> * (declare type ...)
>
> can I use to inform the compiler that (for collections of myrec) vector- 
> ref returns myrec's (likewise list car/cdr, hash-table-ref)? And that it 
> needs not emit any instance-type-checking code for objects extracted 
> from such collections?

For "native" Scheme types, there's at least `list-of` and `vector-of` 
[0]. The type definitions of car/cdr, vector-ref, etc are in the file 
types.db (you can find it at $PREFIX/lib/chicken/11/types.db).

For other data-structures you have to look at the specific 
implementation. For example, SRFI-69 [1] mentions types in the 
changelog. They're not mentioned in the docs, however, so you'll have to 
dig through the code to confirm this.

> Separately, how can I tell the compiler that fields in these records 
> have certain types? Add type declarations for the implicitly-defined 
> per-field accessors and mutators?

To annotate the types of the fields of a record, take a look at 
defstruct[2]. There may be other alternatives, I only know of this one.


[0] https://wiki.call-cc.org/man/5/Types#type-syntax
[1] https://wiki.call-cc.org/eggref/5/srfi-69
[2] https://wiki.call-cc.org/eggref/5/typed-records#defstruct

Good luck!
siiky