🚀 go-pugleaf

Twice (or more) I've bumped heads with a small shortcoming of M2 that may
eventually be best cured by a small extension of M2 syntax.

Both in writing an i/o buffering scheme and a command interpreter the problem
arose of accessing components of a big structure which needs to be viewed as
having two different types: "buft=ARRAY range1 OF WORD", say, and
"datat=ARRAY range2 OF somerecord". Unfortunately, type casts are syntactically
expressions and not "designators", and only designators may be called,
dereferenced, subscripted, or selected. So, "datat(buff)[sub].field" bums out.
The only methods I've found which don't copy the whole durned structure are:
	TYPE dataptr = POINTER TO datat; VAR datap: dataptr
1.	datap := dataptr(ADR(buff));
	use(datap^[sub].field);		(* not beautiful *)
2. deceiving the compiler with untagged variant records (which I am too
honest to do :-).

Has anyone a suggestion on how to type cast AND select components?
My preference would be to allow wild-and-wooly syntax like

ComponentValue ::=
	Factor { "." Ident | "[" ExpList "]" | "^" | ActualParameters }.
ProcedureCall ::=
	ComponentValue [ ActualParameters ].
Factor ::=
	Set | Number | etc... | ComponentValue.


vincent broman, code 632,  naval ocean systems center, san diego, ca 92152, usa
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