[REBOL] Re: What language am I looking for?
From: lmecir:mbox:vol:cz at: 17-May-2001 20:32
> IMHO, block immutability has more to do with notational and
> correctness issues ("principle of least surprise", avoidance
> of subtle bugs, eliminating tricky cases that can "trip" the
> interpreter, etc.) than performance. The performance issues
> I *meant* to be describing require nothing more than block
> construction and evaluation. Modifying or eliminating *these*
> would have a *drastic* effect on REBOL notation.
> Consider the following fragment:
> >> showall: func [b [block!] /local c]
> [ foreach item b
> [ c: compose/deep [print [(mold :item) "=" (item)]]
> [ do c
> [ ]
> [ ]
> >> tot: 17
> == 17
> >> obj: instantiate [a: 1 b: 2 c: 3 d: 4 e: "done!"]
> >> showall [tot obj/a obj/b obj/e]
> tot = 17
> obj/a = 1
> obj/b = 2
> obj/e = done!
> The value of C is not being mutated, but each pass through
> the loop constructs a new block and then DOes that block.
> Therefore, this bit of code would require recompilation of
> C's (new) value on each pass.
Well, the speed penalty for the above code seems to be obvious. But then, is
this a "typical code sample"? I don't think so, and I want to speed up an
average program. The cases like this can run as slow as interpreted and if
you want to make them faster, you may try a faster rewrite to something more