Ticket #0002081

Type	Wish	Status	reviewed	Date	12-Oct-2013 15:59
Version	r3 master	Category	Native	Submitted by	fork
Platform	All	Severity	minor	Priority	normal

Summary	Make REDUCE/INTO and COMPOSE/INTO work when targeting any-string
Description	Given that you can do: >> foo: "foo" >> head insert foo reduce [1 + 2] == "3foo" You should be able to do: >> foo: "foo" >> head reduce/into [1 + 2] foo ** Script error: reduce does not allow string! for its out argument As error message shows, you currently can't.
Example code

Assigned to	n/a	Fixed in	-	Last Update	17-Feb-2014 21:10

Comments
(0004071) BrianH 15-Oct-2013 00:15	REDUCE/into and COMPOSE/into are primarily meant for efficiency, by making intermediate blocks less necessary when doing incremental block construction. However, due to implementation constraints they only reduce the overhead of allocating intermediate blocks in the heap, which reduces GC pressure. They actually use the stack as an intermediate block, and just don't allocate another intermediate block in the heap. Nonetheless, getting rid of this second intermediate block may increase efficiency in the operations that are equivalent to the INSERT something-stringish REDUCE-or-COMPOSE block code pattern. As long as we can do this efficiently, it shouldn't break the model to allow it. And it would allow us to make other mezzanine functions more efficient or flexible as well, like (RE)JOIN or REPEND. It probably won't help much with the other */into functions since they're using chained inserts, but we'll see. We would need to figure out a way to share code with the existing INSERT action, to make it able to take its value parameter from the stack. It's a reshuffle, but it could help increase Rebol's efficiency and flexibility.

Comments

(0004071)
BrianH
15-Oct-2013 00:15

REDUCE/into and COMPOSE/into are primarily meant for efficiency, by making intermediate blocks less necessary when doing incremental block construction. However, due to implementation constraints they only reduce the overhead of allocating intermediate blocks in the heap, which reduces GC pressure. They actually use the stack as an intermediate block, and just don't allocate another intermediate block in the heap.

Nonetheless, getting rid of this second intermediate block may increase efficiency in the operations that are equivalent to the INSERT something-stringish REDUCE-or-COMPOSE block code pattern. As long as we can do this efficiently, it shouldn't break the model to allow it. And it would allow us to make other mezzanine functions more efficient or flexible as well, like (RE)JOIN or REPEND. It probably won't help much with the other */into functions since they're using chained inserts, but we'll see.

We would need to figure out a way to share code with the existing INSERT action, to make it able to take its value parameter from the stack. It's a reshuffle, but it could help increase Rebol's efficiency and flexibility.

Date	User	Field	Action	Change
17-Feb-2014 21:10	BrianH	Category	Modified	Unspecified => Native
17-Feb-2014 21:10	BrianH	Status	Modified	submitted => reviewed
15-Oct-2013 00:16	BrianH	Comment : 0004071	Modified	-
15-Oct-2013 00:15	BrianH	Comment : 0004071	Added	-
14-Oct-2013 03:23	fork	Summary	Modified	Make INSERT/INTO and COMPOSE/INTO work when targeting any-string => Make REDUCE/INTO and COMPOSE/INTO work when targeting any-string
14-Oct-2013 03:23	fork	Description	Modified	-
12-Oct-2013 15:59	fork	Ticket	Added	-