Ticket #0002048

Type	Bug	Status	built	Date	14-Aug-2013 19:16
Version	r3 master	Category	Datatype	Submitted by	Ladislav
Platform	All	Severity	major	Priority	normal

Summary	Rebinding for better compatibility between functions and closures
Description	The example code below shows an incompatibility between functions and closures in R3 that can be resolved using rebinding. Other positive effects of rebinding would be: * rebinding is faster than binding (no word search in context needs to be performed) * rebinding is more "natural" and "intellingent", only the words bound to the source context get rebound to the dst context, which is what resolves the incompatibility described below * rebinding is less "brittle" than binding (the binding algorithm used is not as fast and reentrant as rebinding)
Example code	; example of an R3 function with "special binding" of its body ; create a function with "normally" bound body ; and keep the original of its body for future use f: make function! reduce [[value] f-body: [value + value]] ; some tests f 1 ; == 2 f 2 ; == 4 f 3 ; == 6 ; adjust the binding change f-body 'value value: 1 ; some tests f 1 ; == 2 f 2 ; == 3 f 3 ; == 4 ; example of an R3 closure with "special binding" of its body ; create a "normal" closure ; and keep the original of its body for future use f: make closure! reduce [[value] f-body: [value + value]] ; some tests f 1 ; == 2 f 2 ; == 4 f 3 ; == 6 ; adjust the binding change f-body 'value value: 1 ; some tests f 1 ; == 2 f 2 ; == 4 f 3 ; == 6

Summary

Rebinding for better compatibility between functions and closures

Description

The example code below shows an incompatibility between functions and closures in R3 that can be resolved using rebinding. Other positive effects of rebinding would be:

* rebinding is faster than binding (no word search in context needs to be performed)
* rebinding is more "natural" and "intellingent", only the words bound to the source context get rebound to the dst context, which is what resolves the incompatibility described below
* rebinding is less "brittle" than binding (the binding algorithm used is not as fast and reentrant as rebinding)

Example code

; example of an R3 function with "special binding" of its body
; create a function with "normally" bound body
; and keep the original of its body for future use
f: make function! reduce [[value] f-body: [value + value]]
; some tests
f 1 ; == 2
f 2 ; == 4
f 3 ; == 6
; adjust the binding
change f-body 'value
value: 1
; some tests
f 1 ; == 2
f 2 ; == 3
f 3 ; == 4

; example of an R3 closure with "special binding" of its body
; create a "normal" closure
; and keep the original of its body for future use
f: make closure! reduce [[value] f-body: [value + value]]
; some tests
f 1 ; == 2
f 2 ; == 4
f 3 ; == 6
; adjust the binding
change f-body 'value
value: 1
; some tests
f 1 ; == 2
f 2 ; == 4
f 3 ; == 6

Assigned to	n/a	Fixed in	-	Last Update	11-Mar-2014 19:17

Comments
(0003927) Ladislav 15-Aug-2013 13:52	In the core-tests suite.
(0003928) Ladislav 15-Aug-2013 14:26	Fixed by https://github.com/rebol/rebol/pull/128

Date	User	Field	Action	Change
11-Mar-2014 19:17	Ladislav	Status	Modified	pending => built
20-Aug-2013 22:08	Ladislav	Summary	Modified	Rebinding for compatibility between functions and closures => Rebinding for better compatibility between functions and closures
19-Aug-2013 08:28	Ladislav	Comment : 0003928	Modified	-
19-Aug-2013 08:28	Ladislav	Comment : 0003928	Modified	-
15-Aug-2013 22:41	Ladislav	Severity	Modified	minor => major
15-Aug-2013 14:27	Ladislav	Category	Modified	Unspecified => Datatype
15-Aug-2013 14:26	Ladislav	Status	Modified	submitted => pending
15-Aug-2013 14:26	Ladislav	Comment : 0003928	Added	-
15-Aug-2013 13:52	Ladislav	Comment : 0003927	Added	-
15-Aug-2013 04:49	BrianH	Comment : 0003923	Removed	-
15-Aug-2013 04:49	BrianH	Comment : 0003923	Added	-
14-Aug-2013 19:44	Ladislav	Description	Modified	-
14-Aug-2013 19:31	Ladislav	Description	Modified	-
14-Aug-2013 19:31	Ladislav	Code	Modified	-
14-Aug-2013 19:16	Ladislav	Ticket	Added	-