A NOTE has been added to this issue. ====================================================================== https://www.austingroupbugs.net/view.php?id=1471 ====================================================================== Reported By: joerg Assigned To: ====================================================================== Project: Issue 8 drafts Issue ID: 1471 Category: Shell and Utilities Type: Enhancement Request Severity: Editorial Priority: normal Status: New Name: Jörg Schilling Organization: User Reference: Section: make Page Number: 2888- Line Number: 97001- Final Accepted Text: ====================================================================== Date Submitted: 2021-05-16 12:15 UTC Last Modified: 2021-07-10 18:03 UTC ====================================================================== Summary: Add an orthogonal interface for immediate macro expansion definitions to make ======================================================================
---------------------------------------------------------------------- (0005404) psmith (developer) - 2021-07-10 18:03 https://www.austingroupbugs.net/view.php?id=1471#c5404 ---------------------------------------------------------------------- I reject the assertion that GNU make's documentation doesn't clearly define the behavior of "+=" in the context of immediately expanded variables. There's an entire section of the manual devoted to this, with examples: https://www.gnu.org/software/make/manual/html_node/Appending.html I also don't agree that this behavior wasn't well-described by the request to add ::= and += to the standard. I can't speak to what was or wasn't discussed in the teleconference but the change text is clear: > The following form (the "append" form) modifies a macro by appending additional text to it: > string1 += [string2] > > After the append form: > ... > * If the macro exists and is an immediately-expanded macro, it appends a space and the > evaluation of string2 to the value currently assigned to string1. > ... and this text survived more or less intact through to the final wording. There was nothing hidden about this. Regarding this proposal, I am ambivalent on +:=. One reason I'm ambivalent is that in 25+ years of maintaining GNU make I don't ever recall anyone wanting the ability to add immediately expanded text to a deferred expansion variable. The other reason is that this same behavior can already be had, although it requires using two variables: This: D = a D +:= $(VAR) can be written: D = a I ::= $(VAR) D += $I If it's really the case that you always want this behavior then that's annoying. But as I said, no one has ever asked for this so I question whether it's really something people need a lot. If people use it only occasionally then the two-variable version might even be preferred as more clearly understandable. Another reason for my ambivalence is that these do exactly the same thing: A ::= b A += $(VAR) and A ::= b A +:= $(VAR) which makes the latter seem redundant to me. The :::= operator seems wholly unnecessary. We have two types of variables and we have two assignment operators for them, which is sufficient. If there is a case to be made that putting an already-expanded value into a delayed expansion macro is useful then this: A :::= $(VAR) can be replaced by: A = A +:= $(VAR) or using the current POSIX standard with no changes: A = I ::= $(VAR) A += $I Issue History Date Modified Username Field Change ====================================================================== 2021-05-16 12:15 joerg New Issue 2021-05-16 12:15 joerg Name => Jörg Schilling 2021-05-16 12:15 joerg Section => make 2021-05-16 12:15 joerg Page Number => 2888- 2021-05-16 12:15 joerg Line Number => 97001- 2021-05-16 14:35 shware_systems Note Added: 0005356 2021-05-16 17:18 psmith Note Added: 0005357 2021-05-16 19:02 shware_systems Note Added: 0005358 2021-05-16 19:12 kre Note Added: 0005359 2021-05-16 19:49 shware_systems Note Added: 0005360 2021-05-16 21:26 joerg Note Added: 0005361 2021-05-16 21:27 joerg Note Edited: 0005361 2021-05-22 19:02 psmith Note Added: 0005363 2021-07-08 16:43 geoffclare Note Added: 0005393 2021-07-08 16:57 hvd Note Added: 0005394 2021-07-08 19:30 steffen Note Added: 0005395 2021-07-08 19:32 steffen Note Added: 0005396 2021-07-08 20:01 kre Note Added: 0005397 2021-07-08 20:21 steffen Note Added: 0005398 2021-07-08 20:34 steffen Note Added: 0005399 2021-07-08 21:15 kre Note Added: 0005400 2021-07-08 22:33 steffen Note Added: 0005401 2021-07-08 22:33 steffen Note Added: 0005402 2021-07-10 12:30 joerg Note Added: 0005403 2021-07-10 18:03 psmith Note Added: 0005404 ======================================================================
