0000648: struct declarations need to be defined in the same object

ID	Project	Category	View Status	Date Submitted	Last Update

0000648	LDMud	LPC Compiler/Preprocessor	public	2009-06-01 05:56	2022-10-06 20:13

Reporter	_xtian_	Assigned To	Gnomi
Priority	normal	Severity	minor	Reproducibility	always
Status	closed	Resolution	won't fix

Summary	0000648: struct declarations need to be defined in the same object
Description	From the documentation: This works if it is in the same file: struct Quux; struct Bar { struct Quux quux; }; struct Quux { // Quux needs to be in the same file }; ... but does not work if Quux is not defined in the same file, even if Bar it is not used or even instantiated in this file. The check if all struct declarations have been defined should only happen when such a struct is being used (ie a variable is being instantiated, it is used in a function definition).
Additional Information	Beeing able to declare structs that will be only fully defined in a later object makes it easier to share struct definitions between files. This should compile: struct Quux; struct Bar { struct Quux quux; }; ... and only throw the error later if Bar is used without Quux beeing fully defined.
Tags	No tags attached.

External Data (URL)

zesstra 2009-06-01 06:30 administrator ~0001179	Well... Structs are tied to the program they are defined in. Technically, even recompiling a program with struct defintions creates a new struct, although the driver tries to merge the two definitions if they are identical and from the same file. I don't know, if there a way to relate from a struct bla; in an arbitrary file, that this is meant to be struct bla from /std/comm.c.

Gnomi 2021-04-08 16:30 manager ~0002571	Technically speaking you want something like C++'s templates. The struct Bar in the inherited program is just a template and not a real struct definition, because it is not allowed to be used anywhere unless struct Quux is known (i.e. the struct Bar template is instantiated with a concrete struct Quux). There is an easier solution, just #include the struct definition in the target program. Therefore it might not be worth to implement such a template system.

Gnomi 2022-10-06 20:13 manager ~0002698	Is described in the previous comments, this cannot work with our current type system. You have the option of either using struct mixed (or only mixed) or using includes to simulate variadic structs.

Date Modified	Username	Field	Change
2009-06-01 05:56	_xtian_	New Issue
2009-06-01 06:30	zesstra	Note Added: 0001179
2009-06-01 07:01	zesstra	Relationship added	has duplicate 0000579
2009-06-01 07:03	zesstra	Relationship deleted	has duplicate 0000579
2009-06-01 07:03	zesstra	Relationship added	duplicate of 0000579
2021-04-08 16:30	Gnomi	Note Added: 0002571
2022-10-06 20:13	Gnomi	Assigned To	=> Gnomi
2022-10-06 20:13	Gnomi	Status	new => closed
2022-10-06 20:13	Gnomi	Resolution	open => won't fix
2022-10-06 20:13	Gnomi	Note Added: 0002698