Variable names are missing in hover description for local predicates

[EsGeh]

When I hover over a predicate that has a comment attached like this...

%! output_args( +Rules:list, +State:list, -Ctxt, -Statements ).
output_args(
	Rules,
	State,
	Ctxt,
	Statements
) :- true.

...this is what is printed as description when hovering over the predicate:

output_args(+list,+list,-any,-any) is unknown.

This isn't bad, but it'd be nice if it mentioned the name of the variables (Rules, State, Ctxt, Statements), in order to be able to refer to them in case of a more verbose description.
What I'd expect is s.t. like:

output_args(+Rules:list,+State:list,-Ctxt:any,-Statements:any) is unknown.

Any chance of getting this implemented?

[jamesnvc]

That sounds good, I would prefer that behaviour as well. I believe currently it’s displaying just what library(help) gives us, which is oddly limited as you note. I’ll take a look though.

[EsGeh]

That sounds good, I would prefer that behaviour as well. I believe currently it’s displaying just what library(help) gives us, which is oddly limited as you note. I’ll take a look though.

In case of library predicates, variable names are successfully printed, though...
Example:

random_permutation(+List, -Permutation)                            [det]                                                                                                                                                            
Availability: :- use_module(library(random)). (can be autoloaded)                                                                                                                                                                   
                                                                                                                                                                                                                                    
                                                                                                                                                                                                                                    
random_permutation(-List, +Permutation)                            [det]                                                                                                                                                            
Permutation is a  random permutation  of List.  This is  intended to                                                                                                                                                                
process  the  elements  of List  in random  order. The  predicate is                                                                                                                                                                
symmetric.                                                                                                                                                                                                                          
                                                                                                                                                                                                                                    
Errors                                                                                                                                                                                                                              
instantiation_error, type_error(list, _).

[jamesnvc]

Yeah, I think there's something a bit off when getting help from user-defined predicates; because the LSP server doesn't actually load the modules it's introspecting and just relies on xref to parse, it seems to get differently-formatted help than for modules that have actually been loaded. Testing out the internal predicates that the LSP uses, I see that if the file containing the predicates is loaded, then it displays the arguments as expected, but otherwise, they're only parsed via xref, and display in the other way. I'll have to poke around a bit more and think how to handle this, perhaps write a PR for library(xref) to address the difference.