Style of Objective-C method parameter names

[sirnacnud]

I am noticing some odd behavior when specifying the style of the Objective-C record fields with --ident-objc-field. It seems to also apply this style to any Objective-C method parameter, such as in interface methods. I am also specifying --ident-objc-type-param, but this doesn't seem to do anything.

Styles:

--ident-objc-field mFooBar
--ident-objc-type-param fooBar

IDL:

test_record = record {
    foo: f32;
    bar: f32;
}

test_interface = interface +o {
    do_something(foo: f32, bar: f32);
}

Generated Objective-C Classes:

@interface ObjC_TestRecord : NSObject
- (nonnull instancetype)initWithFoo:(float)foo
                               mBar:(float)bar;
+ (nonnull instancetype)testRecordWithFoo:(float)foo
                                     mBar:(float)bar;

@property (nonatomic, readonly) float mFoo;

@property (nonatomic, readonly) float mBar;

@end


@protocol ObjC_TestInterface <NSObject>

- (void)doSomething:(float)foo
               mBar:(float)bar;

@end

In the doSomething method, the lower case m is applied to the bar parameter even though this is just a regular method.

Playing around with the Java generator seems to work correctly, --ident-java-field only effects the record fields and not all parameters.

Should --ident-objc-type-param be used for method parameters instead of --ident-objc-field?

[a4z]

Should --ident-objc-type-param be used for method parameters instead of --ident-objc-field?

Sorry, I can't tell you. Mabye someone else?
There are so many flags that do not have real test coverage.
They have been there forever (Dropbox time).
And I never used them.

[sirnacnud]

Looking at the Java generator, it uses typeParam here for the parameter names.

In the Objective-C generator it uses field here. I tried switching it to idObjC.typeParam(p.ident) and it seems to fix the issue.

[a4z]

Good catch!
Can you please generate a pull request with the change?

[sirnacnud]

So I did some more digging through the Java and C++ generators to try and understand what this type-param formatting is supposed to be used for.

It seems my initial thought isn't correct, it is used in Java and C++ for the formatting of the template/generic parameter name. In the below examples FooBar is formatted according to --ident-cpp-type-param and --ident-java-type-param.

In C++ it is for a template class:

template<typename FooBar>
class SomeClass {
}

In Java it is for a generic class:

class SomeClass<FooBar> {
...
}

Objective-C does have some support for generic classes, but I don't see them supported in Djinni. So --ident-objc-type-param seems to be unused.

As for the issue I brought up, it seems like this should be a separate option to configure how the Objective-C method parameter label is formatted. This parameter label is a unique concept to Objective-C, as it only applies after the first method parameter and is used to make the function call read like an English sentence.

[a4z]

If you feel that adding this formatting option is a good idea, please do so!
But if you do, please add a test.