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HaxeFoundation / hxcpp

Runtime files for c++ backend for haxe
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Replace `<::cpp::Int64>` with `< ::cpp::Int64>` to fix template errors #1040

Closed jeremyfa closed 1 year ago

jeremyfa commented 1 year ago

On hxcpp 4.3.2, I got template build errors related to usage <::cpp::Int64> when using native code that includes like the one in linc_dialogs.

It seems the way to go is to simply keep a space between < and :: so that the compiler doesn't parse it wrong. This pull request does just that.

@Aidan63 you might be interested in this PR as it's related to your Int64 changes.

Aidan63 commented 1 year ago

Good spot, seems like this error is related to the C++ standard version. Prior to C++ 11 <:: would be treated as a digraph, but C++ 11 added an extra rule stating that it should not be treated as a digraph if the next character is not : or >.

Otherwise, if the next three characters are <:: and the subsequent character is neither : nor >, the < is treated as a preprocessor token by itself and not as the first character of the alternative token <:.

Not sure if hxcpp has a miniumum C++ version it wants to supports, but adding those spaces are an easy fix to get it working pre C++ 11.

jeremyfa commented 1 year ago

Yes, I have seen other places where a space is used, like with: < ::String>, so I came up with the same workaround here

Aidan63 commented 1 year ago

I remember seeing those spaces before < and always wondered if that was a style choice or actually required, since it seemed to work fine for me I assumed it was the former, but now I know!

I wonder if my changes to generic extern classes could generate this sort of invalid C++...