Class: add comparison operators #5645
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| # Int32 <= String # => false | ||
| # ``` | ||
| def <(other : T.class) : Bool forall T | ||
| # This is so that the method is expanded differently for each type |
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Maybe we can bring macro def back, and make it mandatory if you use @type inside of a macro, for clarity... I don't know... |
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@asterite well this is the only use we've found that we still need |
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Yes, I think class comparison should be something core of the language, so probably implemented somehow in the codegen. This is a workaround to have this functionality right now in a simple (kind of hacky way), but as you say I can't imagine other uses for macro defs that don't use |
| end | ||
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| # :nodoc: | ||
| def _lt(other : T.class) forall T |
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Why not make it protected (and all below)?
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I tried, but it doesn't work. The compiler doesn't like it for some reason and I have no time/will to investigate it now.
Fixes #2060
The problem with combining types in a same hierarchy is that the compiler combines them to their parent type as a virtual type. Then when you pass it to a method and match with
other : T.class, thatTis the virtual type.I solve this with using
@typeinside macro code, which signals that the method must be expanded separately for each different type. Well, that solves the problem forself, but the problem still remains forother. That's why I invoke the opposite method inotherusing a helper method and there too, I use@typeinside macro code, and actually use macro code to achieve that.It works. It could always be improved later if we find that's needed. The specs are commented because I also had to change something in the macro comparison code, so those will fail for CI... but we can uncomment those in a next version.