Operating overloading and expr.Function

[purplefox]

I have defined all my custom functions using expr.Function and added them as options during the compile step. This works nicely and my functions are then usable in expressions.

I would now like to overload some operators (e.g. "+", "-") to work on custom types. I followed the instructions for adding an Operator option. The custom function that does the adding is called "_add" and I have defined it using expr.Function just like all my custom functions.

Unfortunately this does not work, compile fails with:

panic: function _add for + operator does not exist in the environment [recovered]
	panic: function _add for + operator does not exist in the environment

goroutine 34 [running]:
testing.tRunner.func1.2({0x100890180, 0x1400010b760})
	/usr/local/go/src/testing/testing.go:1526 +0x1c8
testing.tRunner.func1()
	/usr/local/go/src/testing/testing.go:1529 +0x364
panic({0x100890180, 0x1400010b760})
	/usr/local/go/src/runtime/panic.go:884 +0x1f4
github.com/antonmedv/expr/conf.(*Config).Check(0x1400017e1c0)
	/Users/tfox/go/pkg/mod/github.com/antonmedv/expr@v1.12.5/conf/config.go:85 +0x2a4
github.com/antonmedv/expr.Compile({0x1007dbac5, 0x7}, {0x1400019c0f0, 0x1e, 0x10088e440?})
	/Users/tfox/go/pkg/mod/github.com/antonmedv/expr@v1.12.5/expr.go:133 +0x184

I debugged into expr and this seems to be because the function "_add" does not exists in the Types map. It seems that only functions that exist in the env are added to this map, functions that are defined using expr.Function are not.

Is there a reason why operator overloading does not work with functions defined using expr.Function?

Thanks in advance!

[antonmedv]

This should be fixed

[purplefox]

Should I add an issue for this? :)

[antonmedv]

👍🏻