can a gofmt rewrite rule remove redundant argument types?

Question

If you have code like: func MyFunc(a int, b int)

Can a gofmt rewrite rule change it to: func MyFunc(a, b int)

I tried: gofmt -r "f(x t, y t) -> f(x, y t)" myfile.go

But I get: parsing pattern f(x t, y t) at 1:5: expected ')', found 'IDENT' t

I also tried: gofmt -r "f(x int, y int) -> f(x, y int)" myfile.go

But it gives a similar error for int instead of t

I have read the gofmt documentation. A web search didn't turn up anything helpful.

I am deliberately using single character identifiers to match expressions.

I suspect the problem may be in trying to match the type since it may not be regarded as an "expression"

Is it possible to do this with gofmt?

Answer 1

No, its not possible - because go fmt treat patter as "Expression", look at the http://golang.org/src/cmd/gofmt/rewrite.go parseExpr() function.

Go specification(http://golang.org/ref/spec#Expressions) clearly says what "An expression specifies the computation of a value by applying operators and functions to operands." so go fmt try to parse your pattern "f(x t, y t)" as function call, so instead of "t" it expects comma or parentheses.

you can not write pattern which will much "func MyFunc(a int, b int)" - because its function definition, not a valid go expression