[Go] Can not use BailErrorStrategy since ParseCancellationException is not implement

[olOwOlo]

• runtime version github.com/antlr4-go/antlr/v4 v4.13.0
• panic stack

panic: implement me [recovered]
	panic: implement me

goroutine 7 [running]:
testing.tRunner.func1.2({0x79b8500, 0x7a0c5a0})
	/usr/local/opt/go/libexec/src/testing/testing.go:1631 +0x24a
testing.tRunner.func1()
	/usr/local/opt/go/libexec/src/testing/testing.go:1634 +0x377
panic({0x79b8500?, 0x7a0c5a0?})
	/usr/local/opt/go/libexec/src/runtime/panic.go:770 +0x132
github.com/antlr4-go/antlr/v4.ParseCancellationException.GetMessage(...)
	/Users/me/go/pkg/mod/github.com/antlr4-go/antlr/v4@v4.13.0/errors.go:247
github.com/antlr4-go/antlr/v4.(*DefaultErrorStrategy).ReportError(0x7a114a8?, {0x7a114a8, 0xc0000580e8}, {0x7a0da70, 0x7bdfd20})
	/Users/me/go/pkg/mod/github.com/antlr4-go/antlr/v4@v4.13.0/error_strategy.go:108 +0x18c

• It seems that there are still some TODO. Not sure if panic meets expectations. Does Go runtime currently support this feature? I want to fast error when there are any errors.

antlr4/runtime/Go/antlr/v4/errors.go

Lines 245 to 248 in 380ce4b

 func (p ParseCancellationException) GetMessage() string { 
 	//TODO implement me 
 	panic("implement me") 
 } 

• usage code

	errors := NewSimpleErrorListener()

	chars := antlr.NewInputStream(text)
	lexer := parse.NewStringTemplateLexer(chars)
	lexer.RemoveErrorListeners()
	lexer.AddErrorListener(errors)

	tokens := antlr.NewCommonTokenStream(lexer, antlr.TokenDefaultChannel)
	parser := parse.NewStringTemplateParser(tokens)
	parser.SetErrorHandler(antlr.NewBailErrorStrategy())
	parser.RemoveErrorListeners()
	parser.AddErrorListener(antlr.NewDiagnosticErrorListener(true))
	parser.AddErrorListener(errors)

	parser.T()

[Jim Idle]

It does not implement this at the moment. I will take a look at it, but this strategy relies on Exceptions and came from Java. Painc might in fact be the only possible way. However, unless your grammar is suspect or your input is very very large, there may not be much advantage. I see the convenience idea though.

[Jim Idle]

@parrt this can be closed as won't fix.