Error handling idea

[amokoura]

My problem was not having error messages up on a deep, deep function call stack. Using plain @error was problematic.

I quickly made an interface for exception-like error handling.

There isn't any real code or implementations yet, it's just a raw interface I figured on a bus trip.

_errorCreate( $msg ) - Create global error id. Returns error id.

_errorRaiseMsg( $msg ) - Raise general error with custom message.

_errorRaise( $id ) - Raise defined error

_errorCatch( $id ) - Catch error. If id is null, catch any error. Returns boolean whether error was caught.

_errorCaughtMsg() - Returns caught error message.

_errorCaughtId() - Returns caught error id.

_errorIs() - Returns boolean whether there's an error.

Example use:

; Create custom error id
Global $ERR_SOMEBAD = _errorCreate( "Something bad happened!" )

main()

func main()
    
    foo()
    
    ; Expect something behind foo() to raise an error
    if _errorCatch($ERR_SOMEBAD) Then
        MsgBox(0,"Specific error!", _errorCaughtMsg())
    ElseIf _errorCatch()
        MsgBox(0,"Unknow error!", _errorCaughtMsg())
    Else
        ; No error
    EndIf
EndFunc

func foo()
    badFunction()
    if _errorIs() then Return
    
    ; this will not be executed because badFunction() caused error
    goodFunction()
EndFunc

func badFunction()
    _errorRaise($ERR_SOMEBAD)
    Return

    ; Would also work:
    ;_errorRaiseMsg( "this is a general error")
EndFunc

After a catch the error is erased so that no other function can catch it anymore.

Edited May 8, 2008 by amokoura