Simple Error Handling (_ThrowError)

[mlowery]

I write a lot of scripts for my use only, and so I frequently don't take the time to add in proper error-handling. If a script fails, I'll just dig in and debug it. Recently, I decided to work up a very simple error handler function that would allow me to do basic error handling on a single line, making it easy to add to scripts as I write them.

Thought it would be worth sharing for others or feedback on improvements.

;===============================================================================
; Description:      Display an error message and optionally exit or set
;                   error codes and return values. Enables single-line
;                   error handling for basic needs.
; Parameter(s):     $txt        = message to display
;                   [$exit]     = 1 to exit after error thrown, 0 to return
;                   [$ret]      = return value
;                   [$err]      = error code to return to parent function if $exit = 0
;                   [$ext]      = extended error code to return to parent function if $exit = 0
;                   [$time]     = time to auto-close message box, in seconds (0 = never)
; Requirement(s):   None
; Return Value(s):
; Note(s):          Icon is STOP for EXIT/FATAL errors and EXCLAMATION for NO_EXIT/WARNING errors.
;                   For single-line error-reporting. If reporting an error in a function,
;                   can call this with a Returned value as:
;                       If $fail Then Return _ThrowError("failed",0,$return_value)
;===============================================================================
Func _ThrowError($txt, $exit = 0, $ret = "", $err = 0, $ext = 0, $time = 0)
    If $exit = 0 Then
        MsgBox(48, @ScriptName, $txt, $time) ; Exclamation, return with error code
        Return SetError($err, $ext, $ret)
    Else
        MsgBox(16, @ScriptName, $txt, $time) ; Stop, quit after error
        Exit ($err)
    EndIf
EndFunc

Examples in use:

$file = FileOpen($filename,0)
if $file =-1 then _ThrowError("File " & $file & " not found!",1) ; Exit when msgbox closed

$clip = ClipGet()
if $clip = "" then _ThrowError("Clipboard is empty. Continuing...", 0, 0, 0, 3) ; No exit, no error, auto-close in 3 seconds

Func parse_html_title($source_string)
    Local $title = StringRegExp($source_string,"<title>([^>]*)</title>",1)
    If Not IsArray($title) then Return _ThrowError("Failed to extract title", 0, "-no title found-", 1, 0, 3) ; No exit, error=1, auto-close in 3 seconds
    Return $title[0]
EndFunc

[reb]

I write a lot of scripts for my use only, and so I frequently don't take the time to add in proper error-handling. If a script fails, I'll just dig in and debug it. Recently, I decided to work up a very simple error handler function that would allow me to do basic error handling on a single line, making it easy to add to scripts as I write them.

Thought it would be worth sharing for others or feedback on improvements.

;===============================================================================
; Description:      Display an error message and optionally exit or set
;                   error codes and return values. Enables single-line
;                   error handling for basic needs.
; Parameter(s):     $txt        = message to display
;                   [$exit]     = 1 to exit after error thrown, 0 to return
;                   [$ret]      = return value
;                   [$err]      = error code to return to parent function if $exit = 0
;                   [$ext]      = extended error code to return to parent function if $exit = 0
;                   [$time]     = time to auto-close message box, in seconds (0 = never)
; Requirement(s):   None
; Return Value(s):
; Note(s):          Icon is STOP for EXIT/FATAL errors and EXCLAMATION for NO_EXIT/WARNING errors.
;                   For single-line error-reporting. If reporting an error in a function,
;                   can call this with a Returned value as:
;                       If $fail Then Return _ThrowError("failed",0,$return_value)
;===============================================================================
Func _ThrowError($txt, $exit = 0, $ret = "", $err = 0, $ext = 0, $time = 0)
    If $exit = 0 Then
        MsgBox(48, @ScriptName, $txt, $time) ; Exclamation, return with error code
        Return SetError($err, $ext, $ret)
    Else
        MsgBox(16, @ScriptName, $txt, $time) ; Stop, quit after error
        Exit ($err)
    EndIf
EndFunc

Examples in use:

$file = FileOpen($filename,0)
if $file =-1 then _ThrowError("File " & $file & " not found!",1) ; Exit when msgbox closed

$clip = ClipGet()
if $clip = "" then _ThrowError("Clipboard is empty. Continuing...", 0, 0, 0, 3) ; No exit, no error, auto-close in 3 seconds

Func parse_html_title($source_string)
    Local $title = StringRegExp($source_string,"<title>([^>]*)</title>",1)
    If Not IsArray($title) then Return _ThrowError("Failed to extract title", 0, "-no title found-", 1, 0, 3) ; No exit, error=1, auto-close in 3 seconds
    Return $title[0]
EndFunc

Your code works well. I will find this to be useful when scripting.

Thank you for sharing

REB