Error module

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SoCoder -> Snippet Home -> Misc

mindstorm8191	Created : 14 May 2010 System : Windows Language : Blitz Error module handles errors, part of Mindstorm's collection
I have a load of different modules, and I thought I'd start sharing them here. The first is the Error module, basically a simple wrapper system to manage errors. A lot of my modules use it, so while this one may not be the most valuable, I think it should be up first, so there's no other conflicts with people using my modules. ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Error report library ; ; Records errors for later processing by the user program ; ; By Danny Bartsch (Mindstorm), theory by Morduun ; ; Requires Blitz / Blitz3D to run ; ; No other files in this project ; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; This code is best viewed at 1024x768 resolution ; Last modified 2007.03.08 ; Legal Notice ; * This code is authorized by its author for use in any commercial / noncommercial product ; developed in Blitz3D, BlitzPlus, and/or BlitzMax, to be used however you wish, provided ; you conform to the following conditions. ; * You may not distribute this file to any other users, for any purpose. Please direct ; those interested in this code to https://www.socoder.net ; * You must give me, the author of this library, proper and fair credit in every product & ; program you develop which uses this source. ; * If you port this code to any other language, please give me appropriate credit as well. ; * You are authorized to modify this source as necessary for your work. If your modifications ; are in such a way to enhance features of this library, I ask that you send a copy of this ; modified library back to me, via email to mindstorm8191@yahoo.com. Your contributions will ; benefit other users of this module. In your email, please state your name and what ; modifications you've made. ; * These usage requirements can be changed at any time without notice. Please see ; www.mindstormgames.com for updates to the requirements of using this module. These and all ; modules listed may be updated / upgraded / enhanced at any time, so be sure you check by ; there frequently. ; Usage Instructions ; - Before this module can be used, you must write a function called OnError. This will take a ; single Error instance parameter, i.e. Function OnError(this.Error). Use this function to ; process errors immediately, as they occur. You may wish to delete error instances at this ; time, as this library does not do that for you. ; - This module is designed To manage the errors you may have in your programs. While it is ; unfortunately unable to spot or handle common Blitz errors which may crash your programs (such ; as an image not existing when you draw it), you can detect other errors in your program. This ; module has been made to help you manage your errors more easily. ; - There are two basic ways to handle an error when it occurs: immediately, or a try-catch method. ; When an error instance is created, the callback command OnError is called. You may then handle ; the error at this point. The other method is used commonly in other new languages. ; Essentially, when an operation is done that may cause an error, a try-catch block is set up ; around that operation. If an error occurs in that block, the catch section is then ran, to ; handle the error. ; - While Blitz cannot that kind of structure to be made, you can emulate its effect. When you ; carry out a routine that may generate an error instance, use ErrorOccurred immediately ; afterwards to see if an error has occurred. If it has, handle the error at this point. ; Project Modification History ; 2005.04.09 Mindstorm - Added Usage Requirements section, for fair sharing ; 2005.04.17 Mindstorm - Replaced usage requirements with legal notice. Updated Usage Instructions ; To be more clear. ; 2005.08.16 Mindstorm - Expanded usage instructions to explain things more in detail. Added ; Function ErrorOccurred. Should allow For a mock throw-catch error handling. >:D ; 2005.08.25 Mindstorm - Added an actionCode parameter to error instances. Use this to determine ; what type of action to take, upon receiving an error. This error is ment to be unique to ; each error type. ; 2005.08.26 Mindstorm - Added a LastError globla type reference, for easy access to the last error ; generated. Added FixedError, to handle redirecting of the LastError type reference. ; 2007.03.08 Mindstorm - Added an IgnoreErrors flag to keep from dealing with expected errors. Type Error Field from$ ; what function reported the error Field typeCode ; special error case, for allowing the user program to know what type of ; error this is Field actionCode ; special error code that helps better determine what error occurred and ; what to do about it. Field what$ ; text message describing the error, for showing to the user End Type Global IgnoreErrors = False Global ErrorFlag = False Global LastError.Error Function ReportError(from$, code, what$, action=0) ;-------------------------------------------------- ;Generates an error instance, for reporting an error.------------------------------------------------- ; from$ - what function caused the error ; code - special code from the function, to determine what actually happened ; what$ - text form of the error, to show the user (if necessary) ; action - special code used to determine the kind of action to take ;No return value. If Not(IgnoreErrors) make.Error = New Error make\from$ = from$ make\typeCode = code make\what$ = what$ make\actionCode = action ErrorFlag = True LastError = make OnError make EndIf ;2005.08.16 Mindstorm - Added support for the errorFlag variable. ;2005.08.25 Mindstorm - Added support for the action variable. ;2005.08.26 Mindstorm - Added support for the LastError global type reference. ;2007.03.08 Mindstorm - Added support for an IgnoreErrors flag. End Function Function ErrorOccurred() ;---------------------------------------------------------------------------- ;Returns true if an error has recently occurred, or false if not. If an error has recently----------- ;occurred, once this function is called, it will no longer return true, until another error is-------- ;created.--------------------------------------------------------------------------------------------- If ErrorFlag = True ErrorFlag = False Return True Else Return False EndIf ;2005.08.16 Mindstorm - Created function, to allow for a mock throw-catch error handling in ; Blitz >:D End Function Function FixedError() ;------------------------------------------------------------------------------- ;Frees the last generated error instance from memory. Also sets the LastError global reference to a-- ;new error instance. Use this instead of simply freeing the last error instance, to help with error-- ;handling flow.--------------------------------------------------------------------------------------- ;No parameters. This function relies on global data. ;No return value. Delete LastError LastError = Last Error ;2005.08.26 Mindstorm - Created function. Not tested. There may be a crash problem when the ; LastError reference is null. End Function --v Umm... may look better formatted in the blitz editor. Have fun!

Comments
Friday, 14 May 2010, 10:42
Phoenix	If you have many of these files, why not place them all in a showcase? I'm not sure I'd call this a code snippet; I think it would be more useful if it was collected in one place along with the others.
Friday, 14 May 2010, 12:00
Cower	This probably doesn't need a showcase, given how small it is.
Friday, 14 May 2010, 12:15
JL235	I like how well documented it is. Even if it's small, it's good to write code properly!
Friday, 14 May 2010, 17:23
Phoenix	I didn't mean that this piece of code alone should be a showcase, but he did say that he has "a load of different modules" so I thought it would make sense to group them in a showcase.
Friday, 14 May 2010, 20:00
mindstorm8191	JL, thanks for the compliment. Phoenix, maybe I should put it into a showcase, since I do have a bunch, and several modules are stretched over several files (they're kinda large tools). But at the same time, if I put them all into a single showcase, I don't think people will know the benefits of each module. Its like 3-4 MB of source (I put alot of work into these, too). I could put it all into one showcase, and then describe each one here, but that's a lot of work too... what do you think I should do?
Saturday, 15 May 2010, 05:32
Phoenix	Do it whichever way you find structures the code the best.

Comments