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Debug within an error catching block

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Clinton Blackmore

Debug within an error catching block

Greetings.

In one area of code, I need to set a break point and do some debugging. This code is called deeply within a block that is wrapped up so that the end user does not see errors that occur.

In very simplified form, it is like this:

[ self error: 'Throwing an error' ] ifError: [:err :rcvr | Transcript show: 'Trapped error']

When I 'do it', this example will always trap the error instead of breaking into the debugger (which, quit clearly, it is designed to do.)

While I shudder to think of how easily it could be abused, there is no way to break into a debugger anyway, is there (without finding and disabling the outer block that is sent ifError)? Perhaps a hypothetical self untrappableError or self bringUpTheDebuggerPlease?

Cheers,

Clinton

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Bert Freudenberg

Re: Debug within an error catching block

On 10.12.2010, at 16:37, Clinton Blackmore wrote:

Greetings.

In one area of code, I need to set a break point and do some debugging. This code is called deeply within a block that is wrapped up so that the end user does not see errors that occur.

In very simplified form, it is like this:

[ self error: 'Throwing an error' ] ifError: [:err :rcvr | Transcript show: 'Trapped error']

When I 'do it', this example will always trap the error instead of breaking into the debugger (which, quit clearly, it is designed to do.)

While I shudder to think of how easily it could be abused, there is no way to break into a debugger anyway, is there (without finding and disabling the outer block that is sent ifError)? Perhaps a hypothetical self untrappableError or self bringUpTheDebuggerPlease?

To set a breakpoint do "self halt":

[ self halt. self error: 'Throwing an error' ] ifError: [:err :rcvr | Transcript show: 'Trapped error']

- Bert -

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Clinton Blackmore

Re: Debug within an error catching block

That works perfectly in the example code, thank you.

I'm surprised as I thought I'd tried it and I thought that 'error' sends 'halt'.

Putting a 'self halt' in the problem area doesn't bring up the debugger in my real code. I suspect now that the function in which I'm trying to put a breakpoint is not actually being called, and so I'll have to dig deeper to figure out where the error message I am seeing is coming from.

(Perhaps I'll see if I can find out where the error is being trapped, remove the trap, and hope to get a debugger in the locus of the problem.)

I appreciate the help.

Clinton Blackmore

On Fri, Dec 10, 2010 at 6:55 PM, Bert Freudenberg <[hidden email]> wrote:

On 10.12.2010, at 16:37, Clinton Blackmore wrote:

Greetings.

In one area of code, I need to set a break point and do some debugging. This code is called deeply within a block that is wrapped up so that the end user does not see errors that occur.

In very simplified form, it is like this:

[ self error: 'Throwing an error' ] ifError: [:err :rcvr | Transcript show: 'Trapped error']

When I 'do it', this example will always trap the error instead of breaking into the debugger (which, quit clearly, it is designed to do.)

While I shudder to think of how easily it could be abused, there is no way to break into a debugger anyway, is there (without finding and disabling the outer block that is sent ifError)? Perhaps a hypothetical self untrappableError or self bringUpTheDebuggerPlease?

To set a breakpoint do "self halt":

[ self halt. self error: 'Throwing an error' ] ifError: [:err :rcvr | Transcript show: 'Trapped error']

- Bert -

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Beginners mailing list
[hidden email]
http://lists.squeakfoundation.org/mailman/listinfo/beginners

_______________________________________________
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[hidden email]
http://lists.squeakfoundation.org/mailman/listinfo/beginners