[Ecls-list] Useful backtrace information in the SLIME debugger

Dave Roberts dave at vyatta.com
Wed Dec 20 17:19:57 UTC 2006

Is there an option that I can use when compiling ECL that will provide 
useful backtrace information in the SLIME debugger? Currently, I have 
two main problems:

1. I get a backtrace that simply consists of calls to "LAMBDA". This 
makes it tremendously difficult sometimes to determine where, exactly, 
my code has bombed out. Interestingly, some of the Swank functions seem 
to be visible in my backtraces, but nothing of my own. I have tried both 
interpreted (byte-compiled) and fully compiled (fasl) code, but both 
appear to interact with the SLIME debugger the same way.

2. How can I get local variable information for each call frame? When I 
select a call frame in the Slime Debugger's Backtrace list, I get 
"SWANK-BACKEND:FRAME-LOCALS not implemented". There are three possibile 
reasons for this that I can think of:
	A. Swank just needs to implement this. The support is all there on 
ECL's side, but Swank just hasn't taken advantage of it yet.

	B. ECL doesn't provide the hooks necessary for Swank to get that 
information, so there can't be further implementation in Swank until ECL 
provides the appropriate hooks.

	C. The hooks are there, and Swank does implement things, but for 
whatever reason ECL isn't in the right "mode" for things to happen. 
Maybe there is a compile-time or run-time configuration switch that I'm 
not setting correctly.

Thanks for any leads people can give me. Currently, debugging is painful 
in ECL. Without an accurate indication of which function is blowing up, 
or what the variable values are, I'm reduced to inserting FORMAT/PRINC 
into functions.

-- Dave

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