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0 pointsmalisper11y ago0 comments

Slime is really amazing. It provides tons of features of which here are a few (these work with Common Lisp, I have no clue if they work with Clojure).

Inspector[0]: You can click on objects to "inspect" their values. This includes hash-tables, arrays, and closures. In addition you can execute arbitrary code on these objects at any time, even while a program is running.

Trace Dialog[1]: Most Lisp implementations already provide a way to trace procedures. Tracing normally consists of printing the input and the output as each traced procedure is called. Slime provides something much more powerful. Slime's Trace Dialog is similar to trace in that it creates a buffer of the input and output, but instead it is provided in a tree menu format. In addition it is possible to inspect all of the values in the Trace Dialog with the inspector.

Debugger[2]: When an error is thrown in a program, a window pops up which provides several things. You can click on a stack frame to see all of the variables in that frame and then inspect those variables with the inspector. You are also provided with a list of restarts[3]. In addition, you can return a value from a given stack frame, or retry a procedure call on the stack frame (you may have modified the definitions of some procedures before you did this), and have the program continue as if nothing had ever happened.

There are also many other features, such as the ability to macroexpand code by clicking on it, to look up every procedure which calls a given procedure, to look up every place in which a given variable is set, and many other awesome features.

[0] http://common-lisp.net/project/slime/doc/html/Inspector.html

[1] http://common-lisp.net/project/slime/doc/html/SLIME-Trace-Di...

[2] http://common-lisp.net/project/slime/doc/html/Debugger.html#...

[3] http://en.wikibooks.org/wiki/Common_Lisp/Advanced_topics/Con...

0 comments

TeMPOraL11y ago

Restarts are feature of Common Lisp, for which SLIME only draws a powerful interface. Your ability to return a value/retry a call from a given stack frame is just a bunch of default restarts of your CL implementation. What is really awesome is that you can add your own restarts to the interactive debugger. Or have them execute automatically.

I recommend those who are not familiar with conditions/restarts to read up a bit on them. This is something like exception handling, but an order of magnitude more powerful.

lispm11y ago

> Your ability to return a value/retry a call from a given stack frame is just a bunch of default restarts of your CL implementation.

Almost. Restarts and value/retry on a stack frame are mostly unrelated - Restarts are only the UI for implementation specific features. Common Lisp provides no feature to retry an arbitrary stack frame. This is all implementation specific functionality provided by SOME implementations.

logicchains11y ago

That actually sounds a lot like Smalltalk.

malkia11y ago

Also the editor does not crash if the (lisp) environment becomes unstable (hangs, crashes, etc.) - Such things rarely happen, but they might - for example in Lispworks (which has emacs-like IDE (very nice) but runs the lisp threads in the same process as the editor).

j / k navigate · click thread line to collapse