Chapter 7 - Running graphutils code in Clozure CL on Mountain Lion

[FordPrefect]

Hi there,

I've been working through chapter 7 and wanted to try creating the graph. I grabbed the source from the site and have tried running it like so:

(graph->png *wizard-nodes* *wizard-edges*)

I get this error in return from the listener:

Error: Unbound variable: *WIZARD-NODES*

I see the *wizard-nodes* defined as a global variable at the beginning of the file. Any idea how I can run the sample?

Thanks.

[Kevin Lindsey]

Hi FordPerfect,

I'm a Lisp newbie here, but I did the following in clisp on OS X and it worked for me:

1. Downloaded graph-util.lisp
2. Started clisp
3. (load "graph-util")
4. graph->png wasn't in that file, so I typed it in at the REPL
5. (graph->png "wizard.dot" *wizard-nodes* *wizard-edges*)
   

FWIW, I have seen some strangeness with long REPL sessions where I was typing in the code from the book. Later changes wouldn't seem to work. I found quitting clisp, restarting clisp, and then loading my lisp file oftentimes resolved those issue. Maybe that's what's happening here for you.

HTH,

Kevin

[FordPrefect]

Thanks.