MAKE "TRACE "TRUE
TRACE is a pre-defined name that allows monitoring of procedure or command line execution. TRACE displays each step of a procedure in the trace window without pausing as it is run. TRACE displays the current step being evaluated as well as the procedure name, if any, line, and output.
There are three TRACE levels. Level 1 lists entry and exit from user functions; level 2 lists entry and exit from user and system functions other than arithmetic and relational comparisons; level 3 lists all evaluation calls, user and system functions including arithmetic and relational comparisons.
Level 2 is the default level of TRACE.
MAKE "TRACE.LEVEL integer from one to three sets the active level when tracing is enabled.
To pause during a trace, use Control-Z. To abort a lengthy TRACE, use Control-G. To turn off TRACE, type:
MAKE "TRACE "FALSE
Example? TO SQUARE :SIDE
> REPEAT 4 [FD \
> :SIDE RT 90]
? MAKE "TRACE \
? SQUARE 30