FMSLogo Code

Cleanup: Remove logic to skip over the leading + in cnv_node_to_numnode.
This was dead code because numberp() doesn't allow numbers to begin with a +.

Cleanup: Remove some unneeded vref/deref calls in intern_primitive().
It looked like these calls canceled each other out.

Refactoring: rework intern_primitive() to reduce duplicated code.

Fix some misinformation in a comment.
ufun != NIL doesn't mean "not a lambda" it means "user-defined procedure".

Cleanup: Remove a block of code that indent to the tracelevel for singlestepping.

In UCBLogo, the code looks like:

if (ufun != NIL && flag__caseobj(ufun, PROC_STEPPED)) {
if (tracing) {
int i = 1;
while (i++ < trace_level) print_space(stdout);
}
print_node(stdout, this_line);
(void)reader(stdin, " >>> ");
}

This makes sense in UCBLogo because the trace output is interwoven with the single-step dialog.
However, in FMSLogo, the single-step dialog is a separate dialog box, so adding
indentation to the commander history, where the trace output goes, doesn't make sense.

Refactoring: Extract indent_to_trace_level() to reduce duplicated code.

Refactoring: Extract function retreeify_running_proc()
This is a chunk of logic from the evaluator that doesn't access much of the evaluator's state.
Moving this logic into its own function enables getting rid of a label in evaluator().

Correct some misinformation in a comment.
When the Unbound generation is propagated up, it's not applied to the first line.
It's applied to the "bodylist", which is the container for the first node.

Cleanup: Remove unused local variable "definition"

Fix a bug in the way debug_dump_node printed repated CASEOBJ nodes.