Trace-repl
Enter a read-eval-print loop to explore the FGL state and modify traces.
Invoking (fgl::trace-repl) as part of a trace expression causes
entry into a read-eval-print loop where arbitrary code can be translated using
fancy-translate and executed using fancy-ev. From this REPL, a
user can explore the FGL interpreter state in various ways and examine values
relevant to the current rewriting attempt. The variables discussed in fgl-trace under "Variables usable in tracing expressions" can be referenced
from this REPL, including variables bound in the rule being applied.
To exit from this REPL, submit :exit.
