Alphabetic character (word) options

Although you can enter the word in full, only the capitalized and highlighted letter is needed; all characters following it are ignored. That is why these are referred to as alphabetic character options.

TRACE actions correspond to the alphabetic character options as follows:

All: Traces (that is, displays) all clauses before execution.
Commands: Traces all commands before execution. If the command results in an error or failure, then tracing also displays the return code from the command.
Error: Traces any command resulting in an error or failure after execution, together with the return code from the command.
Failure: Traces any command resulting in a failure after execution, together with the return code from the command. This is the same as the Normal option.
Intermediates: Traces all clauses before execution. Also traces intermediate results during evaluation of expressions and substituted names.
Labels: Traces only labels passed during execution. This is especially useful with debug mode, when the language processor pauses after each label. It also helps the user to note all internal subroutine calls and transfers of control because of the SIGNAL instruction.
Normal: Traces any command resulting in a negative return code after execution, together with the return code from the command. This is the default setting.
Off: Traces nothing and resets the special prefix options (described later) to OFF. Please consider the Note given with the description of the MSG function (see MSG.
Results: Traces all clauses before execution. Displays final results (contrast with Intermediates, preceding) of evaluating an expression. Also displays values assigned during PULL, ARG, and PARSE instructions. This setting is suggested for general debugging.
Scan: Traces all remaining clauses in the data without them being processed. Basic checking (for missing ENDs and so forth) is carried out, and the trace is formatted as usual. This is valid only if the TRACE S clause itself is not nested in any other instruction (including INTERPRET or interactive debug) or in an internal routine.