The ZSTEP command provides the ability to control GT.M execution. When a ZSTEP is issued from Direct Mode, execution continues to the beginning of the next target line and then GT.M XECUTEs the ZSTEP action. The keyword in the optional ZSTEP argument determines the class of eligible target lines.
The format of the ZSTEP command is:
ZST[EP][:tvexpr] [keyword[:expr]][,...]
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The optional truth-valued expression immediately following the command is a command postconditional that controls whether or not GT.M executes the command.
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The optional keyword specifies the nature of the step; the keywords are INTO, OVER, and OUTOF.
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A ZSTEP with no argument performs the default action OVER; in this case, at least two (2) spaces must follow the ZSTEP to separate it from the next command on the line, which will be ignored.
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The optional expression specifies GT.M code to XECUTE when the ZSTEP arrives at its destination.
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If the ZSTEP argument does not contain an expression argument, ZSTEP defaults the action to the value of $ZSTEP, which defaults to "BREAK."
![[Note]](images/note.png)
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The ZSTEP argument keywords are not expressions and ZSTEP does not accept argument indirection. |
In Direct Mode, ZSTEP performs an implicit ZCONTINUE and therefore GT.M ignores all commands on the Direct Mode command line after the ZSTEP.
The keyword arguments define the class of lines where ZSTEP next pauses execution to XECUTE the ZSTEP action. When a ZSTEP command has multiple arguments, it ignores all arguments except the last.