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LNO( ) |
Return Line Number |
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1. Passing a Line Number: |
LNO (stmtref) |
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2. Passing a String Expression: |
LNO (stringexpr$ [ ,ERR=stmtref ]) |
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stmtref |
Statement label for which the LNO function is to return the line number. |
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stringexpr$ |
String expression to be evaluated. |
(Format 2 was added in PxPlus 2021.)
Line number of the statement referred to by stmtref.
The LNO( ) function is used to get the line number of a PxPlus statement. Normally, it is passed a line label and will return the line number that the label is in; however, it can also be passed a line number. While it may seem useless to pass the LNO function a line number, passing a line number to the function assures that, within the program, the line number reference will be adjusted during a RENUMBER directive.
Format 2 can be used wherever a statement number or label is used (i.e. after a GOTO, GOSUB, ERR=, etc.). The LNO function will evaluate the string expression and use that to find and return the line reference to be used:
Example:
GOTO LNO("evt_"+event$,err=Bad_Label)
The above will transfer to the statement labeled evt_xxxxxxx where xxxxxxx is the contents of the variable _event$_. If no such label exists, an error will be thrown.
Consider the following statements:
0100 ! ^100 - Update Logic
0110 print (TRACE)"Start section",lno(0100)
If you were to issue a RENUMBER, the system will recognize the 0100 within the LNO function as a line number and will adjust it accordingly so that if statement 0100 moved to 0200, the value within the LNO function would be adjusted.