Radio Shack TRS-80 PC-3 Owner's Manual page 151

Examples
1(1 INPUT A
20 ON A GOSUB 10(1,200,300
30 END
1(10 PRINT "FIRST"
110 RETURN
200 PRINT "SECOND"
210 RETURN
30(1 PRINT 'THIRD"
310 RETURN
An input of 1 prints "FIRST"; 2 prints "SECOND"; 3 prints "THIRD". Any other
input does not produce any print.
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