RENUM¶

Purpose¶

To renumber program lines and automatically update all line number references in GOTO, GOSUB, THEN, ELSE, ON...GOTO, ON...GOSUB, RESTORE, RUN, and ON ERROR GOTO statements.

Syntax¶

Versions: Disk

RENUM has four forms:

RENUM                              ' Renumber all lines starting at 10, increment 10
RENUM <new_start>                  ' Renumber all lines starting at new_start
RENUM <new_start>,<old_start>      ' Renumber from old_start onwards
RENUM <new_start>,<old_start>,<increment>  ' Full control

Parameters can be omitted using commas:

RENUM 100,,20   ' new_start=100, old_start=0 (all lines), increment=20
RENUM ,50,20    ' new_start=10, old_start=50, increment=20

Parameters¶

new_start: First line number in the renumbered sequence (default: 10)
old_start: First line to renumber - lines before this stay unchanged (default: 0 = all lines)
increment: Gap between line numbers (default: 10)

Remarks¶

Automatic Reference Updates¶

RENUM automatically updates line number references in: - GOTO and GOSUB statements - IF...THEN line_number and ELSE line_number - ON...GOTO and ON...GOSUB lists - RESTORE line_number - RUN line_number - ON ERROR GOTO line_number

Range Renumbering¶

When old_start is specified, only lines with numbers >= old_start are renumbered. Lines before old_start keep their original numbers.

This is useful when: - Adding code sections between existing code - Reorganizing parts of large programs - Making room in a specific section

Limitations¶

Cannot create line numbers > 65529
Cannot reorder lines (e.g., RENUM 15,30 when lines are 10,20,30)
If line number reference doesn't exist, prints: "Undefined line xxxxx in yyyyy"
xxxxx = the bad reference (not changed)
yyyyy = the line containing it (may be renumbered)

Example¶

Example 1: Renumber Entire Program¶

Before:

10 PRINT "START"
25 GOTO 60
40 PRINT "SKIP THIS"
60 PRINT "END"

After RENUM (default: start at 10, increment 10):

10 PRINT "START"
20 GOTO 40  ' Automatically updated from GOTO 60
30 PRINT "SKIP THIS"
40 PRINT "END"

Example 2: Different Starting Line¶

10 PRINT "ONE"
20 PRINT "TWO"
30 PRINT "THREE"

RENUM 100

100 PRINT "ONE"
110 PRINT "TWO"
120 PRINT "THREE"

Example 3: Range Renumbering¶

Original program:

10 PRINT "INIT"
20 PRINT "SETUP"
30 PRINT "PROCESS A"
40 PRINT "PROCESS B"
50 PRINT "DONE"

Renumber from line 30 onwards to make room for more setup code:

RENUM 100,30,10

10 PRINT "INIT"
20 PRINT "SETUP"
100 PRINT "PROCESS A"
110 PRINT "PROCESS B"
120 PRINT "DONE"

Lines 10-20 unchanged, lines 30+ renumbered starting at 100.

Example 4: Custom Increment¶

10 FOR I=1 TO 10
20   PRINT I
30 NEXT I

RENUM 1000,,50

1000 FOR I=1 TO 10
1050   PRINT I
1100 NEXT I

Example 5: GOTO Reference Update¶

10 INPUT X
20 IF X<0 THEN GOTO 50
30 PRINT "POSITIVE"
40 END
50 PRINT "NEGATIVE"

RENUM 100,0,10

100 INPUT X
110 IF X<0 THEN GOTO 140
120 PRINT "POSITIVE"
130 END
140 PRINT "NEGATIVE"

GOTO 50 automatically updated to GOTO 140.

Example 6: ON...GOTO Reference Update¶

10 INPUT CHOICE
20 ON CHOICE GOTO 100,200,300
100 PRINT "OPTION 1"
110 END
200 PRINT "OPTION 2"
210 END
300 PRINT "OPTION 3"
310 END

RENUM 1000,100,100

10 INPUT CHOICE
20 ON CHOICE GOTO 1000,1100,1200
1000 PRINT "OPTION 1"
1010 END
1100 PRINT "OPTION 2"
1110 END
1200 PRINT "OPTION 3"
1210 END

All three target lines in ON...GOTO list updated.

Example 7: Making Room for Insertions¶

You have lines 10-100 but need to add many lines between 30-40:

RENUM 1000,40,10

Result: - Lines 10-30 stay unchanged - Lines 40+ renumbered to 1000, 1010, 1020... - Now you can add lines 40-999 with room to spare

Common Patterns¶

Tidy up cramped program¶

RENUM 10,0,10      ' Reset to nice 10,20,30...

Make room in middle of program¶

RENUM 1000,500,10  ' Lines 500+ move to 1000+

Large increment for big programs¶

RENUM 100,0,100    ' 100, 200, 300... lots of room