RENUM

Syntax

RENUM [start_line [TO end_line];][new_line][,step] or

RENUM [start_line] TO [end_line][;new_line][,step]

Location QL ROM

When developing a SuperBASIC program, you will find that you sometimes run out of space in which to insert a new line, because of the line numbers which you have used. Line numbers can be any integer in the range 1…32767 and it is therefore unlikely that you will not be able to make room to fit any more lines into the program. To make more room, you will need to RENUMber the program. You can either elect to use RENUM in its simplest form, or a more complex form.

The simplest form of RENUM is the command:

RENUM

This will renumber the whole of the SuperBASIC program in memory, so that the first line number becomes line 100 and every subsequent SuperBASIC line number will be in an increment of 10.

You can however also use RENUM to renumber a specified range of lines in a program, by using some of the optional parameters. These parameters have the following effects:

  • Start_line specifies the first line to be RENUMbered (default 1).
  • End_line specifies the last line in the range to be RENUMbered (default 32767).
  • New_line the line number which the start_line will be RENUMbered to (default 100).
  • Step specifies the gap between each new line number (default 10).

RENUM will also alter line numbers referred to in the standard QL ROM commands:

GO SUB
GO TO
RESTORE

provided of course that the line number referred to is within the range of lines being renumbered!.

If the line number originally referred to does not exist, then RENUM will point it to the next program line following that line number.

It is also possible that a reference to a line number is actually calculated when the interpreter reaches that line. In such instances, the line number reference can only be renumbered if it is the first thing in the expression. For example, take the following program:

100 locat = 0
110 REPeat loop
120   RESTORE locat + 1000
125   IF EOF: EXIT loop
130   READ description$
140   PRINT description$
150   locat = locat + 1
155   PAUSE
160 END REPeat loop
888 :
1000 DATA 'Location One'
1001 DATA 'Location Two'
1002 DATA 'Location Three'

RENUM would renumber all of the line numbers beginning with line 100 in steps of 10, however, the program would no longer work as the RESTORE command in line 120 would then point to a non-existant line 1000. To solve this, before using RENUM, alter line 120 to:

120 RESTORE 1000 + locat

Having carried out the renumbering task, if the lines currently shown in the list window are affected, they will be relisted in #2 (except under SMS).

Examples

RENUM 100

or:

RENUM 1 TO

These are both the same as RENUM.

RENUM 100 TO 1000;10,5

This will renumber all lines in the range 100 to 1000, with the new lines beginning from line 10 in steps of 5.

RENUM 1000;2000

This will renumber all lines from line 1000 onwards, with the new line numbers beginning with line 2000, and increasing in steps of 10.

RENUM 1000,20

This will renumber all lines from 1000 onwards, with the new line numbers beginning with line 100 and increasing in steps of 20.

NOTE 1

On pre Minerva v1.77 ROMs, RENUM will not generally work correctly on the line number reference in a RESTORE where this appears on the same line as a DATA statement.

NOTE 2

On non Minerva ROMs, the current DATA pointer and ERLIN line numbers tend to get lost in the process! Although SMS updates the DATA pointer, it still has some problems. For example, try the following program:

1 RENUM TO 170;1,1
2 RESTORE
3 READ x:PRINT x
4 RENUM
5 READ x:PRINT x
6 RESTORE 6: DATA 10,12: RESTORE 6
7 READ x: PRINT x
8 STOP
180 PRINT 'Why have I reached here?'

If you alter line 1 to read:

1 RENUM 1,1

then the program just stops without an error at line 4. Minerva still has problems with the above.

Try entering the command:

RENUM 1 TO 7;1,1

An out of range error is reported even though there is no problem with this range. Minerva does this correctly. We believe other ROMs will show different symptoms (see the WARNING below).

NOTE 3

On Minerva ROMs (pre v1.97), if integer tokenisation is enabled, RENUM cannot renumber line numbers less than 128.

NOTE 4

You cannot use RENUM to renumber lines out of sequence. For example, given the following lines:

100 REPeat loop
110 IF INKEY$=CHR$(27):EXIT loop
120 END REPeat loop

Any attempt to:

RENUM 110 TO 110;200

would report an ‘Out of Range’ error, as you would be trying to renumber line 110 out of order!

NOTE 5

If you try to renumber a line outside of the range of line numbers (see above), or there is not enough space between line numbers outside the given range to fit the newly renumbered program lines into, this will cause an ‘Out of Range’ error. For example, taking the routine listed at note 4:

RENUM 32760

or:

RENUM 100 TO 110;119,1

would both report such an error.

NOTE 6

The Turbo and Supercharge compilers from Digital Precision cannot compile a program with calculated RESTOREs, GO SUBs or GO TOs.

NOTE 7

Unfortunately, RENUM will not handle line number references in commands other than GO TO, GO SUB or RESTORE, which can leave lines such as:

SAVE flp1_Prog_ext,1000 TO 2000

high and dry!

WARNING

It is generally inadvisable to use RENUM within a program as the interpreter tends to lose its place (see Note 2 above).

CROSS-REFERENCE

DLINE allows you to delete lines from a program. ED allows you to edit a program in memory. Also see AUTO.