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!AWSept93/Goodies/ThrowBack/!ThrowBack/!Help
This website contains an archive of files for the Acorn Electron, BBC Micro, Acorn Archimedes, Commodore 16 and Commodore 64 computers, which Dominic Ford has rescued from his private collection of floppy disks and cassettes.
Some of these files were originally commercial releases in the 1980s and 1990s, but they are now widely available online. I assume that copyright over them is no longer being asserted. If you own the copyright and would like files to be removed, please contact me.
| Tape/disk: | Home » Archimedes archive » Archimedes World » AW-1993-09.adf » AWSept93 |
| Filename: | !AWSept93/Goodies/ThrowBack/!ThrowBack/!Help |
| Read OK: | ✔ |
| File size: | 33A5 bytes |
| Load address: | 0000 |
| Exec address: | 0000 |
File contents
--------------------------------------
Application : !Throwback 1.1
Author : � Joe Taylor April 1993
Purpose : BASIC Error throwback
RISCOS 3 only
--------------------------------------
----------------
0. INTRODUCTION
----------------
!Throwback is an application which enables error-throwback for BASIC
programs.
I.e. when an error occurs in BASIC a window opens on the desktop
containing the appropriate error information. Clicking on this window
causes an editor text window to open up with the cursor placed at
the appropriate faulty line.
'C' programmers will already be used to this facility which is part
of Acorn's Desktop Development Environment (DDE).
!Throwback has two modes of operation:
(a) (The 'clean' method)
IF your editor is capable of handling BASIC programs AND 'C'-type
throwback then !Throwback will use this in preference. (Note that this
requires a copy of Acorn's DDEUtils module)
(b) ('Simulated' throwback)
Even if you don't own such facilities never fear we can still produce
error throwback by simulation.
This works perfectly happily with the text editor !Edit in the built-
in Resource filing system for example and !Throwback will use this
editor and method as a last resort.
!Throwback has been written to support the writing of BASIC programs,
without line numbers, using a desktop text editor.Here is a summary of
!Throwback's use with some well-known text editors
Editor 'C'-throwback Simulation line-numbers
������ ������������� ���������� ������������
!Edit � � normal
!DeskEdit �� � normal
!StrongEd � � logical
!Zap � � logical
� N.B.'C'-type throwback for !DeskEdit requires that the text window
is already open on the desktop otherwise the file is not de-tokenised.
Snag 1 : In BASIC the line number reported when an error occurs
------ (given by the value of the BASIC keyword ERL) is the line-number
used by the BASIC command-line and is not necessarily the same
as the "logical" line number.For example the program
10 x=1
20 PRINT x/0
30 END
has a "division-by-zero " error at BASIC line 20 but "logical"
line 2.
Each editor has a different default when you save a program
from its text window without line-numbers.
!Throwback assumes that lines are numbered "normally" i.e
starting with line 10 and then in increments of 10. This
corresponds to !Edit's default
Technical note
��������������
To switch !Throwback to assuming that lines are numbered
'logically' set the system variable, Basic$Options to the
value 'l' i.e
*Set Basic$Options "l"
If this system varaiable contains no 'l' then !Throwback
defaults to 'normal' line numbering.
--------------
1. SETTING UP
--------------
Simply double-click the application !Throwback in the usual way.
This only needs to be done once before each error-throwback session begins.
********************************************************************
* *
* SUGGESTION *
* ---------- *
* *
* *
* Add a line to your !Boot file *
* *
* *Filer_Run <PathName>.!Throwback *
* *
* where <Pathname> is the directory in which you have stored *
* !Throwback on your disc containing the !Boot file. *
* *
* *
********************************************************************
-------------------------------------------------
2. ORGANISING THROWBACK FOR SIMPLE BASIC PROGRAMS
-------------------------------------------------
A "simple" BASIC program is one which is non-multitasking. (E.g. those
programs which are run by double-clicking their icon in a Filer window. For
multi-tasking see below.)
In BASIC the programmer has to "trap" and deal with errors by using the
"ON ERROR" command; see the "BASIC PROGRAMMING MANUAL"
To use the error throwback facilities of !Throwback make the first line
of your program
ON ERROR CHAIN "Edit:Throwback"
or even better (if you understand procedures) make your program of the form
ON ERROR PROCError
<Your program lines here>
END
:
DEF PROCError
ON ERROR OFF
CHAIN "Edit:Throwback"
ENDPROC
N.B. When an error is comitted in BASIC the control is passed to the
=== statements following the most recently executed "ON ERROR" command.
Thus in the second example above the procedure "PROCError" would
be obeyed on the first occurrence of an error. The first command in
this procedure turns the error handler off. THIS IS A VERY WISE
MOVE!!!!!!!!! IF AN ERROR OCCURS IN PROCError AND THE ERROR HANDLER
IS NOT TURNED OFF THE PROCEDURE WOULD CALL ITSELF AD INFINITUM. THE
ONLY WAY OUT WILL BE TO REBOOT THE MACHINE SO RESULTING IN A LOSS
OF DATA - BE WARNED!!!!!!! (Such an error occurs in the above
example if you haven't run !Throwback and the program "Edit:Throwback"
cannot be found, or if you mis-type its name, etc.)
------------------------
3. THE THROWBACK WINDOW
------------------------
If "!Throwback" is used in the manner described in �2 , when an error
occurs in a program, a window opens on the desktop of the form:
_______________________________________
| � | � | Error in Basic Program |
���������������������������������������
| |
| ���Error at line #���������������� |
| | | |
| | <Error message> | |
| | | |
| ���������������������������������� |
| ���line numbers���� |
| | | |
| | �normal | ��������� |
| | �redo | |Throwback| |
| | �logical | ��������� |
| | | |
| ������������������� |
|_____________________________________|
(N.B. The throwback window stays open on the desktop untl you
close it - by clicking on its "close" icon.)
Clicking on the button marked "Throwback" will open a window on the program
file (if none was already open) and the line containing the error will be
highlighted and the cursor placed at the beginning of the line ready for
editing.
PROBLEMS
��������
1. Throwback to WRONG program file.
�����������������������������������
(a) For "simple" BASIC programs this is unlikely to happen.
In this case the file used for throwback is taken from the value of
the system variable Basic$File which was set to the pathname
of the BASIC program file when its icon was double-clicked.
( Note for the technically minded:
�������������������������������
When !Throwback is Run the so-called "Run alias" for BASIC files
[the system variable "Alias$@RunType_FFB"] is changed to include the
command
*Set Basic$File %0
which sets the value to the file double-clicked. This means that
for simple programs the user can ignore the setting of this variable.)
(b) LIBRARIES
���������
Libraries of BASIC procedures are loaded by using the command
LIBRARY "<file>"
from within your program. Any procedure in this library can
be used in your program. If an error occurs in one of the
library procedures !Throwback still works provided that the
first line of the program contains the correct pathname of
the library. I.e. the library has the form
REM > <file>
...
...
library procedure definitions
...
...
The use of pseudo-filing system variables is helpful here.
(c)�Multi-tasking Applications
�������������������������
The value of Basic$File is set to the pathname of the last
BASIC program which was *Run. For multi-tasking programs this
might not be the program in which the error occurs.
Standard applications contain a !Run file (of type "Obey")
which in turn call the BASIC file "!RunImage".
Writers of multi-tasking programs will be know that when a *Obey
file is run the system variable Obey$Dir is set to its path. It
is quite common to store the value of this variable at run time.
Basic$File is playing the same role for BASIC files as
Obey$Dir does for Obey files.
In the !Run file of an application, called !Fred, place a line
*Set Fred$BasicFile <Obey$Dir>.!RunImage
which stores the value at run time. Have a PROCError procedure
as above except include a line which sets the value of
Edit$BasicFile. E.g.
DEF PROCError
ON ERROR OFF
*Set Basic$File <Fred$BasicFile>
CHAIN "Edit:Throwback"
ENDPROC
(d) Programs which are CHAINED
��������������������������
In this case the value of Basic$File has to be set by the
programmer as in (c).
(e) DRAGGING
��������
IF a BASIC program or a "standard" application (i.e. with a BASIC
!RunImage file) is dragged onto the throwback window the pathname
of the file to throw back to changes appropriately.
If you need to do this it is because you haven't been observing
the "rules" in (a)-(d) above!
2. Throwback to the wrong line (but the correct file)
�����������������������������������������������������
As a first resort try toggling between "normal" and "logical" line
numbers. This will probably "cure" your problems.
(Remember that !Throwback assumes line numbers in increments of 10.
If, for example, your program actually has logical line numbers
then an error on line 4 would be shown as "error at line 0.4". The
remedy in this case is simple - choose logical line numbers.)
If the line numbers are neither logical nor normal the program has
to be renumbered. This can be done by clicking on the "redo" button
on the throwback window. (Alternatively,Enter the BASIC command line,
loading the program and giving the command RENUMBER followed by a
SAVE.
SUMMARY
=======
!Throwback is in effect controlled by two system variables:
Basic$File = pathname of file containing error
Basic$Options If contains "l" then logical line numbers
otherwise normal.
If contains "+" the usual error messages will
be given before the throwback window is opened.
Library path names are contained in their first line (as specified
in BASIC programming manual)
00000000 0a 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |.---------------|
00000010 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |----------------|
00000020 2d 2d 2d 2d 2d 2d 2d 0a 41 70 70 6c 69 63 61 74 |-------.Applicat|
00000030 69 6f 6e 20 3a 20 21 54 68 72 6f 77 62 61 63 6b |ion : !Throwback|
00000040 20 20 31 2e 31 0a 41 75 74 68 6f 72 20 20 20 20 | 1.1.Author |
00000050 20 20 3a 20 a9 20 4a 6f 65 20 54 61 79 6c 6f 72 | : . Joe Taylor|
00000060 20 41 70 72 69 6c 20 31 39 39 33 0a 50 75 72 70 | April 1993.Purp|
00000070 6f 73 65 20 20 20 20 20 3a 20 42 41 53 49 43 20 |ose : BASIC |
00000080 45 72 72 6f 72 20 74 68 72 6f 77 62 61 63 6b 0a |Error throwback.|
00000090 0a 20 20 20 20 20 20 20 20 20 20 20 20 20 20 52 |. R|
000000a0 49 53 43 4f 53 20 33 20 6f 6e 6c 79 0a 0a 2d 2d |ISCOS 3 only..--|
000000b0 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |----------------|
*
000000d0 2d 2d 2d 2d 0a 0a 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |----..----------|
000000e0 2d 2d 2d 2d 2d 2d 0a 30 2e 20 49 4e 54 52 4f 44 |------.0. INTROD|
000000f0 55 43 54 49 4f 4e 0a 2d 2d 2d 2d 2d 2d 2d 2d 2d |UCTION.---------|
00000100 2d 2d 2d 2d 2d 2d 2d 0a 0a 20 20 20 21 54 68 72 |-------.. !Thr|
00000110 6f 77 62 61 63 6b 20 69 73 20 61 6e 20 61 70 70 |owback is an app|
00000120 6c 69 63 61 74 69 6f 6e 20 77 68 69 63 68 20 65 |lication which e|
00000130 6e 61 62 6c 65 73 20 65 72 72 6f 72 2d 74 68 72 |nables error-thr|
00000140 6f 77 62 61 63 6b 20 66 6f 72 20 42 41 53 49 43 |owback for BASIC|
00000150 0a 20 20 20 70 72 6f 67 72 61 6d 73 2e 0a 0a 20 |. programs... |
00000160 20 20 49 2e 65 2e 20 77 68 65 6e 20 61 6e 20 65 | I.e. when an e|
00000170 72 72 6f 72 20 6f 63 63 75 72 73 20 69 6e 20 42 |rror occurs in B|
00000180 41 53 49 43 20 61 20 77 69 6e 64 6f 77 20 6f 70 |ASIC a window op|
00000190 65 6e 73 20 6f 6e 20 74 68 65 20 64 65 73 6b 74 |ens on the deskt|
000001a0 6f 70 0a 20 20 20 63 6f 6e 74 61 69 6e 69 6e 67 |op. containing|
000001b0 20 74 68 65 20 61 70 70 72 6f 70 72 69 61 74 65 | the appropriate|
000001c0 20 65 72 72 6f 72 20 69 6e 66 6f 72 6d 61 74 69 | error informati|
000001d0 6f 6e 2e 20 43 6c 69 63 6b 69 6e 67 20 6f 6e 20 |on. Clicking on |
000001e0 74 68 69 73 20 77 69 6e 64 6f 77 0a 20 20 20 63 |this window. c|
000001f0 61 75 73 65 73 20 61 6e 20 65 64 69 74 6f 72 20 |auses an editor |
00000200 74 65 78 74 20 77 69 6e 64 6f 77 20 74 6f 20 6f |text window to o|
00000210 70 65 6e 20 75 70 20 77 69 74 68 20 74 68 65 20 |pen up with the |
00000220 63 75 72 73 6f 72 20 70 6c 61 63 65 64 20 61 74 |cursor placed at|
00000230 0a 20 20 20 74 68 65 20 61 70 70 72 6f 70 72 69 |. the appropri|
00000240 61 74 65 20 66 61 75 6c 74 79 20 6c 69 6e 65 2e |ate faulty line.|
00000250 0a 0a 20 20 20 27 43 27 20 70 72 6f 67 72 61 6d |.. 'C' program|
00000260 6d 65 72 73 20 77 69 6c 6c 20 61 6c 72 65 61 64 |mers will alread|
00000270 79 20 62 65 20 75 73 65 64 20 74 6f 20 74 68 69 |y be used to thi|
00000280 73 20 66 61 63 69 6c 69 74 79 20 77 68 69 63 68 |s facility which|
00000290 20 69 73 20 70 61 72 74 0a 20 20 20 6f 66 20 41 | is part. of A|
000002a0 63 6f 72 6e 27 73 20 44 65 73 6b 74 6f 70 20 44 |corn's Desktop D|
000002b0 65 76 65 6c 6f 70 6d 65 6e 74 20 45 6e 76 69 72 |evelopment Envir|
000002c0 6f 6e 6d 65 6e 74 20 28 44 44 45 29 2e 0a 0a 20 |onment (DDE)... |
000002d0 20 20 21 54 68 72 6f 77 62 61 63 6b 20 68 61 73 | !Throwback has|
000002e0 20 74 77 6f 20 6d 6f 64 65 73 20 6f 66 20 6f 70 | two modes of op|
000002f0 65 72 61 74 69 6f 6e 3a 0a 0a 20 20 20 28 61 29 |eration:.. (a)|
00000300 20 28 54 68 65 20 27 63 6c 65 61 6e 27 20 6d 65 | (The 'clean' me|
00000310 74 68 6f 64 29 0a 20 20 20 0a 20 20 20 20 20 20 |thod). . |
00000320 20 49 46 20 79 6f 75 72 20 65 64 69 74 6f 72 20 | IF your editor |
00000330 69 73 20 63 61 70 61 62 6c 65 20 6f 66 20 68 61 |is capable of ha|
00000340 6e 64 6c 69 6e 67 20 42 41 53 49 43 20 70 72 6f |ndling BASIC pro|
00000350 67 72 61 6d 73 20 41 4e 44 20 27 43 27 2d 74 79 |grams AND 'C'-ty|
00000360 70 65 0a 20 20 20 20 20 20 20 74 68 72 6f 77 62 |pe. throwb|
00000370 61 63 6b 20 74 68 65 6e 20 21 54 68 72 6f 77 62 |ack then !Throwb|
00000380 61 63 6b 20 77 69 6c 6c 20 75 73 65 20 74 68 69 |ack will use thi|
00000390 73 20 69 6e 20 70 72 65 66 65 72 65 6e 63 65 2e |s in preference.|
000003a0 20 28 4e 6f 74 65 20 74 68 61 74 20 74 68 69 73 | (Note that this|
000003b0 0a 20 20 20 20 20 20 20 72 65 71 75 69 72 65 73 |. requires|
000003c0 20 61 20 63 6f 70 79 20 6f 66 20 41 63 6f 72 6e | a copy of Acorn|
000003d0 27 73 20 44 44 45 55 74 69 6c 73 20 6d 6f 64 75 |'s DDEUtils modu|
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000003f0 6d 75 6c 61 74 65 64 27 20 74 68 72 6f 77 62 61 |mulated' throwba|
00000400 63 6b 29 0a 0a 20 20 20 20 20 20 20 45 76 65 6e |ck).. Even|
00000410 20 69 66 20 79 6f 75 20 64 6f 6e 27 74 20 6f 77 | if you don't ow|
00000420 6e 20 73 75 63 68 20 66 61 63 69 6c 69 74 69 65 |n such facilitie|
00000430 73 20 6e 65 76 65 72 20 66 65 61 72 20 77 65 20 |s never fear we |
00000440 63 61 6e 20 73 74 69 6c 6c 20 70 72 6f 64 75 63 |can still produc|
00000450 65 0a 20 20 20 20 20 20 20 65 72 72 6f 72 20 74 |e. error t|
00000460 68 72 6f 77 62 61 63 6b 20 62 79 20 73 69 6d 75 |hrowback by simu|
00000470 6c 61 74 69 6f 6e 2e 0a 0a 20 20 20 20 20 20 20 |lation... |
00000480 54 68 69 73 20 77 6f 72 6b 73 20 70 65 72 66 65 |This works perfe|
00000490 63 74 6c 79 20 68 61 70 70 69 6c 79 20 77 69 74 |ctly happily wit|
000004a0 68 20 74 68 65 20 74 65 78 74 20 65 64 69 74 6f |h the text edito|
000004b0 72 20 21 45 64 69 74 20 69 6e 20 74 68 65 20 62 |r !Edit in the b|
000004c0 75 69 6c 74 2d 0a 20 20 20 20 20 20 20 69 6e 20 |uilt-. in |
000004d0 52 65 73 6f 75 72 63 65 20 66 69 6c 69 6e 67 20 |Resource filing |
000004e0 73 79 73 74 65 6d 20 66 6f 72 20 65 78 61 6d 70 |system for examp|
000004f0 6c 65 20 61 6e 64 20 21 54 68 72 6f 77 62 61 63 |le and !Throwbac|
00000500 6b 20 77 69 6c 6c 20 75 73 65 20 74 68 69 73 0a |k will use this.|
00000510 20 20 20 20 20 20 20 65 64 69 74 6f 72 20 61 6e | editor an|
00000520 64 20 6d 65 74 68 6f 64 20 61 73 20 61 20 6c 61 |d method as a la|
00000530 73 74 20 72 65 73 6f 72 74 2e 0a 20 20 20 20 20 |st resort.. |
00000540 20 20 0a 0a 20 20 20 20 21 54 68 72 6f 77 62 61 | .. !Throwba|
00000550 63 6b 20 68 61 73 20 62 65 65 6e 20 77 72 69 74 |ck has been writ|
00000560 74 65 6e 20 74 6f 20 73 75 70 70 6f 72 74 20 74 |ten to support t|
00000570 68 65 20 77 72 69 74 69 6e 67 20 6f 66 20 42 41 |he writing of BA|
00000580 53 49 43 20 70 72 6f 67 72 61 6d 73 2c 0a 20 20 |SIC programs,. |
00000590 20 20 77 69 74 68 6f 75 74 20 6c 69 6e 65 20 6e | without line n|
000005a0 75 6d 62 65 72 73 2c 20 75 73 69 6e 67 20 61 20 |umbers, using a |
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000005f0 74 68 20 73 6f 6d 65 20 77 65 6c 6c 2d 6b 6e 6f |th some well-kno|
00000600 77 6e 20 74 65 78 74 20 65 64 69 74 6f 72 73 0a |wn text editors.|
00000610 0a 20 20 20 20 20 20 20 20 20 20 20 20 45 64 69 |. Edi|
00000620 74 6f 72 20 20 20 20 20 20 20 20 27 43 27 2d 74 |tor 'C'-t|
00000630 68 72 6f 77 62 61 63 6b 20 20 20 20 20 53 69 6d |hrowback Sim|
00000640 75 6c 61 74 69 6f 6e 20 20 20 20 20 6c 69 6e 65 |ulation line|
00000650 2d 6e 75 6d 62 65 72 73 0a 20 20 20 20 20 20 20 |-numbers. |
00000660 20 20 20 20 20 98 98 98 98 98 98 20 20 20 20 20 | ...... |
00000670 20 20 20 98 98 98 98 98 98 98 98 98 98 98 98 98 | .............|
00000680 20 20 20 20 20 98 98 98 98 98 98 98 98 98 98 20 | .......... |
00000690 20 20 20 20 98 98 98 98 98 98 98 98 98 98 98 98 | ............|
000006a0 0a 20 20 20 20 20 20 20 20 20 20 20 20 21 45 64 |. !Ed|
000006b0 69 74 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |it |
000006c0 84 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |. |
000006d0 20 80 20 20 20 20 20 20 20 20 20 20 20 20 20 6e | . n|
000006e0 6f 72 6d 61 6c 0a 20 20 20 20 20 20 20 20 20 20 |ormal. |
000006f0 20 20 21 44 65 73 6b 45 64 69 74 20 20 20 20 20 | !DeskEdit |
00000700 20 20 20 20 20 80 9c 20 20 20 20 20 20 20 20 20 | .. |
00000710 20 20 20 20 20 20 80 20 20 20 20 20 20 20 20 20 | . |
00000720 20 20 20 20 6e 6f 72 6d 61 6c 0a 20 20 20 20 20 | normal. |
00000730 20 20 20 20 20 20 20 21 53 74 72 6f 6e 67 45 64 | !StrongEd|
00000740 20 20 20 20 20 20 20 20 20 20 80 20 20 20 20 20 | . |
00000750 20 20 20 20 20 20 20 20 20 20 20 80 20 20 20 20 | . |
00000760 20 20 20 20 20 20 20 20 20 6c 6f 67 69 63 61 6c | logical|
00000770 0a 20 20 20 20 20 20 20 20 20 20 20 20 21 5a 61 |. !Za|
00000780 70 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |p |
00000790 80 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |. |
000007a0 20 84 20 20 20 20 20 20 20 20 20 20 20 20 20 6c | . l|
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000007c0 9c 20 4e 2e 42 2e 27 43 27 2d 74 79 70 65 20 74 |. N.B.'C'-type t|
000007d0 68 72 6f 77 62 61 63 6b 20 66 6f 72 20 21 44 65 |hrowback for !De|
000007e0 73 6b 45 64 69 74 20 72 65 71 75 69 72 65 73 20 |skEdit requires |
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00000800 6e 64 6f 77 0a 20 20 20 20 20 20 20 20 20 20 69 |ndow. i|
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00000850 69 73 65 64 2e 0a 0a 20 20 20 20 0a 20 20 20 20 |ised... . |
00000860 20 53 6e 61 67 20 31 20 3a 20 20 49 6e 20 42 41 | Snag 1 : In BA|
00000870 53 49 43 20 74 68 65 20 6c 69 6e 65 20 6e 75 6d |SIC the line num|
00000880 62 65 72 20 72 65 70 6f 72 74 65 64 20 77 68 65 |ber reported whe|
00000890 6e 20 61 6e 20 65 72 72 6f 72 20 6f 63 63 75 72 |n an error occur|
000008a0 73 0a 20 20 20 20 20 2d 2d 2d 2d 2d 2d 20 20 20 |s. ------ |
000008b0 20 28 67 69 76 65 6e 20 62 79 20 74 68 65 20 76 | (given by the v|
000008c0 61 6c 75 65 20 6f 66 20 74 68 65 20 42 41 53 49 |alue of the BASI|
000008d0 43 20 6b 65 79 77 6f 72 64 20 45 52 4c 29 20 69 |C keyword ERL) i|
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000008f0 72 0a 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |r. |
00000900 20 75 73 65 64 20 62 79 20 74 68 65 20 42 41 53 | used by the BAS|
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00000920 61 6e 64 20 69 73 20 6e 6f 74 20 6e 65 63 65 73 |and is not neces|
00000930 73 61 72 69 6c 79 20 74 68 65 20 73 61 6d 65 0a |sarily the same.|
00000940 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 61 | a|
00000950 73 20 74 68 65 20 22 6c 6f 67 69 63 61 6c 22 20 |s the "logical" |
00000960 6c 69 6e 65 20 6e 75 6d 62 65 72 2e 46 6f 72 20 |line number.For |
00000970 65 78 61 6d 70 6c 65 20 74 68 65 20 70 72 6f 67 |example the prog|
00000980 72 61 6d 0a 0a 20 20 20 20 20 20 20 20 20 20 20 |ram.. |
00000990 20 20 20 20 20 20 20 20 20 20 20 20 20 31 30 20 | 10 |
000009a0 78 3d 31 0a 20 20 20 20 20 20 20 20 20 20 20 20 |x=1. |
000009b0 20 20 20 20 20 20 20 20 20 20 20 20 32 30 20 50 | 20 P|
000009c0 52 49 4e 54 20 78 2f 30 0a 20 20 20 20 20 20 20 |RINT x/0. |
000009d0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
000009e0 20 33 30 20 45 4e 44 0a 0a 20 20 20 20 20 20 20 | 30 END.. |
000009f0 20 20 20 20 20 20 20 20 68 61 73 20 61 20 22 64 | has a "d|
00000a00 69 76 69 73 69 6f 6e 2d 62 79 2d 7a 65 72 6f 20 |ivision-by-zero |
00000a10 22 20 20 65 72 72 6f 72 20 61 74 20 42 41 53 49 |" error at BASI|
00000a20 43 20 6c 69 6e 65 20 32 30 20 62 75 74 20 22 6c |C line 20 but "l|
00000a30 6f 67 69 63 61 6c 22 0a 20 20 20 20 20 20 20 20 |ogical". |
00000a40 20 20 20 20 20 20 20 6c 69 6e 65 20 32 2e 0a 0a | line 2...|
00000a50 20 20 20 20 20 20 20 20 20 20 20 20 20 20 45 61 | Ea|
00000a60 63 68 20 65 64 69 74 6f 72 20 68 61 73 20 61 20 |ch editor has a |
00000a70 64 69 66 66 65 72 65 6e 74 20 64 65 66 61 75 6c |different defaul|
00000a80 74 20 77 68 65 6e 20 79 6f 75 20 73 61 76 65 20 |t when you save |
00000a90 61 20 70 72 6f 67 72 61 6d 0a 20 20 20 20 20 20 |a program. |
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00002f30 62 65 72 73 0a 20 20 20 20 20 20 20 20 20 20 20 |bers. |
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00003110 56 45 2e 0a 20 20 20 20 20 20 20 20 20 20 20 0a |VE.. .|
00003120 20 20 20 20 20 20 20 0a 20 20 20 20 20 20 20 20 | . |
00003130 53 55 4d 4d 41 52 59 0a 20 20 20 20 20 20 20 20 |SUMMARY. |
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00003150 20 21 54 68 72 6f 77 62 61 63 6b 20 69 73 20 69 | !Throwback is i|
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00003240 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00003250 20 20 20 20 20 20 20 20 20 49 66 20 63 6f 6e 74 | If cont|
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00003290 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
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000032b0 65 20 74 68 65 20 74 68 72 6f 77 62 61 63 6b 20 |e the throwback |
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00003340 6c 29 0a 20 20 20 20 20 20 20 20 0a 0a 20 20 20 |l). .. |
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00003360 20 20 20 20 20 20 20 0a 20 20 20 20 20 20 20 20 | . |
00003370 20 0a 0a 20 20 20 20 20 20 20 20 0a 0a 20 20 20 | .. .. |
00003380 20 20 20 20 0a 0a 20 20 20 20 0a 0a 20 20 20 0a | .. .. .|
00003390 0a 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |. |
000033a0 0a 20 20 20 0a |. .|
000033a5 
.