Loadstar 24/024.d81/t.perfect input

Text File | 2022-08-26 | 6KB | 424 lines

            PERFECT INPUT
                 by
        Bennett Cookson, Jr.


COMMODORE MICROCOMPUTERS MAGAZINE
May/June, 1986
p. 103


  PERFECT INPUT adds commands to BASIC

that help overcome the INPUT

statement's limitations.  By running

this program before you write your

programs, you will be able to use

commas and colons in your statements,

to redefine the keyboard, and to have

full cursor movement within a set

range.  And those are just SOME of

the features of PERFECT INPUT.


  Keep in mind that if you do write a

program using the PERFECT INPUT

commands, you must always load and run

PERFECT INPUT before you run a program

that uses its commands.


PERFECT INPUT COMMANDS


INPUT A$

INPUT"PROMPT";B$


  When the PERFECT INPUT statement is

used normally, the "?" prompt is gone.

Commas and colons that would normally

elicit an ?EXTRA IGNORED message are

accepted like any other character.

Note that commas and colons are

accepted only into string variables,

not numeric variables.  This means

that you cannot use "INPUT A,B", but

you can use "INPUT A$,B$" to input

numbers.


  Also, cursor movement is limited to

a 79-character range.  The user still

has full cursor movement, but the

cursor seems to hit a barrier before

it gets out of range.


INPUT\10,A$

INPUT\20,"PROMPT",X$


  This syntax allows the programmer to

control the number of characters a

user can type in by setting the

cursor range.  Putting the English

pound sign before the line number

will cause it to be read as "limit".

The limit can range from 1 to 79;

anything larger will cause an ILLEGAL

QUANTITY error.


INPUT 200,A$


  This syntax provides an exit from

INPUT.  When the user presses

a certain key (definable to any key),

BASIC will GOTO the line specified in

the INPUT statement.  (The "certain

key" is defined by the DEFine command,

which will be explained later.)  With

this command, for example, your

program's user could escape from an

INPUT and go back to a menu without

affecting any variables.


INPUT 15,400,"PROMPT";N


  The above features can be used

together.  The limit comes first, then

the exit line number.  If there is a

prompt string, it always comes last,

just before the variable.


AT x,y


 The AT command allows you to

position the cursor anywhere on the

screen by giving the X and Y

coordinates.  X represents the

horizontal position (0-39), Y the

vertical position (0-24).  The values

for X and Y may be expressed in any

form.  These are some examples of how

the AT command is used:


AT 5,7:PRINT"position 5,7"

AT X,Y:INPUT B$

AT J-5+G,INT(W):PRINT" x marks the

spot"

-------


THE DEFine COMMAND


  The DEF key command allows you to

redefine any of the keys except the

SHIFT, CONTROL, COMMODORE, RUN/STOP,

and RESTORE keys.  For example,


DEF"A=B,R=13,133=F"


changes the "A" key to "B", the "R"

key to CHR$(13), and CHR$(133) to "F".

Because the DEFine key routine works

deep inside the operating system, if

you changed "R" to CHR$(13) (RETURN),

R would act like the RETURN key in all

cases.


  The DEFinition list must be written

as a string in quotes or a string

variable.  All characters except

numbers, apostrophes, and back arrows

are considered literally as the

character to DEFine.


  Numbers, however, are considered

ASCII values and to specify a number

as a literal character you must place

an apostrophe just before it.  For

example, 5 would mean CHR$(5), while

'5 means the character "5".


  A range of characters can be used

with this command.  For example:


DEF"91-255=0"


will set all characters with an ASCII

value of 91 through 255 to zero,

thereby disabling all of those keys.

You would use a command like this if

you wanted to disable all graphics

keys.


  Another form of the command can

look like this:


DEF"1-255=0,A-Z=_"


The first part of this line disables

all keys; the second part restores

the A to Z keys to normal.  The left

arrow key means "restore to normal".


  The escape key that exits from an

INPUT statement can be any key defined

as CHR$(1).  For example,


DEF"133=1"


will define F1 as the escape key.

Also, any key defined as CHR$(2) will

act as an erase key, which erases the

character under the cursor.


  The DEF command by itself will

reset the keyboard to normal.

RUN/STOP-RESTORE will also reset the

keyboard, but will not disable the

DEFine key or other commands.  As an

added feature,the keyboard can also

be reset with the END command or if an

error occurs in the program-- making

it easier to edit lines.  If you do

not want the keyboard to reset, you

can remove the two relevant lines

from the loader program with REMs that

say "reset if error" and "reset if

end".


DEMO PROGRAM


  Cookson has added a demo program

that shows some of PERFECT INPUT's

features.  Before running the demo,

first load and run PERFECT INPUT, then

load and run the demo program.


  Lines 70-86 show how to create and

combine present strings.  For example,

once you have set NUMKEY$ to define a

numeric keypad (line 80), you can use

DEF NUMKEY$, which is easier than

defining keys one by one. In line 72,

NOKEY$ will disable all keys.  With

this method, you can disable all keys

and then activate only the keys you

want.  Also, notice how the comma is

used in line 80 when linking strings.


   Lines 100-150 print a box on the

screen and allow the user to fill in

the box, but not move the cursor out

of the box.  Notice that the DELETE

key has been disabled.  Also, it is a

good idea to disable the quote mark

key, because the quote mode can cause

problems in an INPUT statement.


  Lines 450-460 show that the DEF

command can be used easily with the

GET statement, and lines 500-680 show

that the DEF command makes it easy to

use function keys.  Notice that the

function keys are converted to numbers

that can be used with an ON GOSUB

command.  And lines 800-850 show how

the escape key can be used to cause

BASIC to jump out of an INPUT

STATEMENT.


NOTE: Because of the nature of this
program, it cannot be run from the
Loadstar operating system.  Press
RUN/STOP RESTORE and then type:

  LOAD"PERFECT INPUT",8
  RUN

Then to run the demo type:

  LOAD"INPUT DEMO",8
  RUN

Study a listing of the demo to see
how useful PERFECT INPUT can be to
your programs.

FILES REQUIRED:

PERFECT INPUT     INPUT DEMO

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