basic.inputnull Statement/BASIC Program

basic.inputnull

Command basic.inputnull Statement/BASIC Program
Applicable release versions: AP, R83
Category BASIC Program (486)
Description used with the "input @" statement to define the character used to indicate a "null" input on subsequent "input" statements.

The "inputnull" must precede the affected "input @" statement. This statement only works with single character inputs and only one "inputnull" statement is active at any one time. If there is an "inputtrap" active for the same character, the "inputnull" has precedence.
Syntax inputnull 'character'
Options
Example
The "input@" statement requires a numeric value for 
"string". An "x", although not numeric, is accepted as a 
"null" input.

string=''
inputnull 'x'
input @(10,10):string,50 "mr%3"
if string='' then stop

Even though the "inputtrap" reads "x" as an active value, 
the "inputnull" overrides. "x" will not terminate this 
program.

string=''
inputtrap 'x?!' gosub all.done,help.me,whats.da.haps
loop
  inputnull 'x'
  input @(3,5):string,20 "mr#4"
while string='' do repeat
Purpose
Related basic.statements
basic.inputtrap.goto
basic.inputerr
basic.inputtrap.gosub
basic.input@