do / until / while / loop

techElder

techElder

Well-known member
Can't get to hardware to test this, but the double do/loop test passes syntax in PE6. Guess I never ran across this kind of double test before.

Code: 
' sample do nothing code
retry = 12
countTo = 10
wrong = 0
do while ii <= retry                    ; test here for execution within loop
   for countFrom 0 to countTo
      if wrong = 1 then
         inc ii
      endif
   next countFrom
loop until countFrom > countTo   ; test here for complete execution of for/next
 
hippy

hippy

Technical Support
Staff member
Texasclodhopper said:
Can't get to hardware to test this, but the double do/loop test passes syntax in PE6. Guess I never ran across this kind of double test before.
Click to expand...
Not sure what the actual question is but a conditional on both DO and LOOP is valid syntax and will work. Underlying all multi-line block commands are single-line IF-THEN commands so -

Code: 
do while ii <= retry
  [i]code[/i]
loop until countFrom > countTo
Is the equivalent of -

Code: 
DoLoopStart:
  If ii > retry Then DoLoopDone  
  [i]code[/i]
  If countFrom <= countTo Then DoLoopStart
DoLoopDone:
Note the compiler adjusts the comparison used in DO-WHILE and LOOP-UNTIL to create an optimised IF-THEN statement.
 
rq3

rq3

Senior Member
Texasclodhopper said:
Can't get to hardware to test this, but the double do/loop test passes syntax in PE6. Guess I never ran across this kind of double test before.

Code: 
' sample do nothing code
retry = 12
countTo = 10
wrong = 0
do while ii <= retry                    ; test here for execution within loop
   for countFrom 0 to countTo
      if wrong = 1 then
         inc ii
      endif
   next countFrom
loop until countFrom > countTo   ; test here for complete execution of for/next
Click to expand...

I'm certainly not the guy to be reviewing code, but how does "wrong" get to be "1" so that countFrom will increment?
 
I

inglewoodpete

Senior Member
rq3 said:
I'm certainly not the guy to be reviewing code, but how does "wrong" get to be "1" so that countFrom will increment?
Click to expand...
Since this is a code snippet, we don't know what is defined in the rest of the program. "wrong" could easily be updated in the (potential) interrupt routine.
 
techElder

techElder

Well-known member
You guys are too literal to be funny! :D :D :D

PS. Hippy guessed right! As usual!

PPS. Fantastic software from RevEd!
 
Last edited:
erco

erco

Senior Member
Texasclodhopper said:
Can't get to hardware to test this, but the double do/loop test passes syntax in PE6.
Click to expand...
Aw, come on, Tex. Don't you keep a Picaxe in your wallet for emergencies, like the rest of us? There's no telltale ring, but sometimes the pins poke through. :)
 
techElder

techElder

Well-known member
erco said:
Aw, come on, Tex. Don't you keep a Picaxe in your wallet for emergencies, like the rest of us? There's no telltale ring, but sometimes the pins poke through. :)
Click to expand...
I ain't tellin' what that weared out ring is from. ;D

Thanks, folks. I was just glad to solve a do/loop for/next if/then problem and reduce the code in a subroutine. Guess I didn't really explain the situation well enough.

I'm hoping that the next 45 posts will use the above snippet of code to create a line-following robot or at least a laser intervalometer for me! :D :D :D
 
You must log in or register to reply here.
Top