When is a Number a Number?

[tlottrike]

I want a Field to only have numbers entered into ie. no text.

So I looked at the code in the Lessons Book on page 127 and put this together for my Field script

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on keyDown thekey
   If thekey is not a number then answer information "Must be a number"
   else pass keyDown 
PUT me into nareasqm 
end keyDown

However when I test it, it will not let me enter a decimal point eg. 27.5 yet the Dictionary says a Number can have decimal place. So is this a glitch with LC or is my code doing something to make it think it's an Integer

[dunbarx]

The issue is that LC is evaluating each char in each keypress to see if it is a number. So though it is true that "27.5" is a number , it is also true that "." is not.

Do this instead:

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if theKey is in "0123456789." then...

Craig Newman

[tlottrike]

Thanks again that sorted it.

[[-hh]]

Hi all.

Is "1.1.1" a number? No.
Is "+1" a number? Yes.
Is "-1" a number? Yes.

You could try the following in your field's script.
This works also when pasting text into the field.

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on textchanged
  put 0 into k
  repeat for each line L in me
    add 1 to k
    if L is not a number then
      select line k of me
      exit repeat
    end if
  end repeat
end textchanged

[dunbarx]

Hermann.

Your handler will somewhat guard against non-numeric entry. It is a little too tough on the user, though, eh? If you type a series of digits and then a "K", it deletes the whole line on the next keypress. And if you type "55X" and manually select the next line, it keeps that string intact.

I suggest to pre-validate the keypress itself instead of evaluating the line after the entry.

Craig

[[-hh]]

Craig.
Right, of course the user should set what to do if non-numbers were inserted.
But catching keypresses doesn't handle paste, not "1.." what is not even a version number and also not negative numbers.

[dunbarx]

Hermann.

The devil is always in the details. We just need to deal with them (him?), eh?:

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on keyDown tkey
   put word 2 of the selectedLine into tLine
   if tKey = "-" and "-" is in line tLine of me then exit to top
   if tKey = "+" and "+" is in line tLine of me then exit to top
   if tKey = "." and "." is in line tLine of me then exit to top
   if tkey is in "0123456789-+." then pass keyDown
end keyDown

That sort of thing.

Craig

[[-hh]]

Craig.
Perhaps this could go into a prototype of a "numeric text field"?
Before we get too much sympathy for the devil!?

Ah, what's puzzling you
Is the nature of my game

[dunbarx]

@tlottrike

Can you test this and see what else can go wrong? It is devilishly hard to catch every possible case.

Craig

[Mikey]

What about adding 0 and then looking at what comes out?

[dunbarx]

@Mikey.

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 if tkey is in "0123456789-+." and tKey + 0 is a number then pass keyDown

So see if the handler breaks? Not sure how to manage that.

Craig

[jacque]

Another method:

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on keyDown thekey
   If me & thekey is not a number then answer information "Must be a number"
   else pass keyDown  
end keyDown

This assumes the entry is after the existing text though and will fail if the selection is in the middle somewhere. An alternative would be to use keyup and remove the last entry if the text isn't a number.

[dunbarx]

Jacque.

But this would prevent any of the "+-." chars from being loaded the first time.

Craig

[jacque]

Jacque.

But this would prevent any of the "+-." chars from being loaded the first time.

Craig

Yeah, probably. It depends on the context. I often use your method too.

[Mikey]

I meant instead of the other code.