Not quite a mask

[John Cunradi]

I am developing an application that will create a mask for an external device (handheld computer)

The field that will contain the mask pattern for this device is an A5 character field.

How can I limit the characters that can be placed into this character field to only these letters: A N S X ?

Thanks.

[Clunes]

Re: Not quite a mask

There are probably a number of ways. I would look at doing a validation check on the Ondepart event to the field on a form, or the onexit event to a browse.

[Ted Giles]

Re: Not quite a mask

If it's only one character that can be used here John, then a simple lookup with a forced selection from a separate lookup table ( which you can easily change later rather than hard coding the characters) would do the job.
If it is possible to add a string of 4 chars -ANSX, then as Mark says, you will have to check each character. But you could check it against the table contents to avoid changing the hard coded check.

[G Gabriel]

Re: Not quite a mask

1-Does the field contain only ONE of these characters? Or any combination thereof?
2-And if so, is the combination a fixed number of characters? or any number?
3-And if so, are these characters separated by spaces? Are all separated by spaces?
4-Does capitalization matter?

[John Cunradi]

Re: Not quite a mask

The characters can be in any order or any length.
There are no spaces between letters and they will always be transformed into all uppercase.

Here's just one example: AAASNNNSNNXX

In case you are wondering the Pattern is A=Alpha, N=Numerals, S=Symbols and X=Any

If anyone is recording DNA sequences, they will have the same issue come up; only four possible letters can be used...but I guess I'm off the subject a bit here.

[Ted Giles]

Re: Not quite a mask

Bloomin 'eck!
So the only allowable chars are ANSX, no matter how long the string?
Can you give us an example of a completed string?

[G Gabriel]

Re: Not quite a mask

This is more of a validation, rather than a mask.
You could do it the clunky way, by either:
1-OnKey event: the worst possible option, or
2-Testing each letter for validation: :Lousy option, or
3-using character functions to test for existence: Just as lousy
4-Break the string to separate characters and test each: Just as above
5-UDF to do any of the above: clunky
Or the best possible option: Regex.
Here is the expression you need to validate:

dim x as c="AAASNNNSNNXX"
?regex_match(upper(x),"[A\sN\sS\sX\s]+")
= .T.
x="axsASxNa"
?regex_match(upper(x),"[A\sN\sS\sX\s]+")
= .T.

x="[SIZE=4][B]M[/B][/SIZE]anx"
?regex_match(upper(x),"[A\sN\sS\sX\s]+")
=[B][SIZE=4] .F.[/SIZE][/B]

x="AAASNNNSNNXX[SIZE=4][B]b[/B][/SIZE]"
?regex_match(upper(x),"[A\sN\sS\sX\s]+")
=[SIZE=4][B] .F.[/B][/SIZE]

x="AAASNNNSNNXX[SIZE=4][B]123[/B][/SIZE]"
?regex_match(upper(x),"[A\sN\sS\sX\s]+")
= [B][SIZE=4].F.[/SIZE][/B]

[Ted Giles]

Re: Not quite a mask

Cool!
Not used Regex yet. Thanks Gabe.

[John Cunradi]

Re: Not quite a mask

I dropped your code into the Field-Rules validation.

I got the message <invalid or incomplete expression>

I'm not the most versed in XBasic, so bear with me.

[Tom Cone Jr]

Re: Not quite a mask

John,

I've never been a fan of checking the entire string only after the user stops. Prefer to check it character by character.

Here's an example that might help you.

-- tom

[G Gabriel]

Re: Not quite a mask

I dropped your code into the Field-Rules validation.

Works just fine for me. Not sure where you dropped it?