letter?

[wahnoma]

which function determines if a caracter is letter. "is-letter" not available

 

[jdpjamesp]

I think you'll have to write one yourself. Obviously it will depend on your codepage, but if you'll be able to work out the ascii ranges of valid chars and compare the ASC(lv-string) value against your valid range. Alternatively you could create a string containing all valid letters and see if your string is contained in it.

 

[tamhas]

See http://www.oehive.org/project/isNumber for a comprehensive set of tests of input type.