Hi Tim,
> This appears to work:
> CharsAccepted: func [acceptable[string!] submitted[string!] /local
> inter-set exc-set]
> [
> inter-set: intersect acceptable submitted
> if (length? inter-set) <> (length? submitted)
> [make error! rejoin[exclude submitted inter-set " are not acceptable
> characters"]]
> return true
> ]
Alternatively, you can try using the difference/only function. This
will return a series containing elements that are in the first, but not
the second series, ie. any characters in submitted that are not in
acceptable. If the exc-set string is empty, no unacceptable characters
were found.
CharsAccepted: func [
acceptable [string!] submitted [string!] /local exc-set
][
either empty? exc-set: difference/only submitted acceptable [true]
[make error! join exc-set " are not acceptable characters"]
]
And here is another example, a bit more advanced. If the exc-set is
empty, the any function will return true immediately. Otherwise it goes
on to return an error. I've also put a '[catch]' in the function spec,
this means instead of the error occuring inside the CharsAccepted
function, it will occur at whereever the CharsAccepted function was
called.
CharsAccepted: func [[catch]
acceptable [string!] submitted [string!] /local exc-set
][
return any [empty? exc-set: difference/only submitted acceptable
make error! join exc-set " are not acceptable characters"
]
]
An example -
>> test: func [] [CharsAccepted "abc" "abf"]
>> test
** User Error: f are not acceptable characters.
** Where: CharsAccepted "abc" "abf"
Without the [catch] attribute, this is what happens -
>> test
** User Error: f are not acceptable characters.
** Where: return any [empty? exc-set: difference/only submitted
acceptable
make error! join exc-set " are not acceptable characters"
]
In a small function like CharsAccepted, using the [catch] attribute has
a small advantage, but it can probably help a lot in error handling with
larger functions.
Good luck :),
Julian Kinraid
