How do I check if text can be converted to a number in AppleScript?

Question

I'm trying to write a simple AppleScript to do some text manipulation on the contents of the clipboard. The following code works only if the text in the clipboard can be converted to a number:

set CB to the clipboard
set bugNum to CB as number

But if the text in the clipboard is not a number I get an AppleScript error: "Can’t make "foo" into type number."

How do I write an if condition that I can use to check if CB (of class text) can be converted to a number (and put the "set bugNum to CB as number" inside that)? Or can I "catch" the error somehow?

Answer 1

Did you already read working with errors in the Applescript guide?

Sample code:

set CB to the clipboard
try
    set bugNum to CB as number
on error errStr number errNum
    set bugNum to -1
end try
display dialog "Number from the clipboard: " & bugNum

I skipped the code the first time round since I figured the guide was pretty clear, and far more useful than anything I could write here :)