it doesn't seem so, but in the mean time you can take advantage of the # identifier prefix which can be applied to $input() and lets you distinguish between an Ok press and a Cancel press:

Code:
//echo -ag #$input(Press Ok, e) - #$input(Press Cancel, e)


pressing Cancel results in a return value of $null, whereas pressing Ok will always return at least a # character.

of course, this presents a potential problem. the purpose of the # prefix (in this case and certain others) is to attach # to the return value of the identifier only if it isn't already prefixed with it. as such, you won't be able to distinguish between the user having typed 'abc' or '#abc'. with this in mind, you can decide whether or not it's appropriate for your intended purpose.

"The only excuse for making a useless script is that one admires it intensely" - Oscar Wilde