AppleScript: The Definitive Guide

String, Number and Date Coercions

A class or enumerator may be coerced to a string; for example:

string as string -- "string"

A number may be coerced to a string. A string may be coerced to a number, provided it looks like a literal number; whitespace will be ignored, but nothing else will be. So for example "1a" can’t be coerced to a number. But the empty string, or a string consisting solely of whitespace, will be coerced to 0.

An integer may be coerced to a real. A real may be coerced to an integer; it is rounded to the nearest integer. This is a new feature; in earlier versions of AppleScript, a real could be coerced to an integer only if it was an integer. For example, 1.5 couldn’t be coerced to an integer. The round scripting addition command can help here (see Section 20.5.6), and can be used to dictate the desired rounding behavior.

A date may be coerced to a string; this is simply the string that appears in the literal date specifier after compilation. A string may be used to form a date specifier, but it cannot be coerced to a date. A month may be coerced to a string (because it is a class). A month may also be coerced to an integer; this is a new feature.

A string, Unicode text, and styled text may be coerced to one another. When coercing to a string, you can say as text instead of as string. This is confusing, since the class of the result is still string, and text is actually the name of a completely different class (string is 'TEXT', text is 'ctxt').