Is Array.toString() guaranteed to remain as is in ActionScript 3?

Question

Is it fine to display the output of Array.toString() to the user, or is there a possibility that the string format could change in future versions of ActionScript 3 or other compilers?

Answer 1

Here's an excerpt describing Array.toString from ECMA-262, which ActionScript 3 follows very closely:

15.4.4.2

Array.prototype.toString ( ) When the toString method is called, the following steps are taken:
1. Let array be the result of calling ToObject on the this value.
2. Let func be the result of calling the [[Get]] internal method of array with argument "join".
3. If IsCallable(func) is false, then let func be the standard built-in method Object.prototype.toString (15.2.4.2).
4. Return the result of calling the [[Call]] internal method of func providing array as the this value and an empty arguments list.

And Array.join:

15.4.4.5

Array.prototype.join (separator) The elements of the array are converted to Strings, and these Strings are then concatenated, separated by occurrences of the separator. If no separator is provided, a single comma is used as the separator. The join method takes one argument, separator, and performs the following steps:
1. Let O be the result of calling ToObject passing the this value as the argument.
2. Let lenVal be the result of calling the [[Get]] internal method of O with argument "length".
3. Let len be ToUint32(lenVal).
4. If separator is undefined, let separator be the single-character String ",".
5. Let sep be ToString(separator).
6. If len is zero, return the empty String.
7. Let element0 be the result of calling the [[Get]] internal method of O with argument "0".
8. If element0 is undefined or null, let R be the empty String; otherwise, Let R be ToString(element0).
9. Let k be 1.
10. Repeat, while k < len
a. Let S be the String value produced by concatenating R and sep.
b. Let element be the result of calling the [[Get]] internal method of O with argument ToString(k).
c. If element is undefined or null, Let next be the empty String; otherwise, let next be ToString(element).
d. Let R be a String value produced by concatenating S and next.
e. Increase k by 1.
11. Return R.

So, the default behavior is very well defined, and won't change.