What should a lisp implementation return when (car '()) is evaluated? How does a arbitrarily chosen return value differ from a undefined behavior?
Is "" -> 0 a standard conversion in PHP? I get it if we consider the groups (String, +) and (Float, +), but 0 is hardly the standard identity value.
In it being defined, don't you think?
> Is "" -> 0 a standard conversion in PHP?
Erm... yes? `(float)""` returns that, `"" + ""` returns that, `0 + ""` returns that, and so do `intval('')`, `(int)''` or `floatval('')`. More generally, http://www.php.net/manual/en/language.types.string.php#langu...:
> When a string is evaluated in a numeric context, the resulting value and type are determined as follows [...] The value is given by the initial portion of the string. If the string starts with valid numeric data, this will be the value used. Otherwise, the value will be 0 (zero).
> 0 is hardly the standard identity value.
0 remains the standard and defined numeric value of an arbitrary string not prefixed with numeric data in PHP.
You know, I didn't actually know that. Thank you for enlightening me.