> Some languages like Common Lisp have multiple return values. The gethash function in Common Lisp returns a second value which indicates whether the key is pre

> Some languages like Common Lisp have multiple return values. The gethash function in Common Lisp returns a second value which indicates whether the key is present. If the first value is nil, but the second value is t, then it indicates that the nil was actually pulled from the hash table. But this seems to be what you said was an anti-pattern: > That's an anti-pattern. In a properly lexically scoped language, an undefined identifier is erroneous, diagnosable before you even run the code. You were speaking there, presumably, of bare variables, not of hash entries, but Perl's defined-or works just as well on lookups, like `$a{ key } //= "Hi there!"`, in which case it is just a less-verbose version of the two-step lookup you propose.