Jay Foad

"Normal" usage of variables is O(1). There is no run-time searching of stacks or symbol tables or anything like that. Cases that might go slower include:
- referring to a variable via a character vector containing its name, e.g. ⎕NC'foo'. This has to search a symbol table.
- using the same name in different namespaces, e.g. referring to both ns1.foo and ns2.foo. The last namespace a name was seen in is cached; on a cache miss we have to search a symbol table. This also applies to OO-heavy code, which almost inevitably switches into different namespaces all over the place.

There are more hard links you may be missing. See the entries I've marked with ####:

/opt/mdyalog/16.0/64/unicode$ ls -li aplkeys/ apltrans/ fonts/
aplkeys/:
total 40
3408428 -rw-r--r-- 2 root root 7774 Feb 1 03:00 default ####
3408427 -rw-r--r-- 2 root root 575 Feb 1 03:00 file ####
3408374 -rw-r--r-- 1 root root 6731 Feb 1 03:00 file_siso
3408427 -rw-r--r-- 2 root root 575 Feb 1 03:00 utf8 ####
3408424 -rw-r--r-- 1 root root 8173 Feb 1 03:00 utf8codes
3408428 -rw-r--r-- 2 root root 7774 Feb 1 03:00 xterm ####