name: match args: [regex, str]
Returns a list if the extended POSIX regular
expression
regex matches str precisely, otherwise returns null. Each item
in the list is a regex group.
builtins.match "ab" "abc"
Evaluates to null.
builtins.match "abc" "abc"
Evaluates to [ ].
builtins.match "a(b)(c)" "abc"
Evaluates to [ "b" "c" ].
builtins.match "[[:space:]]+([[:upper:]]+)[[:space:]]+" " FOO "
Evaluates to [ "FOO" ].