Updated 2015-03-16 22:15:47 by aspect

Synopsis  edit

namespace qualifiers string

Description  edit

namespace qualifiers is the complement (almost - see below) of namespace tail. It returns the leading namespace qualifiers for string, or, when string is ::, the empty string. Qualifiers are namespace names separated by ::. The operation of namespace qualifiers is purely lexical. It does not check whether the namespace names exist.

Examples  edit

The value of
namespace qualifiers ::foo::bar::x


Issues  edit

Namespace qualifiers is inconsistent when applied to names in the root namespace:
% namespace qualifiers ::foo::bar
% namespace qualifiers foo::bar
% namespace qualifiers foo

% namespace qualifiers ::foo

This makes it a bit tricky to use correctly. Using ensemble extend it's not hard to write a more ergonomic version:
extend namespace {
    proc join {prefix name} {
        if {[string match ::* $name]} {
            return $name
        if {$prefix eq "::"} {
            return ::$name
        return ${prefix}::$name
    proc prefix {name} {
        string range $name 0 end-[string length [namespace tail $name]]

With these two procs, $x is always equal to:
namespace join [
    namespace prefix $x
] [
    namespace tail $x

See Also  edit


Category Command[Category Tcl syntax help]