copy(n)

💖 copy(n) — the TclOO clone-your-faves manual 💖

okay bestie, gather round, because we're about to talk about oo::copy, the TclOO command that lets you make a whole twin of an object or a class. it's giving duplication, it's giving main character energy, and yes it lives in the TclOO command family. let's go 🦋

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✨ SYNOPSIS ✨

package require tcl::oo

oo::copy sourceObject ?targetObject? ?targetNamespace?

like. three whole arguments and two of them are optional. we love a low-maintenance icon 💅

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🌸 DESCRIPTION 🌸

so the oo::copy command creates a copy of an object or class. periodt.

it takes the name of the object or class to be copied — that's your sourceObject, the original, the blueprint, the moment — and optionally:

• the name of the object or class to create, targetObject — and heads up, if that name isn't an absolute qualified name, it gets resolved relative to the current namespace. iykyk.
• targetNamespace, which is the name of the namespace that will hold the internal state of the object (the my command, etc.). ⚠️ and it must not refer to an existing namespace. not negotiable, bestie.

if either targetObject or targetNamespace is omitted, or is given as the empty string, a new name is chosen. and how are those names chosen? with the same algorithm used by the new method of oo::class. slay, consistent naming behavior, we stan. 💖

so what actually gets copied, you ask? 🎀

• the copied object will be of the same class as the source object, and will have all its per-object methods copied.
• if it's a class, it will also have all the class methods in the class copied — but it will not have any of its instances copied. nope. those stay home. 🙈

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🪞 the <cloned> method moment 🪞

after the targetObject has been created and all definitions of its configuration (e.g., methods, filters, mixins) have been copied, the <cloned> method of targetObject will be invoked — this is your customization era, it lets you do stuff like installing related variable traces. ✨

the only argument given will be sourceObject.

the default implementation of this method (in oo::object) just copies the procedures and variables in the namespace of sourceObject to the namespace of targetObject. simple, elegant, iconic.

😭 important though: if this method call does not return a result that is successful (i.e., an error or other kind of exception), then targetObject will be deleted and an error returned. no half-cloned weirdness, we clean up after ourselves.

and the result of the whole oo::copy command? it's the fully-qualified name of the new object or class. 💅

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🔥 EXAMPLES 🔥

this example creates an object, copies it, modifies the source object, and then demonstrates that the copied object is indeed a copy. literally the perfect little demonstration, obsessed.

oo::object create src
oo::objdefine src method msg {} {puts foo}
oo::copy src dst
oo::objdefine src method msg {} {puts bar}
src msg              → prints "bar"
dst msg              → prints "foo"

see how src went off and changed its whole vibe to bar, and dst is still out here printing foo? that's the copy doing its job. no cap. 🫶

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👀 SEE ALSO 👀

• oo::class(n)
• oo::define(n)
• oo::object(n)

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🏷️ KEYWORDS 🏷️

• clone
• copy
• duplication
• object

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and that's the whole page, bestie 🌈 this was TclOO, version 0.1, bringing you the copy(n) manual — go forth and duplicate responsibly, mwah 💜