abstract(n)

✨ abstract(n) — the TclOO commands glow-up ✨

okay bestie, this one's from TclOO, and it's literally the manual page for oo::abstract. yes the whole page. no we're not skipping anything 💅

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🌸 NAME 🌸

oo::abstract — a class that does not allow direct instances of itself 🫶

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⭐ SYNOPSIS ⭐

package require tcl::oo

oo::abstract method ?arg ...?

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🦋 CLASS HIERARCHY 🦋

like, the family tree. the ancestry. the bloodline 👑

oo::object
   → oo::class
       → oo::abstract

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💖 DESCRIPTION 💖

so abstract classes are classes that can totally contain definitions, but you can't directly manufacture them, bestie — no cap. they're intended to only ever be inherited from and instantiated indirectly. it's giving "i don't do solo careers, i only do features" energy ✨

the characteristic methods of oo::class (create and new) are not exported by an instance of oo::abstract. so yeah, you can't just roll up and new one. that's the whole point 🙈

ngl, a plot twist: oo::abstract is not itself an instance of oo::abstract. iconic. the rule doesn't apply to the rule-maker 💀

🎀 CONSTRUCTOR 🎀

the oo::abstract class does not define an explicit constructor. which means it's effectively the same as the constructor of the oo::class class. lowkey just vibing with the default 💜

🧚 DESTRUCTOR 🧚

the oo::abstract class does not define an explicit destructor either. destroying an instance of it is just like destroying an ordinary class — and heads up, it will destroy all its subclasses too. transitive destruction, periodt. the whole family goes down together 😭

🔥 EXPORTED METHODS 🔥

the oo::abstract class defines no new exported methods. zero. none. empty list, main character energy 🌈

💀 NON-EXPORTED METHODS 💀

the oo::abstract class explicitly states that create, createWithNamespace, and new are unexported. so they're right there in the forbidden section, iykyk 🚫

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🍓 EXAMPLES 🍓

this example defines a simple class hierarchy and creates a new instance of it. then it invokes a method of the object before destroying the hierarchy and showing that the destruction is transitive. fr fr, watch:

oo::abstract create fruit {
    method eat {} {
        puts "yummy!"
    }
}
oo::class create banana {
    superclass fruit
    method peel {} {
        puts "skin now off"
    }
}
set b [banana new]
$b peel              → prints 'skin now off'
$b eat               → prints 'yummy!'
set f [fruit new]    → error 'unknown method "new"...'

so banana ate and slayed because it inherited from the abstract fruit 💅 but trying to new the abstract fruit directly? error. unknown method "new".... we love a boundary 🌸

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🌈 SEE ALSO 🌈

• oo::define(n)
• oo::object(n)

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👑 KEYWORDS 👑

abstract class, class, metaclass, object

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and that's the whole page, bestie 💖 this one's TclOO version 0.3, page abstract(n) — go forth and inherit responsibly 🧚‍♀️✨