VOO — Vanilla Object Orientation for Tcl

VOO is a lightweight OO framework that composes classes from Tcl's native data structures — lists and dictionaries — rather than introducing additional framework infrastructure. VOO objects are plain Tcl lists with automatic memory management through copy-on-write semantics, eliminating the destructor burden inherent in TclOO and Itcl.

Benchmarks on Tcl 8.6.13 and Tcl 9.0 show VOO achieves 7–18× faster object creation and 4–6× superior memory efficiency compared to TclOO. A companion C++ migration path further improves field-access speed and memory usage while preserving an identical Tcl call-site API.

Quickstart

source voo.tcl

voo::class Point {
    public {
        double_t x 0.0
        double_t y 0.0
    }

    method distance {} {
        set dx [get.x $this]
        set dy [get.y $this]
        return [expr {sqrt($dx*$dx + $dy*$dy)}]
    }
}

set p [Point::new 3.0 4.0]
puts [Point::get.x $p]       ;# 3.0
puts [Point::distance $p]    ;# 5.0

Point::set.x p 6.0
puts [Point::get.x $p]       ;# 6.0

Quick Reference

Class Declaration

voo::class ClassName ?-virtual? ?-extends ParentClass? {
    public {
        type_t fieldName defaultValue
        type_t -static staticFieldName defaultValue
    }
    private {
        type_t fieldName defaultValue
    }
    method name {args} { body }
    constructor {args} { body }
    importMethods {parentMethod1 parentMethod2}
}

Field Types

ObjType	Description	Default	Example
`double_t`	Floating-point	`0.0`	`double_t x 0.0`
`int_t`	Integer	`0`	`int_t count 0`
`string_t`	String	`""`	`string_t name ""`
`bool_t`	Boolean	`0`	`bool_t active 1`
`list_t`	List	`{}`	`list_t items [list]`
`dict_t`	Dictionary	`{}`	`dict_t data [dict create]`
`obj_t`	Any object	`{}`	`obj_t nested {}`

Constructors (auto-generated)

set obj [Class::new arg1 arg2 ...]        ;# Positional
set obj [Class::new()]                     ;# Default values
set obj [Class::new.args -field1 val ...]  ;# Named arguments

Accessors (auto-generated per field)

set val [Class::get.field $obj]                       ;# Getter
Class::set.field obj value                             ;# Setter
Class::update.field obj temp { modify $temp }          ;# Updater (COW-safe)

set val [Class::class.get.staticField]                 ;# Static getter
Class::class.set.staticField value                     ;# Static setter

Method Modifiers

Modifier	Description
(none)	`$this` passed by value
`-static`	No `this` argument
`-upvar`	`this` passed by reference
`-update {fields}`	Named fields detached during body (COW-safe)
`-override`	Validates parent method exists
`-virtual`	Enables polymorphic dispatch (supports `-upvar` and `-update`)

Inheritance

voo::class Child -extends Parent {
    # Inherits parent fields and accessors
    method parentMethod -override {} { ... }
    importMethods {parentMethod1 parentMethod2}
}

Virtual Polymorphism

voo::class Shape -virtual {
    method area -virtual {} { return 0.0 }
}
voo::class Circle -extends Shape {
    public { double_t radius 1.0 }
    method area -override {} {
        return [expr {3.14159 * [get.radius $this] ** 2}]
    }
}
set s [Circle::new 5.0]
puts [Shape::area $s]   ;# dispatches to Circle::area -> 78.54

Note: a base.<name> method is automatically created for virtual methods, so the original implementation can be called by child classes when overriding it.

Visibility

Fields and methods in private { } blocks receive a my. prefix and are not exported.

API

`voo::class`

Declare a new VOO class.

voo::class ClassName ?-virtual? ?-extends ParentClass? ?-overwrite? body

Parameter	Description
`ClassName`	Name of the class (becomes a Tcl namespace)
`-virtual`	Enable virtual polymorphic dispatch for this class
`-extends`	Inherit from `ParentClass` (single inheritance only)
`-overwrite`	Replace existing VOO class namespace before redefinition
`body`	Class body containing field declarations, methods, etc.

Behavior notes:

If ClassName already exists as a VOO class or namespace, voo::class raises an error unless -overwrite is provided.

# Basic class
voo::class Person {
    public {
        string_t name "unknown"
        int_t age 0
    }
    method greet {} {
        return "Hello, I'm [get.name $this]"
    }
}

# Virtual root class
voo::class Shape -virtual {
    method area -virtual {} { return 0.0 }
}

# Inheriting class
voo::class Circle -extends Shape {
    public { double_t radius 1.0 }
    method area -override {} {
        return [expr {3.14159 * [get.radius $this] ** 2}]
    }
}

Field Types

Declare typed fields inside a class body. Each creates a field with a default value and auto-generates accessors.

double_t  ?-static? name ?initialValue?
int_t     ?-static? name ?initialValue?
string_t  ?-static? name ?initialValue?
bool_t    ?-static? name ?initialValue?
list_t    ?-static? name ?initialValue?
dict_t    ?-static? name ?initialValue?
obj_t     ?-static? name ?initialValue?

Parameter	Description
`-static`	Store as class-level variable instead of instance field
`name`	Field name
`initialValue`	Optional initial value (type default if omitted)

voo::class Config {
    public {
        # Non-static fields
        string_t  host "localhost"
        int_t     port 8080
        bool_t    verbose 0
        list_t    tags [list]
        dict_t    metadata [dict create]
        obj_t     nested {}

        # Static field
        int_t     -static instanceCount 0
    }

    private {
        # Private field => my.get.secret, my.set.secret, my.update.secret
        string_t secret "token"
    }
}

`public` / `private`

Control visibility of field and method declarations.

public { body }
private { body }

Fields and methods declared inside private receive a my. prefix and are not namespace-exported. Fields and methods inside public (the default) are exported normally.

Recommended usage:

Use private fields plus getter/setter when you want to keep representation details abstract (encapsulation).
Use public fields when the class is intentionally struct-like and simplicity is preferred over strict encapsulation.
Even with public fields, consider accessor procs for stable call sites when you expect internals to evolve.

voo::class Account {
    # default mode is public
    string_t id ""

    public {
        string_t owner ""
        method ownerLabel {} {
            return "Owner: [get.owner $this]"
        }
    }

    private {
        double_t balance 0.0
        method rawBalance {} {
            return [my.get.balance $this]
        }
    }
}

set a [Account::new "A-1" "Alice" 0.0]
puts [Account::get.owner $a]           ;# public accessor
puts [Account::ownerLabel $a]          ;# public method
puts [Account::my.rawBalance $a]       ;# private method name has my. prefix
# Account::get.owner   - accessible
# Account::my.get.balance - not exported

`constructor`

Define a custom constructor for the class. If no constructors are declared, VOO auto-generates new (positional), new() (no-args), and new.args (named).

constructor ?options? ?argList body?

Option	Description
`-name ctorName`	Use a custom constructor name
`-noargs body`	No-argument constructor with the given body
`-typed types`	Constructor named `new(type1,type2,...)`

# All constructor scenarios for the same class
voo::class Color {
    public {
        int_t r 0
        int_t g 0
        int_t b 0
    }

    # 1) Explicit positional constructor (same role as auto new)
    constructor {r g b} {
        return [list $r $g $b]
    }

    # 2) Explicit no-args constructor (same role as auto new())
    constructor -noargs {
        variable __defaultObj
        return $__defaultObj
    }

    # 3) Explicit named constructor (same role as auto new.args)
    constructor -name new.args {args} {
        variable __defaultObj
        set obj $__defaultObj
        dict for {key value} $args {
            set field [string range $key 1 end]
            set setter set.$field
            if {[info commands $setter] ne ""} {
                $setter obj $value
            } else {
                error "Unknown field option: $field"
            }
        }
        return $obj
    }

    # 4) Custom named constructor
    constructor -name fromHex {hex} {
        set hex [string trimleft $hex "#"]
        scan [string range $hex 0 1] %x r
        scan [string range $hex 2 3] %x g
        scan [string range $hex 4 5] %x b
        return [list $r $g $b]
    }

    # 5) Typed constructor name
    constructor -typed {int int int} {r g b} {
        return [list $r $g $b]
    }
}

set c1 [Color::new 255 128 0]
set c2 [Color::new()]
set c3 [Color::new.args -r 255 -g 128 -b 0]
set c4 [Color::fromHex "#FF8000"]
set c5 [Color::new(int,int,int) 10 20 30]

Note: Prefer using positional or default constructor for performance.

`method`

Declare a method in the class.

method name ?-virtual? argList ?-static? ?-upvar? ?-update {fields}? ?-override? body

Parameter	Description
`name`	Method name
`argList`	Tcl argument list
`body`	Method body
`-static`	No `this` argument
`-upvar`	`this` passed by reference (variable name)
`-update {fields}`	Fields detached into locals during body (implies `-upvar`)
`-override`	Validates that the method exists in parent class
`-virtual`	Enable polymorphic dispatch (class must be `-virtual`)

# Mixed method option scenarios
voo::class Vec2 {
    public {
        double_t x 0.0
        double_t y 0.0
        list_t tags [list]
    }

    # By value (default)
    method length {} {
        return [expr {sqrt([get.x $this]**2 + [get.y $this]**2)}]
    }

    # By reference
    method scale {factor} -upvar {
        set.x this [expr {[get.x $this] * $factor}]
        set.y this [expr {[get.y $this] * $factor}]
    }

    # With update (COW-safe field detach)
    method appendTag {tag} -update {tags} {
        lappend tags $tag
    }

    # Static
    method origin {} -static {
        return [new 0.0 0.0]
    }
}

set v [Vec2::new 3.0 4.0 [list]]
puts [Vec2::length $v]
Vec2::scale v 2.0
Vec2::appendTag v "scaled"
set o [Vec2::origin]

# Virtual + override + parent original body via base.<name>
voo::class Shape -virtual {
    method area -virtual {} { return 0.0 }
}

voo::class Circle -extends Shape {
    public { double_t radius 1.0 }
    method area -override {} {
        return [expr {3.14159 * [get.radius $this] ** 2}]
    }
}

voo::class ColoredCircle -extends Circle {
    public { string_t color "red" }
    method area -override {} {
        # Calls Circle's original implementation body directly
        set parentArea [Circle::base.area $this]
        return [expr {$parentArea * 1.1}]
    }
}

set s [ColoredCircle::new 5.0 "blue"]
puts [Shape::area $s]   ;# dynamic dispatch => ColoredCircle::area

# Virtual + upvar (by-reference dispatch)
voo::class CounterRoot -virtual {
    public { int_t n 0 }
    method bump {delta} -virtual -upvar {
        set.n this [expr {[get.n $this] + $delta}]
    }
}

voo::class CounterChild -extends CounterRoot {
    method bump {delta} -override -upvar {
        set.n this [expr {[get.n $this] + ($delta * 2)}]
    }
}

set c0 [CounterRoot::new 10]
CounterRoot::bump c0 3
puts [CounterRoot::get.n $c0] ;# 13

set c1 [CounterChild::new 10]
CounterRoot::bump c1 3
puts [CounterChild::get.n $c1] ;# 16 (virtual dispatch to child by reference)

# Virtual + update (COW-safe dispatch)
voo::class BufferRoot -virtual {
    public {
        int_t writes 0
        list_t entries [list]
    }
    method appendEntry {value} -virtual -update {writes entries} {
        incr writes
        lappend entries "root:$value"
    }
}

voo::class BufferChild -extends BufferRoot {
    method appendEntry {value} -override -update {writes entries} {
        BufferRoot::base.appendEntry this $value
        incr writes 2
        lappend entries "child:$value"
    }
}

set b0 [BufferRoot::new 0 [list]]
BufferRoot::appendEntry b0 one
puts [BufferRoot::get.writes $b0]   ;# 1
puts [BufferRoot::get.entries $b0]  ;# root:one

set b1 [BufferChild::new 0 [list]]
BufferRoot::appendEntry b1 one
puts [BufferChild::get.writes $b1]  ;# 3
puts [BufferChild::get.entries $b1] ;# root:one child:one

Note: Virtual dispatch uses tailcall internally, so methods declared with -upvar or -update execute in the original caller frame while preserving by-reference behavior. This also allows Parent::base.<name> this ... calls inside -update overrides.

Field Index Variables and Naming

For each non-static field, VOO creates a namespace variable in the class with the same name as the field. That variable stores the field index in the object list.

voo::class Example {
    public {
        int_t id 0
        int_t myField 10
    }

    # Disambiguated argument name (`myField_`) avoids collision with class var `myField`.
    method setMyFieldByIndex {myField_} -upvar {
        variable myField
        lset this $myField $myField_
    }

    method getMyFieldByIndex {} {
        variable myField
        return [lindex $this $myField]
    }
}

set obj [Example::new 7 11]
puts [namespace eval ::Example {set id}]       ;# 0
puts [namespace eval ::Example {set myField}]  ;# 1

Example::setMyFieldByIndex obj 42
puts [Example::get.myField $obj]               ;# 42

If you use the same name for both a proc argument and a class namespace variable, variable <name> will fail:

# Raises: variable "myField" already exists
method bad {myField} -upvar {
    variable myField
    lset this $myField $myField
}

Suggested naming guidelines for these cases:

Situation	Suggested pattern	Example
Field declaration	lowerCamelCase	`myField`
Argument that carries a new value for same field	trailing underscore	`myField_`
C++-style alternative for class members	`m_<name>`	`m_myFieldIdx`

Recommendations:

Prefer generated accessors (set.myField, get.myField, my.set.myField, my.get.myField) for readability in method implementations.
Use direct index-based updates only when you explicitly need them.
Pick one disambiguation pattern and keep it consistent across classes.

`importMethods`

Import methods from the parent class into the current child class.

importMethods {method1 method2 ...}

Parameter	Description
`methods`	List of method names to import from parent class

Must be called inside a class declared with -extends.

voo::class Base {
    method hello {} { return "hello" }
    method world {} { return "world" }
    method ping {} { return "ping" }
}

# Import a list of methods
voo::class ChildList -extends Base {
    importMethods {hello world}
}

# Import a single method name
voo::class ChildSingle -extends Base {
    importMethods ping
}

set c1 [ChildList::new]
puts [ChildList::hello $c1]

set c2 [ChildSingle::new]
puts [ChildSingle::ping $c2]

`getter` / `setter` / `updater`

Manually generate accessor procedures for a field. These are normally auto-generated by field declarations but can be called explicitly.

getter methodName fieldName
setter methodName fieldName
updater methodName fieldName

Parameter	Description
`methodName`	Name of the generated procedure
`fieldName`	Name of the field to access

voo::class Item {
    public {
        string_t label ""
        list_t tags [list]
    }

    # Custom names
    getter getLabel label
    setter setLabel label
    updater updateTags tags
}

set it [Item::new "pen" [list blue office]]
puts [Item::getLabel $it]
Item::setLabel it "marker"
Item::updateTags it tmp {
    lappend tmp stationery
}
# After updater returns, tmp is reset to {}.
puts $tmp   ;# {}
puts [Item::getLabel $it]

Note: The tmp variable is reset to {} to avoid accidental copy-on-write operations.

Recommendation:

For domain objects and APIs with invariants, keep fields private and expose a controlled public surface through getter/setter.
For simple data-carrier classes (struct-style objects), public fields with auto-generated accessors are usually enough.
Use custom-named getter/setter when names should communicate intent instead of storage details.

Generated Accessors

For each instance field fieldName, VOO generates:

Accessor	Signature	Description
`Class::get.fieldName`	`{this}`	Return field value
`Class::set.fieldName`	`{thisVar value}`	Set field in-place
`Class::update.fieldName`	`{thisVar tempVar body}`	Detach field for COW-safe update

For static fields:

Accessor	Signature	Description
`Class::class.get.fieldName`	`{}`	Return static field value
`Class::class.set.fieldName`	`{value}`	Set static field value
`Class::class.update.fieldName`	`{tempVar body}`	Update static field with COW safety

Private fields use the my. prefix (e.g. Class::my.get.fieldName).

voo::class Point {
    public {
        double_t x 0.0
        double_t y 0.0
        int_t -static count 0
    }
    private {
        string_t note "n/a"
    }
}

# Note: When private fields exist, positional new also includes them if constructor isn't manually defined
set p [Point::new 1.0 2.0 "n/a"]

# One could use named args to set only selected public fields.
set p [Point::new.args -x 1.0 -y 2.0]

# Instance public accessors
puts [Point::get.x $p]
Point::set.x p 5.0
Point::update.x p tmp { set tmp [expr {$tmp * 2}] }

# Static public accessors
puts [Point::class.get.count]
Point::class.set.count 10
Point::class.update.count tmp { incr tmp }

# Instance private accessor naming
puts [Point::my.get.note $p]

Generated Constructors

Unless overridden, VOO generates three constructors per class:

Constructor	Description
`Class::new arg1 arg2 ...`	Positional — one argument per field
`Class::new()`	No-args — returns the default object
`Class::new.args -field1 val -field2 val ...`	Named — set fields by name with `-` prefix

voo::class Person {
    public {
        string_t name "unknown"
        int_t age 0
    }
}

# Positional
set p1 [Person::new "Alice" 30]

# No-args (defaults)
set p2 [Person::new()]

# Named args
set p3 [Person::new.args -name "Bob" -age 25]

# Named args can set partial fields
set p4 [Person::new.args -name "Carol"]

`class.defaultObj` / `class.fields`

Introspection procedures auto-generated for every class.

Procedure	Returns
`Class::class.defaultObj`	The default object (list of default values)
`Class::class.fields`	List of field names in declaration order

voo::class Point {
    public {
        double_t x 0.0
        double_t y 0.0
    }
}

set defaults [Point::class.defaultObj]
set fields [Point::class.fields]

puts $defaults   ;# 0.0 0.0
puts $fields     ;# x y

# Works with inherited classes as well
voo::class ColorPoint -extends Point {
    public { string_t color "red" }
}
puts [ColorPoint::class.fields]       ;# x y color
puts [ColorPoint::class.defaultObj]   ;# 0.0 0.0 red

Coding Guidelines

Use this section as a practical default style for VOO codebases.

1. Model Object Intent First

Encapsulated object: declare fields in private and expose behavior through public methods and explicit getter/setter APIs.
Struct-like object: keep fields public when the type is a simple data carrier and direct access improves clarity.

2. Prefer Accessor Calls Over Manual Indexing

Prefer get.*, set.*, and update.* in normal code.
Use variable <fieldName> + index-level operations only for advanced internals or performance-focused paths.
When mixing field-index variables with similarly named arguments, disambiguate names (for example: myField and myField_).

3. Keep Mutation Explicit

Use default by-value methods for read-only behavior.
Use -upvar for in-place object mutation.
Use -update {fields} when mutating large list/dict fields to leverage copy-on-write-safe detachment.

4. Constructor Preferences

Prefer new (positional) or new() on hot paths.
Use new.args for call sites where readability and optional arguments matter more than raw speed.
Keep constructor argument order aligned with class.fields declaration order.

5. Inheritance and Polymorphism

Use -override for child methods that replace parent behavior.
Use virtual dispatch only where polymorphism is actually required.
In virtual override chains, use Parent::base.<name> when you need to incorporate parent behavior explicitly.

6. Naming Conventions

Field names: lowerCamelCase.
If a method argument mirrors a field name, use a disambiguated argument such as <field>_.
Use consistent naming for custom accessors so call sites stay predictable across classes.

7. API Stability Strategy

For reusable libraries, expose intent-oriented methods (or custom-named accessors) rather than leaking storage layout.
For internal scripts/prototypes, keep the API minimal and favor readability over abstraction ceremony.

Install

Using the Install Script

Run the provided install script to copy VOO into your Tcl installation's lib/ directory:

tclsh scripts/install.tcl

Note: You may need elevated privileges (e.g. sudo) if the Tcl lib/ directory is not writable by your user.

Manual Installation

Locate your Tcl installation's lib/ directory (e.g. /usr/lib/tcl8.6/.. or the parent of [info library]).
Create a voo1.0.0 folder inside that lib/ directory.
Copy voo.tcl and pkgIndex.tcl into the new folder:

mkdir -p /usr/lib/tcl8.6/../voo1.0.0
cp voo.tcl pkgIndex.tcl /usr/lib/tcl8.6/../voo1.0.0/

Usage After Installation

package require voo 1.0.0

Benchmarks

VOO achieves significant performance and memory advantages compared to TclOO and Itcl. All benchmarks ran on a Dual-Core Intel Xeon Gold 6240 CPU under Tcl 8.6.13 and Tcl 9.0, testing a Point class with 5 fields. Memory benchmarks instantiate 100,000 objects; time benchmarks use Tcl's time command with 1,000 iterations.

Demos

Two standalone benchmark scripts are provided in the benchmark/ directory:

Timing Benchmarks (`oo_time_benchmark.tcl`)

Measures object creation, field access, and class declaration speed across frameworks.

Basic usage (all frameworks except C++):

tclsh benchmark/oo_time_benchmark.tcl

Output example:

Benchmark results (microseconds per iteration)
iterations: 1000

Category                       |              VOO |            TclOO |             Itcl
------------------------------+------------------+------------------+------------------
Object Creation (Explicit)     |            0.647 |            6.871 |           41.815
Object Creation (Default)      |            0.537 |            6.814 |           52.973
Setter                         |            0.543 |            0.990 |            2.003
Getter                         |            0.444 |            1.194 |            2.023
Class Declaration              |          392.671 |           35.312 |          262.166

With C++ framework (requires prebuilt library):

cmake -S . -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build

tclsh benchmark/oo_time_benchmark.tcl --frameworks "voo tcloo itcl cpp" --cpp-lib ./build/benchmark/voopoint_pkg.so

NOTE: On macOS/Windows, replace .so with your platform module suffix (.dylib/.dll).

Custom iterations:

tclsh benchmark/oo_time_benchmark.tcl --frameworks tcloo --iterations 5000

Memory Benchmarks (`oo_memory_benchmark.tcl`)

Measures resident memory usage when creating many objects (100,000 by default). Each framework runs in a separate process for accurate isolation.

Basic usage (one framework at a time):

tclsh benchmark/oo_memory_benchmark.tcl --framework voo

Output example:

framework=voo
count=100000
pid=12345
vmrss_kb=23900
objects_list_length=100000
Press Enter to exit (use this pause to inspect with htop)

Other frameworks:

tclsh benchmark/oo_memory_benchmark.tcl --framework tcloo
tclsh benchmark/oo_memory_benchmark.tcl --framework itcl

With C++ framework:

tclsh benchmark/oo_memory_benchmark.tcl --framework cpp --cpp-lib ./build/benchmark/voopoint_pkg.so

NOTE: On macOS/Windows, replace .so with your platform module suffix (.dylib/.dll).

Custom object count:

tclsh benchmark/oo_memory_benchmark.tcl --framework voo --count 500000

Exit without pause (for scripting):

tclsh benchmark/oo_memory_benchmark.tcl --framework voo --no-hold

Object Creation Performance

Tcl 8.6.13

Framework	Explicit (μs)	Default (μs)	Relative to VOO
VOO	0.414	0.397	1.00× (baseline)
VOO C++	0.565	0.334	1.36× slower / 1.19× faster
TclOO	3.536	2.972	8.5× / 7.5× slower
Itcl	26.222	25.734	63× / 65× slower

Tcl 9.0

Framework	Explicit (μs)	Default (μs)	Relative to VOO
VOO	0.525	0.550	1.00× (baseline)
VOO C++	0.576	0.458	1.10× slower / 1.20× faster
TclOO	9.246	3.829	17.6× / 7.0× slower
Itcl	27.808	27.444	53× / 50× slower

VOO achieves direct list allocation with minimal overhead. TclOO's explicit constructor overhead increased dramatically in Tcl 9.0 (+161%).

Field Access Performance

Tcl 8.6.13

Operation	VOO (μs)	VOO C++ (μs)	TclOO (μs)	Itcl (μs)
Getter	0.393	0.298	0.502	1.153
Setter	0.799	0.306	0.563	1.169

Tcl 9.0

Operation	VOO (μs)	VOO C++ (μs)	TclOO (μs)	Itcl (μs)
Getter	0.366	0.286	0.615	1.291
Setter	0.823	0.365	0.613	1.102

VOO C++ delivers the fastest getters (~1.3× faster than VOO Tcl) and setters (2.3–2.6× faster) across all frameworks. VOO delivers good results for getters and setters.

Real-World Scenario: 100,000 Objects

Tcl 8.6.13

Framework	Time	Memory	Bytes/Obj	vs. VOO (Time)	vs. VOO (Mem)
VOO	147 ms	58 MB	~580	1.00×	1.00×
VOO C++	149 ms	38 MB	~380	1.01× slower	1.53× lighter
TclOO	466 ms	257 MB	~2,570	3.2× slower	4.4× heavier
Itcl	2,781 ms	882 MB	~8,820	18.9× slower	15.2× heavier

Tcl 9.0

Framework	Time	Memory	Bytes/Obj	vs. VOO (Time)	vs. VOO (Mem)
VOO	170 ms	66.5 MB	~665	1.00×	1.00×
VOO C++	169 ms	40.3 MB	~403	1.01× faster	1.65× lighter
TclOO	577 ms	395 MB	~3,950	3.4× slower	5.9× heavier
Itcl	3,014 ms	1,118 MB	~11,180	17.7× slower	16.8× heavier

VOO and VOO C++ are virtually identical in wall-clock time (~147–170 ms), while TclOO takes 3.2–3.4× longer and Itcl is 18–19× slower. For million-object applications, VOO projects ~665 MB versus TclOO's ~3.95 GB on Tcl 9.0.

Cross-Version Stability

Performance Change (Tcl 8.6.13 → 9.0)

Operation	VOO	VOO C++	TclOO	Itcl
Creation (Explicit)	+26.8%	+1.9%	+161.5%	+6.1%
Creation (Default)	+38.5%	+37.1%	+28.8%	+6.6%
Getter	-6.9%	-4.0%	+22.5%	+12.0%
Setter	+3.0%	+19.3%	+8.9%	-5.7%

Memory Change (Tcl 8.6.13 → 9.0)

Framework	Memory (8.6)	Memory (9.0)	Change
VOO	58 MB	66.5 MB	+14.7%
VOO C++	38 MB	40.3 MB	+6.1%
TclOO	257 MB	395 MB	+53.7%
Itcl	882 MB	1,118 MB	+26.8%

VOO C++ is virtually immune to interpreter changes, making it the most stable framework across versions. TclOO's 161.5% explicit-construction regression and 53.7% memory increase in Tcl 9.0 are the largest among all frameworks.

Tests

Automated API behavior tests are available in the test/ folder.

To run the full test suite:

tclsh test/test.tcl

The script validates expected behavior for constructors, methods, inheritance, virtual dispatch, accessors, and error scenarios documented in this README.

Migration

Migration guidelines for TclOO and Itcl users are documented in MIGRATION.md.

It includes:

A quick reference mapping table (TclOO/Itcl to VOO)
Code examples for class, inheritance, and method migration
cget/configure migration patterns to get.*, set.*, and new.args

Demos

Framework equivalence examples are available in demo/.

Run the cross-framework demo:

tclsh demo/framework_equivalence.tcl

Documentation

Project documentation is available in the docs/ folder.

In docs/arxiv, you can find the LaTeX source files (.tex) used for the arXiv white paper publication.

White paper link: https://arxiv.org/abs/2604.10399

Contributing

We welcome contributions! Please see CONTRIBUTING.md for guidelines on:

Reporting bugs
Proposing improvements
Submitting code changes via pull requests

License

MIT License — see LICENSE.md for details.

Name		Name	Last commit message	Last commit date
Latest commit History 23 Commits
benchmark		benchmark
demo		demo
docs/arxiv		docs/arxiv
scripts		scripts
tclxx @ 73cb03d		tclxx @ 73cb03d
test		test
.gitignore		.gitignore
.gitmodules		.gitmodules
CMakeLists.txt		CMakeLists.txt
CONTRIBUTING.md		CONTRIBUTING.md
LICENSE.md		LICENSE.md
MIGRATION.md		MIGRATION.md
README.md		README.md
pkgIndex.tcl		pkgIndex.tcl
voo.tcl		voo.tcl

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VOO — Vanilla Object Orientation for Tcl

Table of Contents

Quickstart

Quick Reference

Class Declaration

Field Types

Constructors (auto-generated)

Accessors (auto-generated per field)

Method Modifiers

Inheritance

Virtual Polymorphism

Visibility

API

voo::class

Field Types

public / private

constructor

method

Field Index Variables and Naming

importMethods

getter / setter / updater

Generated Accessors

Generated Constructors

class.defaultObj / class.fields

Coding Guidelines

1. Model Object Intent First

2. Prefer Accessor Calls Over Manual Indexing

3. Keep Mutation Explicit

4. Constructor Preferences

5. Inheritance and Polymorphism

6. Naming Conventions

7. API Stability Strategy

Install

Using the Install Script

Manual Installation

Usage After Installation

Benchmarks

Demos

Timing Benchmarks (oo_time_benchmark.tcl)

Memory Benchmarks (oo_memory_benchmark.tcl)

Object Creation Performance

Field Access Performance

Real-World Scenario: 100,000 Objects

Cross-Version Stability

Tests

Migration

Demos

Documentation

Contributing

License

About

Resources

Contributing

Stars

Watchers

Forks

Releases

Packages

Contributors

Languages

`voo::class`

`public` / `private`

`constructor`

`method`

`importMethods`

`getter` / `setter` / `updater`

`class.defaultObj` / `class.fields`

Timing Benchmarks (`oo_time_benchmark.tcl`)

Memory Benchmarks (`oo_memory_benchmark.tcl`)