Type Methods - BambooBasic

Type Methods

Methods are functions that belong to a Type. They can access and modify the Type's fields using the this\ keyword.

Defining Methods

Methods are defined inside a Type using the Method keyword:

Type TPlayer
    Field name:String
    Field health:Int
    Field maxHealth:Int

    Method Setup(playerName:String)
        this\name = playerName
        this\health = 100
        this\maxHealth = 100
    EndMethod

    Method TakeDamage(amount:Int)
        this\health = this\health - amount
        If this\health < 0
            this\health = 0
        EndIf
    EndMethod

    Method IsAlive:Int()
        If this\health > 0
            Return True
        Else
            Return False
        EndIf
    EndMethod
EndType

The this\ Keyword

Inside a method, use this\ to access the current instance's fields:

Type TCounter
    Field value:Int

    Method Increment()
        this\value = this\value + 1  ; Access field of THIS instance
    EndMethod

    Method GetValue:Int()
        Return this\value  ; Return field of THIS instance
    EndMethod
EndType

Why this\? It distinguishes between the instance's fields and method parameters/local variables.

Calling Methods

Call methods using the backslash operator, just like accessing fields:

Function Main()
    Local player:TPlayer = Create TPlayer

    ; Call method to initialize
    player\Setup("Hero")

    ; Call method to modify state
    player\TakeDamage(25)

    ; Call method that returns a value
    If player\IsAlive()
        Print player\name & " is still alive!"
        Print "Health: " & ToString(player\health)
    Else
        Print player\name & " has died!"
    EndIf

    Return False
EndFunction

Methods with Parameters

Type TCharacter
    Field x:Int
    Field y:Int

    Method MoveTo(newX:Int, newY:Int)
        this\x = newX
        this\y = newY
    EndMethod

    Method MoveBy(deltaX:Int, deltaY:Int)
        this\x = this\x + deltaX
        this\y = this\y + deltaY
    EndMethod

    Method GetDistance:Double(otherX:Int, otherY:Int)
        Local dx:Int = this\x - otherX
        Local dy:Int = this\y - otherY
        ; Calculate distance using Pythagorean theorem
        Return Sqrt(dx * dx + dy * dy)
    EndMethod
EndType

Function Main()
    Local hero:TCharacter = Create TCharacter

    ; Set initial position
    hero\MoveTo(10, 20)
    Print "Position: (" & ToString(hero\x) & ", " & ToString(hero\y) & ")"

    ; Move relative
    hero\MoveBy(5, -3)
    Print "New Position: (" & ToString(hero\x) & ", " & ToString(hero\y) & ")"

    ; Calculate distance to origin
    Local dist:Double = hero\GetDistance(0, 0)
    Print "Distance from origin: " & ToString(dist)

    Return False
EndFunction

Methods with Return Values

Methods can return values just like functions:

Type TInventory
    Field gold:Int
    Field items:Int

    Method AddGold(amount:Int)
        this\gold = this\gold + amount
    EndMethod

    Method CanAfford:Int(cost:Int)
        If this\gold >= cost
            Return True
        Else
            Return False
        EndIf
    EndMethod

    Method Purchase:Int(itemCost:Int)
        If this\CanAfford(itemCost)
            this\gold = this\gold - itemCost
            this\items = this\items + 1
            Return True  ; Success
        Else
            Return False  ; Not enough gold
        EndIf
    EndMethod

    Method GetTotal:Int()
        Return this\gold + (this\items * 10)
    EndMethod
EndType

Function Main()
    Local inv:TInventory = Create TInventory
    inv\AddGold(100)

    Print "Gold: " & ToString(inv\gold)

    ; Try to purchase
    If inv\Purchase(50)
        Print "Purchase successful!"
        Print "Gold remaining: " & ToString(inv\gold)
        Print "Items: " & ToString(inv\items)
    Else
        Print "Not enough gold!"
    EndIf

    ; Get total value
    Local total:Int = inv\GetTotal()
    Print "Total value: " & ToString(total)

    Return False
EndFunction

Methods Calling Other Methods

Methods can call other methods of the same instance:

Type TGameObject
    Field x:Int
    Field y:Int
    Field isActive:Int

    Method Activate()
        this\isActive = True
        this\ResetPosition()  ; Call another method
    EndMethod

    Method Deactivate()
        this\isActive = False
    EndMethod

    Method ResetPosition()
        this\x = 0
        this\y = 0
    EndMethod

    Method Update()
        If this\isActive
            this\x = this\x + 1
            If this\x > 100
                this\Deactivate()  ; Call another method
            EndIf
        EndIf
    EndMethod
EndType

Complete Example: RPG Character

Type TRPGCharacter
    Field name:String
    Field health:Int
    Field maxHealth:Int
    Field mana:Int
    Field maxMana:Int
    Field level:Int
    Field experience:Int

    Method Initialize(charName:String)
        this\name = charName
        this\level = 1
        this\experience = 0
        this\SetMaxStats()
        this\FullHeal()
    EndMethod

    Method SetMaxStats()
        this\maxHealth = 50 + (this\level * 10)
        this\maxMana = 30 + (this\level * 5)
    EndMethod

    Method FullHeal()
        this\health = this\maxHealth
        this\mana = this\maxMana
    EndMethod

    Method TakeDamage(amount:Int)
        this\health = this\health - amount
        If this\health < 0 Then this\health = 0

        If this\health = 0
            Print this\name & " has been defeated!"
        EndIf
    EndMethod

    Method CastSpell:Int(manaCost:Int)
        If this\mana >= manaCost
            this\mana = this\mana - manaCost
            Return True
        Else
            Print "Not enough mana!"
            Return False
        EndIf
    EndMethod

    Method GainExperience(amount:Int)
        this\experience = this\experience + amount
        Print this\name & " gained " & ToString(amount) & " XP"

        ; Check for level up (100 XP per level)
        If this\experience >= this\level * 100
            this\LevelUp()
        EndIf
    EndMethod

    Method LevelUp()
        this\level = this\level + 1
        Print this\name & " leveled up to level " & ToString(this\level) & "!"
        this\SetMaxStats()
        this\FullHeal()
    EndMethod

    Method ShowStats()
        Print "=== " & this\name & " ==="
        Print "Level: " & ToString(this\level)
        Print "HP: " & ToString(this\health) & "/" & ToString(this\maxHealth)
        Print "MP: " & ToString(this\mana) & "/" & ToString(this\maxMana)
        Print "XP: " & ToString(this\experience) & "/" & ToString(this\level * 100)
    EndMethod
EndType

Function Main()
    Local hero:TRPGCharacter = Create TRPGCharacter
    hero\Initialize("Aragorn")
    hero\ShowStats()

    Print ""
    Print "=== Combat ==="
    hero\TakeDamage(20)
    Print "After damage - HP: " & ToString(hero\health)

    Print ""
    If hero\CastSpell(15)
        Print "Spell cast! Mana: " & ToString(hero\mana)
    EndIf

    Print ""
    Print "=== Gaining Experience ==="
    hero\GainExperience(80)
    hero\GainExperience(30)  ; Should trigger level up

    Print ""
    hero\ShowStats()

    Remove hero
    Return False
EndFunction

Key Points

Use Method to define functions inside a Type
Use this\ to access the current instance's fields
Methods are called with instance\MethodName()
Methods can have parameters and return values
Methods can call other methods using this\MethodName()
Each instance's methods work on that instance's fields

See Also

Custom Types - Defining Types with fields
Type Instances - Managing instance lifecycle
Type Iteration (Loops) - Iterating over all instances
With Blocks - its\ shorthand (and how it differs from this\)
Functions - Standalone functions

Examples

See the Types Examples folder for complete demonstrations.