instance.go

// Copyright (c) 2023, Peter Ohler, All rights reserved.

package slip

import (
	"sort"
	"strings"
)

type Instance interface {
	Object
	Receiver

	// Class of the instance.
	Class() Class

	// IsA returns true if the instance's class is the specified class or a
	// sub-class of the specified class.
	IsA(class string) bool

	// Init the instance slots from the provided args list. If the scope is
	// not nil then send :init is called.
	Init(scope *Scope, args List, depth int)

	// SetSynchronized sets the instance to be thread safe (mutex protected
	// slots) or not.
	SetSynchronized(on bool)

	// Synchronized returns true if the instance is thread safe.
	Synchronized() bool

	// SlotNames returns a list of the slots names for the instance.
	SlotNames() []string

	// SlotValue return the value of an instance variable.
	SlotValue(name Symbol) (Object, bool)

	// SetSlotValue sets the value of an instance variable and return true if
	// the name slot exists and was set.
	SetSlotValue(sym Symbol, value Object) (has bool)

	// GetMethod returns the method if it exists.
	GetMethod(name string) *Method

	// MethodNames returns a sorted list of the methods of the class.
	MethodNames() List

	// ID returns unique ID for the instance.
	ID() uint64

	// Dup returns a duplicate of the instance.
	Dup() Instance
}

// InstanceLoadForm created a load form for an instance.
func InstanceLoadForm(obj Instance) (form List) {
	makeInstSym := Symbol("make-instance")
	for _, h := range obj.Hierarchy() {
		if strings.EqualFold(string(h), "condition") {
			makeInstSym = Symbol("make-condition")
			break
		}
	}
	names := obj.SlotNames()
	sort.Strings(names)
	form = List{
		Symbol("let"),
		List{
			List{
				Symbol("inst"),
				List{
					makeInstSym,
					List{
						Symbol("quote"),
						Symbol(obj.Class().Name()),
					},
				},
			},
		},
	}
	for _, name := range names {
		if name == "self" {
			continue
		}
		iv, _ := obj.SlotValue(Symbol(name))
		if iv == Unbound {
			continue
		}
		form = append(form,
			List{
				Symbol("setf"),
				List{
					Symbol("slot-value"),
					Symbol("inst"),
					List{
						Symbol("quote"),
						Symbol(name),
					},
				},
				iv, // TBD handle more complex values
			},
		)
	}
	form = append(form, Symbol("inst"))

	return
}