package entity

// Scoped represents any entity that has its own scope.
type Scoped interface {
	// Variable returns the declaration of the variable with the given name.
	// If no variable is found in this scope, it returns nil. Only the scope
	// in this entity is searched.
	Variable (name string) *Declaration

	// AddVariable adds a variable to this entity's scope.
	AddVariable (declaration *Declaration)

	// OverVariables calls callback for each defined variable, stopping if
	// returns false.
	OverVariables (callback func (*Declaration) bool)
}

// Scope implements a scope.
type Scope struct {
	variables map[string] *Declaration
}

func (this *Scope) Variable (name string) *Declaration {
	if this.variables == nil {
		return nil
	}
	return this.variables[name]
}

func (this *Scope) AddVariable (declaration *Declaration) {
	if this.variables == nil {
		this.variables = make(map[string] *Declaration)
	}
	this.variables[declaration.Name] = declaration
}

func (this *Scope) OverVariables (callback func (*Declaration) bool) {
	for _, declaration := range this.variables {
		if !callback(declaration) { break }
	}
}