Update to tengo v2 (#976)

vendor/github.com/d5/tengo/v2/modules.go

@@ -0,0 +1,93 @@
+package tengo
+
+// Importable interface represents importable module instance.
+type Importable interface {
+	// Import should return either an Object or module source code ([]byte).
+	Import(moduleName string) (interface{}, error)
+}
+
+// ModuleMap represents a set of named modules. Use NewModuleMap to create a
+// new module map.
+type ModuleMap struct {
+	m map[string]Importable
+}
+
+// NewModuleMap creates a new module map.
+func NewModuleMap() *ModuleMap {
+	return &ModuleMap{
+		m: make(map[string]Importable),
+	}
+}
+
+// Add adds an import module.
+func (m *ModuleMap) Add(name string, module Importable) {
+	m.m[name] = module
+}
+
+// AddBuiltinModule adds a builtin module.
+func (m *ModuleMap) AddBuiltinModule(name string, attrs map[string]Object) {
+	m.m[name] = &BuiltinModule{Attrs: attrs}
+}
+
+// AddSourceModule adds a source module.
+func (m *ModuleMap) AddSourceModule(name string, src []byte) {
+	m.m[name] = &SourceModule{Src: src}
+}
+
+// Remove removes a named module.
+func (m *ModuleMap) Remove(name string) {
+	delete(m.m, name)
+}
+
+// Get returns an import module identified by name. It returns if the name is
+// not found.
+func (m *ModuleMap) Get(name string) Importable {
+	return m.m[name]
+}
+
+// GetBuiltinModule returns a builtin module identified by name. It returns
+// if the name is not found or the module is not a builtin module.
+func (m *ModuleMap) GetBuiltinModule(name string) *BuiltinModule {
+	mod, _ := m.m[name].(*BuiltinModule)
+	return mod
+}
+
+// GetSourceModule returns a source module identified by name. It returns if
+// the name is not found or the module is not a source module.
+func (m *ModuleMap) GetSourceModule(name string) *SourceModule {
+	mod, _ := m.m[name].(*SourceModule)
+	return mod
+}
+
+// Copy creates a copy of the module map.
+func (m *ModuleMap) Copy() *ModuleMap {
+	c := &ModuleMap{
+		m: make(map[string]Importable),
+	}
+	for name, mod := range m.m {
+		c.m[name] = mod
+	}
+	return c
+}
+
+// Len returns the number of named modules.
+func (m *ModuleMap) Len() int {
+	return len(m.m)
+}
+
+// AddMap adds named modules from another module map.
+func (m *ModuleMap) AddMap(o *ModuleMap) {
+	for name, mod := range o.m {
+		m.m[name] = mod
+	}
+}
+
+// SourceModule is an importable module that's written in Tengo.
+type SourceModule struct {
+	Src []byte
+}
+
+// Import returns a module source code.
+func (m *SourceModule) Import(_ string) (interface{}, error) {
+	return m.Src, nil
+}