1 files changed, 90 insertions, 0 deletions
diff --git a/vendor/github.com/hashicorp/hil/ast/scope.go b/vendor/github.com/hashicorp/hil/ast/scope.go
new file mode 100644
index 00000000..7a975d99
--- /dev/null
+++ b/vendor/github.com/hashicorp/hil/ast/scope.go
@@ -0,0 +1,90 @@
+package ast
+
+import (
+	"fmt"
+	"reflect"
+)
+
+// Scope is the interface used to look up variables and functions while
+// evaluating. How these functions/variables are defined are up to the caller.
+type Scope interface {
+	LookupFunc(string) (Function, bool)
+	LookupVar(string) (Variable, bool)
+}
+
+// Variable is a variable value for execution given as input to the engine.
+// It records the value of a variables along with their type.
+type Variable struct {
+	Value interface{}
+	Type  Type
+}
+
+// NewVariable creates a new Variable for the given value. This will
+// attempt to infer the correct type. If it can't, an error will be returned.
+func NewVariable(v interface{}) (result Variable, err error) {
+	switch v := reflect.ValueOf(v); v.Kind() {
+	case reflect.String:
+		result.Type = TypeString
+	default:
+		err = fmt.Errorf("Unknown type: %s", v.Kind())
+	}
+
+	result.Value = v
+	return
+}
+
+// String implements Stringer on Variable, displaying the type and value
+// of the Variable.
+func (v Variable) String() string {
+	return fmt.Sprintf("{Variable (%s): %+v}", v.Type, v.Value)
+}
+
+// Function defines a function that can be executed by the engine.
+// The type checker will validate that the proper types will be called
+// to the callback.
+type Function struct {
+	// ArgTypes is the list of types in argument order. These are the
+	// required arguments.
+	//
+	// ReturnType is the type of the returned value. The Callback MUST
+	// return this type.
+	ArgTypes   []Type
+	ReturnType Type
+
+	// Variadic, if true, says that this function is variadic, meaning
+	// it takes a variable number of arguments. In this case, the
+	// VariadicType must be set.
+	Variadic     bool
+	VariadicType Type
+
+	// Callback is the function called for a function. The argument
+	// types are guaranteed to match the spec above by the type checker.
+	// The length of the args is strictly == len(ArgTypes) unless Varidiac
+	// is true, in which case its >= len(ArgTypes).
+	Callback func([]interface{}) (interface{}, error)
+}
+
+// BasicScope is a simple scope that looks up variables and functions
+// using a map.
+type BasicScope struct {
+	FuncMap map[string]Function
+	VarMap  map[string]Variable
+}
+
+func (s *BasicScope) LookupFunc(n string) (Function, bool) {
+	if s == nil {
+		return Function{}, false
+	}
+
+	v, ok := s.FuncMap[n]
+	return v, ok
+}
+
+func (s *BasicScope) LookupVar(n string) (Variable, bool) {
+	if s == nil {
+		return Variable{}, false
+	}
+
+	v, ok := s.VarMap[n]
+	return v, ok
+}