Update to tengo v2 (#976)

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

@@ -0,0 +1,64 @@
+package tengo
+
+import (
+	"errors"
+	"fmt"
+)
+
+var (
+	// ErrStackOverflow is a stack overflow error.
+	ErrStackOverflow = errors.New("stack overflow")
+
+	// ErrObjectAllocLimit is an objects allocation limit error.
+	ErrObjectAllocLimit = errors.New("object allocation limit exceeded")
+
+	// ErrIndexOutOfBounds is an error where a given index is out of the
+	// bounds.
+	ErrIndexOutOfBounds = errors.New("index out of bounds")
+
+	// ErrInvalidIndexType represents an invalid index type.
+	ErrInvalidIndexType = errors.New("invalid index type")
+
+	// ErrInvalidIndexValueType represents an invalid index value type.
+	ErrInvalidIndexValueType = errors.New("invalid index value type")
+
+	// ErrInvalidIndexOnError represents an invalid index on error.
+	ErrInvalidIndexOnError = errors.New("invalid index on error")
+
+	// ErrInvalidOperator represents an error for invalid operator usage.
+	ErrInvalidOperator = errors.New("invalid operator")
+
+	// ErrWrongNumArguments represents a wrong number of arguments error.
+	ErrWrongNumArguments = errors.New("wrong number of arguments")
+
+	// ErrBytesLimit represents an error where the size of bytes value exceeds
+	// the limit.
+	ErrBytesLimit = errors.New("exceeding bytes size limit")
+
+	// ErrStringLimit represents an error where the size of string value
+	// exceeds the limit.
+	ErrStringLimit = errors.New("exceeding string size limit")
+
+	// ErrNotIndexable is an error where an Object is not indexable.
+	ErrNotIndexable = errors.New("not indexable")
+
+	// ErrNotIndexAssignable is an error where an Object is not index
+	// assignable.
+	ErrNotIndexAssignable = errors.New("not index-assignable")
+
+	// ErrNotImplemented is an error where an Object has not implemented a
+	// required method.
+	ErrNotImplemented = errors.New("not implemented")
+)
+
+// ErrInvalidArgumentType represents an invalid argument value type error.
+type ErrInvalidArgumentType struct {
+	Name     string
+	Expected string
+	Found    string
+}
+
+func (e ErrInvalidArgumentType) Error() string {
+	return fmt.Sprintf("invalid type for argument '%s': expected %s, found %s",
+		e.Name, e.Expected, e.Found)
+}