From bb5044d015a4dd37c6c43b387d491e7888a50503 Mon Sep 17 00:00:00 2001
From: Martin Atkins <mart@degeneration.co.uk>
Date: Sat, 20 May 2017 17:40:03 -0700
Subject: [PATCH] Range and StartRange methods on Expression

This gives us some contextual information to use for error handling when
working generically with expressions.
---
 zcl/json/structure.go | 8 ++++++++
 zcl/structure.go      | 3 +++
 2 files changed, 11 insertions(+)

diff --git a/zcl/json/structure.go b/zcl/json/structure.go
index 6ad28ab..0b39861 100644
--- a/zcl/json/structure.go
+++ b/zcl/json/structure.go
@@ -259,3 +259,11 @@ func (e *expression) Value(ctx *zcl.EvalContext) (cty.Value, zcl.Diagnostics) {
 		return cty.DynamicVal, nil
 	}
 }
+
+func (e *expression) Range() zcl.Range {
+	return e.src.Range()
+}
+
+func (e *expression) StartRange() zcl.Range {
+	return e.src.StartRange()
+}
diff --git a/zcl/structure.go b/zcl/structure.go
index 877b33d..96a9857 100644
--- a/zcl/structure.go
+++ b/zcl/structure.go
@@ -101,6 +101,9 @@ type Expression interface {
 	// the specific symbol in question.
 	Value(ctx *EvalContext) (cty.Value, Diagnostics)
 
+	Range() Range
+	StartRange() Range
+
 	// TODO: A "Variables" method that returns a description of all of the
 	// variables used in the expression, so callers can populate the scope
 	// only with variables that are actually used.