From 838a0332e632a374a98a7280e0543fc77a72f1cd Mon Sep 17 00:00:00 2001
From: Martin Atkins <mart@degeneration.co.uk>
Date: Mon, 15 May 2017 08:34:00 -0700
Subject: [PATCH] json: token peeker

This will help our hand-written recursive-descent parser walk the tokens
with one token of lookahead.
---
 zcl/json/peeker.go | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 zcl/json/peeker.go

diff --git a/zcl/json/peeker.go b/zcl/json/peeker.go
new file mode 100644
index 0000000..c04d1b2
--- /dev/null
+++ b/zcl/json/peeker.go
@@ -0,0 +1,24 @@
+package json
+
+type peeker struct {
+	tokens []token
+	pos    int
+}
+
+func newPeeker(tokens []token) *peeker {
+	return &peeker{
+		tokens: tokens,
+		pos:    0,
+	}
+}
+
+func (p *peeker) Peek() token {
+	return p.tokens[p.pos]
+}
+
+func (p *peeker) Read() token {
+	if p.tokens[p.pos].Type != tokenEOF {
+		p.pos++
+	}
+	return p.tokens[p.pos]
+}