zclsyntax: peeker methods to get next and previous token ranges

zcl/zclsyntax/peeker.go

@@ -1,5 +1,9 @@
 package zclsyntax
 
+import (
+	"github.com/zclconf/go-zcl/zcl"
+)
+
 type peeker struct {
 	Tokens    Tokens
 	NextIndex int
@@ -28,6 +32,18 @@ func (p *peeker) Read() Token {
 	return ret
 }
 
+func (p *peeker) NextRange() zcl.Range {
+	return p.Peek().Range
+}
+
+func (p *peeker) PrevRange() zcl.Range {
+	if p.NextIndex == 0 {
+		return p.NextRange()
+	}
+
+	return p.Tokens[p.NextIndex-1].Range
+}
+
 func (p *peeker) nextToken() (Token, int) {
 	for i := p.NextIndex; i < len(p.Tokens); i++ {
 		tok := p.Tokens[i]