lexer: introduce Position.Next()/Position.NextLine() factories

Signed-off-by: Alejandro Mery <amery@jpi.io>

lexer/position.go

@@ -64,3 +64,29 @@ func (p *Position) StepLine() {
 	p.Line++
 	p.Column = 1
 }
+
+// Next returns a new Position one rune forward
+// on the line
+func (p Position) Next() Position {
+	if p.Line == 0 {
+		p.Reset()
+	}
+
+	return Position{
+		Line:   p.Line,
+		Column: p.Column + 1,
+	}
+}
+
+// NextLine returns a new Position at the begining of the next
+// line.
+func (p Position) NextLine() Position {
+	if p.Line == 0 {
+		p.Reset()
+	}
+
+	return Position{
+		Line:   p.Line + 1,
+		Column: 1,
+	}
+}

lexer/runes.go

@@ -21,6 +21,12 @@ func NewIsIn(s string) func(rune) bool {
 	}
 }
 
+// NewIsInRunes generates a rune condition checker that accepts
+// the runes specified
+func NewIsInRunes(s ...rune) func(rune) bool {
+	return NewIsIn(string(s))
+}
+
 // NewIsOneOf generates a run condition checker that accepts runes
 // accepted by any of the given checkers
 func NewIsOneOf(s ...func(rune) bool) func(rune) bool {