lexer: introduce a Position (Line, Column) handler

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

lexer/error.go

@@ -1,7 +1,6 @@
 package lexer
 
 import (
-	"errors"
 	"fmt"
 	"strings"
 )
@@ -10,11 +9,6 @@ var (
 	_ error = (*Error)(nil)
 )
 
-var (
-	// ErrUnacceptableRune indicates the read rune
-	ErrUnacceptableRune = errors.New("rune not acceptable in context")
-)
-
 // Error represents a generic parsing error
 type Error struct {
 	Filename string

lexer/position.go

@@ -41,30 +41,6 @@ func (p *Position) Step() {
 	p.Column++
 }
 
-// StepN moves the column N places forward
-func (p *Position) StepN(n int) {
-	if p.Line == 0 {
-		p.Reset()
-	}
-
-	switch {
-	case n > 0:
-		p.Column += n
-	default:
-		panic(fmt.Errorf("invalid %v increment", n))
-	}
-}
-
-// StepLine moves position to the start of the next line
-func (p *Position) StepLine() {
-	if p.Line == 0 {
-		p.Reset()
-	}
-
-	p.Line++
-	p.Column = 1
-}
-
 // Next returns a new Position one rune forward
 // on the line
 func (p Position) Next() Position {