go-parsekit/cursor.go

30 lines
695 B
Go

package parsekit
import "fmt"
// Cursor represents the position of the input cursor in various ways.
type Cursor struct {
Byte int // The cursor offset in bytes
Rune int // The cursor offset in UTF8 runes
Column int // The column at which the cursor is (0-indexed)
Line int // The line at which the cursor is (0-indexed)
}
func (c *Cursor) String() string {
return fmt.Sprintf("line %d, column %d", c.Line+1, c.Column+1)
}
// move updates the position of the cursor, based on the provided input string.
func (c *Cursor) move(input string) {
c.Byte += len(input)
for _, r := range input {
c.Rune++
if r == '\n' {
c.Column = 0
c.Line++
} else {
c.Column++
}
}
}