positions introduced
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9c3d038fcd
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6
pos_rune.go
Normal file
6
pos_rune.go
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@ -0,0 +1,6 @@
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package bufr
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type posRune struct {
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Rune rune
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Pos Position
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}
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17
position.go
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17
position.go
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@ -0,0 +1,17 @@
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package bufr
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type Position struct {
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Index int
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Line int
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Column int
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}
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func (p *Position) Advance(rn rune) {
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p.Index++
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if rn == '\n' {
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p.Line++
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p.Column = 0
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} else {
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p.Column++
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}
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}
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27
reader.go
27
reader.go
@ -9,22 +9,36 @@ import (
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)
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type Reader struct {
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buf *dstruct.Stack[rune]
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buf *dstruct.Stack[posRune]
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src *bufio.Reader
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pos *Position
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}
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func NewReader(r io.Reader) *Reader {
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return &Reader{
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buf: new(dstruct.Stack[rune]),
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buf: new(dstruct.Stack[posRune]),
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src: bufio.NewReader(r),
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pos: &Position{},
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}
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}
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func (r *Reader) psrn(rn rune) posRune {
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return posRune{
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Rune: rn,
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Pos: *r.pos,
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}
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}
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func (r *Reader) Pos() (index, line, column int) {
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return r.pos.Index, r.pos.Line, r.pos.Column
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}
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// Rune returns the next rune in r
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func (r *Reader) Rune() (rune, error) {
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rn, _, err := r.src.ReadRune()
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if err == nil {
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r.buf.Push(rn)
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r.buf.Push(r.psrn(rn))
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r.pos.Advance(rn)
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}
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return rn, err
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}
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@ -38,9 +52,12 @@ func (r *Reader) UnreadRune() error {
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}
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if err := r.src.UnreadRune(); err == nil {
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r.buf.Pop()
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rn := r.buf.Pop()
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*r.pos = rn.Pos
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} else {
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r.src = prependRune(r.buf.Pop(), r.src)
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rn := r.buf.Pop()
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*r.pos = rn.Pos
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r.src = prependRune(rn.Rune, r.src)
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}
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return nil
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24
reader_test.go
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24
reader_test.go
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@ -0,0 +1,24 @@
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package bufr
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import (
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"fmt"
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"strings"
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"testing"
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)
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func TestPos(t *testing.T) {
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r := NewReader(strings.NewReader("hello world\nsecond line"))
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unread := false
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for rn, err := r.Rune(); err == nil; rn, err = r.Rune() {
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index, line, col := r.Pos()
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fmt.Println(string(rn), index, line, col)
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if !unread && rn == '\n' {
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for i := 0; i < 5; i++ {
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r.UnreadRune()
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}
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unread = true
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}
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}
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}
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