88 lines
1.4 KiB
Go
88 lines
1.4 KiB
Go
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package csexp
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import (
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"bytes"
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"fmt"
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"io"
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"slices"
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"git.codemonkeysoftware.net/b/peachy-go/shortcircuit"
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)
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type Sexp interface {
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isSexp()
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WriteTo(w io.Writer) (n int64, err error)
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String() string
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Equal(Sexp) bool
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Clone() Sexp
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}
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type Atom []byte
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func (a Atom) isSexp() {}
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func (a Atom) WriteTo(w io.Writer) (int64, error) {
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if scw, ok := w.(*shortcircuit.Writer); ok && scw.Failed() {
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return 0, nil
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}
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n, err := fmt.Fprintf(w, "%d:%s", len(a), []byte(a))
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return int64(n), err
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}
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func (a Atom) String() string {
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var buf bytes.Buffer
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a.WriteTo(&buf)
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return buf.String()
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}
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func (a Atom) Equal(s Sexp) bool {
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a2, ok := s.(Atom)
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return ok && bytes.Equal([]byte(a), []byte(a2))
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}
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func (a Atom) Clone() Sexp {
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return Atom(bytes.Clone([]byte(a)))
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}
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type List []Sexp
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func (l List) isSexp() {}
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func (l List) WriteTo(w io.Writer) (int64, error) {
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scw := shortcircuit.EnsureWriter(w)
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if scw.Failed() {
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return 0, nil
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}
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io.WriteString(scw, "(")
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for _, child := range l {
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child.WriteTo(scw)
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}
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io.WriteString(scw, ")")
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return scw.Status()
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}
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func (l List) String() string {
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var buf bytes.Buffer
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l.WriteTo(&buf)
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return buf.String()
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}
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func (l List) Equal(s Sexp) bool {
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l2, ok := s.(List)
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return ok && slices.EqualFunc(l, l2, Sexp.Equal)
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}
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func (l List) Clone() Sexp {
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l2 := make(List, len(l))
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for i, child := range l {
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l2[i] = child.Clone()
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}
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return l2
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}
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func Parse(data []byte) (Sexp, error) {
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return nil, nil
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}
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