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@ -2,7 +2,7 @@ package main
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import (
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"bufio"
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"errors"
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"errors"
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"fmt"
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"io"
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"os"
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@ -17,75 +17,89 @@ type symbol string
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// parses the string lexeme into a value that can be eval'd
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func atom(t token) (interface{}, error) {
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switch t.t {
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case integerToken:
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val, err := strconv.ParseInt(t.lexeme, 10, 64)
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if err != nil {
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return nil, err
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}
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return val, nil
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case floatToken:
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val, err := strconv.ParseFloat(t.lexeme, 64)
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if err != nil {
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return nil, err
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}
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return val, nil
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case stringToken:
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return t.lexeme, nil
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case symbolToken:
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return symbol(t.lexeme), nil
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}
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return nil, fmt.Errorf("unable to atomize token: %v", t)
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switch t.t {
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case integerToken:
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val, err := strconv.ParseInt(t.lexeme, 10, 64)
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if err != nil {
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return nil, err
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}
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return val, nil
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case floatToken:
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val, err := strconv.ParseFloat(t.lexeme, 64)
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if err != nil {
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return nil, err
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}
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return val, nil
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case stringToken:
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return t.lexeme, nil
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case symbolToken:
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return symbol(t.lexeme), nil
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}
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return nil, fmt.Errorf("unable to atomize token: %v", t)
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}
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// reads in tokens on the channel until a matching close paren is found.
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func (s *sexp) readIn(c chan token) error {
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for t := range c {
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switch t.t {
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case closeParenToken:
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return nil
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case openParenToken:
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child := make(sexp, 0)
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if err := child.readIn(c); err != nil {
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return err
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}
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*s = append(*s, child)
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default:
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v, err := atom(t)
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if err != nil {
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return err
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}
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*s = append(*s, v)
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}
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}
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return errors.New("unexpected EOF in sexp.readIn")
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for t := range c {
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switch t.t {
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case closeParenToken:
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return nil
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case openParenToken:
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child := make(sexp, 0)
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if err := child.readIn(c); err != nil {
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return err
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}
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*s = append(*s, child)
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default:
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v, err := atom(t)
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if err != nil {
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return err
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}
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*s = append(*s, v)
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}
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}
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return errors.New("unexpected EOF in sexp.readIn")
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}
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// parses one value that can be evaled from the channel
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func parse(c chan token) (interface{}, error) {
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for t := range c {
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switch t.t {
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case closeParenToken:
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return nil, errors.New("unexpected EOF in read")
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case openParenToken:
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s := make(sexp, 0)
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if err := s.readIn(c); err != nil {
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return nil, err
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}
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return s, nil
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default:
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return atom(t)
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}
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}
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return nil, io.EOF
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for t := range c {
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switch t.t {
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case closeParenToken:
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return nil, errors.New("unexpected EOF in read")
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case openParenToken:
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s := make(sexp, 0)
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if err := s.readIn(c); err != nil {
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return nil, err
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}
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return s, nil
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default:
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return atom(t)
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}
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}
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return nil, io.EOF
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}
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func eval(v interface{}) {
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fmt.Println(v)
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fmt.Println(v)
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}
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func evalall(c chan token) {
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for {
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v, err := parse(c)
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switch err {
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case io.EOF:
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return
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case nil:
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eval(v)
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default:
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fmt.Println("error in eval: %v", err)
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}
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}
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}
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func args() {
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@ -99,18 +113,7 @@ func args() {
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c := make(chan token, 32)
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go lex(bufio.NewReader(f), c)
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for {
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v, err := parse(c)
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switch err {
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case io.EOF:
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return
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case nil:
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eval(v)
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default:
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fmt.Println("error in args(): %v", err)
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}
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}
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evalall(c)
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}
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func main() {
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@ -139,17 +142,6 @@ func main() {
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c := make(chan token, 32)
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go lexs(string(line)+"\n", c)
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for {
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v, err := parse(c)
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switch err {
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case io.EOF:
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goto OUT
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case nil:
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eval(v)
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default:
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fmt.Println("error in repl: %v", err)
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}
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}
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OUT:
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evalall(c)
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}
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}
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