121 lines
2.4 KiB
Go
121 lines
2.4 KiB
Go
package read
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import (
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"fmt"
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"mal-go/hash_map"
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"mal-go/symbol"
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"mal-go/vector"
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"strconv"
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"strings"
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)
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func ReadString(s string) (any, any) {
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res, err, _ := readForm(s, 0, "user")
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return res, err
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}
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func isDigitChar(c byte) bool {
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return c >= '0' && c <= '9'
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}
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func isSpaceChar(c byte) bool {
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return c == ' ' || c == '\n' || c == ','
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}
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func isSymbolChar(c byte) bool {
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return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_' || c == '/' || c == '\'' || c == '+' || c == '-' || c == '*'
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}
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func readForm(s string, pos int, ns string) (any, any, int) {
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if pos >= len(s) {
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return nil, "unterminated input", pos
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}
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c := s[pos]
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var res, err any
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if isSpaceChar(c) {
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res, err, pos = readForm(s, pos+1, ns)
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} else if isDigitChar(c) {
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res, err, pos = readInt(s, pos, ns)
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} else if isSymbolChar(c) {
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res, err, pos = readSymbol(s, pos, ns)
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} else {
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switch c {
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case '{':
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res, err, pos = readMap(s, pos, ns)
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case '[':
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res, err, pos = readVector(s, pos, ns)
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case '(':
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res, err, pos = readList(s, pos, ns)
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default:
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return nil, "unexpected char: '" + fmt.Sprint(c) + "'", pos
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}
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}
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return res, err, pos
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}
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func readMap(s string, pos int, ns string) (any, any, int) {
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m := hash_map.New()
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if s[pos+1] == '}' {
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return m, nil, pos + 2
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}
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return nil, "unimplemented", pos
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}
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func readList(s string, pos int, ns string) (any, any, int) {
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pos += 1
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forms := vector.New()
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for rune(s[pos]) != ')' {
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res, _, pos2 := readForm(s, pos, ns)
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forms = forms.Conj(res)
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pos = pos2
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}
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return forms.ToList(), nil, pos + 1
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}
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func readVector(s string, pos int, ns string) (any, any, int) {
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pos += 1
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forms := vector.New()
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for rune(s[pos]) != ']' {
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res, _, pos2 := readForm(s, pos, ns)
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forms = forms.Conj(res)
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pos = pos2
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}
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return forms, nil, pos + 1
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}
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func readInt(s string, pos int, ns string) (any, any, int) {
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startingPos := pos
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c := s[pos]
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for isDigitChar(c) {
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pos += 1
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if pos >= len(s) {
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break
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}
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c = s[pos]
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}
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res, _ := strconv.Atoi(s[startingPos:pos])
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return res, nil, pos
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}
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func readSymbol(s string, pos int, ns string) (any, any, int) {
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startingPos := pos
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c := s[pos]
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for isSymbolChar(c) {
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pos += 1
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if pos >= len(s) {
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break
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}
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c = s[pos]
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}
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sym := s[startingPos:pos]
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symNs := ns
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if strings.Contains(sym, "/") {
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splitIdx := strings.Index(s, "/")
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symNs = s[startingPos:splitIdx]
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sym = s[splitIdx+1 : pos]
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}
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return symbol.Intern(symNs, sym), nil, pos
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}
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