140 lines
3.1 KiB
Go
140 lines
3.1 KiB
Go
/* SHS: Syntactically Homogeneous Shell
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* Copyright (C) 2019 Aidan Hahn
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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package shs;
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import (
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"strings"
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"unicode"
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)
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type token_t int
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const (
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LIST token_t = iota
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STRING token_t = iota
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NUMBER token_t = iota
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SYMBOL token_t = iota
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)
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type Token struct {
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next *Token
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tag token_t
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position int
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_inner interface{}
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}
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func Lex(input string) *Token {
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if len(input) == 0 {
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return nil
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}
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var ret *Token
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var tok strings.Builder
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iter := &ret
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delim := ' '
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is_list := false
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is_str := false
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tokenBuilder := func (pos int, tok string) {
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if len(tok) == 0 && !is_list && !is_str {
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return
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}
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*iter = new(Token)
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(*iter).position = pos
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if is_list {
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(*iter)._inner = Lex(tok)
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(*iter).tag = LIST
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is_list = false
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} else {
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(*iter)._inner = tok
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if is_str {
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(*iter).tag = STRING
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is_str = false
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} else if tokenIsNumber(tok) {
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(*iter).tag = NUMBER
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} else {
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(*iter).tag = SYMBOL
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}
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}
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iter = &(*iter).next
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}
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for pos, char := range input {
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if char == delim {
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if is_str && is_list {
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// String just ended inside list
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is_str = false
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delim = ')'
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tok.WriteRune(char)
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continue
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}
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delim = ' '
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tokenBuilder(pos, tok.String())
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tok.Reset()
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} else {
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if strings.ContainsRune("\"'`", char) {
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is_str = true
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delim = char
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if !is_list {
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continue
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}
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} else if char == '(' && !is_str {
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is_list = true
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delim = ')'
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continue
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}
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tok.WriteRune(char)
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}
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}
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if tok.Len() > 0 {
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if is_list || is_str {
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// TODO: Throw hella lex error here
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return ret
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}
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tokenBuilder(len(input), tok.String())
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}
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return ret
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}
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func tokenIsNumber(arg string) bool {
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dotCount := 0
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for _, char := range arg {
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if !unicode.IsDigit(char) {
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if char == '.' && dotCount == 0 {
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dotCount++
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} else {
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return false
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}
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}
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}
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return true
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}
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