swissChili | c71acc6 | 2021-12-07 08:03:37 -0800 | [diff] [blame^] | 1 | #include "Parser.h" |
| 2 | |
| 3 | #include <QDebug> |
| 4 | |
| 5 | Parser::Parser(QString input) |
| 6 | { |
| 7 | _input = input; |
| 8 | } |
| 9 | |
| 10 | QChar Parser::peek() |
| 11 | { |
| 12 | if (atEnd()) |
| 13 | return 0; |
| 14 | |
| 15 | return _input[_pos]; |
| 16 | } |
| 17 | |
| 18 | QChar Parser::get() |
| 19 | { |
| 20 | return _input[_pos++]; |
| 21 | } |
| 22 | |
| 23 | bool Parser::atEnd() |
| 24 | { |
| 25 | return _pos >= _input.length(); |
| 26 | } |
| 27 | |
| 28 | void Parser::skip() |
| 29 | { |
| 30 | while (peek().isSpace()) |
| 31 | get(); |
| 32 | } |
| 33 | |
| 34 | bool Parser::parseSymbol(AstNode *node) |
| 35 | { |
| 36 | skip(); |
| 37 | |
| 38 | if (peek().isLetter()) |
| 39 | { |
| 40 | *node = AstNode(get()); |
| 41 | return true; |
| 42 | } |
| 43 | |
| 44 | return false; |
| 45 | } |
| 46 | |
| 47 | bool Parser::parseIdentifier(AstNode *node) |
| 48 | { |
| 49 | skip(); |
| 50 | |
| 51 | QString buffer; |
| 52 | |
| 53 | if (peek().isUpper()) |
| 54 | { |
| 55 | while (peek().isLetter() || peek() == '-' || peek() == '_' || peek().isNumber()) |
| 56 | { |
| 57 | buffer += get(); |
| 58 | } |
| 59 | |
| 60 | *node = AstNode(buffer); |
| 61 | return true; |
| 62 | } |
| 63 | |
| 64 | return false; |
| 65 | } |
| 66 | |
| 67 | bool Parser::parseNumber(AstNode *node) |
| 68 | { |
| 69 | skip(); |
| 70 | |
| 71 | QString buffer; |
| 72 | |
| 73 | if (peek().isDigit()) |
| 74 | { |
| 75 | while (peek().isDigit()) |
| 76 | buffer += get(); |
| 77 | |
| 78 | *node = AstNode(buffer.toInt()); |
| 79 | return true; |
| 80 | } |
| 81 | |
| 82 | return false; |
| 83 | } |
| 84 | |
| 85 | bool Parser::parseVariable(AstNode *node) |
| 86 | { |
| 87 | skip(); |
| 88 | |
| 89 | int pos = _pos; |
| 90 | |
| 91 | if (peek() == 's' || peek() == 'e' || peek() == 't') |
| 92 | { |
| 93 | char type = get().toLatin1(); |
| 94 | |
| 95 | if (peek() == '.') |
| 96 | { |
| 97 | get(); |
| 98 | |
| 99 | AstNode identNode; |
| 100 | |
| 101 | if (parseIdentifier(&identNode)) |
| 102 | { |
| 103 | *node = AstNode(type, identNode.name()); |
| 104 | return true; |
| 105 | } |
| 106 | } |
| 107 | } |
| 108 | |
| 109 | _pos = pos; |
| 110 | return false; |
| 111 | } |
| 112 | |
| 113 | bool Parser::parseOne(AstNode *node) |
| 114 | { |
| 115 | return parseFunction(node) || |
| 116 | parseVariable(node) || |
| 117 | parseNumber(node) || |
| 118 | parseIdentifier(node) || |
| 119 | parseSymbol(node) || |
| 120 | parseParens(node); |
| 121 | } |
| 122 | |
| 123 | QList<AstNode> Parser::parseMany() |
| 124 | { |
| 125 | QList<AstNode> nodes; |
| 126 | AstNode next; |
| 127 | |
| 128 | while (parseOne(&next)) |
| 129 | { |
| 130 | nodes.append(next); |
| 131 | } |
| 132 | |
| 133 | return nodes; |
| 134 | } |
| 135 | |
| 136 | bool Parser::parseParens(AstNode *node) |
| 137 | { |
| 138 | skip(); |
| 139 | |
| 140 | int pos = _pos; |
| 141 | |
| 142 | if (peek() != '(') |
| 143 | return false; |
| 144 | |
| 145 | get(); |
| 146 | |
| 147 | QList<AstNode> many = parseMany(); |
| 148 | *node = AstNode(many); |
| 149 | |
| 150 | skip(); |
| 151 | if (peek() != ')') |
| 152 | { |
| 153 | _pos = pos; |
| 154 | return false; |
| 155 | } |
| 156 | |
| 157 | get(); |
| 158 | |
| 159 | return true; |
| 160 | } |
| 161 | |
| 162 | bool Parser::parseFunction(AstNode *node) |
| 163 | { |
| 164 | skip(); |
| 165 | |
| 166 | int pos = _pos; |
| 167 | |
| 168 | if (peek() != '<') |
| 169 | return false; |
| 170 | |
| 171 | get(); |
| 172 | |
| 173 | AstNode head; |
| 174 | if (!parseIdentifier(&head)) |
| 175 | { |
| 176 | _pos = pos; |
| 177 | return false; |
| 178 | } |
| 179 | |
| 180 | QList<AstNode> body = parseMany(); |
| 181 | *node = AstNode(head.name(), body); |
| 182 | |
| 183 | skip(); |
| 184 | if (peek() != '>') |
| 185 | { |
| 186 | _pos = pos; |
| 187 | return false; |
| 188 | } |
| 189 | |
| 190 | get(); |
| 191 | |
| 192 | return true; |
| 193 | } |