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comparison src/luan/modules/parsers/LuanParser.java @ 1447:851b9a48cc44

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Luan.parse
author Franklin Schmidt <fschmidt@gmail.com>
date Tue, 18 Feb 2020 14:54:35 -0700
parents
children b89212fd04b5
comparison
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1446:f2082e9aeaa9 1447:851b9a48cc44
1 package luan.modules.parsers;
2
3 import goodjava.parser.Parser;
4 import goodjava.parser.ParseException;
5 import luan.Luan;
6 import luan.LuanTable;
7 import luan.LuanException;
8
9
10 public final class LuanParser {
11
12 public static Object parse(Luan luan,String text) throws ParseException {
13 return new LuanParser(luan,text).parse();
14 }
15
16 private static final Object NULL = new Object();
17 private final Luan luan;
18 private final Parser parser;
19
20 private LuanParser(Luan luan,String text) {
21 this.luan = luan;
22 this.parser = new Parser(text);
23 }
24
25 private ParseException exception(String msg) {
26 return new ParseException(parser,msg);
27 }
28
29 private Object parse() throws ParseException {
30 do { spaces(); } while( endOfLine() );
31 Object value = requiredValue();
32 do { spaces(); } while( endOfLine() );
33 if( !parser.endOfInput() )
34 throw exception("unexpected text");
35 return value;
36 }
37
38 private Object requiredValue() throws ParseException {
39 Object value = value();
40 if( value == null )
41 throw exception("invalid value");
42 if( value == NULL )
43 return null;
44 return value;
45 }
46
47 private Object value() throws ParseException {
48 if( parser.match("nil") )
49 return NULL;
50 if( parser.match("true") )
51 return Boolean.TRUE;
52 if( parser.match("false") )
53 return Boolean.FALSE;
54 String s = string();
55 if( s != null )
56 return s;
57 Number n = number();
58 if( n != null )
59 return n;
60 LuanTable tbl = table();
61 if( tbl != null )
62 return tbl;
63 return null;
64 }
65
66 private String string() throws ParseException {
67 parser.begin();
68 if( !parser.match('"') )
69 return parser.failure(null);
70 StringBuilder sb = new StringBuilder();
71 while( parser.anyChar() ) {
72 char c = parser.lastChar();
73 switch(c) {
74 case '"':
75 return parser.success(sb.toString());
76 case '\\':
77 if( parser.anyChar() ) {
78 c = parser.lastChar();
79 switch(c) {
80 case '"':
81 case '\'':
82 case '\\':
83 sb.append(c);
84 continue;
85 case 'b':
86 sb.append('\b');
87 continue;
88 case 'f':
89 sb.append('\f');
90 continue;
91 case 'n':
92 sb.append('\n');
93 continue;
94 case 'r':
95 sb.append('\r');
96 continue;
97 case 't':
98 sb.append('\t');
99 continue;
100 case 'u':
101 int n = 0;
102 for( int i=0; i<4; i++ ) {
103 int d;
104 if( parser.inCharRange('0','9') ) {
105 d = parser.lastChar() - '0';
106 } else if( parser.inCharRange('a','f') ) {
107 d = parser.lastChar() - 'a' + 10;
108 } else if( parser.inCharRange('A','F') ) {
109 d = parser.lastChar() - 'A' + 10;
110 } else {
111 throw exception("invalid hex digit");
112 }
113 n = 16*n + d;
114 }
115 sb.append((char)n);
116 continue;
117 }
118 }
119 throw exception("invalid escape char");
120 default:
121 sb.append(c);
122 }
123 }
124 parser.failure();
125 throw exception("unclosed string");
126 }
127
128 private Number number() {
129 parser.begin();
130 if( parser.match("double") ) {
131 Number n = inParens();
132 if( n==null )
133 return parser.failure(null);
134 n = Luan.asDouble(n);
135 if( n==null )
136 return parser.failure(null);
137 return n;
138 } else if( parser.match("float") ) {
139 Number n = inParens();
140 if( n==null )
141 return parser.failure(null);
142 n = Luan.asFloat(n);
143 if( n==null )
144 return parser.failure(null);
145 return n;
146 } else if( parser.match("integer") ) {
147 Number n = inParens();
148 if( n==null )
149 return parser.failure(null);
150 n = Luan.asInteger(n);
151 if( n==null )
152 return parser.failure(null);
153 return n;
154 } else if( parser.match("long") ) {
155 Number n = inParens();
156 if( n==null )
157 return parser.failure(null);
158 n = Luan.asLong(n);
159 if( n==null )
160 return parser.failure(null);
161 return n;
162 } else {
163 Number n = untypedNumber();
164 if( n != null )
165 return parser.success(n);
166 else
167 return parser.failure(null);
168 }
169 }
170
171 private Number inParens() {
172 spaces();
173 if( !parser.match('(') )
174 return null;
175 spaces();
176 Number n = untypedNumber();
177 if( n==null )
178 return null;
179 spaces();
180 if( !parser.match(')') )
181 return null;
182 return n;
183 }
184
185 private Number untypedNumber() {
186 int start = parser.begin();
187 boolean isFloat = false;
188 parser.match('-');
189 if( !parser.match('0') ) {
190 if( !parser.inCharRange('1','9') )
191 return parser.failure(null);
192 while( parser.inCharRange('0','9') );
193 }
194 if( parser.match('.') ) {
195 if( !parser.inCharRange('0','9') )
196 return parser.failure(null);
197 while( parser.inCharRange('0','9') );
198 isFloat = true;
199 }
200 if( parser.anyOf("eE") ) {
201 parser.anyOf("+-");
202 if( !parser.inCharRange('0','9') )
203 return parser.failure(null);
204 while( parser.inCharRange('0','9') );
205 isFloat = true;
206 }
207 String s = parser.textFrom(start);
208 Number n;
209 if(isFloat)
210 n = Double.valueOf(s);
211 else
212 n = Long.valueOf(s);
213 return parser.success(n);
214 }
215
216 private LuanTable table() throws ParseException {
217 parser.begin();
218 if( !parser.match('{') )
219 return parser.failure(null);
220 LuanTable tbl = new LuanTable(luan);
221 do {
222 spaces();
223 Object obj = value();
224 if( obj != null ) {
225 if( obj != NULL )
226 tbl.rawAdd(obj);
227 spaces();
228 continue;
229 }
230 Object key = key();
231 if( key != null ) {
232 spaces();
233 requiredMatch('=');
234 spaces();
235 Object value = requiredValue();
236 spaces();
237 try {
238 tbl.rawPut(key,value);
239 } catch(LuanException e) {
240 throw new RuntimeException(e);
241 }
242 }
243 } while( fieldSep() );
244 requiredMatch('}');
245 return parser.success(tbl);
246 }
247
248 private Object key() throws ParseException {
249 if( parser.match('[') ) {
250 spaces();
251 Object key = requiredValue();
252 spaces();
253 requiredMatch(']');
254 return key;
255 }
256 int start = parser.currentIndex();
257 if( nameFirstChar() ) {
258 while( nameChar() );
259 return parser.textFrom(start);
260 }
261 return null;
262 }
263
264 private boolean nameChar() {
265 return nameFirstChar() || parser.inCharRange('0','9');
266 }
267
268 private boolean nameFirstChar() {
269 return parser.inCharRange('a','z') || parser.inCharRange('A','Z') || parser.match('_');
270 }
271
272 private boolean fieldSep() throws ParseException {
273 return parser.anyOf(",;") || endOfLine();
274 }
275
276 private boolean endOfLine() {
277 return parser.match( "\r\n" ) || parser.match( '\r' ) || parser.match( '\n' );
278 }
279
280 private void requiredMatch(char c) throws ParseException {
281 if( !parser.match(c) )
282 throw exception("'"+c+"' expected");
283 }
284
285 private void spaces() {
286 while( parser.anyOf(" \t") );
287 }
288
289 }