tlex.c - plan9port - [fork] Plan 9 from user space
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tlex.c (6568B)
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1 #include "rc.h"
2 #include "exec.h"
3 #include "io.h"
4 #include "getflags.h"
5 #include "fns.h"
6 int getnext(void);
7
8 int
9 wordchr(int c)
10 {
11 return !strchr("\n \t#;&|^$=`'{}()<>", c) && c!=EOF;
12 }
13
14 int
15 idchr(int c)
16 {
17 /*
18 * Formerly:
19 * return 'a'<=c && c<='z' || 'A'<=c && c<='Z' || '0'<=c && c<='9'
20 * || c=='_' || c=='*';
21 */
22 return c>' ' && !strchr("!\"#$%&'()+,-./:;<=>?@[\\]^`{|}~", c);
23 }
24 int future = EOF;
25 int doprompt = 1;
26 int inquote;
27 int incomm;
28 /*
29 * Look ahead in the input stream
30 */
31
32 int
33 nextc(void)
34 {
35 if(future==EOF)
36 future = getnext();
37 return future;
38 }
39 /*
40 * Consume the lookahead character.
41 */
42
43 int
44 advance(void)
45 {
46 int c = nextc();
47 lastc = future;
48 future = EOF;
49 return c;
50 }
51 /*
52 * read a character from the input stream
53 */
54
55 int
56 getnext(void)
57 {
58 int c;
59 static int peekc = EOF;
60 if(peekc!=EOF){
61 c = peekc;
62 peekc = EOF;
63 return c;
64 }
65 if(runq->eof)
66 return EOF;
67 if(doprompt)
68 pprompt();
69 c = rchr(runq->cmdfd);
70 if(!inquote && c=='\\'){
71 c = rchr(runq->cmdfd);
72 if(c=='\n' && !incomm){ /* don't continue a comment */
73 doprompt = 1;
74 c=' ';
75 }
76 else{
77 peekc = c;
78 c='\\';
79 }
80 }
81 doprompt = doprompt || c=='\n' || c==EOF;
82 if(c==EOF)
83 runq->eof++;
84 else if(flag['V'] || ndot>=2 && flag['v']) pchr(err, c);
85 return c;
86 }
87
88 void
89 pprompt(void)
90 {
91 var *prompt;
92 if(runq->iflag){
93 pstr(err, promptstr);
94 flush(err);
95 prompt = vlook("prompt");
96 if(prompt->val && prompt->val->next)
97 promptstr = prompt->val->next->word;
98 else
99 promptstr="\t";
100 }
101 runq->lineno++;
102 doprompt = 0;
103 }
104
105 int
106 skipwhite(void)
107 {
108 int c, skipped;
109 skipped = 0;
110 for(;;){
111 c = nextc();
112 /* Why did this used to be if(!inquote && c=='#') ?? */
113 if(c=='#'){
114 incomm = 1;
115 skipped = 1;
116 for(;;){
117 c = nextc();
118 if(c=='\n' || c==EOF) {
119 incomm = 0;
120 break;
121 }
122 advance();
123 }
124 }
125 if(c==' ' || c=='\t') {
126 skipped = 1;
127 advance();
128 }
129 else
130 return skipped;
131 }
132 }
133
134 void
135 skipnl(void)
136 {
137 int c;
138 for(;;){
139 skipwhite();
140 c = nextc();
141 if(c!='\n')
142 return;
143 advance();
144 }
145 }
146
147 int
148 nextis(int c)
149 {
150 if(nextc()==c){
151 advance();
152 return 1;
153 }
154 return 0;
155 }
156
157 char*
158 addtok(char *p, int val)
159 {
160 if(p==0)
161 return 0;
162 if(p==&tok[NTOK-1]){
163 *p = 0;
164 yyerror("token buffer too short");
165 return 0;
166 }
167 *p++=val;
168 return p;
169 }
170
171 char*
172 addutf(char *p, int c)
173 {
174 p = addtok(p, c);
175 if(twobyte(c)) /* 2-byte escape */
176 return addtok(p, advance());
177 if(threebyte(c)){ /* 3-byte escape */
178 p = addtok(p, advance());
179 return addtok(p, advance());
180 }
181 if(fourbyte(c)){ /* 4-byte escape */
182 p = addtok(p, advance());
183 p = addtok(p, advance());
184 return addtok(p, advance());
185 }
186 return p;
187 }
188 int lastdol; /* was the last token read '$' or '$#' or '"'? */
189 int lastword; /* was the last token read a word or compound word terminator? */
190
191 int
192 yylex(void)
193 {
194 int c, d = nextc();
195 char *w = tok;
196 tree *t;
197 yylval.tree = 0;
198 /*
199 * Embarassing sneakiness: if the last token read was a quoted or unquoted
200 * WORD then we alter the meaning of what follows. If the next character
201 * is `(', we return SUB (a subscript paren) and consume the `('. Otherwise,
202 * if the next character is the first character of a simple or compound word,
203 * we insert a `^' before it.
204 */
205 if(lastword && flag['Y']){
206 lastword = 0;
207 if(d=='('){
208 advance();
209 strcpy(tok, "(");
210 return SUB;
211 }
212 if(wordchr(d) || d=='\'' || d=='`' || d=='$' || d=='"'){
213 strcpy(tok, "^");
214 return '^';
215 }
216 }
217 inquote = 0;
218 if(skipwhite() && !flag['Y'])
219 return ' ';
220 switch(c = advance()){
221 case EOF:
222 lastdol = 0;
223 strcpy(tok, "EOF");
224 return EOF;
225 case '$':
226 lastdol = 1;
227 if(nextis('#')){
228 strcpy(tok, "$#");
229 return COUNT;
230 }
231 if(nextis('"')){
232 strcpy(tok, "$\"");
233 return '"';
234 }
235 strcpy(tok, "$");
236 return '$';
237 case '&':
238 lastdol = 0;
239 if(nextis('&')){
240 if(flag['Y'])
241 skipnl();
242 strcpy(tok, "&&");
243 return ANDAND;
244 }
245 strcpy(tok, "&");
246 return '&';
247 case '|':
248 lastdol = 0;
249 if(nextis(c)){
250 if(flag['Y'])
251 skipnl();
252 strcpy(tok, "||");
253 return OROR;
254 }
255 case '<':
256 case '>':
257 lastdol = 0;
258 /*
259 * funny redirection tokens:
260 * redir: arrow | arrow '[' fd ']'
261 * arrow: '<' | '<<' | '>' | '>>' | '|'
262 * fd: digit | digit '=' | digit '=' digit
263 * digit: '0'|'1'|'2'|'3'|'4'|'5'|'6'|'7'|'8'|'9'
264 * some possibilities are nonsensical and get a message.
265 */
266 *w++=c;
267 t = newtree();
268 switch(c){
269 case '|':
270 t->type = PIPE;
271 t->fd0 = 1;
272 t->fd1 = 0;
273 break;
274 case '>':
275 t->type = REDIR;
276 if(nextis(c)){
277 t->rtype = APPEND;
278 *w++=c;
279 }
280 else t->rtype = WRITE;
281 t->fd0 = 1;
282 break;
283 case '<':
284 t->type = REDIR;
285 if(nextis(c)){
286 t->rtype = HERE;
287 *w++=c;
288 } else if (nextis('>')){
289 t->rtype = RDWR;
290 *w++=c;
291 } else t->rtype = READ;
292 t->fd0 = 0;
293 break;
294 }
295 if(nextis('[')){
296 *w++='[';
297 c = advance();
298 *w++=c;
299 if(c<'0' || '9'<c){
300 RedirErr:
301 *w = 0;
302 yyerror(t->type==PIPE?"pipe syntax"
303 :"redirection syntax");
304 return EOF;
305 }
306 t->fd0 = 0;
307 do{
308 t->fd0 = t->fd0*10+c-'0';
309 *w++=c;
310 c = advance();
311 }while('0'<=c && c<='9');
312 if(c=='='){
313 *w++='=';
314 if(t->type==REDIR)
315 t->type = DUP;
316 c = advance();
317 if('0'<=c && c<='9'){
318 t->rtype = DUPFD;
319 t->fd1 = t->fd0;
320 t->fd0 = 0;
321 do{
322 t->fd0 = t->fd0*10+c-'0';
323 *w++=c;
324 c = advance();
325 }while('0'<=c && c<='9');
326 }
327 else{
328 if(t->type==PIPE)
329 goto RedirErr;
330 t->rtype = CLOSE;
331 }
332 }
333 if(c!=']'
334 || t->type==DUP && (t->rtype==HERE || t->rtype==APPEND))
335 goto RedirErr;
336 *w++=']';
337 }
338 *w='\0';
339 yylval.tree = t;
340 if(t->type==PIPE && flag['Y'])
341 skipnl();
342 if(t->type==REDIR) {
343 skipwhite();
344 if(nextc() == '{')
345 t->type = REDIRW;
346 }
347 return t->type;
348 case '\'':
349 lastdol = 0;
350 lastword = 1;
351 inquote = 1;
352 for(;;){
353 c = advance();
354 if(c==EOF)
355 break;
356 if(c=='\''){
357 if(nextc()!='\'')
358 break;
359 advance();
360 }
361 w = addutf(w, c);
362 }
363 if(w!=0)
364 *w='\0';
365 t = token(tok, WORD);
366 t->quoted = 1;
367 yylval.tree = t;
368 return t->type;
369 }
370 if(!wordchr(c)){
371 lastdol = 0;
372 tok[0] = c;
373 tok[1]='\0';
374 return c;
375 }
376 for(;;){
377 /* next line should have (char)c==GLOB, but ken's compiler is broken */
378 if(c=='*' || c=='[' || c=='?' || c==(unsigned char)GLOB)
379 w = addtok(w, GLOB);
380 w = addutf(w, c);
381 c = nextc();
382 if(lastdol?!idchr(c):!wordchr(c)) break;
383 advance();
384 }
385
386 lastword = 1;
387 lastdol = 0;
388 if(w!=0)
389 *w='\0';
390 t = klook(tok);
391 if(t->type!=WORD)
392 lastword = 0;
393 t->quoted = 0;
394 yylval.tree = t;
395 return t->type;
396 }