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Date:: Tue May 5 03:41:15 2020 UTC
Message:: rc: add recursive descent parser The old yacc-based parser is available with the -Y flag, which will probably be removed at some point. The new -D flag dumps a parse tree of the input, without executing it. This allows comparing the output of rc -D and rc -DY on different scripts to see that the two parsers behave the same. The rc paper ends by saying: It is remarkable that in the four most recent editions of the UNIX system programmer’s manual the Bourne shell grammar described in the manual page does not admit the command who|wc. This is surely an oversight, but it suggests something darker: nobody really knows what the Bourne shell’s grammar is. Even examination of the source code is little help. The parser is implemented by recursive descent, but the routines corresponding to the syntactic categories all have a flag argument that subtly changes their operation depending on the context. Rc’s parser is implemented using yacc, so I can say precisely what the grammar is. The new recursive descent parser here has no such flags. It is a straightforward translation of the yacc. The new parser will make it easier to handle free carats in more generality as well as potentially allow the use of unquoted = as a word character. Going through this exercise has highlighted a few dark corners here as well. For example, I was surprised to find that x >f | y >f x | y are different commands (the latter redirects y's output). It is similarly surprising that a=b x | y sets a during the execution of y. It is also a bit counter-intuitive x | y | z x | if(c) y | z are not both 3-phase pipelines. These are certainly not things we should change, but they are not entirely obvious from the man page description, undercutting the quoted claim a bit. On the other hand, who | wc is clearly accepted by the grammar in the manual page, and the new parser still handles that test case.
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  1 f08fdedc 2003-11-23 devnull #include "rc.h"
  2 f08fdedc 2003-11-23 devnull #include "io.h"
  3 f08fdedc 2003-11-23 devnull #include "exec.h"
  4 f08fdedc 2003-11-23 devnull #include "fns.h"
  5 f08fdedc 2003-11-23 devnull #include "getflags.h"
  6 f08fdedc 2003-11-23 devnull #define	c0	t->child[0]
  7 f08fdedc 2003-11-23 devnull #define	c1	t->child[1]
  8 f08fdedc 2003-11-23 devnull #define	c2	t->child[2]
  9 f08fdedc 2003-11-23 devnull int codep, ncode;
 10 c8f53842 2007-03-26 devnull #define	emitf(x) ((void)(codep!=ncode || morecode()), codebuf[codep].f = (x), codep++)
 11 c8f53842 2007-03-26 devnull #define	emiti(x) ((void)(codep!=ncode || morecode()), codebuf[codep].i = (x), codep++)
 12 c8f53842 2007-03-26 devnull #define	emits(x) ((void)(codep!=ncode || morecode()), codebuf[codep].s = (x), codep++)
 13 f08fdedc 2003-11-23 devnull void stuffdot(int);
 14 f08fdedc 2003-11-23 devnull char *fnstr(tree*);
 15 f08fdedc 2003-11-23 devnull void outcode(tree*, int);
 16 f08fdedc 2003-11-23 devnull void codeswitch(tree*, int);
 17 f08fdedc 2003-11-23 devnull int iscase(tree*);
 18 f08fdedc 2003-11-23 devnull code *codecopy(code*);
 19 f08fdedc 2003-11-23 devnull void codefree(code*);
 20 c8f53842 2007-03-26 devnull 
 21 c8f53842 2007-03-26 devnull int
 22 c8f53842 2007-03-26 devnull morecode(void)
 23 c8f53842 2007-03-26 devnull {
 24 f08fdedc 2003-11-23 devnull 	ncode+=100;
 25 c8f53842 2007-03-26 devnull 	codebuf = (code *)realloc((char *)codebuf, ncode*sizeof codebuf[0]);
 26 c8f53842 2007-03-26 devnull 	if(codebuf==0)
 27 c8f53842 2007-03-26 devnull 		panic("Can't realloc %d bytes in morecode!",
 28 f08fdedc 2003-11-23 devnull 				ncode*sizeof codebuf[0]);
 29 40402738 2007-03-26 devnull 	memset(codebuf+ncode-100, 0, 100*sizeof codebuf[0]);
 30 f08fdedc 2003-11-23 devnull 	return 0;
 31 f08fdedc 2003-11-23 devnull }
 32 c8f53842 2007-03-26 devnull 
 33 c8f53842 2007-03-26 devnull void
 34 c8f53842 2007-03-26 devnull stuffdot(int a)
 35 c8f53842 2007-03-26 devnull {
 36 c8f53842 2007-03-26 devnull 	if(a<0 || codep<=a)
 37 c8f53842 2007-03-26 devnull 		panic("Bad address %d in stuffdot", a);
 38 c8f53842 2007-03-26 devnull 	codebuf[a].i = codep;
 39 f08fdedc 2003-11-23 devnull }
 40 c8f53842 2007-03-26 devnull 
 41 c8f53842 2007-03-26 devnull int
 42 c8f53842 2007-03-26 devnull compile(tree *t)
 43 f08fdedc 2003-11-23 devnull {
 44 47d4646e 2020-05-05 rsc 	if(flag['D']) {
 45 47d4646e 2020-05-05 rsc 		struct io *s;
 46 47d4646e 2020-05-05 rsc 		s = openstr();
 47 47d4646e 2020-05-05 rsc 		pfmt(s, "compile: %u\n", t);
 48 47d4646e 2020-05-05 rsc 		write(2, s->strp, strlen(s->strp));
 49 47d4646e 2020-05-05 rsc 		closeio(s);
 50 47d4646e 2020-05-05 rsc 		if(eflagok) // made it out of rcmain - stop executing commands, just print them
 51 47d4646e 2020-05-05 rsc 			t = nil;
 52 47d4646e 2020-05-05 rsc 	}
 53 47d4646e 2020-05-05 rsc 
 54 c8f53842 2007-03-26 devnull 	ncode = 100;
 55 c8f53842 2007-03-26 devnull 	codebuf = (code *)emalloc(ncode*sizeof codebuf[0]);
 56 c8f53842 2007-03-26 devnull 	codep = 0;
 57 f08fdedc 2003-11-23 devnull 	emiti(0);			/* reference count */
 58 f08fdedc 2003-11-23 devnull 	outcode(t, flag['e']?1:0);
 59 f08fdedc 2003-11-23 devnull 	if(nerror){
 60 f08fdedc 2003-11-23 devnull 		efree((char *)codebuf);
 61 f08fdedc 2003-11-23 devnull 		return 0;
 62 f08fdedc 2003-11-23 devnull 	}
 63 f08fdedc 2003-11-23 devnull 	readhere();
 64 f08fdedc 2003-11-23 devnull 	emitf(Xreturn);
 65 f08fdedc 2003-11-23 devnull 	emitf(0);
 66 f08fdedc 2003-11-23 devnull 	return 1;
 67 f08fdedc 2003-11-23 devnull }
 68 c8f53842 2007-03-26 devnull 
 69 c8f53842 2007-03-26 devnull void
 70 c8f53842 2007-03-26 devnull cleanhere(char *f)
 71 f08fdedc 2003-11-23 devnull {
 72 f08fdedc 2003-11-23 devnull 	emitf(Xdelhere);
 73 f08fdedc 2003-11-23 devnull 	emits(strdup(f));
 74 f08fdedc 2003-11-23 devnull }
 75 c8f53842 2007-03-26 devnull 
 76 c8f53842 2007-03-26 devnull char*
 77 c8f53842 2007-03-26 devnull fnstr(tree *t)
 78 f08fdedc 2003-11-23 devnull {
 79 c8f53842 2007-03-26 devnull 	io *f = openstr();
 80 f08fdedc 2003-11-23 devnull 	char *v;
 81 f08fdedc 2003-11-23 devnull 	extern char nl;
 82 c8f53842 2007-03-26 devnull 	char svnl = nl;
 83 f08fdedc 2003-11-23 devnull 	nl=';';
 84 f08fdedc 2003-11-23 devnull 	pfmt(f, "%t", t);
 85 c8f53842 2007-03-26 devnull 	nl = svnl;
 86 c8f53842 2007-03-26 devnull 	v = f->strp;
 87 c8f53842 2007-03-26 devnull 	f->strp = 0;
 88 f08fdedc 2003-11-23 devnull 	closeio(f);
 89 f08fdedc 2003-11-23 devnull 	return v;
 90 f08fdedc 2003-11-23 devnull }
 91 c8f53842 2007-03-26 devnull 
 92 c8f53842 2007-03-26 devnull void
 93 c8f53842 2007-03-26 devnull outcode(tree *t, int eflag)
 94 f08fdedc 2003-11-23 devnull {
 95 f08fdedc 2003-11-23 devnull 	int p, q;
 96 f08fdedc 2003-11-23 devnull 	tree *tt;
 97 c8f53842 2007-03-26 devnull 	if(t==0)
 98 c8f53842 2007-03-26 devnull 		return;
 99 c8f53842 2007-03-26 devnull 	if(t->type!=NOT && t->type!=';')
100 c8f53842 2007-03-26 devnull 		runq->iflast = 0;
101 f08fdedc 2003-11-23 devnull 	switch(t->type){
102 f08fdedc 2003-11-23 devnull 	default:
103 f08fdedc 2003-11-23 devnull 		pfmt(err, "bad type %d in outcode\n", t->type);
104 f08fdedc 2003-11-23 devnull 		break;
105 f08fdedc 2003-11-23 devnull 	case '$':
106 f08fdedc 2003-11-23 devnull 		emitf(Xmark);
107 f08fdedc 2003-11-23 devnull 		outcode(c0, eflag);
108 f08fdedc 2003-11-23 devnull 		emitf(Xdol);
109 f08fdedc 2003-11-23 devnull 		break;
110 f08fdedc 2003-11-23 devnull 	case '"':
111 f08fdedc 2003-11-23 devnull 		emitf(Xmark);
112 f08fdedc 2003-11-23 devnull 		outcode(c0, eflag);
113 f08fdedc 2003-11-23 devnull 		emitf(Xqdol);
114 f08fdedc 2003-11-23 devnull 		break;
115 f08fdedc 2003-11-23 devnull 	case SUB:
116 f08fdedc 2003-11-23 devnull 		emitf(Xmark);
117 f08fdedc 2003-11-23 devnull 		outcode(c0, eflag);
118 f08fdedc 2003-11-23 devnull 		emitf(Xmark);
119 f08fdedc 2003-11-23 devnull 		outcode(c1, eflag);
120 f08fdedc 2003-11-23 devnull 		emitf(Xsub);
121 f08fdedc 2003-11-23 devnull 		break;
122 f08fdedc 2003-11-23 devnull 	case '&':
123 f08fdedc 2003-11-23 devnull 		emitf(Xasync);
124 c8f53842 2007-03-26 devnull 		if(havefork){
125 c8f53842 2007-03-26 devnull 			p = emiti(0);
126 c8f53842 2007-03-26 devnull 			outcode(c0, eflag);
127 c8f53842 2007-03-26 devnull 			emitf(Xexit);
128 c8f53842 2007-03-26 devnull 			stuffdot(p);
129 c8f53842 2007-03-26 devnull 		} else
130 c8f53842 2007-03-26 devnull 			emits(fnstr(c0));
131 f08fdedc 2003-11-23 devnull 		break;
132 f08fdedc 2003-11-23 devnull 	case ';':
133 f08fdedc 2003-11-23 devnull 		outcode(c0, eflag);
134 f08fdedc 2003-11-23 devnull 		outcode(c1, eflag);
135 f08fdedc 2003-11-23 devnull 		break;
136 f08fdedc 2003-11-23 devnull 	case '^':
137 f08fdedc 2003-11-23 devnull 		emitf(Xmark);
138 f08fdedc 2003-11-23 devnull 		outcode(c1, eflag);
139 f08fdedc 2003-11-23 devnull 		emitf(Xmark);
140 f08fdedc 2003-11-23 devnull 		outcode(c0, eflag);
141 f08fdedc 2003-11-23 devnull 		emitf(Xconc);
142 f08fdedc 2003-11-23 devnull 		break;
143 f08fdedc 2003-11-23 devnull 	case '`':
144 f08fdedc 2003-11-23 devnull 		emitf(Xbackq);
145 c8f53842 2007-03-26 devnull 		if(havefork){
146 c8f53842 2007-03-26 devnull 			p = emiti(0);
147 c8f53842 2007-03-26 devnull 			outcode(c0, 0);
148 c8f53842 2007-03-26 devnull 			emitf(Xexit);
149 c8f53842 2007-03-26 devnull 			stuffdot(p);
150 c8f53842 2007-03-26 devnull 		} else
151 c8f53842 2007-03-26 devnull 			emits(fnstr(c0));
152 f08fdedc 2003-11-23 devnull 		break;
153 f08fdedc 2003-11-23 devnull 	case ANDAND:
154 f08fdedc 2003-11-23 devnull 		outcode(c0, 0);
155 f08fdedc 2003-11-23 devnull 		emitf(Xtrue);
156 c8f53842 2007-03-26 devnull 		p = emiti(0);
157 f08fdedc 2003-11-23 devnull 		outcode(c1, eflag);
158 f08fdedc 2003-11-23 devnull 		stuffdot(p);
159 f08fdedc 2003-11-23 devnull 		break;
160 f08fdedc 2003-11-23 devnull 	case ARGLIST:
161 f08fdedc 2003-11-23 devnull 		outcode(c1, eflag);
162 f08fdedc 2003-11-23 devnull 		outcode(c0, eflag);
163 f08fdedc 2003-11-23 devnull 		break;
164 f08fdedc 2003-11-23 devnull 	case BANG:
165 f08fdedc 2003-11-23 devnull 		outcode(c0, eflag);
166 f08fdedc 2003-11-23 devnull 		emitf(Xbang);
167 f08fdedc 2003-11-23 devnull 		break;
168 f08fdedc 2003-11-23 devnull 	case PCMD:
169 f08fdedc 2003-11-23 devnull 	case BRACE:
170 f08fdedc 2003-11-23 devnull 		outcode(c0, eflag);
171 f08fdedc 2003-11-23 devnull 		break;
172 f08fdedc 2003-11-23 devnull 	case COUNT:
173 f08fdedc 2003-11-23 devnull 		emitf(Xmark);
174 f08fdedc 2003-11-23 devnull 		outcode(c0, eflag);
175 f08fdedc 2003-11-23 devnull 		emitf(Xcount);
176 f08fdedc 2003-11-23 devnull 		break;
177 f08fdedc 2003-11-23 devnull 	case FN:
178 f08fdedc 2003-11-23 devnull 		emitf(Xmark);
179 f08fdedc 2003-11-23 devnull 		outcode(c0, eflag);
180 f08fdedc 2003-11-23 devnull 		if(c1){
181 f08fdedc 2003-11-23 devnull 			emitf(Xfn);
182 c8f53842 2007-03-26 devnull 			p = emiti(0);
183 f08fdedc 2003-11-23 devnull 			emits(fnstr(c1));
184 f08fdedc 2003-11-23 devnull 			outcode(c1, eflag);
185 f08fdedc 2003-11-23 devnull 			emitf(Xunlocal);	/* get rid of $* */
186 f08fdedc 2003-11-23 devnull 			emitf(Xreturn);
187 f08fdedc 2003-11-23 devnull 			stuffdot(p);
188 f08fdedc 2003-11-23 devnull 		}
189 f08fdedc 2003-11-23 devnull 		else
190 f08fdedc 2003-11-23 devnull 			emitf(Xdelfn);
191 f08fdedc 2003-11-23 devnull 		break;
192 f08fdedc 2003-11-23 devnull 	case IF:
193 f08fdedc 2003-11-23 devnull 		outcode(c0, 0);
194 f08fdedc 2003-11-23 devnull 		emitf(Xif);
195 c8f53842 2007-03-26 devnull 		p = emiti(0);
196 f08fdedc 2003-11-23 devnull 		outcode(c1, eflag);
197 f08fdedc 2003-11-23 devnull 		emitf(Xwastrue);
198 f08fdedc 2003-11-23 devnull 		stuffdot(p);
199 f08fdedc 2003-11-23 devnull 		break;
200 f08fdedc 2003-11-23 devnull 	case NOT:
201 c8f53842 2007-03-26 devnull 		if(!runq->iflast)
202 c8f53842 2007-03-26 devnull 			yyerror("`if not' does not follow `if(...)'");
203 f08fdedc 2003-11-23 devnull 		emitf(Xifnot);
204 c8f53842 2007-03-26 devnull 		p = emiti(0);
205 f08fdedc 2003-11-23 devnull 		outcode(c0, eflag);
206 f08fdedc 2003-11-23 devnull 		stuffdot(p);
207 f08fdedc 2003-11-23 devnull 		break;
208 f08fdedc 2003-11-23 devnull 	case OROR:
209 f08fdedc 2003-11-23 devnull 		outcode(c0, 0);
210 f08fdedc 2003-11-23 devnull 		emitf(Xfalse);
211 c8f53842 2007-03-26 devnull 		p = emiti(0);
212 f08fdedc 2003-11-23 devnull 		outcode(c1, eflag);
213 f08fdedc 2003-11-23 devnull 		stuffdot(p);
214 f08fdedc 2003-11-23 devnull 		break;
215 f08fdedc 2003-11-23 devnull 	case PAREN:
216 f08fdedc 2003-11-23 devnull 		outcode(c0, eflag);
217 f08fdedc 2003-11-23 devnull 		break;
218 f08fdedc 2003-11-23 devnull 	case SIMPLE:
219 f08fdedc 2003-11-23 devnull 		emitf(Xmark);
220 f08fdedc 2003-11-23 devnull 		outcode(c0, eflag);
221 f08fdedc 2003-11-23 devnull 		emitf(Xsimple);
222 c8f53842 2007-03-26 devnull 		if(eflag)
223 c8f53842 2007-03-26 devnull 			emitf(Xeflag);
224 f08fdedc 2003-11-23 devnull 		break;
225 f08fdedc 2003-11-23 devnull 	case SUBSHELL:
226 f08fdedc 2003-11-23 devnull 		emitf(Xsubshell);
227 c8f53842 2007-03-26 devnull 		if(havefork){
228 c8f53842 2007-03-26 devnull 			p = emiti(0);
229 c8f53842 2007-03-26 devnull 			outcode(c0, eflag);
230 c8f53842 2007-03-26 devnull 			emitf(Xexit);
231 c8f53842 2007-03-26 devnull 			stuffdot(p);
232 c8f53842 2007-03-26 devnull 		} else
233 c8f53842 2007-03-26 devnull 			emits(fnstr(c0));
234 c8f53842 2007-03-26 devnull 		if(eflag)
235 c8f53842 2007-03-26 devnull 			emitf(Xeflag);
236 f08fdedc 2003-11-23 devnull 		break;
237 f08fdedc 2003-11-23 devnull 	case SWITCH:
238 f08fdedc 2003-11-23 devnull 		codeswitch(t, eflag);
239 f08fdedc 2003-11-23 devnull 		break;
240 f08fdedc 2003-11-23 devnull 	case TWIDDLE:
241 f08fdedc 2003-11-23 devnull 		emitf(Xmark);
242 f08fdedc 2003-11-23 devnull 		outcode(c1, eflag);
243 f08fdedc 2003-11-23 devnull 		emitf(Xmark);
244 f08fdedc 2003-11-23 devnull 		outcode(c0, eflag);
245 f08fdedc 2003-11-23 devnull 		emitf(Xmatch);
246 c8f53842 2007-03-26 devnull 		if(eflag)
247 c8f53842 2007-03-26 devnull 			emitf(Xeflag);
248 f08fdedc 2003-11-23 devnull 		break;
249 f08fdedc 2003-11-23 devnull 	case WHILE:
250 c8f53842 2007-03-26 devnull 		q = codep;
251 f08fdedc 2003-11-23 devnull 		outcode(c0, 0);
252 c8f53842 2007-03-26 devnull 		if(q==codep)
253 c8f53842 2007-03-26 devnull 			emitf(Xsettrue);	/* empty condition == while(true) */
254 f08fdedc 2003-11-23 devnull 		emitf(Xtrue);
255 c8f53842 2007-03-26 devnull 		p = emiti(0);
256 f08fdedc 2003-11-23 devnull 		outcode(c1, eflag);
257 f08fdedc 2003-11-23 devnull 		emitf(Xjump);
258 f08fdedc 2003-11-23 devnull 		emiti(q);
259 f08fdedc 2003-11-23 devnull 		stuffdot(p);
260 f08fdedc 2003-11-23 devnull 		break;
261 f08fdedc 2003-11-23 devnull 	case WORDS:
262 f08fdedc 2003-11-23 devnull 		outcode(c1, eflag);
263 f08fdedc 2003-11-23 devnull 		outcode(c0, eflag);
264 f08fdedc 2003-11-23 devnull 		break;
265 f08fdedc 2003-11-23 devnull 	case FOR:
266 f08fdedc 2003-11-23 devnull 		emitf(Xmark);
267 f08fdedc 2003-11-23 devnull 		if(c1){
268 f08fdedc 2003-11-23 devnull 			outcode(c1, eflag);
269 f08fdedc 2003-11-23 devnull 			emitf(Xglob);
270 f08fdedc 2003-11-23 devnull 		}
271 f08fdedc 2003-11-23 devnull 		else{
272 f08fdedc 2003-11-23 devnull 			emitf(Xmark);
273 f08fdedc 2003-11-23 devnull 			emitf(Xword);
274 f08fdedc 2003-11-23 devnull 			emits(strdup("*"));
275 f08fdedc 2003-11-23 devnull 			emitf(Xdol);
276 f08fdedc 2003-11-23 devnull 		}
277 f08fdedc 2003-11-23 devnull 		emitf(Xmark);		/* dummy value for Xlocal */
278 f08fdedc 2003-11-23 devnull 		emitf(Xmark);
279 f08fdedc 2003-11-23 devnull 		outcode(c0, eflag);
280 f08fdedc 2003-11-23 devnull 		emitf(Xlocal);
281 c8f53842 2007-03-26 devnull 		p = emitf(Xfor);
282 c8f53842 2007-03-26 devnull 		q = emiti(0);
283 f08fdedc 2003-11-23 devnull 		outcode(c2, eflag);
284 f08fdedc 2003-11-23 devnull 		emitf(Xjump);
285 f08fdedc 2003-11-23 devnull 		emiti(p);
286 f08fdedc 2003-11-23 devnull 		stuffdot(q);
287 f08fdedc 2003-11-23 devnull 		emitf(Xunlocal);
288 f08fdedc 2003-11-23 devnull 		break;
289 f08fdedc 2003-11-23 devnull 	case WORD:
290 f08fdedc 2003-11-23 devnull 		emitf(Xword);
291 f08fdedc 2003-11-23 devnull 		emits(strdup(t->str));
292 f08fdedc 2003-11-23 devnull 		break;
293 f08fdedc 2003-11-23 devnull 	case DUP:
294 f08fdedc 2003-11-23 devnull 		if(t->rtype==DUPFD){
295 f08fdedc 2003-11-23 devnull 			emitf(Xdup);
296 f08fdedc 2003-11-23 devnull 			emiti(t->fd0);
297 f08fdedc 2003-11-23 devnull 			emiti(t->fd1);
298 f08fdedc 2003-11-23 devnull 		}
299 f08fdedc 2003-11-23 devnull 		else{
300 f08fdedc 2003-11-23 devnull 			emitf(Xclose);
301 f08fdedc 2003-11-23 devnull 			emiti(t->fd0);
302 f08fdedc 2003-11-23 devnull 		}
303 f08fdedc 2003-11-23 devnull 		outcode(c1, eflag);
304 f08fdedc 2003-11-23 devnull 		emitf(Xpopredir);
305 f08fdedc 2003-11-23 devnull 		break;
306 f08fdedc 2003-11-23 devnull 	case PIPEFD:
307 f08fdedc 2003-11-23 devnull 		emitf(Xpipefd);
308 f08fdedc 2003-11-23 devnull 		emiti(t->rtype);
309 c8f53842 2007-03-26 devnull 		if(havefork){
310 c8f53842 2007-03-26 devnull 			p = emiti(0);
311 c8f53842 2007-03-26 devnull 			outcode(c0, eflag);
312 c8f53842 2007-03-26 devnull 			emitf(Xexit);
313 c8f53842 2007-03-26 devnull 			stuffdot(p);
314 c8f53842 2007-03-26 devnull 		} else {
315 c8f53842 2007-03-26 devnull 			emits(fnstr(c0));
316 c8f53842 2007-03-26 devnull 		}
317 f08fdedc 2003-11-23 devnull 		break;
318 f08fdedc 2003-11-23 devnull 	case REDIR:
319 f08fdedc 2003-11-23 devnull 		emitf(Xmark);
320 f08fdedc 2003-11-23 devnull 		outcode(c0, eflag);
321 f08fdedc 2003-11-23 devnull 		emitf(Xglob);
322 f08fdedc 2003-11-23 devnull 		switch(t->rtype){
323 f08fdedc 2003-11-23 devnull 		case APPEND:
324 f08fdedc 2003-11-23 devnull 			emitf(Xappend);
325 f08fdedc 2003-11-23 devnull 			break;
326 f08fdedc 2003-11-23 devnull 		case WRITE:
327 f08fdedc 2003-11-23 devnull 			emitf(Xwrite);
328 f08fdedc 2003-11-23 devnull 			break;
329 f08fdedc 2003-11-23 devnull 		case READ:
330 f08fdedc 2003-11-23 devnull 		case HERE:
331 f08fdedc 2003-11-23 devnull 			emitf(Xread);
332 f08fdedc 2003-11-23 devnull 			break;
333 c8f53842 2007-03-26 devnull 		case RDWR:
334 c8f53842 2007-03-26 devnull 			emitf(Xrdwr);
335 c8f53842 2007-03-26 devnull 			break;
336 f08fdedc 2003-11-23 devnull 		}
337 f08fdedc 2003-11-23 devnull 		emiti(t->fd0);
338 f08fdedc 2003-11-23 devnull 		outcode(c1, eflag);
339 f08fdedc 2003-11-23 devnull 		emitf(Xpopredir);
340 f08fdedc 2003-11-23 devnull 		break;
341 f08fdedc 2003-11-23 devnull 	case '=':
342 c8f53842 2007-03-26 devnull 		tt = t;
343 c8f53842 2007-03-26 devnull 		for(;t && t->type=='=';t = c2);
344 f08fdedc 2003-11-23 devnull 		if(t){
345 c8f53842 2007-03-26 devnull 			for(t = tt;t->type=='=';t = c2){
346 f08fdedc 2003-11-23 devnull 				emitf(Xmark);
347 f08fdedc 2003-11-23 devnull 				outcode(c1, eflag);
348 f08fdedc 2003-11-23 devnull 				emitf(Xmark);
349 f08fdedc 2003-11-23 devnull 				outcode(c0, eflag);
350 f08fdedc 2003-11-23 devnull 				emitf(Xlocal);
351 f08fdedc 2003-11-23 devnull 			}
352 362264eb 2008-08-14 rsc 			outcode(t, eflag);
353 362264eb 2008-08-14 rsc 			for(t = tt; t->type=='='; t = c2)
354 362264eb 2008-08-14 rsc 				emitf(Xunlocal);
355 f08fdedc 2003-11-23 devnull 		}
356 f08fdedc 2003-11-23 devnull 		else{
357 c8f53842 2007-03-26 devnull 			for(t = tt;t;t = c2){
358 f08fdedc 2003-11-23 devnull 				emitf(Xmark);
359 f08fdedc 2003-11-23 devnull 				outcode(c1, eflag);
360 f08fdedc 2003-11-23 devnull 				emitf(Xmark);
361 f08fdedc 2003-11-23 devnull 				outcode(c0, eflag);
362 f08fdedc 2003-11-23 devnull 				emitf(Xassign);
363 f08fdedc 2003-11-23 devnull 			}
364 f08fdedc 2003-11-23 devnull 		}
365 c8f53842 2007-03-26 devnull 		t = tt;	/* so tests below will work */
366 f08fdedc 2003-11-23 devnull 		break;
367 f08fdedc 2003-11-23 devnull 	case PIPE:
368 f08fdedc 2003-11-23 devnull 		emitf(Xpipe);
369 f08fdedc 2003-11-23 devnull 		emiti(t->fd0);
370 f08fdedc 2003-11-23 devnull 		emiti(t->fd1);
371 c8f53842 2007-03-26 devnull 		if(havefork){
372 c8f53842 2007-03-26 devnull 			p = emiti(0);
373 c8f53842 2007-03-26 devnull 			q = emiti(0);
374 c8f53842 2007-03-26 devnull 			outcode(c0, eflag);
375 c8f53842 2007-03-26 devnull 			emitf(Xexit);
376 c8f53842 2007-03-26 devnull 			stuffdot(p);
377 c8f53842 2007-03-26 devnull 		} else {
378 c8f53842 2007-03-26 devnull 			emits(fnstr(c0));
379 c8f53842 2007-03-26 devnull 			q = emiti(0);
380 c8f53842 2007-03-26 devnull 		}
381 f08fdedc 2003-11-23 devnull 		outcode(c1, eflag);
382 f08fdedc 2003-11-23 devnull 		emitf(Xreturn);
383 f08fdedc 2003-11-23 devnull 		stuffdot(q);
384 f08fdedc 2003-11-23 devnull 		emitf(Xpipewait);
385 f08fdedc 2003-11-23 devnull 		break;
386 f08fdedc 2003-11-23 devnull 	}
387 f08fdedc 2003-11-23 devnull 	if(t->type!=NOT && t->type!=';')
388 c8f53842 2007-03-26 devnull 		runq->iflast = t->type==IF;
389 c8f53842 2007-03-26 devnull 	else if(c0) runq->iflast = c0->type==IF;
390 f08fdedc 2003-11-23 devnull }
391 f08fdedc 2003-11-23 devnull /*
392 f08fdedc 2003-11-23 devnull  * switch code looks like this:
393 f08fdedc 2003-11-23 devnull  *	Xmark
394 f08fdedc 2003-11-23 devnull  *	(get switch value)
395 f08fdedc 2003-11-23 devnull  *	Xjump	1f
396 f08fdedc 2003-11-23 devnull  * out:	Xjump	leave
397 f08fdedc 2003-11-23 devnull  * 1:	Xmark
398 f08fdedc 2003-11-23 devnull  *	(get case values)
399 f08fdedc 2003-11-23 devnull  *	Xcase	1f
400 f08fdedc 2003-11-23 devnull  *	(commands)
401 f08fdedc 2003-11-23 devnull  *	Xjump	out
402 f08fdedc 2003-11-23 devnull  * 1:	Xmark
403 f08fdedc 2003-11-23 devnull  *	(get case values)
404 f08fdedc 2003-11-23 devnull  *	Xcase	1f
405 f08fdedc 2003-11-23 devnull  *	(commands)
406 f08fdedc 2003-11-23 devnull  *	Xjump	out
407 f08fdedc 2003-11-23 devnull  * 1:
408 f08fdedc 2003-11-23 devnull  * leave:
409 f08fdedc 2003-11-23 devnull  *	Xpopm
410 f08fdedc 2003-11-23 devnull  */
411 c8f53842 2007-03-26 devnull 
412 c8f53842 2007-03-26 devnull void
413 c8f53842 2007-03-26 devnull codeswitch(tree *t, int eflag)
414 f08fdedc 2003-11-23 devnull {
415 f08fdedc 2003-11-23 devnull 	int leave;		/* patch jump address to leave switch */
416 f08fdedc 2003-11-23 devnull 	int out;		/* jump here to leave switch */
417 f08fdedc 2003-11-23 devnull 	int nextcase;	/* patch jump address to next case */
418 f08fdedc 2003-11-23 devnull 	tree *tt;
419 f08fdedc 2003-11-23 devnull 	if(c1->child[0]==nil
420 f08fdedc 2003-11-23 devnull 	|| c1->child[0]->type!=';'
421 f08fdedc 2003-11-23 devnull 	|| !iscase(c1->child[0]->child[0])){
422 f08fdedc 2003-11-23 devnull 		yyerror("case missing in switch");
423 f08fdedc 2003-11-23 devnull 		return;
424 f08fdedc 2003-11-23 devnull 	}
425 f08fdedc 2003-11-23 devnull 	emitf(Xmark);
426 f08fdedc 2003-11-23 devnull 	outcode(c0, eflag);
427 f08fdedc 2003-11-23 devnull 	emitf(Xjump);
428 c8f53842 2007-03-26 devnull 	nextcase = emiti(0);
429 c8f53842 2007-03-26 devnull 	out = emitf(Xjump);
430 c8f53842 2007-03-26 devnull 	leave = emiti(0);
431 f08fdedc 2003-11-23 devnull 	stuffdot(nextcase);
432 c8f53842 2007-03-26 devnull 	t = c1->child[0];
433 f08fdedc 2003-11-23 devnull 	while(t->type==';'){
434 c8f53842 2007-03-26 devnull 		tt = c1;
435 f08fdedc 2003-11-23 devnull 		emitf(Xmark);
436 c8f53842 2007-03-26 devnull 		for(t = c0->child[0];t->type==ARGLIST;t = c0) outcode(c1, eflag);
437 f08fdedc 2003-11-23 devnull 		emitf(Xcase);
438 c8f53842 2007-03-26 devnull 		nextcase = emiti(0);
439 c8f53842 2007-03-26 devnull 		t = tt;
440 f08fdedc 2003-11-23 devnull 		for(;;){
441 f08fdedc 2003-11-23 devnull 			if(t->type==';'){
442 f08fdedc 2003-11-23 devnull 				if(iscase(c0)) break;
443 f08fdedc 2003-11-23 devnull 				outcode(c0, eflag);
444 c8f53842 2007-03-26 devnull 				t = c1;
445 f08fdedc 2003-11-23 devnull 			}
446 f08fdedc 2003-11-23 devnull 			else{
447 f08fdedc 2003-11-23 devnull 				if(!iscase(t)) outcode(t, eflag);
448 f08fdedc 2003-11-23 devnull 				break;
449 f08fdedc 2003-11-23 devnull 			}
450 f08fdedc 2003-11-23 devnull 		}
451 f08fdedc 2003-11-23 devnull 		emitf(Xjump);
452 f08fdedc 2003-11-23 devnull 		emiti(out);
453 f08fdedc 2003-11-23 devnull 		stuffdot(nextcase);
454 f08fdedc 2003-11-23 devnull 	}
455 f08fdedc 2003-11-23 devnull 	stuffdot(leave);
456 f08fdedc 2003-11-23 devnull 	emitf(Xpopm);
457 f08fdedc 2003-11-23 devnull }
458 c8f53842 2007-03-26 devnull 
459 c8f53842 2007-03-26 devnull int
460 c8f53842 2007-03-26 devnull iscase(tree *t)
461 f08fdedc 2003-11-23 devnull {
462 c8f53842 2007-03-26 devnull 	if(t->type!=SIMPLE)
463 c8f53842 2007-03-26 devnull 		return 0;
464 c8f53842 2007-03-26 devnull 	do t = c0; while(t->type==ARGLIST);
465 f08fdedc 2003-11-23 devnull 	return t->type==WORD && !t->quoted && strcmp(t->str, "case")==0;
466 f08fdedc 2003-11-23 devnull }
467 c8f53842 2007-03-26 devnull 
468 c8f53842 2007-03-26 devnull code*
469 c8f53842 2007-03-26 devnull codecopy(code *cp)
470 f08fdedc 2003-11-23 devnull {
471 f08fdedc 2003-11-23 devnull 	cp[0].i++;
472 f08fdedc 2003-11-23 devnull 	return cp;
473 f08fdedc 2003-11-23 devnull }
474 c8f53842 2007-03-26 devnull 
475 c8f53842 2007-03-26 devnull void
476 c8f53842 2007-03-26 devnull codefree(code *cp)
477 f08fdedc 2003-11-23 devnull {
478 f08fdedc 2003-11-23 devnull 	code *p;
479 c8f53842 2007-03-26 devnull 	if(--cp[0].i!=0)
480 c8f53842 2007-03-26 devnull 		return;
481 c8f53842 2007-03-26 devnull 	for(p = cp+1;p->f;p++){
482 f08fdedc 2003-11-23 devnull 		if(p->f==Xappend || p->f==Xclose || p->f==Xread || p->f==Xwrite
483 c8f53842 2007-03-26 devnull 		|| p->f==Xrdwr
484 f08fdedc 2003-11-23 devnull 		|| p->f==Xasync || p->f==Xbackq || p->f==Xcase || p->f==Xfalse
485 f08fdedc 2003-11-23 devnull 		|| p->f==Xfor || p->f==Xjump
486 f08fdedc 2003-11-23 devnull 		|| p->f==Xsubshell || p->f==Xtrue) p++;
487 f08fdedc 2003-11-23 devnull 		else if(p->f==Xdup || p->f==Xpipefd) p+=2;
488 f08fdedc 2003-11-23 devnull 		else if(p->f==Xpipe) p+=4;
489 f08fdedc 2003-11-23 devnull 		else if(p->f==Xword || p->f==Xdelhere) efree((++p)->s);
490 f08fdedc 2003-11-23 devnull 		else if(p->f==Xfn){
491 f08fdedc 2003-11-23 devnull 			efree(p[2].s);
492 f08fdedc 2003-11-23 devnull 			p+=2;
493 f08fdedc 2003-11-23 devnull 		}
494 f08fdedc 2003-11-23 devnull 	}
495 f08fdedc 2003-11-23 devnull 	efree((char *)cp);
496 f08fdedc 2003-11-23 devnull }