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#include	"mk.h"
2 
 
3 
static	Word		*subsub(Word*, char*, char*);
4 
static	Word		*expandvar(char**);
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static	Bufblock	*varname(char**);
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static	Word		*extractpat(char*, char**, char*, char*);
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static	int		submatch(char*, Word*, Word*, int*, char**);
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static	Word		*varmatch(char *);
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10 
Word *
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varsub(char **s)
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{
13 
	Bufblock *b;
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	Word *w;
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16 
	if(**s == '{')		/* either ${name} or ${name: A%B==C%D}*/
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		return expandvar(s);
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	b = varname(s);
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	if(b == 0)
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		return 0;
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	w = varmatch(b->start);
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	freebuf(b);
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	return w;
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}
27 
 
28 
/*
29 
 *	extract a variable name
30 
 */
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static Bufblock*
32 
varname(char **s)
33 
{
34 
	Bufblock *b;
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	char *cp;
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	Rune r;
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	int n;
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39 
	b = newbuf();
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	cp = *s;
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	for(;;){
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		n = chartorune(&r, cp);
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		if (!WORDCHR(r))
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			break;
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		rinsert(b, r);
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		cp += n;
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	}
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	if (b->current == b->start){
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		SYNERR(-1);
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		fprint(2, "missing variable name <%s>\n", *s);
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		freebuf(b);
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		return 0;
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	}
54 
	*s = cp;
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	insert(b, 0);
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	return b;
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}
58 
 
59 
static Word*
60 
varmatch(char *name)
61 
{
62 
	Word *w;
63 
	Symtab *sym;
64 
 
65 
	sym = symlook(name, S_VAR, 0);
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	if(sym){
67 
			/* check for at least one non-NULL value */
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		for (w = sym->u.ptr; w; w = w->next)
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			if(w->s && *w->s)
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				return wdup(w);
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	}
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	return 0;
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}
74 
 
75 
static Word*
76 
expandvar(char **s)
77 
{
78 
	Word *w;
79 
	Bufblock *buf;
80 
	Symtab *sym;
81 
	char *cp, *begin, *end;
82 
 
83 
	begin = *s;
84 
	(*s)++;						/* skip the '{' */
85 
	buf = varname(s);
86 
	if (buf == 0)
87 
		return 0;
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	cp = *s;
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	if (*cp == '}') {				/* ${name} variant*/
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		(*s)++;					/* skip the '}' */
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		w = varmatch(buf->start);
92 
		freebuf(buf);
93 
		return w;
94 
	}
95 
	if (*cp != ':') {
96 
		SYNERR(-1);
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		fprint(2, "bad variable name <%s>\n", buf->start);
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		freebuf(buf);
99 
		return 0;
100 
	}
101 
	cp++;
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	end = charin(cp , "}");
103 
	if(end == 0){
104 
		SYNERR(-1);
105 
		fprint(2, "missing '}': %s\n", begin);
106 
		Exit();
107 
	}
108 
	*end = 0;
109 
	*s = end+1;
110 
 
111 
	sym = symlook(buf->start, S_VAR, 0);
112 
	if(sym == 0 || sym->u.value == 0)
113 
		w = newword(buf->start);
114 
	else
115 
		w = subsub(sym->u.ptr, cp, end);
116 
	freebuf(buf);
117 
	return w;
118 
}
119 
 
120 
static Word*
121 
extractpat(char *s, char **r, char *term, char *end)
122 
{
123 
	int save;
124 
	char *cp;
125 
	Word *w;
126 
 
127 
	cp = charin(s, term);
128 
	if(cp){
129 
		*r = cp;
130 
		if(cp == s)
131 
			return 0;
132 
		save = *cp;
133 
		*cp = 0;
134 
		w = stow(s);
135 
		*cp = save;
136 
	} else {
137 
		*r = end;
138 
		w = stow(s);
139 
	}
140 
	return w;
141 
}
142 
 
143 
static Word*
144 
subsub(Word *v, char *s, char *end)
145 
{
146 
	int nmid;
147 
	Word *head, *tail, *w, *h;
148 
	Word *a, *b, *c, *d;
149 
	Bufblock *buf;
150 
	char *cp, *enda;
151 
 
152 
	a = extractpat(s, &cp, "=%&", end);
153 
	b = c = d = 0;
154 
	if(PERCENT(*cp))
155 
		b = extractpat(cp+1, &cp, "=", end);
156 
	if(*cp == '=')
157 
		c = extractpat(cp+1, &cp, "&%", end);
158 
	if(PERCENT(*cp))
159 
		d = stow(cp+1);
160 
	else if(*cp)
161 
		d = stow(cp);
162 
 
163 
	head = tail = 0;
164 
	buf = newbuf();
165 
	for(; v; v = v->next){
166 
		h = w = 0;
167 
		if(submatch(v->s, a, b, &nmid, &enda)){
168 
			/* enda points to end of A match in source;
169 
			 * nmid = number of chars between end of A and start of B
170 
			 */
171 
			if(c){
172 
				h = w = wdup(c);
173 
				while(w->next)
174 
					w = w->next;
175 
			}
176 
			if(PERCENT(*cp) && nmid > 0){
177 
				if(w){
178 
					bufcpy(buf, w->s, strlen(w->s));
179 
					bufcpy(buf, enda, nmid);
180 
					insert(buf, 0);
181 
					free(w->s);
182 
					w->s = strdup(buf->start);
183 
				} else {
184 
					bufcpy(buf, enda, nmid);
185 
					insert(buf, 0);
186 
					h = w = newword(buf->start);
187 
				}
188 
				buf->current = buf->start;
189 
			}
190 
			if(d && *d->s){
191 
				if(w){
192 
 
193 
					bufcpy(buf, w->s, strlen(w->s));
194 
					bufcpy(buf, d->s, strlen(d->s));
195 
					insert(buf, 0);
196 
					free(w->s);
197 
					w->s = strdup(buf->start);
198 
					w->next = wdup(d->next);
199 
					while(w->next)
200 
						w = w->next;
201 
					buf->current = buf->start;
202 
				} else
203 
					h = w = wdup(d);
204 
			}
205 
		}
206 
		if(w == 0)
207 
			h = w = newword(v->s);
208 
 
209 
		if(head == 0)
210 
			head = h;
211 
		else
212 
			tail->next = h;
213 
		tail = w;
214 
	}
215 
	freebuf(buf);
216 
	delword(a);
217 
	delword(b);
218 
	delword(c);
219 
	delword(d);
220 
	return head;
221 
}
222 
 
223 
static int
224 
submatch(char *s, Word *a, Word *b, int *nmid, char **enda)
225 
{
226 
	Word *w;
227 
	int n;
228 
	char *end;
229 
 
230 
	n = 0;
231 
	for(w = a; w; w = w->next){
232 
		n = strlen(w->s);
233 
		if(strncmp(s, w->s, n) == 0)
234 
			break;
235 
	}
236 
	if(a && w == 0)		/*  a == NULL matches everything*/
237 
		return 0;
238 
 
239 
	*enda = s+n;		/* pointer to end a A part match */
240 
	*nmid = strlen(s)-n;	/* size of remainder of source */
241 
	end = *enda+*nmid;
242 
	for(w = b; w; w = w->next){
243 
		n = strlen(w->s);
244 
		if(strcmp(w->s, end-n) == 0){
245 
			*nmid -= n;
246 
			break;
247 
		}
248 
	}
249 
	if(b && w == 0)		/* b == NULL matches everything */
250 
		return 0;
251 
	return 1;
252 
}