1 c42a1d3d 2006-02-21 devnull #include "a.h"
  2 c42a1d3d 2006-02-21 devnull 
  3 c42a1d3d 2006-02-21 devnull /*
  4 c42a1d3d 2006-02-21 devnull  * 16. Conditional acceptance of input.
  5 c42a1d3d 2006-02-21 devnull  *
  6 c42a1d3d 2006-02-21 devnull  *	conditions are
  7 c42a1d3d 2006-02-21 devnull  *		c - condition letter (o, e, t, n)
  8 c42a1d3d 2006-02-21 devnull  *		!c - not c
  9 c42a1d3d 2006-02-21 devnull  *		N - N>0
 10 c42a1d3d 2006-02-21 devnull  *		!N - N <= 0
 11 c42a1d3d 2006-02-21 devnull  *		'a'b' - if a==b
 12 c42a1d3d 2006-02-21 devnull  *		!'a'b'	- if a!=b
 13 c42a1d3d 2006-02-21 devnull  *
 14 c42a1d3d 2006-02-21 devnull  *	\{xxx\} can be used for newline in bodies
 15 c42a1d3d 2006-02-21 devnull  *
 16 c42a1d3d 2006-02-21 devnull  *	.if .ie .el
 17 c42a1d3d 2006-02-21 devnull  *
 18 c42a1d3d 2006-02-21 devnull  */
 19 c42a1d3d 2006-02-21 devnull 
 20 c42a1d3d 2006-02-21 devnull int iftrue[20];
 21 c42a1d3d 2006-02-21 devnull int niftrue;
 22 c42a1d3d 2006-02-21 devnull 
 23 c42a1d3d 2006-02-21 devnull void
 24 c42a1d3d 2006-02-21 devnull startbody(void)
 25 c42a1d3d 2006-02-21 devnull {
 26 c42a1d3d 2006-02-21 devnull 	int c;
 27 fa325e9b 2020-01-10 cross 
 28 c42a1d3d 2006-02-21 devnull 	while((c = getrune()) == ' ' || c == '\t')
 29 c42a1d3d 2006-02-21 devnull 		;
 30 c42a1d3d 2006-02-21 devnull 	ungetrune(c);
 31 c42a1d3d 2006-02-21 devnull }
 32 c42a1d3d 2006-02-21 devnull 
 33 c42a1d3d 2006-02-21 devnull void
 34 c42a1d3d 2006-02-21 devnull skipbody(void)
 35 c42a1d3d 2006-02-21 devnull {
 36 c42a1d3d 2006-02-21 devnull 	int c, cc, nbrace;
 37 c42a1d3d 2006-02-21 devnull 
 38 c42a1d3d 2006-02-21 devnull 	nbrace = 0;
 39 c42a1d3d 2006-02-21 devnull 	for(cc=0; (c = getrune()) >= 0; cc=c){
 40 c42a1d3d 2006-02-21 devnull 		if(c == '\n' && nbrace <= 0)
 41 c42a1d3d 2006-02-21 devnull 			break;
 42 c42a1d3d 2006-02-21 devnull 		if(cc == '\\' && c == '{')
 43 c42a1d3d 2006-02-21 devnull 			nbrace++;
 44 c42a1d3d 2006-02-21 devnull 		if(cc == '\\' && c == '}')
 45 c42a1d3d 2006-02-21 devnull 			nbrace--;
 46 c42a1d3d 2006-02-21 devnull 	}
 47 c42a1d3d 2006-02-21 devnull }
 48 c42a1d3d 2006-02-21 devnull 
 49 c42a1d3d 2006-02-21 devnull int
 50 c42a1d3d 2006-02-21 devnull ifeval(void)
 51 c42a1d3d 2006-02-21 devnull {
 52 c42a1d3d 2006-02-21 devnull 	int c, cc, neg, nc;
 53 c42a1d3d 2006-02-21 devnull 	Rune line[MaxLine], *p, *e, *q;
 54 c42a1d3d 2006-02-21 devnull 	Rune *a;
 55 fa325e9b 2020-01-10 cross 
 56 c42a1d3d 2006-02-21 devnull 	while((c = getnext()) == ' ' || c == '\t')
 57 c42a1d3d 2006-02-21 devnull 		;
 58 c42a1d3d 2006-02-21 devnull 	neg = 0;
 59 c42a1d3d 2006-02-21 devnull 	while(c == '!'){
 60 c42a1d3d 2006-02-21 devnull 		neg = !neg;
 61 c42a1d3d 2006-02-21 devnull 		c = getnext();
 62 c42a1d3d 2006-02-21 devnull 	}
 63 c42a1d3d 2006-02-21 devnull 
 64 c42a1d3d 2006-02-21 devnull 	if('0' <= c && c <= '9'){
 65 c42a1d3d 2006-02-21 devnull 		ungetnext(c);
 66 c42a1d3d 2006-02-21 devnull 		a = copyarg();
 67 c42a1d3d 2006-02-21 devnull 		c = (eval(a)>0) ^ neg;
 68 c42a1d3d 2006-02-21 devnull 		free(a);
 69 c42a1d3d 2006-02-21 devnull 		return c;
 70 c42a1d3d 2006-02-21 devnull 	}
 71 fa325e9b 2020-01-10 cross 
 72 c42a1d3d 2006-02-21 devnull 	switch(c){
 73 c42a1d3d 2006-02-21 devnull 	case ' ':
 74 c42a1d3d 2006-02-21 devnull 	case '\n':
 75 c42a1d3d 2006-02-21 devnull 		ungetnext(c);
 76 c42a1d3d 2006-02-21 devnull 		return !neg;
 77 c42a1d3d 2006-02-21 devnull 	case 'o':	/* odd page */
 78 c42a1d3d 2006-02-21 devnull 	case 't':	/* troff */
 79 c42a1d3d 2006-02-21 devnull 	case 'h':	/* htmlroff */
 80 c42a1d3d 2006-02-21 devnull 		while((c = getrune()) != ' ' && c != '\t' && c != '\n' && c >= 0)
 81 c42a1d3d 2006-02-21 devnull 			;
 82 c42a1d3d 2006-02-21 devnull 		return 1 ^ neg;
 83 c42a1d3d 2006-02-21 devnull 	case 'n':	/* nroff */
 84 c42a1d3d 2006-02-21 devnull 	case 'e':	/* even page */
 85 c42a1d3d 2006-02-21 devnull 		while((c = getnext()) != ' ' && c != '\t' && c != '\n' && c >= 0)
 86 c42a1d3d 2006-02-21 devnull 			;
 87 c42a1d3d 2006-02-21 devnull 		return 0 ^ neg;
 88 c42a1d3d 2006-02-21 devnull 	}
 89 c42a1d3d 2006-02-21 devnull 
 90 c42a1d3d 2006-02-21 devnull 	/* string comparison 'string1'string2' */
 91 c42a1d3d 2006-02-21 devnull 	p = line;
 92 c42a1d3d 2006-02-21 devnull 	e = p+nelem(line);
 93 c42a1d3d 2006-02-21 devnull 	nc = 0;
 94 c42a1d3d 2006-02-21 devnull 	q = nil;
 95 c42a1d3d 2006-02-21 devnull 	while((cc=getnext()) >= 0 && cc != '\n' && p<e){
 96 c42a1d3d 2006-02-21 devnull 		if(cc == c){
 97 c42a1d3d 2006-02-21 devnull 			if(++nc == 2)
 98 c42a1d3d 2006-02-21 devnull 				break;
 99 c42a1d3d 2006-02-21 devnull 			q = p;
100 c42a1d3d 2006-02-21 devnull 		}
101 c42a1d3d 2006-02-21 devnull 		*p++ = cc;
102 c42a1d3d 2006-02-21 devnull 	}
103 c42a1d3d 2006-02-21 devnull 	if(cc != c){
104 c42a1d3d 2006-02-21 devnull 		ungetnext(cc);
105 c42a1d3d 2006-02-21 devnull 		return 0;
106 c42a1d3d 2006-02-21 devnull 	}
107 c42a1d3d 2006-02-21 devnull 	if(nc < 2){
108 c42a1d3d 2006-02-21 devnull 		return 0;
109 c42a1d3d 2006-02-21 devnull 	}
110 c42a1d3d 2006-02-21 devnull 	*p = 0;
111 c42a1d3d 2006-02-21 devnull 	return (q-line == p-(q+1)
112 c42a1d3d 2006-02-21 devnull 		&& memcmp(line, q+1, (q-line)*sizeof(Rune))==0) ^ neg;
113 c42a1d3d 2006-02-21 devnull }
114 fa325e9b 2020-01-10 cross 
115 c42a1d3d 2006-02-21 devnull void
116 c42a1d3d 2006-02-21 devnull r_if(Rune *name)
117 c42a1d3d 2006-02-21 devnull {
118 c42a1d3d 2006-02-21 devnull 	int n;
119 fa325e9b 2020-01-10 cross 
120 c42a1d3d 2006-02-21 devnull 	n = ifeval();
121 c42a1d3d 2006-02-21 devnull 	if(runestrcmp(name, L("ie")) == 0){
122 c42a1d3d 2006-02-21 devnull 		if(niftrue >= nelem(iftrue))
123 c42a1d3d 2006-02-21 devnull 			sysfatal("%Cie overflow", dot);
124 c42a1d3d 2006-02-21 devnull 		iftrue[niftrue++] = n;
125 c42a1d3d 2006-02-21 devnull 	}
126 c42a1d3d 2006-02-21 devnull 	if(n)
127 c42a1d3d 2006-02-21 devnull 		startbody();
128 c42a1d3d 2006-02-21 devnull 	else
129 c42a1d3d 2006-02-21 devnull 		skipbody();
130 c42a1d3d 2006-02-21 devnull }
131 c42a1d3d 2006-02-21 devnull 
132 c42a1d3d 2006-02-21 devnull void
133 c42a1d3d 2006-02-21 devnull r_el(Rune *name)
134 c42a1d3d 2006-02-21 devnull {
135 c42a1d3d 2006-02-21 devnull 	USED(name);
136 fa325e9b 2020-01-10 cross 
137 c42a1d3d 2006-02-21 devnull 	if(niftrue <= 0){
138 c42a1d3d 2006-02-21 devnull 		warn("%Cel underflow", dot);
139 c42a1d3d 2006-02-21 devnull 		return;
140 c42a1d3d 2006-02-21 devnull 	}
141 c42a1d3d 2006-02-21 devnull 	if(iftrue[--niftrue])
142 c42a1d3d 2006-02-21 devnull 		skipbody();
143 c42a1d3d 2006-02-21 devnull 	else
144 c42a1d3d 2006-02-21 devnull 		startbody();
145 c42a1d3d 2006-02-21 devnull }
146 c42a1d3d 2006-02-21 devnull 
147 c42a1d3d 2006-02-21 devnull void
148 c42a1d3d 2006-02-21 devnull t16init(void)
149 c42a1d3d 2006-02-21 devnull {
150 c42a1d3d 2006-02-21 devnull 	addraw(L("if"), r_if);
151 c42a1d3d 2006-02-21 devnull 	addraw(L("ie"), r_if);
152 c42a1d3d 2006-02-21 devnull 	addraw(L("el"), r_el);
153 fa325e9b 2020-01-10 cross 
154 c42a1d3d 2006-02-21 devnull 	addesc('{', e_nop, HtmlMode|ArgMode);
155 c42a1d3d 2006-02-21 devnull 	addesc('}', e_nop, HtmlMode|ArgMode);
156 c42a1d3d 2006-02-21 devnull }