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1.1 root 1: static char *sccsid = "@(#)rmothers.c 1.3 (Berkeley) 7/26/83";
2: /* Copyright (c) 1983 Regents of the University of California */
3: #ifdef RMOTHERS
4: /* and the rest of the file */
5:
6: #include "0.h"
7: #include "tree.h"
8:
9: /*
10: * translate extended case statements to pascal (for tex).
11: * don knuth should know better. enough said.
12: * ... peter 5/4/83
13: *
14: * extended case statements have the form:
15: * case expresion of
16: * label1,label2,...: statement1;
17: * ...
18: * others: otherstatement
19: * end
20: * which i am going to translate to:
21: * if expression in [ label1,label2,...] then
22: * case expression of
23: * label1,label2,...: statement1;
24: * ...
25: * end
26: * else otherstatement
27: * which has the effect that the expression will be evaluated twice.
28: * i've looked very briefly at all cases in tex and
29: * they seem to be variables or pure functions.
30: * for simplicity i'm assuming that the others is the last labeled
31: * statement, and that no other labels appear with the label others.
32: * this appears correct from the tex82 documentation.
33: */
34:
35: /*
36: * given a case statement tree and the address of an others pointer,
37: * amputate the others statement from the case statement tree
38: * and hang it on the the others pointer.
39: *
40: * Case statement
41: * r [0] T_CASE
42: * [1] lineof "case"
43: * [2] expression
44: * [3] list of cased statements:
45: * cstat [0] T_CSTAT
46: * [1] lineof ":"
47: * [2] list of constant labels
48: * [3] statement
49: */
50: needscaseguard(r, otherspp)
51: int *r;
52: int **otherspp;
53: {
54: int *statlistp;
55: int *cutpointer;
56: int *lstatementp;
57: int *lablistp;
58: int *label;
59: int hasothers;
60:
61: *otherspp = NIL;
62: hasothers = 0;
63: if (!rmothers) {
64: return hasothers;
65: }
66: for (cutpointer = &r[3], statlistp = r[3];
67: statlistp != NIL;
68: cutpointer = &statlistp[2], statlistp = statlistp[2]) {
69: lstatementp = statlistp[1];
70: if (lstatementp == NIL)
71: continue;
72: lablistp = lstatementp[2];
73: if (lablistp != NIL) {
74: label = lablistp[1];
75: /* only look at the first label */
76: if (label != NIL &&
77: label[0] == T_ID && !strcmp(label[1],"others")) {
78: hasothers = 1;
79: *otherspp = lstatementp[3];
80: *cutpointer = NIL;
81: if (statlistp[2] != NIL) {
82: panic("others not last case");
83: }
84: if (lablistp[2] != NIL) {
85: panic("others not only case label");
86: }
87: }
88: }
89: }
90: return hasothers;
91: }
92:
93: precaseguard(r)
94: int *r;
95: {
96: int *statlistp;
97: int *cutpointer;
98: int *lstatementp;
99: int *lablistp;
100: int *label;
101: int hadsome;
102: int counter;
103:
104: if (!rmothers) {
105: return;
106: }
107: ppkw("if");
108: ppspac();
109: rvalue(r[2], NIL);
110: ppspac();
111: ppkw("in");
112: ppgoin(DECL);
113: ppnl();
114: indent();
115: ppsep("[");
116: hadsome = 0;
117: counter = 0;
118: for (statlistp = r[3]; statlistp != NIL; statlistp = statlistp[2]) {
119: lstatementp = statlistp[1];
120: if (lstatementp == NIL)
121: continue;
122: for (lablistp = lstatementp[2];lablistp != NIL;lablistp = lablistp[2]) {
123: label = lablistp[1];
124: if (hadsome) {
125: if (counter < 8) {
126: ppsep(", ");
127: } else {
128: ppsep(",");
129: ppnl();
130: indent();
131: ppspac();
132: counter = 0;
133: }
134: } else {
135: hadsome = 1;
136: }
137: gconst(label);
138: counter += 1;
139: }
140: }
141: ppsep("]");
142: ppspac();
143: ppkw("then");
144: ppgoout(DECL);
145: ppgoin(STAT);
146: ppnl();
147: indent();
148: }
149:
150: /*
151: * given an others statement, hang it on the else branch of the guard.
152: */
153: postcaseguard(othersp)
154: int *othersp;
155: {
156: if (!rmothers) {
157: return;
158: }
159: ppgoout(STAT);
160: ppnl();
161: indent();
162: ppkw("else");
163: ppgoin(STAT);
164: if (othersp == NIL) {
165: /*
166: * this will print a call to the routine ``null''.
167: * but it has to be checked first, or we will indirect through
168: * NIL to check the statement type.
169: */
170: statement(NIL);
171: ppgoout(STAT);
172: return;
173: }
174: if (othersp[0] == T_BLOCK) {
175: ppnl();
176: indent();
177: ppstbl1(othersp, STAT);
178: ppstbl2();
179: } else {
180: statement(othersp);
181: }
182: ppgoout(STAT);
183: }
184: #endif RMOTHERS
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