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1.1 root 1: /*
2: * Copyright (c) 1985 Sun Microsystems, Inc.
3: * Copyright (c) 1980 The Regents of the University of California.
4: * Copyright (c) 1976 Board of Trustees of the University of Illinois.
5: * All rights reserved.
6: *
7: * Redistribution and use in source and binary forms are permitted
8: * provided that: (1) source distributions retain this entire copyright
9: * notice and comment, and (2) distributions including binaries display
10: * the following acknowledgement: ``This product includes software
11: * developed by the University of California, Berkeley and its contributors''
12: * in the documentation or other materials provided with the distribution
13: * and in all advertising materials mentioning features or use of this
14: * software. Neither the name of the University nor the names of its
15: * contributors may be used to endorse or promote products derived
16: * from this software without specific prior written permission.
17: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
18: * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
19: * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20: */
21:
22: #ifndef lint
23: static char sccsid[] = "@(#)parse.c 5.11 (Berkeley) 6/1/90";
24: #endif /* not lint */
25:
26: #include "indent_globs.h"
27: #include "indent_codes.h"
28:
29: parse(tk)
30: int tk; /* the code for the construct scanned */
31: {
32: int i;
33:
34: #ifdef debug
35: printf("%2d - %s\n", tk, token);
36: #endif
37:
38: while (ps.p_stack[ps.tos] == ifhead && tk != elselit) {
39: /* true if we have an if without an else */
40: ps.p_stack[ps.tos] = stmt; /* apply the if(..) stmt ::= stmt
41: * reduction */
42: reduce(); /* see if this allows any reduction */
43: }
44:
45:
46: switch (tk) { /* go on and figure out what to do with the
47: * input */
48:
49: case decl: /* scanned a declaration word */
50: ps.search_brace = btype_2;
51: /* indicate that following brace should be on same line */
52: if (ps.p_stack[ps.tos] != decl) { /* only put one declaration
53: * onto stack */
54: break_comma = true; /* while in declaration, newline should be
55: * forced after comma */
56: ps.p_stack[++ps.tos] = decl;
57: ps.il[ps.tos] = ps.i_l_follow;
58:
59: if (ps.ljust_decl) {/* only do if we want left justified
60: * declarations */
61: ps.ind_level = 0;
62: for (i = ps.tos - 1; i > 0; --i)
63: if (ps.p_stack[i] == decl)
64: ++ps.ind_level; /* indentation is number of
65: * declaration levels deep we are */
66: ps.i_l_follow = ps.ind_level;
67: }
68: }
69: break;
70:
71: case ifstmt: /* scanned if (...) */
72: if (ps.p_stack[ps.tos] == elsehead && ps.else_if) /* "else if ..." */
73: ps.i_l_follow = ps.il[ps.tos];
74: case dolit: /* 'do' */
75: case forstmt: /* for (...) */
76: ps.p_stack[++ps.tos] = tk;
77: ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
78: ++ps.i_l_follow; /* subsequent statements should be indented 1 */
79: ps.search_brace = btype_2;
80: break;
81:
82: case lbrace: /* scanned { */
83: break_comma = false; /* don't break comma in an initial list */
84: if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl
85: || ps.p_stack[ps.tos] == stmtl)
86: ++ps.i_l_follow; /* it is a random, isolated stmt group or a
87: * declaration */
88: else {
89: if (s_code == e_code) {
90: /*
91: * only do this if there is nothing on the line
92: */
93: --ps.ind_level;
94: /*
95: * it is a group as part of a while, for, etc.
96: */
97: if (ps.p_stack[ps.tos] == swstmt && ps.case_indent >= 1)
98: --ps.ind_level;
99: /*
100: * for a switch, brace should be two levels out from the code
101: */
102: }
103: }
104:
105: ps.p_stack[++ps.tos] = lbrace;
106: ps.il[ps.tos] = ps.ind_level;
107: ps.p_stack[++ps.tos] = stmt;
108: /* allow null stmt between braces */
109: ps.il[ps.tos] = ps.i_l_follow;
110: break;
111:
112: case whilestmt: /* scanned while (...) */
113: if (ps.p_stack[ps.tos] == dohead) {
114: /* it is matched with do stmt */
115: ps.ind_level = ps.i_l_follow = ps.il[ps.tos];
116: ps.p_stack[++ps.tos] = whilestmt;
117: ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
118: }
119: else { /* it is a while loop */
120: ps.p_stack[++ps.tos] = whilestmt;
121: ps.il[ps.tos] = ps.i_l_follow;
122: ++ps.i_l_follow;
123: ps.search_brace = btype_2;
124: }
125:
126: break;
127:
128: case elselit: /* scanned an else */
129:
130: if (ps.p_stack[ps.tos] != ifhead)
131: diag(1, "Unmatched 'else'");
132: else {
133: ps.ind_level = ps.il[ps.tos]; /* indentation for else should
134: * be same as for if */
135: ps.i_l_follow = ps.ind_level + 1; /* everything following should
136: * be in 1 level */
137: ps.p_stack[ps.tos] = elsehead;
138: /* remember if with else */
139: ps.search_brace = btype_2 | ps.else_if;
140: }
141: break;
142:
143: case rbrace: /* scanned a } */
144: /* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */
145: if (ps.p_stack[ps.tos - 1] == lbrace) {
146: ps.ind_level = ps.i_l_follow = ps.il[--ps.tos];
147: ps.p_stack[ps.tos] = stmt;
148: }
149: else
150: diag(1, "Stmt nesting error.");
151: break;
152:
153: case swstmt: /* had switch (...) */
154: ps.p_stack[++ps.tos] = swstmt;
155: ps.cstk[ps.tos] = case_ind;
156: /* save current case indent level */
157: ps.il[ps.tos] = ps.i_l_follow;
158: case_ind = ps.i_l_follow + ps.case_indent; /* cases should be one
159: * level down from
160: * switch */
161: ps.i_l_follow += ps.case_indent + 1; /* statements should be two
162: * levels in */
163: ps.search_brace = btype_2;
164: break;
165:
166: case semicolon: /* this indicates a simple stmt */
167: break_comma = false; /* turn off flag to break after commas in a
168: * declaration */
169: ps.p_stack[++ps.tos] = stmt;
170: ps.il[ps.tos] = ps.ind_level;
171: break;
172:
173: default: /* this is an error */
174: diag(1, "Unknown code to parser");
175: return;
176:
177:
178: } /* end of switch */
179:
180: reduce(); /* see if any reduction can be done */
181:
182: #ifdef debug
183: for (i = 1; i <= ps.tos; ++i)
184: printf("(%d %d)", ps.p_stack[i], ps.il[i]);
185: printf("\n");
186: #endif
187:
188: return;
189: }
190:
191: /*
192: * NAME: reduce
193: *
194: * FUNCTION: Implements the reduce part of the parsing algorithm
195: *
196: * ALGORITHM: The following reductions are done. Reductions are repeated
197: * until no more are possible.
198: *
199: * Old TOS New TOS
200: * <stmt> <stmt> <stmtl>
201: * <stmtl> <stmt> <stmtl>
202: * do <stmt> "dostmt"
203: * if <stmt> "ifstmt"
204: * switch <stmt> <stmt>
205: * decl <stmt> <stmt>
206: * "ifelse" <stmt> <stmt>
207: * for <stmt> <stmt>
208: * while <stmt> <stmt>
209: * "dostmt" while <stmt>
210: *
211: * On each reduction, ps.i_l_follow (the indentation for the following line)
212: * is set to the indentation level associated with the old TOS.
213: *
214: * PARAMETERS: None
215: *
216: * RETURNS: Nothing
217: *
218: * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos =
219: *
220: * CALLS: None
221: *
222: * CALLED BY: parse
223: *
224: * HISTORY: initial coding November 1976 D A Willcox of CAC
225: *
226: */
227: /*----------------------------------------------*\
228: | REDUCTION PHASE |
229: \*----------------------------------------------*/
230: reduce()
231: {
232:
233: register int i;
234:
235: for (;;) { /* keep looping until there is nothing left to
236: * reduce */
237:
238: switch (ps.p_stack[ps.tos]) {
239:
240: case stmt:
241: switch (ps.p_stack[ps.tos - 1]) {
242:
243: case stmt:
244: case stmtl:
245: /* stmtl stmt or stmt stmt */
246: ps.p_stack[--ps.tos] = stmtl;
247: break;
248:
249: case dolit: /* <do> <stmt> */
250: ps.p_stack[--ps.tos] = dohead;
251: ps.i_l_follow = ps.il[ps.tos];
252: break;
253:
254: case ifstmt:
255: /* <if> <stmt> */
256: ps.p_stack[--ps.tos] = ifhead;
257: for (i = ps.tos - 1;
258: (
259: ps.p_stack[i] != stmt
260: &&
261: ps.p_stack[i] != stmtl
262: &&
263: ps.p_stack[i] != lbrace
264: );
265: --i);
266: ps.i_l_follow = ps.il[i];
267: /*
268: * for the time being, we will assume that there is no else on
269: * this if, and set the indentation level accordingly. If an
270: * else is scanned, it will be fixed up later
271: */
272: break;
273:
274: case swstmt:
275: /* <switch> <stmt> */
276: case_ind = ps.cstk[ps.tos - 1];
277:
278: case decl: /* finish of a declaration */
279: case elsehead:
280: /* <<if> <stmt> else> <stmt> */
281: case forstmt:
282: /* <for> <stmt> */
283: case whilestmt:
284: /* <while> <stmt> */
285: ps.p_stack[--ps.tos] = stmt;
286: ps.i_l_follow = ps.il[ps.tos];
287: break;
288:
289: default: /* <anything else> <stmt> */
290: return;
291:
292: } /* end of section for <stmt> on top of stack */
293: break;
294:
295: case whilestmt: /* while (...) on top */
296: if (ps.p_stack[ps.tos - 1] == dohead) {
297: /* it is termination of a do while */
298: ps.p_stack[--ps.tos] = stmt;
299: break;
300: }
301: else
302: return;
303:
304: default: /* anything else on top */
305: return;
306:
307: }
308: }
309: }
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