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 the above copyright notice and this paragraph are 9 * duplicated in all such forms and that any documentation, 10 * advertising materials, and other materials related to such 11 * distribution and use acknowledge that the software was developed 12 * by the University of California, Berkeley, the University of Illinois, 13 * Urbana, and Sun Microsystems, Inc. The name of either University 14 * or Sun Microsystems may not be used to endorse or promote products 15 * derived from this software without specific prior written permission. 16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 18 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 19 */ 20 21 #ifndef lint 22 static char sccsid[] = "@(#)parse.c 5.10 (Berkeley) 03/05/89"; 23 #endif /* not lint */ 24 25 #include "indent_globs.h" 26 #include "indent_codes.h" 27 28 parse(tk) 29 int tk; /* the code for the construct scanned */ 30 { 31 int i; 32 33 #ifdef debug 34 printf("%2d - %s\n", tk, token); 35 #endif 36 37 while (ps.p_stack[ps.tos] == ifhead && tk != elselit) { 38 /* true if we have an if without an else */ 39 ps.p_stack[ps.tos] = stmt; /* apply the if(..) stmt ::= stmt 40 * reduction */ 41 reduce(); /* see if this allows any reduction */ 42 } 43 44 45 switch (tk) { /* go on and figure out what to do with the 46 * input */ 47 48 case decl: /* scanned a declaration word */ 49 ps.search_brace = btype_2; 50 /* indicate that following brace should be on same line */ 51 if (ps.p_stack[ps.tos] != decl) { /* only put one declaration 52 * onto stack */ 53 break_comma = true; /* while in declaration, newline should be 54 * forced after comma */ 55 ps.p_stack[++ps.tos] = decl; 56 ps.il[ps.tos] = ps.i_l_follow; 57 58 if (ps.ljust_decl) {/* only do if we want left justified 59 * declarations */ 60 ps.ind_level = 0; 61 for (i = ps.tos - 1; i > 0; --i) 62 if (ps.p_stack[i] == decl) 63 ++ps.ind_level; /* indentation is number of 64 * declaration levels deep we are */ 65 ps.i_l_follow = ps.ind_level; 66 } 67 } 68 break; 69 70 case ifstmt: /* scanned if (...) */ 71 if (ps.p_stack[ps.tos] == elsehead && ps.else_if) /* "else if ..." */ 72 ps.i_l_follow = ps.il[ps.tos]; 73 case dolit: /* 'do' */ 74 case forstmt: /* for (...) */ 75 ps.p_stack[++ps.tos] = tk; 76 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; 77 ++ps.i_l_follow; /* subsequent statements should be indented 1 */ 78 ps.search_brace = btype_2; 79 break; 80 81 case lbrace: /* scanned { */ 82 break_comma = false; /* don't break comma in an initial list */ 83 if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl 84 || ps.p_stack[ps.tos] == stmtl) 85 ++ps.i_l_follow; /* it is a random, isolated stmt group or a 86 * declaration */ 87 else { 88 if (s_code == e_code) { 89 /* 90 * only do this if there is nothing on the line 91 */ 92 --ps.ind_level; 93 /* 94 * it is a group as part of a while, for, etc. 95 */ 96 if (ps.p_stack[ps.tos] == swstmt && ps.case_indent >= 1) 97 --ps.ind_level; 98 /* 99 * for a switch, brace should be two levels out from the code 100 */ 101 } 102 } 103 104 ps.p_stack[++ps.tos] = lbrace; 105 ps.il[ps.tos] = ps.ind_level; 106 ps.p_stack[++ps.tos] = stmt; 107 /* allow null stmt between braces */ 108 ps.il[ps.tos] = ps.i_l_follow; 109 break; 110 111 case whilestmt: /* scanned while (...) */ 112 if (ps.p_stack[ps.tos] == dohead) { 113 /* it is matched with do stmt */ 114 ps.ind_level = ps.i_l_follow = ps.il[ps.tos]; 115 ps.p_stack[++ps.tos] = whilestmt; 116 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; 117 } 118 else { /* it is a while loop */ 119 ps.p_stack[++ps.tos] = whilestmt; 120 ps.il[ps.tos] = ps.i_l_follow; 121 ++ps.i_l_follow; 122 ps.search_brace = btype_2; 123 } 124 125 break; 126 127 case elselit: /* scanned an else */ 128 129 if (ps.p_stack[ps.tos] != ifhead) 130 diag(1, "Unmatched 'else'"); 131 else { 132 ps.ind_level = ps.il[ps.tos]; /* indentation for else should 133 * be same as for if */ 134 ps.i_l_follow = ps.ind_level + 1; /* everything following should 135 * be in 1 level */ 136 ps.p_stack[ps.tos] = elsehead; 137 /* remember if with else */ 138 ps.search_brace = btype_2 | ps.else_if; 139 } 140 break; 141 142 case rbrace: /* scanned a } */ 143 /* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */ 144 if (ps.p_stack[ps.tos - 1] == lbrace) { 145 ps.ind_level = ps.i_l_follow = ps.il[--ps.tos]; 146 ps.p_stack[ps.tos] = stmt; 147 } 148 else 149 diag(1, "Stmt nesting error."); 150 break; 151 152 case swstmt: /* had switch (...) */ 153 ps.p_stack[++ps.tos] = swstmt; 154 ps.cstk[ps.tos] = case_ind; 155 /* save current case indent level */ 156 ps.il[ps.tos] = ps.i_l_follow; 157 case_ind = ps.i_l_follow + ps.case_indent; /* cases should be one 158 * level down from 159 * switch */ 160 ps.i_l_follow += ps.case_indent + 1; /* statements should be two 161 * levels in */ 162 ps.search_brace = btype_2; 163 break; 164 165 case semicolon: /* this indicates a simple stmt */ 166 break_comma = false; /* turn off flag to break after commas in a 167 * declaration */ 168 ps.p_stack[++ps.tos] = stmt; 169 ps.il[ps.tos] = ps.ind_level; 170 break; 171 172 default: /* this is an error */ 173 diag(1, "Unknown code to parser"); 174 return; 175 176 177 } /* end of switch */ 178 179 reduce(); /* see if any reduction can be done */ 180 181 #ifdef debug 182 for (i = 1; i <= ps.tos; ++i) 183 printf("(%d %d)", ps.p_stack[i], ps.il[i]); 184 printf("\n"); 185 #endif 186 187 return; 188 } 189 190 /* 191 * NAME: reduce 192 * 193 * FUNCTION: Implements the reduce part of the parsing algorithm 194 * 195 * ALGORITHM: The following reductions are done. Reductions are repeated 196 * until no more are possible. 197 * 198 * Old TOS New TOS 199 * <stmt> <stmt> <stmtl> 200 * <stmtl> <stmt> <stmtl> 201 * do <stmt> "dostmt" 202 * if <stmt> "ifstmt" 203 * switch <stmt> <stmt> 204 * decl <stmt> <stmt> 205 * "ifelse" <stmt> <stmt> 206 * for <stmt> <stmt> 207 * while <stmt> <stmt> 208 * "dostmt" while <stmt> 209 * 210 * On each reduction, ps.i_l_follow (the indentation for the following line) 211 * is set to the indentation level associated with the old TOS. 212 * 213 * PARAMETERS: None 214 * 215 * RETURNS: Nothing 216 * 217 * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos = 218 * 219 * CALLS: None 220 * 221 * CALLED BY: parse 222 * 223 * HISTORY: initial coding November 1976 D A Willcox of CAC 224 * 225 */ 226 /*----------------------------------------------*\ 227 | REDUCTION PHASE | 228 \*----------------------------------------------*/ 229 reduce() 230 { 231 232 register int i; 233 234 for (;;) { /* keep looping until there is nothing left to 235 * reduce */ 236 237 switch (ps.p_stack[ps.tos]) { 238 239 case stmt: 240 switch (ps.p_stack[ps.tos - 1]) { 241 242 case stmt: 243 case stmtl: 244 /* stmtl stmt or stmt stmt */ 245 ps.p_stack[--ps.tos] = stmtl; 246 break; 247 248 case dolit: /* <do> <stmt> */ 249 ps.p_stack[--ps.tos] = dohead; 250 ps.i_l_follow = ps.il[ps.tos]; 251 break; 252 253 case ifstmt: 254 /* <if> <stmt> */ 255 ps.p_stack[--ps.tos] = ifhead; 256 for (i = ps.tos - 1; 257 ( 258 ps.p_stack[i] != stmt 259 && 260 ps.p_stack[i] != stmtl 261 && 262 ps.p_stack[i] != lbrace 263 ); 264 --i); 265 ps.i_l_follow = ps.il[i]; 266 /* 267 * for the time being, we will assume that there is no else on 268 * this if, and set the indentation level accordingly. If an 269 * else is scanned, it will be fixed up later 270 */ 271 break; 272 273 case swstmt: 274 /* <switch> <stmt> */ 275 case_ind = ps.cstk[ps.tos - 1]; 276 277 case decl: /* finish of a declaration */ 278 case elsehead: 279 /* <<if> <stmt> else> <stmt> */ 280 case forstmt: 281 /* <for> <stmt> */ 282 case whilestmt: 283 /* <while> <stmt> */ 284 ps.p_stack[--ps.tos] = stmt; 285 ps.i_l_follow = ps.il[ps.tos]; 286 break; 287 288 default: /* <anything else> <stmt> */ 289 return; 290 291 } /* end of section for <stmt> on top of stack */ 292 break; 293 294 case whilestmt: /* while (...) on top */ 295 if (ps.p_stack[ps.tos - 1] == dohead) { 296 /* it is termination of a do while */ 297 ps.p_stack[--ps.tos] = stmt; 298 break; 299 } 300 else 301 return; 302 303 default: /* anything else on top */ 304 return; 305 306 } 307 } 308 } 309