/* $OpenBSD: parse.c,v 1.9 2009/10/27 23:59:39 deraadt Exp $ */ /* * Copyright (c) 1980, 1993 * The Regents of the University of California. * Copyright (c) 1976 Board of Trustees of the University of Illinois. * Copyright (c) 1985 Sun Microsystems, Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include <stdio.h> #include "indent_globs.h" #include "indent_codes.h" void reduce(void); void parse(int tk) /* the code for the construct scanned */ { int i; #ifdef debug printf("%2d - %s\n", tk, token); #endif while (ps.p_stack[ps.tos] == ifhead && tk != elselit) { /* true if we have an if without an else */ ps.p_stack[ps.tos] = stmt; /* apply the if(..) stmt ::= stmt * reduction */ reduce(); /* see if this allows any reduction */ } switch (tk) { /* go on and figure out what to do with the * input */ case decl: /* scanned a declaration word */ ps.search_brace = btype_2; /* indicate that following brace should be on same line */ if (ps.p_stack[ps.tos] != decl) { /* only put one declaration * onto stack */ break_comma = true; /* while in declaration, newline should be * forced after comma */ ps.p_stack[++ps.tos] = decl; ps.il[ps.tos] = ps.i_l_follow; if (ps.ljust_decl) {/* only do if we want left justified * declarations */ ps.ind_level = 0; for (i = ps.tos - 1; i > 0; --i) if (ps.p_stack[i] == decl) ++ps.ind_level; /* indentation is number of * declaration levels deep we are */ ps.i_l_follow = ps.ind_level; } } break; case ifstmt: /* scanned if (...) */ if (ps.p_stack[ps.tos] == elsehead && ps.else_if) /* "else if ..." */ ps.i_l_follow = ps.il[ps.tos]; case dolit: /* 'do' */ case forstmt: /* for (...) */ ps.p_stack[++ps.tos] = tk; ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; ++ps.i_l_follow; /* subsequent statements should be indented 1 */ ps.search_brace = btype_2; break; case lbrace: /* scanned { */ break_comma = false; /* don't break comma in an initial list */ if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl || ps.p_stack[ps.tos] == stmtl) ++ps.i_l_follow; /* it is a random, isolated stmt group or a * declaration */ else { if (s_code == e_code) { /* * only do this if there is nothing on the line */ --ps.ind_level; /* * it is a group as part of a while, for, etc. */ if (ps.p_stack[ps.tos] == swstmt && ps.case_indent >= 1) --ps.ind_level; /* * for a switch, brace should be two levels out from the code */ } } ps.p_stack[++ps.tos] = lbrace; ps.il[ps.tos] = ps.ind_level; ps.p_stack[++ps.tos] = stmt; /* allow null stmt between braces */ ps.il[ps.tos] = ps.i_l_follow; break; case whilestmt: /* scanned while (...) */ if (ps.p_stack[ps.tos] == dohead) { /* it is matched with do stmt */ ps.ind_level = ps.i_l_follow = ps.il[ps.tos]; ps.p_stack[++ps.tos] = whilestmt; ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; } else { /* it is a while loop */ ps.p_stack[++ps.tos] = whilestmt; ps.il[ps.tos] = ps.i_l_follow; ++ps.i_l_follow; ps.search_brace = btype_2; } break; case elselit: /* scanned an else */ if (ps.p_stack[ps.tos] != ifhead) diag(1, "Unmatched 'else'"); else { ps.ind_level = ps.il[ps.tos]; /* indentation for else should * be same as for if */ ps.i_l_follow = ps.ind_level + 1; /* everything following should * be in 1 level */ ps.p_stack[ps.tos] = elsehead; /* remember if with else */ ps.search_brace = btype_2 | ps.else_if; } break; case rbrace: /* scanned a } */ /* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */ if (ps.p_stack[ps.tos - 1] == lbrace) { ps.ind_level = ps.i_l_follow = ps.il[--ps.tos]; ps.p_stack[ps.tos] = stmt; } else diag(1, "Stmt nesting error."); break; case swstmt: /* had switch (...) */ ps.p_stack[++ps.tos] = swstmt; ps.cstk[ps.tos] = case_ind; /* save current case indent level */ ps.il[ps.tos] = ps.i_l_follow; case_ind = ps.i_l_follow + ps.case_indent; /* cases should be one * level down from * switch */ ps.i_l_follow += ps.case_indent + 1; /* statements should be two * levels in */ ps.search_brace = btype_2; break; case semicolon: /* this indicates a simple stmt */ break_comma = false; /* turn off flag to break after commas in a * declaration */ ps.p_stack[++ps.tos] = stmt; ps.il[ps.tos] = ps.ind_level; break; default: /* this is an error */ diag(1, "Unknown code to parser"); return; } /* end of switch */ reduce(); /* see if any reduction can be done */ #ifdef debug for (i = 1; i <= ps.tos; ++i) printf("(%d %d)", ps.p_stack[i], ps.il[i]); printf("\n"); #endif return; } /* * NAME: reduce * * FUNCTION: Implements the reduce part of the parsing algorithm * * ALGORITHM: The following reductions are done. Reductions are repeated * until no more are possible. * * Old TOS New TOS * <stmt> <stmt> <stmtl> * <stmtl> <stmt> <stmtl> * do <stmt> "dostmt" * if <stmt> "ifstmt" * switch <stmt> <stmt> * decl <stmt> <stmt> * "ifelse" <stmt> <stmt> * for <stmt> <stmt> * while <stmt> <stmt> * "dostmt" while <stmt> * * On each reduction, ps.i_l_follow (the indentation for the following line) * is set to the indentation level associated with the old TOS. * * PARAMETERS: None * * RETURNS: Nothing * * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos = * * CALLS: None * * CALLED BY: parse * * HISTORY: initial coding November 1976 D A Willcox of CAC * */ /*----------------------------------------------*\ | REDUCTION PHASE | \*----------------------------------------------*/ void reduce(void) { int i; for (;;) { /* keep looping until there is nothing left to * reduce */ switch (ps.p_stack[ps.tos]) { case stmt: switch (ps.p_stack[ps.tos - 1]) { case stmt: case stmtl: /* stmtl stmt or stmt stmt */ ps.p_stack[--ps.tos] = stmtl; break; case dolit: /* <do> <stmt> */ ps.p_stack[--ps.tos] = dohead; ps.i_l_follow = ps.il[ps.tos]; break; case ifstmt: /* <if> <stmt> */ ps.p_stack[--ps.tos] = ifhead; for (i = ps.tos - 1; ( ps.p_stack[i] != stmt && ps.p_stack[i] != stmtl && ps.p_stack[i] != lbrace ); --i); ps.i_l_follow = ps.il[i]; /* * for the time being, we will assume that there is no else on * this if, and set the indentation level accordingly. If an * else is scanned, it will be fixed up later */ break; case swstmt: /* <switch> <stmt> */ case_ind = ps.cstk[ps.tos - 1]; case decl: /* finish of a declaration */ case elsehead: /* <<if> <stmt> else> <stmt> */ case forstmt: /* <for> <stmt> */ case whilestmt: /* <while> <stmt> */ ps.p_stack[--ps.tos] = stmt; ps.i_l_follow = ps.il[ps.tos]; break; default: /* <anything else> <stmt> */ return; } /* end of section for <stmt> on top of stack */ break; case whilestmt: /* while (...) on top */ if (ps.p_stack[ps.tos - 1] == dohead) { /* it is termination of a do while */ ps.p_stack[--ps.tos] = stmt; break; } else return; default: /* anything else on top */ return; } } }
