325 lines
8.8 KiB
C
325 lines
8.8 KiB
C
/*
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* Copyright (c) 1985 Sun Microsystems, Inc.
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* Copyright (c) 1980, 1993
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* The Regents of the University of California. All rights reserved.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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static char sccsid[] = "@(#)parse.c 8.1 (Berkeley) 6/6/93";
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#endif /* not lint */
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#include <stdio.h>
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#include "indent_globs.h"
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#include "indent_codes.h"
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parse(tk)
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int tk; /* the code for the construct scanned */
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{
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int i;
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#ifdef debug
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printf("%2d - %s\n", tk, token);
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#endif
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while (ps.p_stack[ps.tos] == ifhead && tk != elselit) {
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/* true if we have an if without an else */
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ps.p_stack[ps.tos] = stmt; /* apply the if(..) stmt ::= stmt
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* reduction */
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reduce(); /* see if this allows any reduction */
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}
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switch (tk) { /* go on and figure out what to do with the
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* input */
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case decl: /* scanned a declaration word */
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ps.search_brace = btype_2;
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/* indicate that following brace should be on same line */
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if (ps.p_stack[ps.tos] != decl) { /* only put one declaration
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* onto stack */
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break_comma = true; /* while in declaration, newline should be
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* forced after comma */
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ps.p_stack[++ps.tos] = decl;
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ps.il[ps.tos] = ps.i_l_follow;
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if (ps.ljust_decl) {/* only do if we want left justified
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* declarations */
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ps.ind_level = 0;
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for (i = ps.tos - 1; i > 0; --i)
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if (ps.p_stack[i] == decl)
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++ps.ind_level; /* indentation is number of
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* declaration levels deep we are */
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ps.i_l_follow = ps.ind_level;
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}
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}
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break;
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case ifstmt: /* scanned if (...) */
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if (ps.p_stack[ps.tos] == elsehead && ps.else_if) /* "else if ..." */
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ps.i_l_follow = ps.il[ps.tos];
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case dolit: /* 'do' */
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case forstmt: /* for (...) */
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ps.p_stack[++ps.tos] = tk;
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ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
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++ps.i_l_follow; /* subsequent statements should be indented 1 */
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ps.search_brace = btype_2;
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break;
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case lbrace: /* scanned { */
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break_comma = false; /* don't break comma in an initial list */
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if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl
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|| ps.p_stack[ps.tos] == stmtl)
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++ps.i_l_follow; /* it is a random, isolated stmt group or a
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* declaration */
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else {
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if (s_code == e_code) {
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/*
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* only do this if there is nothing on the line
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*/
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--ps.ind_level;
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/*
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* it is a group as part of a while, for, etc.
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*/
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if (ps.p_stack[ps.tos] == swstmt && ps.case_indent >= 1)
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--ps.ind_level;
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/*
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* for a switch, brace should be two levels out from the code
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*/
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}
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}
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ps.p_stack[++ps.tos] = lbrace;
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ps.il[ps.tos] = ps.ind_level;
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ps.p_stack[++ps.tos] = stmt;
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/* allow null stmt between braces */
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ps.il[ps.tos] = ps.i_l_follow;
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break;
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case whilestmt: /* scanned while (...) */
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if (ps.p_stack[ps.tos] == dohead) {
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/* it is matched with do stmt */
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ps.ind_level = ps.i_l_follow = ps.il[ps.tos];
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ps.p_stack[++ps.tos] = whilestmt;
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ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
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}
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else { /* it is a while loop */
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ps.p_stack[++ps.tos] = whilestmt;
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ps.il[ps.tos] = ps.i_l_follow;
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++ps.i_l_follow;
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ps.search_brace = btype_2;
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}
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break;
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case elselit: /* scanned an else */
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if (ps.p_stack[ps.tos] != ifhead)
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diag(1, "Unmatched 'else'");
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else {
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ps.ind_level = ps.il[ps.tos]; /* indentation for else should
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* be same as for if */
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ps.i_l_follow = ps.ind_level + 1; /* everything following should
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* be in 1 level */
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ps.p_stack[ps.tos] = elsehead;
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/* remember if with else */
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ps.search_brace = btype_2 | ps.else_if;
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}
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break;
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case rbrace: /* scanned a } */
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/* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */
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if (ps.p_stack[ps.tos - 1] == lbrace) {
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ps.ind_level = ps.i_l_follow = ps.il[--ps.tos];
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ps.p_stack[ps.tos] = stmt;
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}
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else
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diag(1, "Stmt nesting error.");
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break;
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case swstmt: /* had switch (...) */
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ps.p_stack[++ps.tos] = swstmt;
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ps.cstk[ps.tos] = case_ind;
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/* save current case indent level */
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ps.il[ps.tos] = ps.i_l_follow;
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case_ind = ps.i_l_follow + ps.case_indent; /* cases should be one
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* level down from
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* switch */
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ps.i_l_follow += ps.case_indent + 1; /* statements should be two
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* levels in */
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ps.search_brace = btype_2;
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break;
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case semicolon: /* this indicates a simple stmt */
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break_comma = false; /* turn off flag to break after commas in a
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* declaration */
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ps.p_stack[++ps.tos] = stmt;
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ps.il[ps.tos] = ps.ind_level;
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break;
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default: /* this is an error */
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diag(1, "Unknown code to parser");
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return;
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} /* end of switch */
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reduce(); /* see if any reduction can be done */
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#ifdef debug
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for (i = 1; i <= ps.tos; ++i)
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printf("(%d %d)", ps.p_stack[i], ps.il[i]);
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printf("\n");
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#endif
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return;
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}
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/*
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* NAME: reduce
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*
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* FUNCTION: Implements the reduce part of the parsing algorithm
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*
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* ALGORITHM: The following reductions are done. Reductions are repeated
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* until no more are possible.
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*
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* Old TOS New TOS
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* <stmt> <stmt> <stmtl>
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* <stmtl> <stmt> <stmtl>
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* do <stmt> "dostmt"
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* if <stmt> "ifstmt"
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* switch <stmt> <stmt>
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* decl <stmt> <stmt>
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* "ifelse" <stmt> <stmt>
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* for <stmt> <stmt>
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* while <stmt> <stmt>
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* "dostmt" while <stmt>
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*
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* On each reduction, ps.i_l_follow (the indentation for the following line)
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* is set to the indentation level associated with the old TOS.
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*
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* PARAMETERS: None
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*
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* RETURNS: Nothing
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*
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* GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos =
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*
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* CALLS: None
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*
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* CALLED BY: parse
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*
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* HISTORY: initial coding November 1976 D A Willcox of CAC
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*
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*/
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/*----------------------------------------------*\
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| REDUCTION PHASE |
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\*----------------------------------------------*/
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reduce()
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{
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register int i;
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for (;;) { /* keep looping until there is nothing left to
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* reduce */
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switch (ps.p_stack[ps.tos]) {
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case stmt:
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switch (ps.p_stack[ps.tos - 1]) {
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case stmt:
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case stmtl:
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/* stmtl stmt or stmt stmt */
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ps.p_stack[--ps.tos] = stmtl;
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break;
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case dolit: /* <do> <stmt> */
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ps.p_stack[--ps.tos] = dohead;
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ps.i_l_follow = ps.il[ps.tos];
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break;
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case ifstmt:
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/* <if> <stmt> */
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ps.p_stack[--ps.tos] = ifhead;
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for (i = ps.tos - 1;
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(
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ps.p_stack[i] != stmt
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&&
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ps.p_stack[i] != stmtl
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&&
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ps.p_stack[i] != lbrace
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);
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--i);
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ps.i_l_follow = ps.il[i];
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/*
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* for the time being, we will assume that there is no else on
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* this if, and set the indentation level accordingly. If an
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* else is scanned, it will be fixed up later
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*/
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break;
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case swstmt:
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/* <switch> <stmt> */
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case_ind = ps.cstk[ps.tos - 1];
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case decl: /* finish of a declaration */
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case elsehead:
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/* <<if> <stmt> else> <stmt> */
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case forstmt:
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/* <for> <stmt> */
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case whilestmt:
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/* <while> <stmt> */
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ps.p_stack[--ps.tos] = stmt;
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ps.i_l_follow = ps.il[ps.tos];
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break;
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default: /* <anything else> <stmt> */
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return;
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} /* end of section for <stmt> on top of stack */
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break;
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case whilestmt: /* while (...) on top */
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if (ps.p_stack[ps.tos - 1] == dohead) {
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/* it is termination of a do while */
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ps.tos -= 2;
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break;
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}
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else
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return;
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default: /* anything else on top */
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return;
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}
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}
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}
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