320 lines
8.4 KiB
C
320 lines
8.4 KiB
C
/**
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* Copyright (c) 1985 Sun Microsystems, Inc.
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* Copyright (c) 1980 The Regents of the University of California.
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* Copyright (c) 1976 Board of Trustees of the University of Illinois.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that the above copyright notice and this paragraph are
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* duplicated in all such forms and that any documentation,
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* advertising materials, and other materials related to such
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* distribution and use acknowledge that the software was developed
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* by the University of California, Berkeley, the University of Illinois,
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* Urbana, and Sun Microsystems, Inc. The name of either University
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* or Sun Microsystems may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*/
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#define PUBLIC extern
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#include "./globs.h"
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#include "./codes.h"
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#include "proto.h"
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void parse(tk)
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int tk; /* the code for the construct
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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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{
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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 ::=
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stmt reduction */
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reduce(); /* see if this allows any
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reduction */
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}
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switch (tk)
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{ /* go on and figure out what to
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do with the 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)
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{ /* only put one declaration
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onto stack */
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break_comma = true; /* while in declaration,
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newline should be forced
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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)
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{ /* only do if we want left
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justified 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
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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
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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
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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
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stmt group or a declaration */
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else
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{
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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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--ps.ind_level;
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/* it is a group as part of a while, for, etc. */
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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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/* for a switch, brace should be two levels out from the
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code */
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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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{
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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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} else
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{ /* 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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{
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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
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should 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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{
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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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} 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
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two 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
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commas in a 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
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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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* Copyright (C) 1976 by the Board of Trustees of the University of Illinois
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*
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* All rights reserved
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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 until
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* no more are possible.
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*
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* Old TOS New TOS <stmt> <stmt> <stmtl> <stmtl> <stmt> <stmtl> do
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* <stmt> "dostmt" if <stmt> "ifstmt" switch <stmt> <stmt> decl
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* <stmt> <stmt> "ifelse" <stmt> <stmt> for <stmt> <stmt> while
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* <stmt> <stmt> "dostmt" while <stmt>
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*
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* On each reduction, ps.i_l_follow (the indentation for the following line) is
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* 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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void reduce()
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{
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register int i;
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for (;;)
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{ /* keep looping until there is
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nothing left to reduce */
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switch (ps.p_stack[ps.tos])
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{
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case stmt:
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switch (ps.p_stack[ps.tos - 1])
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{
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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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/* for the time being, we will assume that there is no else
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on this if, and set the indentation level accordingly.
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If an else is scanned, it will be fixed up later */
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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
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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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{
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/* it is termination of a do while */
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ps.p_stack[--ps.tos] = stmt;
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break;
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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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