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parse.c
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1993-05-30
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11KB
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309 lines
/**
* Copyright (c) 1985 Sun Microsystems, Inc.
* Copyright (c) 1980 The Regents of the University of California.
* Copyright (c) 1976 Board of Trustees of the University of Illinois.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted provided
* that the above copyright notice and this paragraph are duplicated in all
* such forms and that any documentation, advertising materials, and other
* materials related to such distribution and use acknowledge that the
* software was developed by the University of California, Berkeley, the
* University of Illinois, Urbana, and Sun Microsystems, Inc. The name of
* either University or Sun Microsystems may not be used to endorse or
* promote products derived from this software without specific prior written
* permission. THIS SOFTWARE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES
* OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#include "globals.h"
#include "codes.h"
#ifndef lint
# ifndef ANSIC
static char sccsid[] = "@(#)parse.c 5.8 (Berkeley) 92/06/15";
# endif /* ANSIC */
#endif /* not lint */
#ifdef ANSIC
static void reduce(void);
void parse(int tk)
#else /* ANSIC */
parse(tk)
int tk; /* the code for the construct scanned */
#endif /* ANSIC */
{
int i;
#ifdef debug
printf("%2d - %s\n", tk, token);
#endif /* debug */
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 && !btype_3;
/* 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 && !btype_3;
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
&& ((float) ps.case_indent / (float) ps.ind_size) >= 1
&& ((float) ps.case_code_indent / (float) ps.ind_size) >= 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 && !btype_3;
}
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 && !btype_3) | ps.else_if;
}
break;
case rbrace: /* scanned a } */
/* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */
if (ps.p_stack[ps.tos - 1] == lbrace) {
if (btype_3)
ps.i_l_follow = ps.il[--ps.tos];
else
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 + ((float) ps.case_indent / (float) ps.ind_size);
/* cases should be one level down from switch */
ps.i_l_follow += ((float) ps.case_indent / (float) ps.ind_size)
+ ((float) ps.case_code_indent / (float) ps.ind_size);
/* statements should be two levels in */
ps.search_brace = btype_2 && !btype_3;
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 /* debug */
return;
}
/**
* Copyright (C) 1976 by the Board of Trustees of the University of Illinois
*
* All rights reserved
*
*
* 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> "