cmd/awk_xpg4/awk3.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * awk -- executor
 *
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright 1985, 1994 by Mortice Kern Systems Inc.  All rights reserved.
 *
 * Based on MKS awk(1) ported to be /usr/xpg4/bin/awk with POSIX/XCU4 changes
 */

#pragma ident	"%Z%%M%	%I%	%E% SMI"

#include "awk.h"
#include "y.tab.h"

static int	dohash(wchar_t *name);
static NODE	*arithmetic(NODE *np);
static NODE	*comparison(NODE *np);
static int	type_of(NODE *np);
static NODE	*lfield(INT fieldno, NODE *value);
static NODE	*rfield(INT fieldno);
static NODE	*userfunc(NODE *np);
static wchar_t	*lltoa(long long l);
static NODE	*exprconcat(NODE *np, int len);
static int	s_if(NODE *np);
static int	s_while(NODE *np);
static int	s_for(NODE *np);
static int	s_forin(NODE *np);
static void	setrefield(NODE *value);
static void	freetemps(void);
static int	action(NODE *np);
static wchar_t	*makeindex(NODE *np, wchar_t *array, int tag);
static int	exprtest(NODE *np);

#define	regmatch(rp, s) REGWEXEC(rp, s, 0, (REGWMATCH_T*)NULL, 0)

/*
 * This code allows for integers to be stored in longs (type INT) and
 * only promoted to double precision floating point numbers (type REAL)
 * when overflow occurs during +, -, or * operations.  This is very
 * non-portable if you desire such a speed optimisation.  You may wish
 * to put something here for your system.  This "something" would likely
 * include either an assembler "jump on overflow" instruction or a
 * method to get traps on overflows from the hardware.
 *
 * This portable method works for ones and twos complement integer
 * representations (which is, realistically) almost all machines.
 */
#if	__TURBOC__
#define	addoverflow()	asm	jo	overflow
#define	suboverflow()	asm	jo	overflow
#else
/*
 * These are portable to two's complement integer machines
 */
#define	addoverflow()	if ((i1^i2) >= 0 && (iresult^i1) < 0) goto overflow
#define	suboverflow()	if ((i1^i2) < 0 && (iresult^i2) >= 0) goto overflow
#endif
#define	muloverflow()	if (((short)i1 != i1 || (short)i2 != i2) &&	\
			    ((i2 != 0 && iresult/i2 != i1) ||		\
			    (i1 == LONG_MIN && i2 == -1)))	  goto overflow

static char	notarray[] = "scalar \"%s\" cannot be used as array";
static char	badarray[] = "array \"%s\" cannot be used as a scalar";
static char	varnotfunc[] = "variable \"%s\" cannot be used as a function";
static char	tmfld[] = "Too many fields (LIMIT: %d)";
static char	toolong[] = "Record too long (LIMIT: %d bytes)";
static char	divzero[] =  "division (/ or %%) by zero";
static char	toodeep[] = "too deeply nested for in loop (LIMIT: %d)";

static wchar_t	numbuf[NUMSIZE];	/* Used to convert INTs to strings */
static wchar_t	*fields[NFIELD];	/* Cache of pointers into fieldbuf */
static wchar_t	*fieldbuf;		/* '\0' separated copy of linebuf */
static NODE	nodes[NSNODE];		/* Cache of quick access nodes */
static NODE	*fnodep = &nodes[0];
#define	NINDEXBUF	50
static wchar_t	indexbuf[NINDEXBUF];	/* Used for simple array indices */
static int	concflag;		/* In CONCAT operation (no frees) */
static NODE	*retval;		/* Last return value of a function */

/*
 * The following stack is used to store the next pointers for all nested
 * for-in loops. This needs to be global so that delete can check to see
 * if it is deleting the next node to be used by a loop.
 */
#define	NFORINLOOP	10
static NODE*	forindex[NFORINLOOP];
static NODE**	next_forin = forindex;

/*
 * Assign a string directly to a NODE without creating an intermediate
 * NODE.  This can handle either FALLOC, FSTATIC, FNOALLOC or FSENSE for
 * "flags" argument.  Also the NODE "np" must be reduced to an lvalue
 * (PARM nodes are not acceptable).
 */
void
strassign(NODE *np, STRING string, int flags, size_t length)
{
	if (np->n_type == FUNC)
		awkerr(gettext("attempt to redefine builtin function"));
	else if (np->n_type == GETLINE || np->n_type == KEYWORD)
		awkerr(gettext("inadmissible use of reserved keyword"));
	if (np->n_flags & FSPECIAL) {
		(void) nassign(np, stringnode(string, flags, length));
		return;
	}
	if (isastring(np->n_flags))
		free((wchar_t *)np->n_string);
	np->n_strlen = length++;
	if (flags & FALLOC) {
		length *= sizeof (wchar_t);
		np->n_string = (STRING) emalloc(length);
		(void) memcpy((void *)np->n_string, string, length);
	} else {
		np->n_string = string;
		if (flags & FNOALLOC) {
			flags &= ~FNOALLOC;
			flags |= FALLOC;
		}
	}
	np->n_flags &= FSAVE;
	if (flags & FSENSE) {
		flags &= ~FSENSE;
		flags |= type_of(np);
	} else
		flags |= FSTRING;
	np->n_flags |= flags;
}

/*
 * Assign to a variable node.
 * LHS must be a VAR type and RHS must be reduced by now.
 * To speed certain operations up, check for
 * certain things here and do special assignments.
 */
NODE *
nassign(NODE *np, NODE *value)
{
	register wchar_t *cp;
	register int len;

	/* short circuit assignment of a node to itself */
	if (np == value)
		return (np);
	if (np->n_flags & FSPECIAL) {
		if (np == varRS || np == varFS) {
			if (isastring(np->n_flags))
				free((void *)np->n_string);
			len = sizeof (wchar_t) * ((np->n_strlen =
				wcslen(cp = exprstring(value)))+1);
			np->n_string = emalloc(len);
			(void) memcpy((wchar_t *)np->n_string, cp, len);
			np->n_flags = FALLOC|FSTRING|FSPECIAL;
			if (np == varRS) {
				if (np->n_string[0] == '\n')
					awkrecord = defrecord;
				else if (np->n_string[0] == '\0')
					awkrecord = multirecord;
				else
					awkrecord = charrecord;
			} else if (np == varFS) {
				if (resep != (REGEXP)NULL) {
					REGWFREE(resep);
					resep = (REGEXP)NULL;
				}
				if (wcslen((wchar_t *)np->n_string) > 1)
					setrefield(np);
				else if (np->n_string[0] == ' ')
					awkfield = whitefield;
				else
					awkfield = blackfield;
			}
			return (np);
		}
	}
	if (isastring(np->n_flags))
		free((wchar_t *)np->n_string);
	if (isstring(value->n_flags)) {
		np->n_strlen = value->n_strlen;
		if (value->n_flags&FALLOC || value->n_string != _null) {
			len = (np->n_strlen+1) * sizeof (wchar_t);
			np->n_string = emalloc(len);
			(void) memcpy(np->n_string, value->n_string, len);
			np->n_flags &= FSAVE;
			np->n_flags |= value->n_flags & ~FSAVE;
			np->n_flags |= FALLOC;
			return (np);
		} else
			np->n_string = value->n_string;
	} else if (value->n_flags & FINT)
		np->n_int = value->n_int;
	else
		np->n_real = value->n_real;
	np->n_flags &= FSAVE;
	np->n_flags |= value->n_flags & ~FSAVE;
	return (np);
}

/*
 * Set regular expression FS value.
 */
static void
setrefield(NODE *np)
{
	static REGEXP re;
	int n;

	if ((n = REGWCOMP(&re, np->n_string)) != REG_OK) {
		REGWERROR(n, &re, (char *)linebuf, sizeof (linebuf));
		awkerr(gettext("syntax error \"%s\" in /%s/\n"),
			(char *)linebuf, np->n_string);
	}
	resep = re;
	awkfield = refield;
}

/*
 * Assign to an l-value node.
 */
NODE *
assign(NODE *left, NODE *right)
{
	if (isleaf(right->n_flags)) {
		if (right->n_type == PARM)
			right = right->n_next;
	} else
		right = exprreduce(right);
top:
	switch (left->n_type) {
	case INDEX:
		left = exprreduce(left);
	/*FALLTHRU*/
	case VAR:
		return (nassign(left, right));

	case PARM:
		/*
		 * If it's a parameter then link to the actual value node and
		 * do the checks again.
		 */
		left = left->n_next;
		goto top;

	case FIELD:
		return (lfield(exprint(left->n_left), right));

	case CALLUFUNC:
	case UFUNC:
		awkerr(gettext("cannot assign to function \"%s\""),
		    left->n_name);

	default:
		awkerr(gettext("lvalue required in assignment"));
	}
	/* NOTREACHED */
	return (0);
}

/*
 * Compiled tree non-terminal node.
 */
NODE *
node(int type, NODE *left, NODE *right)
{
	register NODE *np;

	np = emptynode(type, 0);
	np->n_left = left;
	np->n_right = right;
	np->n_lineno = lineno;
	return (np);
}

/*
 * Create an integer node.
 */
NODE *
intnode(INT i)
{
	register NODE *np;

	np = emptynode(CONSTANT, 0);
	np->n_flags = FINT|FVINT;
	np->n_int = i;
	return (np);
}

/*
 * Create a real number node.
 */
NODE *
realnode(REAL real)
{
	register NODE *np;

	np = emptynode(CONSTANT, 0);
	np->n_flags = FREAL|FVREAL;
	np->n_real = real;
	return (np);
}

/*
 * Make a node for a string.
 */
NODE *
stringnode(STRING s, int how, size_t length)
{
	register NODE *np;

	np = emptynode(CONSTANT, 0);
	np->n_strlen = length;
	if (how & FALLOC) {
		np->n_string = emalloc(length = (length+1) * sizeof (wchar_t));
		(void) memcpy(np->n_string, s, length);
	} else {
		np->n_string = s;
		if (how & FNOALLOC) {
			how &= ~FNOALLOC;
			how |= FALLOC;
		}
	}
	if (how & FSENSE) {
		np->n_flags = type_of(np);
		how &= ~FSENSE;
	} else
		np->n_flags = FSTRING;
	np->n_flags |= how;
	return (np);
}

/*
 * Save a copy of a string.
 */
STRING
strsave(wchar_t *old)
{
	STRING new;
	register size_t len;

	new = (STRING)emalloc(len = (wcslen(old)+1) * sizeof (wchar_t));
	(void) memcpy(new, old, len);
	return (new);
}

/*
 * Allocate an empty node of given type.
 * String space for the node is given by `length'.
 */
NODE *
emptynode(int type, size_t length)
{
	register NODE *np;

	if (length == 0 && running && fnodep < &nodes[NSNODE]) {
		np = fnodep++;
	} else {
		np = (NODE *)emalloc(sizeof (NODE) +
		    (length * sizeof (wchar_t)));
		if (running && type != VAR && type != ARRAY) {
			np->n_next = freelist;
			freelist = np;
		}
	}
	np->n_flags = FNONTOK;
	np->n_type = type;
	np->n_alink = NNULL;

	return (np);
}

/*
 * Free a node.
 */
void
freenode(NODE *np)
{
	if (isastring(np->n_flags))
		free((wchar_t *)np->n_string);
	else if (np->n_type == RE) {
		REGWFREE(np->n_regexp);
	}
	free((wchar_t *)np);
}

/*
 * Install a keyword of given `type'.
 */
void
kinstall(LOCCHARP name, int type)
{
	register NODE *np;
	register size_t l;

	l = wcslen(name);
	np = emptynode(KEYWORD, l);
	np->n_keywtype = type;
	(void) memcpy(np->n_name, name, (l+1) * sizeof (wchar_t));
	addsymtab(np);
}

/*
 * Install built-in function.
 */
NODE *
finstall(LOCCHARP name, FUNCTION func, int type)
{
	register NODE *np;
	register size_t l;

	l = wcslen(name);
	np = emptynode(type, l);
	np->n_function = func;
	(void) memcpy(np->n_name, name, (l+1) * sizeof (wchar_t));
	addsymtab(np);
	return (np);
}

/*
 * Lookup an identifier.
 * nocreate contains the following flag values:
 *	1 if no creation of a new NODE,
 *	0 if ok to create new NODE
 */
NODE *
vlookup(wchar_t *name, int nocreate)
{
	register ushort_t hash;
	register NODE *np;

	np = symtab[hashbuck(hash = dohash((wchar_t *)name))];
	while (np != NNULL) {
		if (np->n_hash == hash && wcscmp(name, np->n_name) == 0)
			return (np);
		np = np->n_next;
	}
	if (nocreate) {
		np = NNULL;
	} else {
		np = emptynode(VAR, hash = wcslen(name));
		np->n_flags = FSTRING|FVINT;
		np->n_strlen = 0;
		np->n_string = _null;
		(void) memcpy(np->n_name, name,
			(hash+1) * sizeof (wchar_t));
		addsymtab(np);
	}
	return (np);
}

/*
 * Add a symbol to the table.
 */
void
addsymtab(NODE *np)
{
	register NODE **spp;

	np->n_hash = dohash((wchar_t *)np->n_name);
	spp = &symtab[hashbuck(np->n_hash)];
	np->n_next = *spp;
	*spp = np;
}

/*
 * Delete the given node from the symbol table.
 * If fflag is non-zero, also free the node space.
 * This routine must also check the stack of forin loop pointers. If
 * we are deleting the next item to be used, then the pointer must be
 * advanced.
 */
void
delsymtab(NODE *np, int fflag)
{
	register NODE *rnp;
	register NODE *prevp;
	register NODE **sptr;
	register ushort_t h;


	h = hashbuck(np->n_hash);
	prevp = NNULL;
	for (rnp = symtab[h]; rnp != NNULL; rnp = rnp->n_next) {
		if (rnp == np) {
			/*
			 * check all of the for-in loop pointers
			 * to see if any need to be advanced because
			 * this element is being deleted.
			 */
			if (next_forin != forindex) {
				sptr = next_forin;
				do {
					if (*--sptr == rnp) {
						*sptr = rnp->n_next;
						break;
					}
				} while (sptr != forindex);
			}
			if (prevp == NNULL)
				symtab[h] = rnp->n_next; else
				prevp->n_next = rnp->n_next;
			if (fflag)
				freenode(rnp);
			break;
		}
		prevp = rnp;
	}
}

/*
 * Hashing function.
 */
static int
dohash(wchar_t *name)
{
	register int hash = 0;

	while (*name != '\0')
		hash += *name++;
	return (hash);
}

/*
 * Top level executor for an awk programme.
 * This will be passed: pattern, action or a list of these.
 * The former function to evaluate a pattern has been
 * subsumed into this function for speed.
 * Patterns are:
 *	BEGIN,
 *	END,
 *	other expressions (including regular expressions)
 */
void
execute(NODE *wp)
{
	register NODE *np;
	register int type;
	register NODE *tnp;

	curnode = wp;
	if (phase != 0) {
		linebuf[0] = '\0';
		lbuflen = 0;
	}
	while (wp != NNULL) {
		if (wp->n_type == COMMA) {
			np = wp->n_left;
			wp = wp->n_right;
		} else {
			np = wp;
			wp = NNULL;
		}
		if (np->n_type != PACT)
			awkerr(interr, "PACT");
		/*
		 * Save the parent node and evaluate the pattern.
		 * If it evaluates to false (0) just continue
		 * to the next pattern/action (PACT) pair.
		 */
		tnp = np;
		np = np->n_left;
		if (np == NNULL) {
			if (phase != 0)
				continue;
		} else if (phase != 0) {
			if (np->n_type != phase)
				continue;
		} else if ((type = np->n_type) == BEGIN || type == END) {
			continue;
		} else if (type == COMMA) {
			/*
			 * The grammar only allows expressions
			 * to be separated by the ',' operator
			 * for range patterns.
			 */
			if (np->n_flags & FMATCH) {
				if (exprint(np->n_right) != 0)
					np->n_flags &= ~FMATCH;
			} else if (exprint(np->n_left) != 0) {
				if (exprint(np->n_right) == 0)
					np->n_flags |= FMATCH;
			} else
				continue;
		} else if (exprint(np) == 0)
			continue;
		np = tnp;
		if (action(np->n_right)) {
			loopexit = 0;
			break;
		}
	}
	if (freelist != NNULL)
		freetemps();
}

/*
 * Free all temporary nodes.
 */
static void
freetemps()
{
	register NODE *np, *nnp;

	if (concflag)
		return;
	for (np = &nodes[0]; np < fnodep; np++) {
		if (isastring(np->n_flags)) {
			free((wchar_t *)np->n_string);
		} else if (np->n_type == RE) {
			REGWFREE(np->n_regexp);
		}
	}
	fnodep = &nodes[0];
	for (np = freelist; np != NNULL; np = nnp) {
		nnp = np->n_next;
		freenode(np);
	}
	freelist = NNULL;
}

/*
 * Do the given action.
 * Actions are statements or expressions.
 */
static int
action(NODE *wp)
{
	register NODE *np;
	register int act = 0;
	register NODE *l;

	while (wp != NNULL) {
		if (wp->n_type == COMMA) {
			np = wp->n_left;
			wp = wp->n_right;
		} else {
			np = wp;
			wp = NNULL;
		}
		if (freelist != NNULL)
			freetemps();
		curnode = np;
		/*
		 * Don't change order of these cases without
		 * changing order in awk.y declarations.
		 * The order is optimised.
		 */
		switch (np->n_type) {
		case ASG:
			(void) assign(np->n_left, np->n_right);
			continue;

		case PRINT:
			s_print(np);
			continue;

		case PRINTF:
			s_prf(np);
			continue;

		case EXIT:
			if (np->n_left != NNULL)
				act = (int)exprint(np->n_left); else
				act = 0;
			doend(act);
			/* NOTREACHED */

		case RETURN:
			if (slevel == 0)
				awkerr(gettext("return outside of a function"));
			np = np->n_left != NNULL
			    ? exprreduce(np->n_left)
			    : const0;
			retval = emptynode(CONSTANT, 0);
			retval->n_flags = FINT;
			(void) nassign(retval, np);
			return (RETURN);

		case NEXT:
			loopexit = NEXT;
		/*FALLTHRU*/
		case BREAK:
		case CONTINUE:
			return (np->n_type);

		case DELETE:
			if ((l = np->n_left)->n_type == PARM) {
				l = l->n_next;
				if (!(l->n_flags & FLARRAY))
					l = l->n_alink;
			}
			switch (l->n_type) {
			case ARRAY:
				delarray(l);
				break;

			case INDEX:
				if ((np = l->n_left)->n_type == PARM) {
					np = np->n_next;
					if (!(np->n_flags & FLARRAY))
						np = np->n_alink;
				}
				/*
				 * get pointer to the node for this array
				 * element using the hash key.
				 */
				l = exprreduce(l);
				/*
				 * now search linearly from the beginning of
				 * the list to find the element before the
				 * one being deleted. This must be done
				 * because arrays are singley-linked.
				 */
				while (np != NNULL) {
					if (np->n_alink == l) {
						np->n_alink = l->n_alink;
						break;
					}
					np = np->n_alink;
				}
				delsymtab(l, 1);
				break;

			case VAR:
				if (isstring(l->n_flags) &&
				    l->n_string == _null)
					break;
			default:
				awkerr(gettext(
				    "may delete only array element or array"));
				break;
			}
			continue;

		case WHILE:
		case DO:
			if ((act = s_while(np)) != 0)
				break;
			continue;

		case FOR:
			if ((act = s_for(np)) != 0)
				break;
			continue;

		case FORIN:
			if ((act = s_forin(np)) != 0)
				break;
			continue;

		case IF:
			if ((act = s_if(np)) != 0)
				break;
			continue;

		default:
			(void) exprreduce(np);
			if (loopexit != 0) {
				act = loopexit;
				break;
			}
			continue;
		}
		return (act);
	}
	return (0);
}

/*
 * Delete an entire array
 */
void
delarray(NODE *np)
{
	register NODE *nnp;

	nnp = np->n_alink;
	np->n_alink = NNULL;
	while (nnp != NNULL) {
		np = nnp->n_alink;
		delsymtab(nnp, 1);
		nnp = np;
	}
}

/*
 * Return the INT value of an expression.
 */
INT
exprint(NODE *np)
{
	if (isleaf(np->n_flags)) {
		if (np->n_type == PARM)
			np = np->n_next;
		goto leaf;
	}
	np = exprreduce(np);
	switch (np->n_type) {
	case CONSTANT:
	case VAR:
	leaf:
		if (np->n_flags & FINT)
			return (np->n_int);
		if (np->n_flags & FREAL)
			return ((INT)np->n_real);
		return ((INT)wcstoll(np->n_string, NULL, 10));

	default:
		awkerr(interr, "exprint");
	}
	/* NOTREACHED */
	return (0);
}

/*
 * Return a real number from an expression tree.
 */
REAL
exprreal(NODE *np)
{
	if (loopexit)
		return ((REAL)loopexit);
	if (isleaf(np->n_flags)) {
		if (np->n_type == PARM)
			np = np->n_next;
		goto leaf;
	}
	np = exprreduce(np);
	switch (np->n_type) {
	case CONSTANT:
	case VAR:
	leaf:
		if (np->n_flags & FREAL)
			return (np->n_real);
		if (np->n_flags & FINT)
			return ((REAL)np->n_int);
		return ((REAL)wcstod((wchar_t *)np->n_string, (wchar_t **)0));

	default:
		awkerr(interr, "exprreal");
	}
	/* NOTREACHED */
	return ((REAL)0);
}

/*
 * Return a string from an expression tree.
 */
STRING
exprstring(NODE *np)
{
	if (isleaf(np->n_flags)) {
		if (np->n_type == PARM)
			np = np->n_next;
		goto leaf;
	}
	np = exprreduce(np);
	switch (np->n_type) {
	case CONSTANT:
	case VAR:
	leaf:
		if (isstring(np->n_flags))
			return (np->n_string);
		if (np->n_flags & FINT)
			return (STRING)lltoa((long long)np->n_int);
		{
			char *tmp;
			(void) wsprintf(numbuf,
		(const char *) (tmp = wcstombsdup(exprstring(varCONVFMT))),
				(double)np->n_real);
			if (tmp != NULL)
				free(tmp);
		}
		return ((STRING)numbuf);

	default:
		awkerr(interr, "exprstring");
	}
	/* NOTREACHED */
	return (0);
}

/*
 * Convert number to string.
 */
static wchar_t *
lltoa(long long l)
{
	register wchar_t *p = &numbuf[NUMSIZE];
	register int s;
	register int neg;
	static wchar_t zero[] = M_MB_L("0");

	if (l == 0)
		return (zero);
	*--p = '\0';
	if (l < 0)
		neg = 1, l = -l; else
		neg = 0;
	if ((s = (short)l) == l) {
		while (s != 0) {
			*--p = s%10 + '0';
			s /= 10;
		}
	} else {
		while (l != 0) {
			*--p = l%10 + '0';
			l /= 10;
		}
	}
	if (neg)
		*--p = '-';
	return (wcscpy(numbuf, p));
}

/*
 * Return pointer to node with concatenation of operands of CONCAT node.
 * In the interest of speed, a left recursive tree of CONCAT nodes
 * is handled with a single malloc.  The accumulated lengths of the
 * right operands are passed down recursive invocations of this
 * routine, which allocates a large enough string when the left
 * operand is not a CONCAT node.
 */
static NODE *
exprconcat(NODE *np, int len)
{
	/* we KNOW (np->n_type==CONCAT) */
	register NODE *lnp = np->n_left;
	register NODE *rnp = np->n_right;
	register STRING	rsp;
	int rlen;
	size_t llen;
	wchar_t *cp;
	wchar_t rnumbuf[NUMSIZE];

	if (isleaf(rnp->n_flags) && rnp->n_type == PARM)
		rnp = rnp->n_next;
	if (isstring(rnp->n_flags)) {
		rsp = rnp->n_string;
		rlen = rnp->n_strlen;
	} else
		rlen = wcslen((wchar_t *)(rsp = exprstring(rnp)));
	if (rsp == numbuf) {	/* static, so save a copy */
		(void) memcpy(rnumbuf, (wchar_t *)rsp,
			(rlen+1) * sizeof (wchar_t));
		rsp = rnumbuf;
	}
	len += rlen;
	if (lnp->n_type == CONCAT) {
		lnp = exprconcat(lnp, len);
		cp = lnp->n_string;
		llen = lnp->n_strlen;
	} else {
		register STRING	lsp;

		if (isleaf(lnp->n_flags) && lnp->n_type == PARM)
			lnp = lnp->n_next;
		if (isstring(lnp->n_flags)) {
			lsp = lnp->n_string;
			llen = lnp->n_strlen;
		} else
			llen = wcslen((wchar_t *)(lsp = exprstring(lnp)));
		cp = emalloc((llen+len+1) * sizeof (wchar_t));
		(void) memcpy(cp, (wchar_t *)lsp, llen * sizeof (wchar_t));
		lnp = stringnode(cp, FNOALLOC, llen);
	}
	(void) memcpy(cp+llen, (wchar_t *)rsp, (rlen+1) * sizeof (wchar_t));
	lnp->n_strlen += rlen;
	return (lnp);
}

/*
 * Reduce an expression to a terminal node.
 */
NODE *
exprreduce(NODE *np)
{
	register wchar_t *cp;
	NODE *tnp;
	register int temp;
	register int t;
	register int  tag;
	register wchar_t *fname;
	register wchar_t *aname;

	/*
	 * a var or constant is a leaf-node (no further reduction required)
	 * so return immediately.
	 */
	if ((t = np->n_type) == VAR || t == CONSTANT)
		return (np);
	/*
	 * If it's a parameter then it is probably a leaf node but it
	 * might be an array so we check.. If it is an array, then signal
	 * an error as an array by itself cannot be used in this context.
	 */
	if (t == PARM)
		if ((np = np->n_next)->n_type == ARRAY)
			awkerr(badarray, np->n_name);
		else
			return (np);
	/*
	 * All the rest are non-leaf nodes.
	 */
	curnode = np;
	switch (t) {
	case CALLUFUNC:
		return (userfunc(np));

	case FIELD:
		return (rfield(exprint(np->n_left)));

	case IN:
	case INDEX:
		tag = 0;
		temp = np->n_type;
		tnp = np->n_left;
		np = np->n_right;
		/* initially formal var name and array key name are the same */
		fname = aname = tnp->n_name;
		if (tnp->n_type == PARM) {
			tnp = tnp->n_next;
			tag = tnp->n_scope;
			if (!(tnp->n_flags & FLARRAY)) {
				tnp = tnp->n_alink;
			}
			aname = tnp->n_name;
		}
		if (tnp->n_type != ARRAY) {
			if (!isstring(tnp->n_flags) || tnp->n_string != _null)
				awkerr(notarray, fname);
			else {
				/* promotion to array */
				promote(tnp);
				if (tnp->n_alink != NNULL) {
					tag = tnp->n_scope;
					if (!(tnp->n_flags & FLARRAY))
						tnp = tnp->n_alink;
					aname = tnp->n_name;
				} else {
					tag = 0;
					if (tnp->n_flags & FLARRAY)
						tag = tnp->n_scope;
				}
			}
		}
		if (tnp == varSYMTAB) {
			if (np == NNULL || np->n_type == COMMA)
				awkerr(gettext(
				    "SYMTAB must have exactly one index"));
			np = vlook(exprstring(np));
			return (np);
		}
		cp = makeindex(np, aname, tag);
		if (temp == INDEX) {
			np = vlook(cp);
			if (!(np->n_flags & FINARRAY)) {
				np->n_alink = tnp->n_alink;
				tnp->n_alink = np;
				np->n_flags |= FINARRAY;
			}
		} else
			np = vlookup(cp, 1) == NNULL ? const0 : const1;
		if (cp != indexbuf)
			free(cp);
		return (np);

	case CONCAT:
		++concflag;
		np = exprconcat(np, 0);
		--concflag;
		return (np);

	case NOT:
		return (intnode(exprtest(np->n_left) == 0 ? (INT)1 : (INT)0));

	case AND:
		return ((exprtest(np->n_left) != 0 &&
		    exprtest(np->n_right) != 0) ? const1 : const0);

	case OR:
		return ((exprtest(np->n_left) != 0 ||
		    exprtest(np->n_right) != 0) ? const1 : const0);

	case EXP:
		{
			double f1, f2;

			/*
			 * evaluate expressions in proper order before
			 * calling pow().
			 *