NAME    eval - evaluate a stringSYNOPSIS    eval(str)TYPES    str		string    return	anyDESCRIPTION   For eval(str), the value of str is to be a string that could be the body   of the definition of a function f().	 This string may declare local   variables and include keywords (while, for, ...) other than the   reserved keywords (define, show, help, read, write, show, cd) intended   for interactive use or for reading from a file.   If str is the empty string "", eval(str) returns the null value.   The call to eval(str) may return a value by explicit use of a return   statement: "return;" returns the null value, "return expr;" returns the   value of expr.  If execution reaches the end of str and the   value on the execution stack is not null, eval(str) returns that value;   otherwise eval(str) returns the most recently saved value.   Each time eval(str) is called, a temporary function is compiled from   the commands in str, and if there are no syntax errors, this function   is then evaluated.  If str contains syntax errors, eval(str) displays   the scanerror messages and returns the value error(49).EXAMPLE   ; str1 = "2 + 3"; print eval(str1);   5   ; i = 10; str2 = "local i = 0; 7; while (i++ < 5) print i^2,:;"   ; print i, eval(str2), i   10 1 4 9 16 25 7 10   (The print statements in str2 return the null value, so execution of   eval(str2) ends by returning the saved value 7.  The global variable   i is unchanged.)   ; eval("2 + ");   Missing expression	49LIMITS   The string str in eval(str) should not include a call to itself as in	str = "2 + eval(str)"   For this str, eval(str) causes an "Evaluation stack depth exceeded" error.   Similarly, if str1 = "2 + eval(str2)", str2 should not include a call   to eval(str1), etc.LINK LIBRARY   noneSEE ALSO    command, expression, define, prompt## Copyright (C) 1999  Landon Curt Noll#### Calc is open software; you can redistribute it and/or modify it under## the terms of the version 2.1 of the GNU Lesser General Public License## as published by the Free Software Foundation.#### Calc is distributed in the hope that it will be useful, but WITHOUT## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY## or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU Lesser General## Public License for more details.#### A copy of version 2.1 of the GNU Lesser General Public License is## distributed with calc under the filename COPYING-LGPL.  You should have## received a copy with calc; if not, write to Free Software Foundation, Inc.## 59 Temple Place, Suite 330, Boston, MA  02111-1307, USA.#### @(#) $Revision: 29.3 $## @(#) $Id: eval,v 29.3 2006/05/07 07:25:46 chongo Exp $## @(#) $Source: /usr/local/src/cmd/calc/help/RCS/eval,v $#### Under source code control:	1995/12/18 03:30:59## File existed as early as:	1995#### chongo <was here> /\oo/\	http://www.isthe.com/chongo/## Share and enjoy!  :-)	http://www.isthe.com/chongo/tech/comp/calc/