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NAME
. - oldvalue
SYNOPSIS
. (with no adjacent letters or digits or _ or .)
TYPES
return any
DESCRIPTION
The "old value" is essentially a global variable with identifier "."
which at top level when directly from a file or keyboard
is automatically assigned the saved value for a line
of statements when evaluation of that line is completed and this saved
value is not null. A line of statements is normally completed by a
'\n' not within a block bounded by braces or an expression bounded by
parentheses.
Disabling of saving by calling saveval(0) causes lines to return a
null value and . then becomes in effect a global variable whose
value may be changed by assignments and operations like ++ and --.
A null value may be assigned to . by . = null() or free(.).
EXAMPLE
; saveval(1);
; a = 2
; .
2
; . += 3; b = . + 4
; print ., b
9 9
; . += 3; b = . + 4; null()
; print ., b
12 16
; list(a, b, a + b)
list (3 elements, 3 nonzero):
[[0]] = 2
[[1]] = 16
[[2]] = 18
; saveval(0)
; print pop(.), .[[1]]
2 18
LIMITS
none
LINK LIBRARY
none
SEE ALSO
saveval
## 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.
## 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
##
## Under source code control: 1997/09/06 20:03:35
## File existed as early as: 1997
##
## chongo <was here> /\oo/\ http://www.isthe.com/chongo/
## Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/
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