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2.11.5t4.1
calc/help/command
Landon Curt Noll 61dd47526f Release calc version 2.11.2t1.0
2017-05-21 15:38:38 -07:00

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Command sequence
This is a sequence of any the following command formats, where
each command is terminated by a semicolon or newline. Long command
lines can be extended by using a back-slash followed by a newline
character. When this is done, the prompt shows a double angle
bracket to indicate that the line is still in progress. Certain
cases will automatically prompt for more input in a similar manner,
even without the back-slash. The most common case for this is when
a function is being defined, but is not yet completed.
Each command sequence terminates only on an end of file. In
addition, commands can consist of expression sequences, which are
described in the next section.
define a function
-----------------
define function(params) { body }
define function(params) = expression
This first form defines a full function which can consist
of declarations followed by many statements which implement
the function.
The second form defines a simple function which calculates
the specified expression value from the specified parameters.
The expression cannot be a statement. However, the comma
and question mark operators can be useful. Examples of
simple functions are:
define sumcubes(a, b) = a^3 + b^3
define pimod(a) = a % pi()
define printnum(a, n, p)
{
if (p == 0) {
print a: "^": n, "=", a^n;
} else {
print a: "^": n, "mod", p, "=", pmod(a,n,p);
}
}
read calc commands
------------------
read filename
read -once filename
This reads definitions from the specified calc resource filename.
The name can be quoted if desired. The calculator uses the
CALCPATH environment variable to search through the specified
directories for the filename, similarly to the use of the
PATH environment variable. If CALCPATH is not defined,
then a default path which is usually ":/usr/local/lib/calc"
is used.
The ".cal" extension is defaulted for input files, so that
if "filename" is not found, then "filename.cal" is then
searched for. The contents of the filename are command
sequences which can consist of expressions to evaluate or
functions to define, just like at the top level command level.
When -once is given, the read command acts like the regular
read expect that it will ignore filename if is has been
previously read.
The read -once form is particularly useful in a resource
file that needs to read a 2nd resource file. By using the
READ -once command, one will not reread that 2nd resource
file, nor will once risk entering into a infinite READ loop
(where that 2nd resource file directly or indirectly does
a READ of the first resource file).
If the -m mode disallows opening of files for reading,
this command will be disabled.
write calc commands
-------------------
write filename
This writes the values of all global variables to the
specified filename, in such a way that the file can be
later read in order to recreate the variable values.
For speed reasons, values are written as hex fractions.
This command currently only saves simple types, so that
matrices, lists, and objects are not saved. Function
definitions are also not saved.
If the -m mode disallows opening of files for writing,
this command will be disabled.
quit or exit
------------
quit
quit string
exit
exit string
The action of these commands depends on where they are used.
At the interactive level, they will cause calc it edit.
This is the normal way to leave the calculator. In any
other use, they will stop the current calculation as if
an error had occurred.
If a string is given, then the string is printed as the reason
for quitting, otherwise a general quit message is printed.
The routine name and line number which executed the quit is
also printed in either case.
Exit is an alias for quit.
Quit is useful when a routine detects invalid arguments,
in order to stop a calculation cleanly. For example,
for a square root routine, an error can be given if the
supplied parameter was a negative number, as in:
define mysqrt(n)
{
if (! isnum(n))
quit "non-numeric argument";
if (n < 0)
quit "Negative argument";
return sqrt(n);
}
See 'more information about abort and quit' below for
more information.
abort
-----
abort
abort string
This command behaves like QUIT except that it will attempt
to return to the interactive level if permitted, otherwise
calc exit.
See 'more information about abort and quit' below for
more information.
change current directory
------------------------
cd
cd dir
Change the current directory to 'dir'. If 'dir' is ommitted,
change the current directory to the home directory, if $HOME
is set in the environment.
show information
----------------
show item
This command displays some information where 'item' is
one of the following:
blocks unfreed named blocks
builtin built in functions
config config parameters and values
constants cache of numeric constants
custom custom functions if calc -C was used
errors new error-values created
files open files, file position and sizes
function user-defined functions
globaltypes global variables
objfunctions possible object functions
objtypes defined objects
opcodes func internal opcodes for function `func'
sizes size in octets of calc value types
realglobals numeric global variables
statics unscoped static variables
numbers calc number cache
redcdata REDC data defined
strings calc string cache
literals calc literal cache
Only the first 4 characters of item are examined, so:
show globals
show global
show glob
do the same thing.
calc help
---------
help
help name
This displays a help related to 'name' or general
help of none is given.
=-=
more information about abort and quit
=====================================
Consider the following calc file called myfile.cal:
print "start of myfile.cal";
define q() {quit "quit from q()"; print "end of q()"}
define a() {abort "abort from a()"}
x = 3;
{print "start #1"; if (x > 1) q()} print "after #1";
{print "start #2"; if (x > 1) a()} print "after #2";
{print "start #3"; if (x > 1) quit "quit from 3rd statement"}
print "end of myfile.cal";
The command:
calc read myfile
will produce:
q() defined
a() defined
start statment #1
quit from q()
after statment #1
start statment #2
abort from a()
The QUIT within the q() function prevented the ``end of q()''
statement from being evaluated. This QUIT command caused
control to be returned to just after the place where q()
was called.
Notice that unlike QUIT, the ABORT inside function a() halts
the processing of statements from the input source (myfile.cal).
Because calc was not interactive, ABORT causes calc to exit.
The command:
calc -i read myfile
will produce:
q() defined
a() defined
start statment #1
quit from q()
after statment #1
start statment #2
abort from a()
> <==== calc interactive prompt
because the '-i' calc causes ABORT to drop into an
interactive prompt. However typing a QUIT or ABORT
at the interactive prompt level will always calc to exit,
even when calc is invoked with '-i'.
Also observe that both of these commands:
cat myfile.cal | calc
cat myfile.cal | calc -i
will produce:
q() defined
a() defined
start statment #1
quit from q()
after statment #1
start statment #2
abort from a()
The ABORT inside function a() halts the processing of statements
from the input source (standard input). Because standard input
is not a terminal, using '-i' does not force it to drop into
an interactive prompt.
If one were to type in the contents of myfile.cal interactively,
calc will produce:
> print "start of myfile.cal";
start of myfile.cal
> define q() {quit "quit from q()"; print "end of q()"}
q() defined
> define a() {abort "abort from a()"}
a() defined
> x = 3;
> {print "start #1"; if (x > 1) q()} print "after #1";
start statment #1
quit from q()
after statment #1
> {print "start #2"; if (x > 1) a()} print "after #2";
start statment #2
abort from a()
> {print "start #3"; if (x > 1) quit "quit from 3rd statement"}
start #3
quit from 3rd statement
The ABORT from within the a() function returned control to
the interactive level.
The QUIT (after the if (x > 1) ...) will cause calc to exit
because it was given at the interactive prompt level.
=-=
Also see the help topic:
statement flow control and declaration statements
usage how to invoke the calc command and calc -options
## 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: 29.2 $
## @(#) $Id: command,v 29.2 2000/06/07 14:02:33 chongo Exp $
## @(#) $Source: /usr/local/src/cmd/calc/help/RCS/command,v $
##
## Under source code control: 1991/07/21 04:37:17
## File existed as early as: 1991
##
## chongo <was here> /\oo/\ http://www.isthe.com/chongo/
## Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/
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