calc - Online in the Cloud

PROGRAM:

NAME

calc - arbitrary precision calculator

SYNOPSIS

calc [-c] [-C] [-d]
[-D calc_debug[:resource_debug[:user_debug]]]
[-e] [-h] [-i] [-m mode] [-O]
[-p] [-q] [-s] [-u] [-v] [[--] calc_cmd ...]

#!/usr/bin/calc [other_flags ...] -f

DESCRIPTION

CALC OPTIONS

-c Continue reading command lines even after a scan/parse error has caused the
abandonment of a line. Note that this option only deals with scanning and parsing
of the calc language. It does not deal with execution or run-time errors.

For example:

calc read many_errors.cal

will cause calc to abort on the first syntax error, whereas:

calc -c read many_errors.cal

will cause calc to try to process each line being read despite the scan/parse
errors that it encounters.

By default, calc startup resource files are silently ignored if not found. This
flag will report missing startup resource files unless -d is also given.

-C Permit the execution of custom builtin functions. Without this flag, calling the
custom() builtin function will simply generate an error.

Use of this flag may cause calc to execute functions that are non-standard and that
are not portable. Custom builtin functions are disabled by default for this
reason.

-d Disable the printing of the opening title. The printing of resource file debug and
informational messages is also disabled as if config("resource_debug", 0) had been
executed.

For example:

calc "read qtime; qtime(2)"

will output something like:

qtime(utc_hr_offset) defined
It's nearly ten past six.

whereas:

calc -d "read qtime; qtime(2)"

will just say:

It's nearly ten past six.

This flag disables the reporting of missing calc startup resource files.

-D calc_debug[:resource_debug[:user_debug]]
Force the initial value of config("calc_debug"), config("resource_debug") and
config("user_debug").

The : separated strings are interpreted as signed 32 bit integers. After an
optional leading sign a leading zero indicates octal conversion, and a leading
``0x'' or ``0X'' hexadecimal conversion. Otherwise, decimal conversion is assumed.

By default, calc_debug is 0, resource_debug is 3 and user_debug is 0.

For more information use the following calc command:

help config

-e Ignore any environment variables on startup. The getenv() builtin will still
return values, however.

-f This flag is required when using calc in shell script mode. It must be at the end
of the initial #! line of the script.

This flag is normally only at the end of a calc shell script. If the first line of
an executable file begins #! followed by the absolute pathname of the calc program
and the flag -f as in:

#!/usr/bin/calc [other_flags ...] -f

the rest of the file will be processed in shell script mode. See SHELL SCRIPT MODE
section of this man page below for details.

The actual form of this flag is:

-f filename

On systems that treat an executable that begins with #! as a script, the path of
the executable is appended by the kernel as the final argument to the exec() system
call. This is why the -f flag at the very end of the #! line.

It is possible use -f filename on the command line:

calc [other_flags ...] -f filename

This will cause calc to process lines in filename in shell script mode.

Use of -f implies -s. In addition, -d and -p are implied if -i is not given.

-h Print a help message. This option implies -q. This is equivalent to the calc
command help help. The help facility is disabled unless the mode is 5 or 7. See
-m.

-i Become interactive if possible. This flag will cause calc to drop into interactive
mode after the calc_cmd arguments on the command line are evaluated. Without this
flag, calc will exit after they are evaluated.

For example:

calc 2+5

will print the value 7 and exit whereas:

calc -i 2+5

will print the value 7 and prompt the user for more calc commands.

-m mode
This flag sets the permission mode of calc. It controls the ability for calc to
open files and execute programs. Mode may be a number from 0 to 7.

The mode value is interpreted in a way similar to that of the chmod(1) octal mode:

0 do not open any file, do not execute progs
1 do not open any file
2 do not open files for reading, do not execute progs
3 do not open files for reading
4 do not open files for writing, do not execute progs
5 do not open files for writing
6 do not execute any program
7 allow everything (default mode)

If one wished to run calc from a privileged user, one might want to use -m 0 in an
effort to make calc somewhat more secure.

Mode bits for reading and writing apply only on an open. Files already open are
not effected. Thus if one wanted to use the -m 0 in an effort to make calc
somewhat more secure, but still wanted to read and write a specific file, one might
want to do in sh(1), ksh(1), bash(1)-like shells:

calc -m 0 3<a.file

Files presented to calc in this way are opened in an unknown mode. Calc will
attempt to read or write them if directed.

If the mode disables opening of files for reading, then the startup resource files
are disabled as if -q was given. The reading of key bindings is also disabled when
the mode disables opening of files for reading.

-O Use the old classic defaults instead of the default configuration. This flag as
the same effect as executing config("all", "oldcfg") at startup time.

NOTE: Older versions of calc used -n to setup a modified form of the default calc
configuration. The -n flag currently does nothing. Use of the -n flag is now
deprecated and may be used for something else in the future.

-p Pipe processing is enabled by use of -p. For example:

calc -p "2^21701-1" | fizzbin

In pipe mode, calc does not prompt, does not print leading tabs and does not print
the initial header. The -p flag overrides -i.

-q Disable the reading of the startup scripts.

-s By default, all calc_cmd args are evaluated and executed. This flag will disable
their evaluation and instead make them available as strings for the argv() builtin
function.

-u Disable buffering of stdin and stdout.

-v Print the calc version number and exit.

-- The double dash indicates to calc that no more options follow. Thus calc will
ignore a later argument on the command line even if it starts with a dash. This is
useful when entering negative values on the command line as in:

calc -p -- -1 - -7

CALC COMMAND LINE

With no calc_cmd arguments, calc operates interactively. If one or more arguments are
given on the command line and -s is NOT given, then calc will read and execute them and
either attempt to go interactive according as the -i flag was present or absent.

If -s is given, calc will not evaluate any calc_cmd arguments but instead make them
available as strings to the argv() builtin function.

Sufficiently simple commands with no characters like parentheses, brackets, semicolons,
'*', which have special interpretations in UNIX shells may be entered, possibly with
spaces, until the terminating newline. For example:

calc 23 + 47

will print 70. However, command lines will have problems:

calc 23 * 47

calc -23 + 47

The first example above fails because the shell interprets the '*' as a file glob. The
second example fails because '-23' is viewed as a calc option (which it is not) and do
calc objects to that it thinks of as an unknown option. These cases can usually be made
to work as expected by enclosing the command between quotes:

calc '23 * 47'

calc "print sqrt(2), exp(1)"

or in parentheses and quotes to avoid leading -'s as in:

calc '(-23 + 47)'

One may also use a double dash to denote that calc options have ended as in:

calc -- -23 + 47

calc -q -- -23 + 47

If '!' is to be used to indicate the factorial function, for shells like csh(1) for which
'!' followed by a non-space character is used for history substitution, it may be
necessary to include a space or use a backslash to escape the special meaning of '!'. For
example, the command:

print 27!^2

may have to be replaced by:

print 27! ^2 or print 27^2

CALC STARTUP FILES

Normally on startup, if the environment variable $CALCRC is undefined and calc is invoked
without the -q flag, or if $CALCRC is defined and calc is invoked with -e, calc looks for
a file "startup" in the calc resource directory .calcrc in the user's home directory, and
.calcinit in the current directory. If one or more of these are found, they are read in
succession as calc scripts and their commands executed. When defined, $CALCRC is to
contain a ':' separated list of names of files, and if calc is then invoked without either
the -q or -e flags, these files are read in succession and their commands executed. No
error condition is produced if a listed file is not found.

If the mode specified by -m disables opening of files for reading, then the reading of
startup files is also disabled as if -q was given.

CALC FILE SEARCH PATH

If the environment variable $CALCPATH is undefined, or if it is defined and calc is
invoked with the -e flag, when a file name not beginning with /, ~ or ./, is specified as
in:

calc read myfile

calc searches in succession:

./myfile
./myfile.cal
/usr/lib/myfile
/usr/lib/myfile.cal
/usr/share/calc/custom/myfile
/usr/share/calc/custom/myfile.cal

If the file is found, the search stops and the commands in the file are executed. It is
an error if no readable file with the specified name is found. An alternative search path
can be specified by defining $CALCPATH in the same way as PATH is defined, as a ':'
separated list of directories, and then invoking calc without the -e flag.

Calc treats all open files, other than stdin, stdout and stderr as files available for
reading and writing. One may present calc with an already open file using sh(1), ksh(1),
bash(1)-like shells is to:

calc 3<open_file 4<open_file2

For more information use the following calc commands:

help help
help overview
help usage
help environment
help config

SHELL SCRIPT MODE

If the first line of an executable file begins #! followed by the absolute pathname of
the calc program and the flag -f as in:

#!/usr/bin/calc [other_flags ...] -f

the rest of the file will be processed in shell script mode. Note that -f must be at the
end of the initial ``#!'' line. Any other optional other_flags must come before the -f.

In shell script mode the contents of the file are read and executed as if they were in a
file being processed by a read command, except that a "command" beginning with '#'
followed by whitespace and ending at the next newline is treated as a comment. Any
optional other_flags will be parsed first followed by the later lines within the script
itself.

In shell script mode, -s is always assumed. In addition, -d and -p are automatically set
if -i is not given.

For example, if the file /tmp/mersenne:

#!/usr/bin/calc -q -f
#
# mersenne - an example of a calc shell script file

/* parse args */
if (argv() != 1) {
fprintf(files(2), "usage: %s exp\n", config("program"));
abort "must give one exponent arg";
}

/* print the mersenne number */
print "2^": argv(0) : "-1 =", 2^eval(argv(0))-1;

is made an executable file by:

chmod +x /tmp/mersenne

then the command line:

/tmp/mersenne 127

will print:

2^127-1 = 170141183460469231731687303715884105727

Note that because -s is assumed in shell script mode and non-dashed args are made
available as strings via the argv() builtin function. Therefore:

2^eval(argv(0))-1

will print the decimal value of 2^n-1 but

2^argv(0)-1

will not.

DATA TYPES

Fundamental builtin data types include integers, real numbers, rational numbers, complex
numbers and strings.

By use of an object, one may define an arbitrarily complex data types. One may define how
such objects behave a wide range of operations such as addition, subtraction,
multiplication, division, negation, squaring, modulus, rounding, exponentiation, equality,
comparison, printing and so on.

For more information use the following calc commands:

help types
help obj
show objfuncs

VARIABLES

Variables in calc are typeless. In other words, the fundamental type of a variable is
determined by its content. Before a variable is assigned a value it has the value of
zero.

The scope of a variable may be global, local to a file, or local to a procedure. Values
may be grouped together in a matrix, or into a list that permits stack and queue style
operations.

For more information use the following calc commands:

help variable
help mat
help list
show globals

INPUT/OUTPUT

A leading ``0x'' implies a hexadecimal value, a leading ``0b'' implies a binary value, and
a ``0'' followed by a digit implies an octal value. Complex numbers are indicated by a
trailing ``i'' such as in ``3+4i''. Strings may be delimited by either a pair of single
or double quotes. By default, calc prints values as if they were floating point numbers.
One may change the default to print values in a number of modes including fractions,
integers and exponentials.

A number of stdio-like file I/O operations are provided. One may open, read, write, seek
and close files. Filenames are subject to `` '' expansion to home directories in a way
similar to that of the Korn or C-Shell.

For example:

~/.calcrc
~chongo/lib/fft_multiply.cal

For more information use the following calc command:

help file

CALC LANGUAGE

The calc language is a C-like language. The language includes commands such as variable
declarations, expressions, tests, labels, loops, file operations, function calls. These
commands are very similar to their counterparts in C.

The language also include a number of commands particular to calc itself. These include
commands such as function definition, help, reading in resource files, dump files to a
file, error notification, configuration control and status.

For more information use the following calc command:

help command
help statement
help expression
help operator
help config

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