NAME¶
intercalc - CLC-INTERCAL desk calculator
SYNOPSIS¶
intercalc [options]
DESCRIPTION¶
intercalc is a simple desk calculator, allowing the user to enter
INTERCAL statements (to see what they do) and expressions (to see what value
they produce); it uses an interpreter object from CLC-INTERCAL to provide
immediate feedback.
The desk calculator accepts several options, some of which are documented here.
User Interface Options
- -X / --graphic
- Enters X-based graphical user interface. Requires Perl-GTK.
This is the default if Perl-GTK is installed, the environment variable
$DISPLAY is set and the opening of the X display succeeds.
- -c / --curses
- Enters full screen, curses-based interface. This is the
default if the X based interface cannot be started, the environment
variable $TERM is set and the terminal name is known.
- --line
- Enters the line-mode user interface. This is the default if
the X based and the curses based interfaces do not work.
In this mode, the program executes each line from standard input according
to the current mode and language, and prints results to standard output. A
line starting with a backspark is interpreted as a command to the
calculator. Use backspark-g to GIVE UP (you'll need to do it twice), or
backspark-h to display the ehm, help page. Things which are available via
menu entries on the Curses and X interfaces are also available via the
backspark. For now, you can refer to the source code for a list.
Command-line editing and command history is provided by the readline
library. Command completion works if the underlying compiler supports it
(the compilers provided with the distributions do).
- --batch
- Avoids entering interactive mode. This is the default if
the standard input and output are not connected to a terminal and the X
based interface cannot be started. This mode is very similar to the line
mode except that command-line editing and command history are not
implemented. Backspark escapes work just the same.
- -itype / --interface=type
- Selects the user interface type. Currently, only
X, Curses, Line and None are defined, but more
can be installed as compiler plug-ins. If the interface selected is
None, intercalc will work in batch mode. In addition, an
empty string will reinstate the default behaviour.
Source language and compilation options
- --bug=number
- Selects a different probability for the compiler bug. The
compiler bug is implemented by initialising the compiler's state with the
required probability: when a statement is compiled (usually at runtime), a
"BUG" instruction is emitted with the required probability. The
default is 1%.
- --ubug=number
- Selects a probability for the unexplainable compiler bug.
This is the compiler bug which occurs when the probability of a
(explainable) compiler bug is zero. Only wimps would use this option. The
default is 0.01%.
- -Ipath / --include=path
- Adds a directory before the standard search path for
compiler objects and source code. If a file is accessible from the current
directory, it is never searched in any include path.
If this option is repeated, the given paths will be searched in the order
given, followed by the standard paths.
- -llanguage /
--language=language
- Selects the language to use when interpreting user input.
This should correspond to the name of a compiler, which is an INTERCAL
object which was originally built by iacc. Only the expression and
statement parsers are used, so it is possible to test incomplete compilers
by loading them into intercalc even if they don't work with
sick. The default is obtained from the sickrc option
.INTERCALC.LANGUAGE.
- --ooption ---option=option
- Adds a language option. For example, --o3
selects base 3 calculation, and - -owimp selects wimp mode.
If no options are provided, and the default language was taken from the
sickrc file, the default options are taken from the sickrc
file. Note that if an option or a language is specified on the command
line, the sickrc defaults are ignored.
Unlike previous versions of intercalc, this version checks that the
options make sense in the context of the calculator; for example trying to
load a compiler as an option will cause an error, but a compiler extension
will be OK.
- -mmode / --mode=mode
- Select operation mode. Currently, the only valid modes are
full, expr and one. See "Operating Modes".
If this is not specified, the default is taken from the sickrc
option ..INTERCALC.MODE.
Misc Options
- -rname / --rcfile=name
- Executes commands from file name before starting to
accept input. This option can be repeated, to execute more than one file.
If it is not specified, the standard library, the current directory, and
the current user's home directory are searched for files with name
system.sickrc or .sickrc, which are then executed. The order
for this search is: specified library ( --include), system library,
home directory, current directory. This is different from the search order
used when looking for objects or source code. If a directory contains both
.sickrc and system.sickrc, the system.sickrc is
executed first, followed by .sickrc. Also note that if the current
directory or the home directory appear in the search path and contain one
of these files, they will be executed twice.
If filenames are explicitely specified, they must be fully qualified: the
search path is not used to find them.
- --nouserrc
- Prevents loading a user rcfile (.sickrc); also limits
loading of system.sickrc to the first one found. This option is normally
only used when testing the installation, to prevent interference from
previous versions of CLC-INTERCAL.
Operating Modes¶
The calculator can operate in the following modes:
- full Fully functional INTERCAL interpreter.
- The calculator can parse and execute any statement or
expression.
Statements are compiled as a one-statement program, and executed; any
register value etc. will be preserved between statements, so entering a
list of statements is equivalent to running a program in which all these
statements are executed in sequence.
It is important to note that some statements will not execute in the normal
manner. For example, a COME FROM will be parsed but have no effect, unless
it is something like:
(1) PLEASE COME FROM (1)
which causes the calculator to hang. On the other hand, an ABSTAIN FROM or a
REINSTATE will work as expected, as will CREATE and DESTROY. A GIVE UP
does not cause the calculator to terminate. One final difference is that
comments are not parsed, and therefore you get a "Syntax Error"
from the calculator rather than a splat *000 from the INTERCAL
interpreter.
For expressions, the calculator READs OUT the expression's result. Any side
effects will be remembered, so if the expression contains overloads they
will remain to haunt the calculator.
- expr INTERCAL expression interpreter
- The calculator can only parse expressions or assignments.
In either case, the calculated values are READ OUT; assignments will also
store the value to the destination, while expressions will then discard
the result.
- oic The One Instruction
Calculator.
- This is something we've made up one early morning while
discussing desk calculators (as one does). It is not INTERCAL at all, in
fact it is inspired from the One Instruction Set Computer.
The calculator has a number of memories (default 100 - these can be changed
by appending a number to the operating mode, for example oic10 will
use a 10-memory calculator). These memories are identified by the letter
m followed by a number; in the default 100-memory version, the
first two digits after m are the memory, and any subsequent digit
forms part of the next operand. At the start, all memories are initialised
to 0.
Since there is only one operation, there is no need to specify it, so an
"operation" is a sequence of three operands and a result. The
result must be a memory, while each operand can be a number or a memory,
with the limitation that consecutive numbers are acceptable only if the
parser can determine where one ends and the next one starts. So for
example "1-0" is two numeric operands, 1 and -0 (aka 0);
"1.2.3" is also two operands, 1.2 and 3; "12" is a
single operand, even if you intended it to be two operands, 1 and 2, and
even if you put spaces: "1 2" is still interpreted as the single
operand 12.
The operation performed is the difference between the first two operands,
divided by the third. For example, the three operations:
7 m01 2 M01
1 m02 1 m02
m1 .5 m2 m03
will produce results m01=3.5 ((7-0)/2); m02=1 ((1-0)/1); m03=3 ((3.5-.5)/1).
and will produce the following output if the calculator is running in
batch mode:
m01 3.5 (7 - m01) / 2
m02 1 (1 - m02) / 1
m03 3 (m01 - .5) / m02
SEE ALSO¶
The INTERCAL on-line documentation, by running
intercalc and finding the
"help" menu or key (X and Curses) or backspark escape (Line and
None).