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The symbol % represents the last expression obtained by Jacal. It
can be used in formulas like any other constant or variable or
expression.
e21: 5 e22 : %; e22: 5 e23 : %^2; e23: 25
The command batch is used to read in a file containing programs
written in Jacal. Here, filename is a string in double quotes. The
precise way in which one refers to a file is, of course, system
dependent.
batch("demo");
of the file demo in the JACAL directory will give a demonstration of JACAL’s capabilities.
Displays expr in TeX, Jacal’s two-dimensional output format, Jacal’s infix input format, or compressed infix format respectively.
Read TeX expression string.
Read Scheme expression string.
Reads string in Jacal’s infix input format.
e24 : b^2-4*a*c;
2
e24: b - 4 a c
e25 : tex(e24);
b^{2} - 4\,a\,c
e25 : tex("b^{2} - 4\,a\,c");
2
e25: b - 4 a c
e26 : disp2d(e25);
2
b - 4 a c
e26 : disp2d("b^2-4*a*c");
2
e26: b - 4 a c
e27 : scheme(e26);
(- (^ b 2) (* 4 a c))
e27 : scheme("(- (^ b 2) (* 4 a c))");
2
e27: b - 4 a c
The command commands produces a list of all of the command
available in Jacal. It is called as a function of no arguments.
e21 : commands();
% * + - / = ^ ^^ abs args augcoefmatrix b+/- b-/+ batch berl bunch cabs cartprod chain charpoly coeff coeffs coefmatrix cofactor col commands compose content continue crossproduct decompose degree denom depends describe determinant diagmatrix diff differential discriminant disp2d divide dotproduct elementwise eliminate equatecoeffs example extrule factor factorial factors ffsff finv flatten func gcd genmatrix help ident imagpart integrate interp interp.lagrange interp.neville interp.newton jacobi jacobian listofvars load matrix minor mod ncmult negate num or over parallel parfrac partial poly polydiff polyelim prime? qed quit rank rapply realpart require restart resultant row scalarmatrix scheme set sff shadow show standard std sylvester system taylor terms tex transcript transpose u+/- u-/+ usff verify wronski wronskian
The command describe is the heart of the online help facility of
Jacal. Here, command is a string which is the name of a command
and describe produces a brief description of the command and in
many cases includes an example of its use. Together with the command
commands(), which prints a list of all available Jacal commands,
and the command example, which gives an example of the use of the
command, one can in principle use Jacal without a manual after one has
learned how to get started.
e27 : describe(col); column. column of a matrix e27 : describe(resultant); resultant. The result of eliminating a variable between 2 equations (or polynomials). 27 : describe(+); Addition, plus. a + b
Here, command is a string which is the name of a Jacal command.
example gives an example of the use of the command.
See also describe.
e43 : example(+); a + b e43: a + b
The Jacal command load takes as input a string and reads in a
‘Scheme’ file whose name is obtained by appending the extension
.scm to the string. If you want to read in a file of Jacal
commands, do not use load. Instead use the command
batch. To load in the file foo.scm,
e9 : load("foo");
e9: foo
Exit from Jacal to Scheme. With interactive Scheme systems (such as
SCM), It does not return you to the operating system. Instead it
suspends Jacal and returns you to the underlying scheme. You can return
to the Jacal session where you left off by simply typing (math).
If you do not wish to return to Jacal but really want to terminate the
session and return to the operating system, then after typing
qed();, type (slib:exit) or use quit.
Exit directly from Jacal to the operating system. You will not be able to continue your Jacal session.
type qed(); to return to scheme e1 : qed(); scheme > (math) type qed(); to return to scheme e2 : quit(); unix>
One can issue commands to the operating system without leaving Jacal. To
do this, one uses the command system. For example, in a UNIX
operating system, the command system("ls"); will print the
directory. One way in which the command system might be
especially useful is to edit files containing Jacal scripts without
leaving Jacal, particularly in non-UNIX machines or on machines without
GNU emacs.
e0 : system("echo hi there");
hi there
e0: 0
Prints a copy of the GNU General Public License
e1 : terms();
GNU GENERAL PUBLIC LICENSE
Version 3, 29 June 2007
Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
[ rest deleted for brevity]
The command transcript allows one to record a Jacal session. It
is called with the syntax transcript(string);, where
string is the name of the file in which one wants to keep the
transcript of the session. When one wishes to stop recording, one types
transcript();. One is then free to use transcript again
later in the session on another file. One can use it on the same file,
but the file is overwritten. Presently, the command transcript
does not echo commands to a file.
e9 : a:[1,2,3];
e9: [1, 2, 3]
e10 : transcript("foo");
e10: foo
e11 : a;
e11: [1, 2, 3]
e12 : transcript();
e12 : system("cat foo");
e10: foo
e11 : a;
e11: [1, 2, 3]
e12 : transcript();
e12: 0
There are various flags that the Jacal user can control, namely the
Jacal command line prompt, the priority for printing terms in Jacal
output, the input grammar and the output grammar. For a discussion of
the various grammars please See Flags. The command show is
closely related, allowing one to see what the current settings are.
The command show enables the Jacal user to examine the current
setting of various flags as well as to list the flags that can be set by
the user and to display other information. To change the settings of the
flags, use the command set. To see all the information accessible
through the show command, type show all. To see the
available grammars, type show grammars. To see the current input
grammar type show ingrammar. To see the current output grammar,
type show outgrammar. To see the current priority for printing
expressions, type show priority.
e1 : show all;
all debug echogrammar grammars horner ingrammar linkradicals outgrammar page phases priority prompt trace version width
e1 : show prompt;
e1: e1
e3 : show priority;
:@ (differential :@) @3 @2 @1 y x wronskian wronski verify u-/+ u+/- transpose transcript tex terms t system sylvester standard show shadow set scheme scalarmatrix row resultant restart require realpart rapply rank quit qed prompt priority prime? polyelim polydiff poly partial parallel over or num negate ncmult mod minor matrix load listofvars jacobian jacobi interp.newton interp.neville interp.lagrange interp imagpart ident help genmatrix gcd func flatten finv factors factorial factor extrule example equatecoeffs eliminate elementwise e0 dotproduct divide disp2d discriminant differential diff diagmatrix determinant describe depends denom degree crossproduct continue content commands col cofactor coefmatrix coeffs coeff charpoly chain cartprod cabs c bunch batch b-/+ b+/- b augcoefmatrix args all abs a ^^ ^ ? = ::@ / - + * % %sqrt1 %i
e3 : show outgrammar;
e3: disp2d
e4 : show ingrammar;
e4: standard
e5 : show grammars;
e5: [scheme, null, schemepretty, standard, disp2d, tex]
Next: Flags, Previous: Lambda Calculus, Up: JACAL [Contents][Index]