Free language lessons software for linux

V language is a tiny concatenative language implemented for experimentation.
The source is under Public Domain (un-copyrighted.)
The full featured language is on top of JVM, A native version (in alpha state) is also there in the codebase.
To run it, extract the distribution in any directory and do #gmake run.
gmake
gmake run
V
|
The language is a close relative of postscript, forth and joy. and is stack based. ie:
|2 3 *
=6
|2 3 * 5 +
=11
See status for a tutorial and more info.
The Functions available in V are available in this page: functions
(The releases are out of date and multiple fixes have gone in. Please check out and build rather than use them.)
Example functions in V. getting the roots (with out using the stack shuffling word view)
[quad-formula
[a b c] let
[minisub 0 b -].
[radical b b * 4 a * c * - sqrt].
[divisor 2 a *].
[root1 minisub radical + divisor /].
[root2 minisub radical - divisor /].
root1 root2
].
|2 4 -30 quad-formula ??
=(-5.0 3.0)
using view
[quad-root
[a b c : [0 b - b b * 4 a * c * - sqrt + 2 a * /]] view i
].
|2 4 -30 quad-root ??
=(3)
contrast this with the definition in scheme here
(define quadratic-formula
(lambda (a b c)
(let ([minusb (- 0 b)]
[radical (sqrt (- (* b b) (* 4 ( * a c))))]
[divisor (* 2 a)] )
let ([root1 (/ (+ minusb radical) divisor)]
[root2 (/ (- minusb radical) divisor)])
(cons root1 root2)))))
Definition of Qsort.
[qsort
#definitions
[joinparts [pivot [*list1] [*list2] : [*list1 pivot *list2]] view].
[split_on_first_element uncons [>] split&].
#args starts for binrec. notice that 2 arguments (termination condition
#and its result) are on first line.
[small?] []
[split_on_first_element]
#binrec recurses on the result of split_on_first_element before applying joinparts.
[joinparts]
binrec].
Some explanations.
The first and second lines (terminated by .) are internal function definitions
(Notice how qsort is also terminated by .) . is the definition syntax in V.
The first function joinparts
============================
The function joinpart contains just an application of the operator view.
view is list translator. It takes a list of the form [template : result]
then it tries to apply the template to the current stack. If it can be applied on the
stack, then the arguments named in the template are bound to values in stack. The result is then processed, and all the bound elements in result are replaced by their values.
[pivot [*list1] [*list2] : [*list1 pivot *list2]] view expects 3 arguments on the stack,
the first a single element pivot, then two lists list1 and list2.
It returns a list that is composed of elements of list1 followed by pivot
followed by elements of list2 (as defined in result - RHS of :).
ie:
44 [1 2 3] [5 6 7] [pivot [*list1] [*list2] : [*list1 pivot *list2]] view ??
=> [1 2 3 44 5 6 7]
(The function ?? is used to print out the elements in the stack now.)
The second function split_on_first_element
==========================================
The definition is [uncons [>] split&]
The uncons splits a list into the first element and the rest of the list.
ie:
[1 2 3 4 5] uncons ??
=1 [2 3 4 5]
split& takes two arguments, the first is the function F to split a list with,
and the second the list itself. All elements in the list that passes the function F
is put into the first list, and all that do not are put into the second list.
ie:
[1 2 3 4 5 6 7] [4 >] split& ??
=[5 6 7] [1 2 3 4]
The function F can also take an argument from the stack. so this also works.
4 [1 2 3 4 5 6 7] [>] split& ??
=[5 6 7] [1 2 3 4]
Thus the split_on_first_element takes the first element of a list, and split that
list based on that element as a filter.
binrec
=======
binrec expects 4 arguments,
Arg1 is the terminating condition,
Arg2 is the result if the terminating condition is met.
Arg3 is an executable statement that returns two entities.
The entire binrec statement is performed on each of the
two entities until the terminating condition is met.
Arg4 is what to do with the result of the previous statement.
Algorithm.
Here, the small? checks if the list is empty or contains just one element.
if it is, then the result is arg2 - []
ie:
[] small? ??
=true
[1] small? ??
=true
[1 2 3 4] small? ??
=false
split_on_first_element takes is executed on all lists that are larger than size 1
and as explained above, splits them into two based on the first element.
on the resultent lists, the entire qsort is performed again due to binrec.
The last joinparts takes these elements (pivot list1 list2) which are present now
on the stack, and combines them to produce a single sorted list.
A slightly friendlier function (with out the binrec.)
[qsort
[joinparts [pivot [*list1] [*list2] : [*list1 pivot *list2]] view].
[split_on_first_element uncons [>] split&].
[small?]
[]
[split_on_first_element [list1 list2 : [list1 qsort list2 qsort joinparts]] view i]
ifte].
The binrec and friends are more powerful than the explicit recursion done above, but for people new to concatenative languages, this kind of recursion may look more intuitive.
Enhancements:
- The language has become relatively stable.
- Lots of bugfixes were made in scope handling.
- Tree operations were added.
- Generic combinators were moved out into a separate library.

Language::Basic::Expression is a Perl package to handle string, numeric, and boolean expressions.

SYNOPSIS

See Language::Basic for the overview of how the Language::Basic module works. This pod page is more technical.
# Given an LB::Token::Group, create an expression I parse it
my $exp = new LB::Expression::Arithmetic $token_group;
# Whats the value of the expression?
print $exp->evaluate;
# Perl equivalent of the BASIC expression
print $exp->output_perl;

Expressions are basically the building blocks of Statements, in that every BASIC statement is made up of keywords (like GOTO, TO, STEP) and expressions. So expressions include not just the standard arithmetic and boolean expressions (like 1 + 2), but also lvalues (scalar variables or arrays), functions, and constants. See Language::Basic::Syntax for details on the way expressions are built.

BASIC expressions are represented by various objects of subclasses of Language::Basic::Expression. Most LB::Expressions are in turn made up of other LB::Expressions. For example an LBE::Arithmetic may be made up of two LBE::Multiplicative and a "plus". "Atoms" (indivisible LBEs) include things like LBE::Constants and LBE::Lvalues (variables).

ADML language is a server-side scripting language with Mysql database suport.

About Apache:

Apache HTTP Server is a free software/open source HTTP web server for Unix-like systems (BSD, Linux, and UNIX systems), Microsoft Windows, Novell NetWare and other platforms. Apache is notable for playing a key role in the initial growth of the World Wide Web, and continues to be the most popular web server in use, serving as the reference platform against which other web servers are designed and judged.

Apache features highly configurable error messages, DBMS-based authentication databases, and content negotiation. It is also supported by several graphical user interfaces (GUIs) which permit easier, more intuitive configuration of the server.
The Apache HTTP Server is developed and maintained by an open community of developers under the auspices of the Apache Software Foundation.

Russian Language Learning is a Java application that helps you to learn Russian using the Leitner system.

Memorizing words and phrases will not only be more efficient, but the system is a joy to use. Each card also has the phrase spoken by a native russian speaker, to help with pronunciation.

The Leitner system is a way of progressively learning words by placing them in stacks. The words you know are placed in stacks seperate from the words that are still troubling you, for more efficient learning.

And there is one other thing about Tanooshka.com language learning. Each set of cards, are the words to a movie, so when youve learned the set of words, you can watch the movie, and understand it! In Russian!

Language::Functional is a Perl module which makes Perl slightly more functional.

SYNOPSIS

use Language::Functional :all;
print The first ten primes are: ,
show(take(10, filter { prime(shift) } integers)), "n";

Perl already contains some functional-like functions, such as map and grep. The purpose of this module is to add other functional-like functions to Perl, such as foldl and foldr, as well as the use of infinite lists.

Think as to how you would express the first ten prime numbers in a simple way in your favourite programming language? So the example in the synopsis is a killer app, if you will (until I think up a better one.

The idea is mostly based on Haskell, from which most of the functions are taken. There are a couple of major omissions: currying and types. Lists (and tuples) are simply Perl list references, none of this cons business, and strings are simple strings, not lists of characters.

The idea is to make Perl slightly more functional, rather than completely replace it. Hence, this slots in very well with whatever else your program may be doing, and is very Perl-ish. Other modules are expected to try a much more functional approach.

The Language Machine is a free software toolkit for language and grammar. It includes a shared library, a main program, and several metalanguage compilers with one frontend. The system is easy to use on its own or as a component.
The Language Machine directly implements unrestricted rule-based grammars with actions and external interfaces. A unique diagram shows rulesets in action.
Main features:
- rules describe how to recognise and transform grammatical input
- the left-side of a rule describes a pattern
- the right-side of a rule describes how the pattern is treated
- the left- and right- sides are unrestricted pattern generators
- the system is a kind of symbolic engine for grammar
- the metalanguage is very simple and very concise
- multiple grammars, rule priorities, left-recursion, right-recursion ...
- variables and associative arrays, a subset of javascript
- transformed representations can include actions and side-effects
- transformed representations can themselves be analysed as input
- can be used as a free-standing engine or as a shared library
- can be packaged together with precompiled rules
- very simple interface to external procedures in C and D languages
- built-in diagnostics with lm-diagram generator
- several self-hosted metalanguage compilers with a single front end
- compiled rules can be wrapped as shell scripts, or as C or D programs
- rules can be compiled to C or D code
- metalanguage source can be treated as wiki text in the Mediawiki format
Enhancements:
- modifications for compatibility with gdc-0.22 and dmd-1.010
- element.d - wrong indices to non-keyword array literal cells
- add src/dmd/Makefile for building with dmd compiler

Language::Zcode::Parser is a Perl module that reads and parses a Z-code file into a big Perl hash.

SYNOPSIS

# Create a Pure Perl Parser
my $pParser = new Language::Zcode::Parser "Perl";

# If they didnt put ".z5" at the end, find it anyway
$infile = $pParser->find_zfile($infile) || exit;

# Read in the file, store it in memory
$pParser->read_memory($infile);

# Parse header of the Z-file
$pParser->parse_header();

# Get the subroutines in the file (LZ::Parser::Routine objects)
my @subs = $pParser->find_subs($infile);

For finding where the subroutines start and end, you can either depend on an external call to txd, a 1992 C program available at ifarchive.org, or a pure Perl version.

Everything else is done in pure Perl.

new (class, how to find subs, args...)

This is a factory method. Called with Perl or TXD (or txd) as arguments, it will create Parsers of LZ::Parser::Perl or LZ::Parser::TXD, which are subclasses of LZ::Parser::Generic.

That class new method will be called with any other passed-in args.