Lazy evaluations library
========================

Introduction
------------
The purpose of this library is to provide easy way to use lazy evaluated
variables. This library provide ability to use lazy evaluated variables as
they were regular variables of any type.

Please, note, that this library was intended to be C++0x compliant, not
C++03 or C++98.

Rationale
---------
This library provides ability to calculate value only if it is required in
calculations. I.e. you declare variable, specify how it should be calculated
and stop worry about excessive calculations if this value isn't required, e.g.
when class member is not accessed.

Overview
--------
The only thing you need to use lazy evaluating variables is to include
`lazy.hpp` file. After that you can simply declare lazy variables like this:

    TLazy<int> five([](){ return 2 + 3; });
    TLazy<double> root([](){ return sqrt(3); });
    TLazy<double> sum([&five, &root](){ return five + root; });
    std::cout << sum << std::endl;  // no calculations performed until
                                    // execution reach this line

Value for variable is being calculated when you refers to it first time, but
no calculations performed if you just copy the whole lazy variable. This let
you declare lazy variables as class members and copy class object without
calculating values you're not using.

Installation
------------
You require bjam (a.k.a. boost build) to install this package.
In order to launch sanity test you need Boost.Test to be installed.

  * In order to install, execute bjam with argument
    `dist --includedir=<prefix>`, where `<prefix>` is the installation path
    where library will be installed. More precisely, `reinvented-wheels`
    subfolder will be created, containing all required headers.
  * In order to launch the test, execute bjam with `-d0 test` argument and
    ensure that return code was 0.