.. -*- mode: rst -*-
.. -*-  coding: utf-8 -*-

.. default-role:: code

.. contents::

===========
Compilation
===========

licht requires ocaml >= 4.03 and ncurses


.. code-block:: console

  # sudo aptitude install opam libncures-dev libiconv-dev
  $ opam install ocamlbuild curses camlzip ezxmlm ounit text menhir calendar
  $ make

Tester avec un encoding non UTF_8
=================================


Lancement du terminal avec l'encoding

.. code-block:: console

    LANG=fr_FR.iso8859-1 xterm -en iso8859-1


Définir l'encoding suivant :

.. code-block:: console

    export LC_ALL=fr_FR.iso8859-1

Pour la définir avec rxvt :

.. code-block:: console

    export LC_CTYPE=fr_FR.ISO8859-1
    export LANG=fr_FR.iso8859-1
    printf "\33]701;$LC_CTYPE\007"

=====
Usage
=====

Modes
=====

You can switch between differents mode :

Normal mode
-----------

Allow edition and sheet modification

======= ===========================
Key     Action
======= ===========================
**v**   switch to `selection mode`_
**:**   Insert commands_
**/**   Search for a value
**e**   edit a cell content (`edition mode`_)
**=**   insert a formula (`edition mode`_)
**y**   yank a cell
**p**   paste a cell
**DEL** delete a cell
**u**   undo the last action
======= ===========================

Commands
--------

You can insert commands with the key `:` in `Normal mode`_

=================== ======================================
Command             Action
=================== ======================================
**:enew**           Start a new spreadsheet
**:w** *filename*   Save the file with the given name
**:q**              Quit the spreadsheet. (No confirmation will be asked if the
                    spreadsheet has been modified)
=================== ======================================

Selection mode
--------------

In this mode, you can select and apply action to many cells. You can use arrow
keys to extend the selection in any direction.

========= =========================
Key       Action
========= =========================
**ESC**   go back to `normal mode`_
**y**     yank the selection
**DEL**   delete the selection
========= =========================

Edition mode
------------

Use the arrows to insert a reference to an other cell.

Data types
==========

String
------

Any value wich does not match the following types is considered as a string.

You can enter a string in formula by enclosing it with a `"` (`="this a \"quote"`).

Numeric
-------

Any numeric value can be written directly : `123`, `-.43`.

Date
----

Date are represented with this format `YYYY/MM/DD`. Any operation that can
apply to Numeric can also by applied to Date.

Bool
----

This type cannot be created directly. You can instead use the function `true()`
and `false()` or comparaison operator.

References
----------

You can reference cells in the formulas

Reference to a single cell
~~~~~~~~~~~~~~~~~~~~~~~~~~

You can reference a cell by naming it (`A1`, `B22`).

The value for a reference to a single cell is the value of the pointed cell.
(In case of cycle between differents cell the result is unspecified but it is
garanted to not loop.)

Range
~~~~~

Yan can reference a range by naming the two bounds (`C6:A1`). The value is
typed as a List.

Undefined
~~~~~~~~~

If a reference point to an an empty cell, the content will be interpreted as Undefined


Formulas
========

You can enter a formula by starting the value with `=`. The evaluation always
expands the reference to other cells.

Licht is provided with built-in functions.

Generic comparaison
-------------------

Thoses function can be applied to any value, they will never raise error

=============== ===============================
Function        Value
=============== ===============================
*x* `=` *y*     True if *x* equals *y*
*x* `<>` *y*    True if *x* does not equals *y*
=============== ===============================

Boolean
-------

=============== ===============================
Function        Value
=============== ===============================
`true()`        True
`false()`       False
`not(Bool)`     True  if the parameter is False,
                False if the parameter is True
=============== ===============================

Numeric
-------

In numeric functions, Undefined_ value are considered as `O`

=================== =====================================
Function            Value
=================== =====================================
`sum(Numeric List)` Compute the sum of the list.
*x* `+` *y*         Add two values
*x* `**` *y*        Compute *x* ^ *y*
=================== =====================================