Veeyu Primer
============

This documentation is an introduction to the Veeyu programming language
for programmers.


Strings
-------

``<string>`` objects have several useful methods and properties:

.. sourcecode:: text

   >>> "hello"
   "hello"
   >>> s := 'Veeyu language'
   "Veeyu language"
   >>> s.split(" ")
   ["Veeyu", "language"]
   >>> "hello, " ++ "world!"
   "hello, world!"
   >>> "abc"[0]
   c"a"
   >>> "veeyu".make-uppercase()
   "VEEYU"
   >>> "hello world"[2 ~ 7]
   "llo w"
   >>> "veeyu" as <list>
   [c"v", c"e", c"e", c"y", c"u"]


Literals
^^^^^^^^

There are four types of string literals:

**string** e.g. ``"like this"``
    This is the most commonly used string literal. It accepts C-style
    metacharacters like ``\n``, ``\r``, ``\t`` and Python-style metacharacters
    that represents unicode codepoints like ``\xff``, ``\uffff``,
    ``\Uffffffff``.

    .. seealso:: :ref:`veeyu-string-metacharacter`

**Raw string** e.g. ``'like this'``
    This is a raw string literal that doesn't take any metacharacters except
    ``\'``. For example, ``'\'this\'\ncode\\'`` equals to
    ``"'this'\\ncode\\\\"``.

**Multiline string** e.g. ``"""like this"""``

    .. seealso:: :ref:`veeyu-string-metacharacter`

**Multiline raw string** e.g. ``'''like this'''``


.. _veeyu-string-metacharacter:

Metacharacters
^^^^^^^^^^^^^^

================= =================================================
Escaping Sequence Meaning
================= =================================================
``\\``            Backslash (``\``)
``\'``            Single quote (``'``)
``\"``            Double quote (``"``)
``\a``            ASCII Bell (BEL)
``\b``            ASCII Backspace (BS)
``\f``            ASCII Formfeed (FF)
``\n``            ASCII Linefeed (LF)
``\r``            ASCII Carriage Return (CR)
``\t``            ASCII Horizontal Tab (TAB)
``\uxxxx``        Unicode character with 16-bit hex value `xxxx`
``\Uxxxxxxxx``    Unicode character with 32-bit hex value `xxxxxxxx`
``\v``            ASCII Vertical Tab (VT)
``\xhh``          Unicode character with hex value `hh`
================= =================================================


Numbers
-------

.. sourcecode:: text

   >>> 1 + 2 + 3
   6

There are some numeric types according to standards:

- ``<number>``

  - ``<integer>``
  - ``<decimal>``

Implementations may add some subclasses for numeric types for performance 
optimization or ease of implementation, so Comedy implements ``<int>`` and
``<long>`` classes that have the common superclass ``<integer>`` and match to
Python's :class:`int` and :class:`long` classes.

- ``<number>``

  - ``<integer>``

    - ``<long>``
    - ``<int>``

  - ``<decimal>``

.. sourcecode:: text

   >>> 1.class
   <int>
   >>> 999999999999999999.class
   <long>
   >>> 1 isa? <integer>
   true
   >>> 999999999999999999 isa? <integer>
   true