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---
format: rst
toc: no
...
==================
Ruby
==================
.. note:: This information is very rough, it's mostly my notes about what is
different about Ruby syntax compared to similar modern interpreted
pan-paradigm languages like Python.
A unique intro to ruby is `"Why's Poignant Guide to Ruby"`__, a web-comic-y
short free online book by why the luck stiff. The more serious reference is
the "pickax" book.
__ http://poignantguide.net/
Blocks
---------
Blocks of code can be passed to functions, making ruby code more of a first
order data type.
Ranges
----------
>>> 2..7 # => 2..7
>>> (2..7).to_a # => [2, 3, 4, 5, 6, 7]
>>> (2...7).to_a # => [2, 3, 4, 5, 6]
>>> ('e'..'h').to_a # => ["e", "f", "g", "h"]
Control Structures
--------------------
Can use ``if`` after a statement::
>>> a = c if c > b
Along with the usual ``break`` and ``next``, there is ``redo`` which redoes
the current loop (initial conditions may have been changed).
Boolean Operators
--------------------
Anything that is not ``nill`` or ``false`` is true. To force interpretation
as boolean, use ``!!`` (not not)::
>>> !!(nil) # => false
>>> !!(true) # => true
>>> !!('') # => true
>>> !!(0) # => true
>>> !!({}) # => true
Misc
----------------
Can use nasty Perl style regular expression stuff::
>>> re1 = /\d+/
>>> "There are 5 kilos of chunky bacon on the table!" =~ re1 # => 10, the index
>>> $~ # => #<MatchData:0xb7c36754>
>>> $~.pre_hash # => "There are "
Also $1, $2, etc.
The "splat operator", '*', either collects or expands extra arguments depending
on syntax (I think this is kind of icky)::
>>> a, b = 1, 2, 3, 4 # a=1, b=2
>>> a, *b = 1, 2, 3, 4 # a=1, b=[2,3,4]
>>> c, d = 5, [6, 7, 8] # c=5, d=[6,7,8]
>>> c, d = 5, *[6, 7, 8] # c=5, b=6
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