Home Accessibility Courses Twitter The Mouth Facebook Resources Site Map About Us Contact
 
Python, Lua, Tcl, C and C++ training - public course schedule [here]
Private courses on your site - see [here]
Please ask about maintenance training for Perl, PHP, Java, Ruby, MySQL and Linux / Tomcat systems
 
Dot or Colon separator between table name and member in Lua - what is the difference?

When do I use a dot and when do I use a colon in referencing a table member in Lua? It's a good question and one that we answer (and demonstrate to help make clear) on our Lua Programming Course.

Dot refers to a table member. So if I write
  source.read()
I am saying "run the read function in the table called source". Perhaps that's all I want to do, but it's more likely that the read funiction needs to refer to other things in that same table, so it needs to be passed in as a parameter - so
  source.read(source)
and that works perfectly well. But it looks clumsy, and it means the table name has to be entered twice into the code. So that can be rewritten as
  source:read()

Coded example [here]. Lua course run by us here.
(written 2014-05-06)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
U105 - Lua - Tables and the table library.
  [4571] Lua - using modules to add your own utilities - (2015-11-04)
  [4248] Metatables, Metamethods, classes and objects in Lua - (2014-03-18)
  [3725] Lua Tables - (2012-05-10)
  [3694] Special __ methods you can use in Lua metatables - (2012-04-12)
  [2703] Lua Metatables - (2010-04-02)
  [2699] Lua tables - they are everything - (2010-03-30)
  [2499] ourdog is Greyhound, Staffie and Ginger Cake - (2009-11-09)
  [2346] The indexed and hashed parts of a Lua table - (2009-08-10)
  [1742] Lua - Table elements v table as a whole - (2008-08-07)
  [1697] Sorting in lua - specifying your own sort routine - (2008-07-05)

U107 - Object Orientation - the Lua way
  [4753] Lua, Tcl, Python, C and C++ courses - at our Melksham HQ or on your site - forward from July 2017 - (2017-07-02)
  [4573] Classic style OO code - in Lua - (2015-11-05)
  [4572] Tables with values and code in Lua - looks like an object? - (2015-11-05)
  [4117] Is Lua an Object Oriented language? - (2013-06-15)
  [3730] What is a metatable? How do I set one up? How do I use them? Lua - (2012-05-12)
  [3727] Using Lua tables as objects - (2012-05-11)
  [3683] Weak references in Lua - what are they, and why use them? - (2012-04-04)
  [3524] Metaclasses (Python) and Metatables (Lua) - (2011-11-17)
  [3396] Tables as Objects in Lua - a gentle introduction to data driven programming - (2011-08-17)
  [3142] Private and Public - and things between - (2011-01-22)
  [2710] __index and __newindex in Lua - metatable methods - (2010-04-05)
  [2701] Is Lua an Object Oriented language? - (2010-04-01)
  [2455] Lua examples - coroutines, error handling, objects, etc - (2009-10-15)
  [2359] A fresh example - objects the Lua way - (2009-08-13)
  [2318] For Lua Programmers AND for Town Planners - (2009-08-02)
  [1819] Calling base class constructors - (2008-10-03)
  [1743] First class functions in Lua lead to powerful OO facilities - (2008-08-07)
  [1699] If you are learning Lua, here are some more examples - (2008-07-06)
  [1692] Towards Object Oriented Programming in Lua - (2008-06-30)


Back to
Lazy operators in Lua - what they mean, and examples
Previous and next
or
Horse's mouth home
Forward to
String formatting in Lua - string.format as a wrapper for sprintf
Some other Articles
Sending a message to the server and changing text on a page when a button is pressed
Swindon to Weymouth - by train, the traditional way - 2014
Eurpoean Elections, and other elections ahead. Some thoughts on campaigns and policies
String formatting in Lua - string.format as a wrapper for sprintf
Dot or Colon separator between table name and member in Lua - what is the difference?
Lazy operators in Lua - what they mean, and examples
Line, block and nested comments - Lua compared to other languages
Embedding Lua to perform tailored code at an interval
Survey - Journeys
Metrics - historic and current TransWilts train use
4754 posts, page by page
Link to page ... 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96 at 50 posts per page


This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

Link to Ezine home page (for reading).
Link to Blogging home page (to add comments).

You can Add a comment or ranking to this page

© WELL HOUSE CONSULTANTS LTD., 2017: 404 The Spa • Melksham, Wiltshire • United Kingdom • SN12 6QL
PH: 01144 1225 708225 • EMAIL: info@wellho.net • WEB: http://www.wellho.net • SKYPE: wellho

PAGE: http://www.wellho.net/mouth/4273_Dot ... ence-.html • PAGE BUILT: Sat May 27 16:49:10 2017 • BUILD SYSTEM: WomanWithCat