Home Accessibility Courses Diary The Mouth Forum Resources Site Map About Us Contact
Dynamic code loading
Functions. example from a Well House Consultants training course
More on Functions. [link]

This example is described in the following article(s):
   • Lua examples - coroutines, error handling, objects, etc - [link]

Source code: fcv Module: U106
--[[

Because functions are "first class variables" in Lua and share the
same name space, you can dynamically load and assign them. In this
example, we've re-used a variable called john that contained a number
to contain a function, given it another name called jane are then
assigned a string to john !!!

It's very much a demonstration in this case - I would NOT normally
replace a piece of code with an integer or string (or vice versa) but
the reassignment of a function IS useful. It means that standard code
can be provided by a vendor who embeds lua, but then the knowledgable
user can override it. A very powerful facility ...

]]


io.write ("How old? ")
john = tonumber(io.read())

print (john)

if john > 30 then
function john()
        return 42
        end
else
function john()
        return 22
        end
end

jane = john

john = "A person"

print (jane())
Learn about this subject
This module and example are covered on the following public courses:
 * Learning to program in Lua
 * Lua Programming
Also available on on site courses for larger groups

Books covering this topic
Yes. We have over 700 books in our library. Books covering Lua are listed here and when you've selected a relevant book we'll link you on to Amazon to order.

Other Examples
This example comes from our "Functions." training module. You'll find a description of the topic and some other closely related examples on the "Functions." module index page.

Full description of the source code
You can learn more about this example on the training courses listed on this page, on which you'll be given a full set of training notes.

Many other training modules are available for download (for limited use) from our download centre or under an Open Training Notes License from our sister site http://www.training-notes.co.uk.

Other resources
• Our Solutions centre provides a number of longer technical articles.
• Our Opentalk forum archive provides a question and answer centre.
The Horse's mouth provides a daily tip or thought.
• Further resources are available via the resources centre.
• All of these resources can be searched through through our search engine
• And there's a global index here.

Web site author
This web site is written and maintained by Well House Consultants.

Purpose of this website
This is a sample program, class demonstration or answer from a training course. It's main purpose is to provide an after-course service to customers who have attended our public private or on site courses, but the examples are made generally available under conditions described below.

Conditions of use
Past attendees on our training courses are welcome to use individual examples in the course of their programming, but must check the examples they use to ensure that they are suitable for their job. Remember that some of our examples show you how not to do things - check in your notes. Well House Consultants take no responsibility for the suitability of these example programs to customer's needs.

This program is copyright Well House Consultants Ltd. You are forbidden from using it for running your own training courses without our prior written permission. See our page on courseware provision for more details.

Any of our images within this code may NOT be reused on a public URL without our prior permission. For Bona Fide personal use, we will often grant you permission provided that you provide a link back. Commercial use on a website will incur a license fee for each image used - details on request.

You can Add a comment or ranking to this page

© WELL HOUSE CONSULTANTS LTD., 2014: Well House Manor • 48 Spa Road • Melksham, Wiltshire • United Kingdom • SN12 7NY
PH: 01144 1225 708225 • FAX: 01144 1225 899360 • EMAIL: info@wellho.net • WEB: http://www.wellho.net • SKYPE: wellho

PAGE: http://www.wellho.net/resources/ex.php4 • PAGE BUILT: Sat Apr 13 08:12:34 2013 • BUILD SYSTEM: wizard