Tutorial Examples
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Tutorial Examples |
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If we run the Lua executable without parameters we get the following message and a > command prompt.
Lua 5.0 Copyright (C) 1994-2003 Tecgraf, PUC-Rio >
All of the examples in the tutorial are typed at the command prompt > and the output copied and pasted into the wiki.
> print("hello Lua user")
hello Lua user
> print(10*10)
100
If a line begins with an = Lua evaluates the line as an expression. Its shorthand for having to use the print() function.
> = "hello Lua user" hello Lua user > = 10*10 100
We can enter commands over multiple lines if necessary. Lua will try and evaluate what you typed on a given line and assess whether the command is complete. If it is not considered complete a double command prompt appears >> so you can continue typing. E.g.,
> print( >> "Hello lua user" >> ) Hello lua user
print( statement is incomplete as the matching closing bracket is missing. The Lua command line assumes that you have more to type so the >> prompt is displayed. This continues until the statement is deemed complete. If you made a mistake you will get an error. This also works for the evaluation shorthand:
> = 10 * >> 10 + >> 5 105
Where you see "--", followed by text, this is a comment. Everything after the -- is ignored by the Lua compiler on that line.
> = 1+1 -- this is ignored 2 > = 1+1 no comment stdin:1: <eof> expected near `no'
Note: You do not have to type the comments in! They are just comments about what is happening for clarity.