lua-users home
lua-l archive

[Date Prev][Date Next][Thread Prev][Thread Next] [Date Index] [Thread Index]

I am trying to understand how to use properly the t:f() syntax, and how it is 
useful, mostly looking at other people code. Unfortunately still scarse on the 
while rereading the Lua 4.0 manua, I have meet a potential discrepancy:

In section 3, you say "The form t:f(x) is syntactic sugar for t.f(t,x), which 
calls the method f from the table t passing the table itself as the first 
parameter (see Section 4.5.9).".

In section 4.5.9, you say "The statement function v:f (...) ... end is just 
syntactic sugar for v.f = function (self, ...) ... end
Note that the function gets an extra formal parameter called self."

Perhaps it is intended, but I find it a bit confusing...
It seems that t is available as global variable in f, anyway.
So I bet it is the section 4.5.9 which is correct.

Also the status of "self" and "arg" variables are a bit ambiguous. They are 
not reserved words, nor internal variables (as defined in section 4.1) because 
they have no underscore prefix, nor capital names. I suppose they are actually 
local variables.
What I am trying to explain is... Well, I am not sure. Perhaps you should 
stress out the fact that they are special, eg. in the 4.1 section, where you 
give some conventions.

the only internal variables, or are there others? Most of them are defined in 
libraries, can we create our internal variables in our libraries, using the 
same convention? Any risk of conflict?

Sorry for the dumb questions, I am still learning, and certainly on a par with 
the gentlemen discuting coroutines or OO...



Philippe Lhoste (Paris -- France)
Professional programmer and amateur artist