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On 28.07.2016 20:37, Tim Hill wrote:
On 28.07.2016 13:37, Dirk
Laurie wrote:
2016-07-28 12:47 GMT+02:00 Thomas Jericke <tjericke@indel.ch>:
From the top of my head this is the most
explicit statement.
"Lua supports coroutines, also called collaborative multithreading. A
coroutine in Lua represents an independent thread of
execution. Unlike threads in multithread systems,
however, a coroutine only suspends its execution by
explicitly calling a yield function."
As you see in my example (that you cut from the quote),
there is no yield in it. So the programmer rightfully can
expect that the function is run uninterrupted.
—
Come now. As an imperative language, it is safe to assume
that Lua will execute statements in the order listed. That is:
a; b
c
Will execute in the order a, b, c with each statement
completed before the next begins. However, the order of
execution within a statements is explicitly not
guaranteed:
a = b() + c()
Could call b() first or c() first. Similarly, table
constructor expressions may be evaluated in any order (as can an
_expression_ list). There are good reasons for not specifying this
order, as on some architectures it is easier to do things in one
order rather than another.
Specifying that ‘#’ assignments are special just makes things
messier:
a = {1, #, 2, 3}
I don’t think many people would intuitively expect # to be 3
in this case.
—Tim
Totally agree. But while I was trying to sleep I found out that the
order of execution doesn't matter at all for the simple list
constructor style like { 1, #, 2, 3}.
Why? Because the value of # is already known at compile time, and
the parser therefore can easily compute the length of the array
already.
This is of course not true for the statement { [a] = 1, [b] = 2, [#]
= # }, here you have no chance to calculate the array length at
compile time unless
you are really, really sure what the values of a and b are at
runtime. (So never if you consider the debug library).
Anyway I am currently think {(1, 2, 3)} is the more intuitive array
constructor syntax. This because (1, 2, 3) is already the syntax for
an argument list.
To me {(1, 2, 3)} reads like: I have this list here that you should
back me into a table please.
--
Thomas
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