Hi
I wondered today about function calls in lua and there
exist function calls that
don't require round brackets, i.e.
require "modulex"
or
dothis {1,2,3}
What I wanted to do today is to figure out how a table
could provide a
polymorphic function call. So I wanted to construct a
table which is a
collection of multiple functions that are each called
depending on the passed
arguments. Well, it's more theory than practical, but I
wondered how to
implement such a system in lua ;).
So I thought about this
foo = polymorphic()
foo:define(function () print "no arg" end)
foo:define("number",function (num) print("number:",num)
end)
foo:define("string","number",function (str,num)
print("str,num:",str,num) end)
foo() -- "no arg"
foo(1) -- "number: 1"
foo("blah",1) -- "str,num: blah 1"
So that's the idea and it should work that way, however
I wondered if I could
leave the brackets away when defining the functions,
which could look this
way:
foo:define
function ()
print "no arg"
end
foo:define "string" "number"
function (str,num)
print("str,num:",str,num)
end
Compared with the currently required syntax, it's a
little bit more beautiful.
For example
foo:define "string" "number" ( -- opener must be here
function (str,num)
print("str,num:",str,num)
end)
I wonder now if the brackets could be left away without
confusing the compiler,
just like it is the case with strings.
Since it's a anonymous function declaration, the
compiler is right now aware
about the fact that something must be done with it -
just like a string causes
either a call or is assigned to a variable.
So could this be a language feature or would it not work
(due to something that
I am right now not aware of) or would it be too
confusing?
Eike
