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- Subject: function calls without brackets
- From: Eike Decker <eike@...>
- Date: Thu, 5 Jun 2008 11:11:13 +0200
I wondered today about function calls in lua and there exist function calls that
don't require round brackets, i.e.
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
print "no arg"
foo:define "string" "number"
Compared with the currently required syntax, it's a little bit more beautiful.
foo:define "string" "number" ( -- opener must be here
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?