Zhichu Chen wrote:
> Hi,
>
> I'm learning to use luatex these days, one day actually. It's very
> interesting. Although reference manuals are available, I still don't
> know how to implement my designation.
>
> The thing is, I know there's a "self" variable for object-oriented
> programming, like
> ==================================================================
> \startluacode
> testdata = { a = 0,
> b = 0,
> c = 0,
> plus = function (self)
> self.c = self.a + self.b
> end
> }
> mytest = testdata
> mytest.a=10
> mytest.b=100
> mytest:plus()
> tex.print(mytest.c)
> \stopluacode
> ==================================================================
> OK, but what if I wanna do something more, like substract? I would
> like to use another object, like
> ==================================================================
> \startluacode
> testdata = { a = 0,
> b = 0,
> c = 0,
> calc = Calc
> }
> Calc = { plus = function (self)
> self.c = self.a + self.b
> end,
> substract = function (self)
> self.c = self.a - self.b
> end
> }
> mytest = testdata
> mytest.a=10
> mytest.b=100
> mytest.calc:plus()
> tex.print(mytest.c)
> \stopluacode
> ==================================================================
> Of course this won't work, for the "self" in Calc refers to mytest.calc
> rather than mytest. How to implement things like that?
Calc = { add = function (self)
self.c = self.a + self.b
end,
substract = function (self)
self.c = self.a - self.b
end
}
testdata = { a = 0,
b = 0,
c = 0,
calc = function(self,f) return Calc[f](self) end
}
mytest = testdata
mytest.a=10
mytest.b=100
Calc.add(testdata)
print(mytest.c)
testdata:calc("substract")
print(mytest.c)
but it might make more sense to look into metatables (i assume that you
own the programming in lua book which explains that)
Hans
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