Why macros don't accept parameter types?

[Justin]

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Macro test(a.l)
	a+1
EndMacro

is a bit confusing, specially if you pass structures

[thefool]

Well since the macro basically just puts the text you write in the code, it would be weird to let it have different types. This is one of the great things about macro's

[Dare2]

Hi Justin,

My take:

Macros are not procedures/functions/etc. They are code blocks that PureBasic "copies" and "pastes" into place when it encounters the macro name elsewhere in the code.

The "parameters" in the macros are placemarkers that are further replaced by the parameters encountered where the macro is used.

Everything is text.

So:

Code: Select all

Macro AddOne(a)
   a+1
EndMacro

Is really saying to PureBasic: When you see "AddOne" in the code, then:

• Replace it with "a + 1"

Further, where you see "a" in the macro,

• Replace it with the "parameter" value supplied by the macro placemarker.

Manually done, we would copy some code, paste it elsewhere, change a few bits.

So in code:

Any "AddOne(z)" becomes "z+1". It is like an automatic copy/paste with bells on. It saves retyping repetitive code, and gives the macro name a temporary importance or keyword status in the code containing the macro. But it is not a procedure in and of itself.

Another Eg:

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Macro AddToList(myList)
  AddElement(myList())
EndMacro
...
AddToList(things)

becomes

Code: Select all

AddElement(things())

And then PureBasic compiles it.

[Justin]

I thought they were like C macros(HIWORD(), MAKELONG()...), all the SendMessage() macro/wrappers, or to wrap get/put properties in objects. without types doing it will be very weird.

[Fred]

Look carefully, in C you don't specify the type as well:

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#define ListView_GetItem(h,p) SendMessage(h,LVM_GETITEM,0,(LPARAM)(p))

With parameter type it would look like:

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#define ListView_GetItem(HWND h, LPARAM p) SendMessage(h,LVM_GETITEM,0,(LPARAM)(p))

Which is not the case.

[venom]

The only thing I can think of thats closest to this are inline functions, which PureBasic doesn't have.

[Justin]

yes there are no types in C either, although they are later cast inside the macro so you have some clue. i was looking at the wrong place

i'll use a commented syntax at the macro beginning