.lb1:
rept 0 {
Print a
Write b, 2
include 'data.inc'
} 
;how get this or load ? 
Macro Get a, line {} 

Get a1, 1 ;do a1 equ Print a
Get a2, 2 ;do a2 equ Write b,2

    

macro Get_1 v { v equ Print a }
macro Get_2 v { v equ Write b, 2 }
Get_1 a1
Get_2 a2    

;this macros no needed any rept data.
macro Get_1 v { v equ Print a }
macro Get_2 v { v equ Write b, 2 }
Get_1 a1
Get_2 a2     

macro Get v, line {
  match =1, line \{ v equ Print a \}
  match =2, line \{ v equ Write b, 2 \}
}    

.lb1:
rept 0 {
Set a,4
Read buffer1, 20
}

.lb2:
rept 0 { ;like obj 3d model data
vrtx 5.5,4,6
vrtx 1.5,2,5.2
faces 0,1,0,1
}

     

Its bad idea.

Container A {
;ignored for compiler, but store text. And mechanism get this text in the macro.
Any text.
Or include text from file.
 }

Container B { }
Container C { }
    

Nice if fasm have mechanism store text.
Any text.
Or include text from file.

include <file>
    

    virtual at 0
        file 'a.txt':10h,1
        load char from 0
    end virtual
loads the single byte from offset 10h in file a.txt into the char constant.