Z80 compilation with fasmg

Last weekend I started the fasmg Z80 coding as I was saying some time ago.
I thought about it and my approach for simplicity and effectiveness would be to encode each different instruction in a different macro, and if it is not possible (as I assume) in a different "match" instruction (as below)...

Following a "not working" example of 4 instructions: I tried to read documentation but no success. Posting here with hope that is possible to easily correct and so I might understand it better and continue to implement the full instruction set.

Code:

; example macro (see examples below for instructions encodings)
macro LD first , second , notusedthirdpartoleave
    match first,HL?
        if second relativeto 0
            db $21
            dw second
        end if
    else match first,=( HL? =)
        if second relativeto 0
            db $36
            db second
        end if
    else match first,=( HL? =)
        match second,A?
            db $77
        end match
    else if first relativeto IX? ; ... missing check of enlcosing ( )
        if second relativeto 0
            db $DD,$36
            db first-IX?,second
        end if
    end if
end macro

; example instructions to compile
LD HL, $1200 + $34  ; $21,$34,$12
LD (HL) , $11 + 1   ; $36,$12
LD ( HL ) , A       ; $77
LD (IX+5-2),1       ; $DD,$36,3,1

macro LD? first , second match =HL?,first db $21 dw second else match ( =HL? ) =, =A?, first,second db $77 else match ( =HL? ), first db $36 db second else match ( expr ),first if expr relativeto IX? db $DD,$36 db first-IX?,second end if end match end macro element IX? ; example instructions to compile LD HL, $1200 + $34 ; $21,$34,$12 LD (HL) , $11 + 1 ; $36,$12 LD ( HL ) , A ; $77 LD (IX+5-2),1 ; $DD,$36,3,1