.                Structure member selector                           Operator

  memptr.fieldname

    Selects a structure member.

    The period (.) structure member operator is far more strict in Ideal
    mode when accurately specifying the structure members you're referring
    to. The expression to the left of a period must be a structure
    pointer. The expression to the right must be a member name in that
    structure. Here are some examples:

       Ideal
       struc demo                              ; Declare structure type
          Ord      dw  ?
          Tipe     db  5  dup (?)
          Numbers  dw  12 dup (?)
       ends

       DATASEG
       fordA   demo   <16,,>                   ; Define variables
       fordT   demo   { Tipe='FordT' }
       UDATASEG
       fords   demo   200 dup (?)

       CODESEG
       assume ds:dgroup
       mov    dx,[fordA.Ord]                   ;
       mov    ax,[(demo PTR bx).Ord]           ; MASM: mov ax,Ord[bx]
       mov    ax,[(demo bx).Ord]               ; PTR operator is optional
       mov    cx,OFFSET (demo).Numbers         ; MASM: mov cx,Numbers
       mov    ax,[(demo (fordT + bx)).Ord]     ; MASM: mov ax,fordT[bx].Ord
       mov    ax,[((demo bx).Numbers) + 2]     ; MASM: mov ax,2[bx].Numbers
       mov    ax,SIZE demo                     ; ax = 31
       MASM
       ; Can't do this in Ideal mode:
       mov    ax,SIZE Numbers                  ; ax = 24