util.mac

 macro
&lab stzl &address
 stz &address
 stz &address+2
 mend
 macro
&lab plax
&lab pla
 plx
 mend
 macro
&lab ldax &address,&off
 lclc &c
&lab anop
&c amid &address,1,1
 aif "&c"="[",.deref
 aif "&c"="#",.imm
 lda &address
 ldx &address+2
 mexit
.deref
 mexit
.imm
 aif "&address"="0",.imm0
&address amid &address,2,l:&address-1
 lda #&address
 ldx #^&address
 mexit
.imm0
 lda #0
 tax
 mexit
.deref
&address amid &address,2,l:&address-2
 aif c:&off=0,.deref0
 aif "&off"="y",.derefy
&c amid &off,1,1
 aif "&c"<>"#",.derefldy
 ldy &off+2
 ago .deref2
.derefldy
 ldy &off
.derefy
 iny
 iny
.deref2
 lda [&address],y
 tax
 dey
 dey
 lda [&address],y
 mexit
.deref0
 ldy #2
 lda [&address],y
 tax
 lda [&address]
 mend
 macro
&lab stax &address
 lclc &c
&lab anop
&c amid &address,1,1
 sta &address
 stx &address+2
 mend