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using less generic names for the example to avoid confusion, adding cautionary example for what I think is the most error prone case

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bbbradsmith 2023-12-17 05:40:00 -05:00
parent 302c4f7409
commit 9892c8f6c4
1 changed files with 16 additions and 10 deletions
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26
doc/ca65.sgml
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@ -5003,23 +5003,29 @@ continuing through that scope. Example:
<tscreen><verb>
.struct Object
member .byte ; Object::member = 0
named .struct Point ; Object::named = 1
id .byte ; Object::id = 0
target .struct Point ; Object::target = 1
xcoord .word ; Object::Point::xcoord = 0
ycoord .word ; Object::Point::ycoord = 2
.endstruct
unnamed .struct ; Object::unnamed = 5
un1 .word ; Object::un1 = 5
un2 .word ; Object::un2 = 7
cost .struct ; Object::cost = 5
price .word ; Object::price = 5
tax .word ; Object::tax = 7
.endstruct
.struct
un3 .word ; Object::un3 = 9
radius .word ; Object::radius = 9
.endstruct
.endstruct
O: .tag Object
lda O + Object::named + Object::Point::ycoord
lda O + Object::un2
lda O + Object::target + Object::Point::ycoord ; Named struct
lda O + Object::tax ; Anonymous
lda O + Object::radius ; Anonymous
; Be careful not to use a named nested structure without also adding the
; offset to the nested structure itself.
lda O + Object::Point::ycoord ; Incorrect!
lda O + Object::target + Object::Point::ycoord ; Correct
</verb></tscreen>
In this example, the first nested structure is named "Point", and its member
@ -5027,8 +5033,8 @@ offsets begin at 0. On the other hand, the two anonymous structures simply
continue to add members to the enclosing "Object" structure.
Note that an anonymous structure does not need a member name, since all of its
members become part of the enclosing structure. The "unnamed" member in the
example is redundantly the same offset as its first member "un1".
members become part of the enclosing structure. The "cost" member in the
example is redundantly the same offset as its first member "price".
<sect1>Limitations<p>