Hello,
This is a much more experimental suggestion than the 'eval:' slot attribute.
This:
TUPLE: <abc> { a model-slot } b c ;
Indicates that the 'a' slot will be a model and the reader and writer will act
accordingly. I.e. given:
10 <model> 20 30 <abc> boa
The 'a>>' will return '10' and '>>a' will update the model via 'set-model' so
that observers are notified.
It's somewhat controversial because the jury is still out on whether or not
custom reader and writer methods should be used. This idiom is worth
exploring. If custom methods enjoy wide usage, then words which access the
slot directly by name would be good to have (can be achived via mirrors...).
Code attached.
Ed
----------------------------------------------------------------------
IN: syntax
SYMBOL: model-slot
! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
IN: slots
TUPLE: slot-spec name offset class initial read-only model-slot ;
! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
: peel-off-attributes ( slot-spec array -- slot-spec array )
dup empty?
[
unclip
{
{ initial: [ [ first >>initial ] [ rest ] bi ] }
{ model-slot [ [ t >>model-slot ] dip ] }
{ read-only [ [ t >>read-only ] dip ] }
[ bad-slot-attribute ]
}
case
]
unless ;
! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
:: model-reader-quot ( SLOT-SPEC -- quot )
[let | OFFSET [ SLOT-SPEC offset>> ] |
[ OFFSET slot value>> ] ] ;
! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
:: define-model-reader ( CLASS SLOT-SPEC -- )
CLASS
SLOT-SPEC name>> reader-word
SLOT-SPEC model-reader-quot
SLOT-SPEC reader-props
define-typecheck ;
! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
:: model-writer-quot ( SLOT-SPEC -- quot )
[let | OFFSET [ SLOT-SPEC offset>> ] |
! ( val obj -- )
[ OFFSET slot set-model ] ] ;
:: define-model-writer ( CLASS SLOT-SPEC -- )
CLASS
SLOT-SPEC name>> writer-word
SLOT-SPEC model-writer-quot
SLOT-SPEC writer-props
define-typecheck ;
! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
:: define-slot-methods ( CLASS SLOT-SPEC -- )
SLOT-SPEC model-slot>>
[
CLASS SLOT-SPEC define-model-reader
CLASS SLOT-SPEC define-model-writer
]
[
CLASS SLOT-SPEC
[ define-reader ]
[
dup read-only>> [ 2drop ] [
[ name>> define-setter drop ]
[ name>> define-changer drop ]
[ define-writer ]
2tri
] if
] 2bi
]
if ;
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