cl: cffi - type translation

• the translate-* methods are called at run-time, the expand-* methods are called at macro-expansion-time (à la compiler macros).
  • usually!
  • expand-* "bail-out" to translate-* methods
    • again, very similar to compiler-macros
• defcfun and foreign-funcall uses the internal function translate-objects, which in turns uses expand-from-foreign, expand-to-foreign-dyn-indirect and expand-to-foreign-dyn

• ~(namespace-table :default)
• parse-type
• define-parse-method
• find-type-parser

• defcstruct
  • always define a clos class
    • the default name of the class is <name>-tclass
    • it has the superclasses foreign-struct-type and translatable-foreign-type
    • it has no slot!
  • calls notice-foreign-struct-definition
    • it does a lot: validation, compute offsets, padding, alignment, etc
    • it creates an instance of the class 🤔
    • with-tentative-type-definition
      • notice-foreign-type + unwind-protect
        • (setf (find-type-parser name namespace) (lambda () type))
        • namespace defaults to… :default
        • type is actually the instance created at the start of notice-foreign-type
      • in the body:
        • make-struct-slot
          • either an instance of aggregate-struct-slot or simple-struct-slot
  • calls ~generate-struct-accessors-
    • only if the option :conc-name is not nil
    • defines a function and a setf function for each slots
    • named <conc-name>-<slot>
  • also define-parse-method

• declass
  • the slots are NOT the slots of the instance, they are part of the TYPE.
• define-parse-method

maybe I need to add a define-parse-method??