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|
;;; File: ast/type-structs Author: John
;;; This contains AST structures for the type-related declarations,
;;; including `data', `class', `instance', and `type' decls. Basic type
;;; syntax is also defined here.
;;; Structures declared here:
;;; type type-var type-con context signature synonym-decl
;;; data-decl class-decl instance-decl
;;; <type> -> <atype>
;;; -> <type> -> <type> ***
;;; -> <tycon> <atype> ... <atype> tycon
;;;
;;; <atype> -> <tyvar> tyvar
;;; -> <tycon> tycon
;;; -> () ***
;;; -> ( <type> ) grouping syntax
;;; -> ( <type> , ... , <type>) ***
;;; -> [ <type> ] ***
;;; *** Special <tycon> cases
;;; Type with no context - either a tyvar or a constructor
(define-struct type
(include ast-node))
(define-struct tyvar
(include type)
(predicate tyvar?)
(slots
(name (type symbol))))
(define-struct tycon
(include type)
(predicate tycon?)
(slots
(name (type symbol))
(def (type def))
(args (type (list type)))))
;;; <signature> -> [<context> =>] <type>
;;;
;;; <context> -> <class>
;;; -> (<class> , ... , <class>)
;;; A single class, variable pair
(define-struct context
(include ast-node)
(slots
(class (type class-ref))
(tyvar (type symbol))))
;;; Type + context
(define-struct signature
(include type)
(slots
(context (type (list context)))
(type (type type))))
;;; Major type declarations. Note: no explicit structures for <simple>
;;; or <inst> are needed - these are just special cases of type.
;;; <synonym-decl> -> type <simple> = <type>
;;;
;;; <simple> -> <tycon> <tyvar> ... <tyvar>
(define-struct synonym-decl
(include ast-node)
(slots
(simple (type type))
(body (type type))))
;;; <aldata-decl> -> data [<context> => ] <simple> = <constrs>
;;; [deriving <tycls> | ( <tycls> , ... <tycls>) ]
;;;
;;; <constrs> -> <constr> | ... | <constr>
;;;
(define-struct data-decl
(include ast-node)
(slots
(context (type (list context)))
(simple (type type))
(constrs (type (list constr)))
(deriving (type (list class-ref)))
(annotations (type (list annotation-value)))))
;;; <constr> -> <con> <atype> ... <atype>
;;; -> <type> <conop> <type>
(define-struct constr
(include ast-node)
(slots
(constructor (type con-ref)) ; this con-ref has an infix? flag.
(types (type (list (tuple type (list annotation-value)))))))
;;; <class-decl> -> class [<context> => ] <class> [where { <cbody> [;] } ]
;;;
;;; <cbody> -> [<csigns> ; ] [ <valdefs> ]
;;;
;;; <csigns> -> <signdecl> ; ... ; <signdecl>
(define-struct class-decl
(include ast-node)
(slots
(class (type class-ref))
(super-classes (type (list context)))
(class-var (type symbol)) ; name of type var for this class in decls
(decls (type (list decl))))) ; <cbody>
;;; <instance-decl> -> instance [<context> =>] <tycls> <inst>
;;; [where { <valdefs> [;] } ]
;;;
;;; <inst> -> <tycon>
;;; -> ( <tycon> <tyvar> ... <tyvar> )
;;; -> ( <tyvar> , ... , <tyvar>)
;;; -> ()
;;; -> [ <tyvar> ]
;;; -> ( <tyvar> -> <tyvar>)
;;;
(define-struct instance-decl
(include ast-node)
(slots
;; <context>
(context (type (list context)))
;; <tycls>
(class (type class-ref))
;;
(simple (type type))
;; <valdefs>
(decls (type (list valdef)))
))
;;; <default-decl> -> default <type>
;;; -> default ( <type> , ... , <type> )
(define-struct default-decl
(include ast-node)
(slots
(types (type (list type)))))
;;; <tycls> -> <aconid>
(define-struct class-ref
(include ast-node)
(slots
(name (type symbol))
(class (type def))))
|
