From 4e987026148fe65c323afbc93cd560c07bf06b3f Mon Sep 17 00:00:00 2001
From: Yale AI Dept <ai@nebula.cs.yale.edu>
Date: Wed, 14 Jul 1993 13:08:00 -0500
Subject: Import to github.

---
 ast/type-structs.scm | 159 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 159 insertions(+)
 create mode 100644 ast/type-structs.scm

(limited to 'ast/type-structs.scm')

diff --git a/ast/type-structs.scm b/ast/type-structs.scm
new file mode 100644
index 0000000..0ba4705
--- /dev/null
+++ b/ast/type-structs.scm
@@ -0,0 +1,159 @@
+;;;  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))))
+
-- 
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