#lang typed/racket/base

(provide (all-defined-out))


;;  Lexical environments

;; A toplevel prefix contains a list of toplevel variables.  Some of the
;; names may be masked out by #f.
(define-struct: Prefix ([names : (Listof (U False Symbol GlobalBucket ModuleVariable))])

(define-struct: GlobalBucket ([name : Symbol])

;; A ModuleLocator is an identifier for a Module.
(define-struct: ModuleLocator ([name : Symbol]
                            [real-path : (U Symbol Path)])

(define-struct: ModuleVariable ([name : Symbol]
                                [module-name : ModuleLocator])

(define-struct: NamedBinding ([name : Symbol]
                              [parameter? : Boolean]
                              [boxed? : Boolean])

(define-type ParseTimeEnvironmentEntry (U Prefix ;; a prefix

;; A compile-time environment is a (listof (listof symbol)).
;; A lexical address is either a 2-tuple (depth pos), or 'not-found.
(define-type ParseTimeEnvironment (Listof ParseTimeEnvironmentEntry))

;; A lexical address is a reference to an value in the environment stack.
(define-type LexicalAddress (U EnvLexicalReference EnvPrefixReference))

(define-struct: EnvLexicalReference ([depth : Natural]
                                     [unbox? : Boolean])

(define-struct: EnvPrefixReference ([depth : Natural]
                                    [pos : Natural]
                                    [modvar? : Boolean])

(define-struct: EnvWholePrefixReference ([depth : Natural])

;; An environment reference is either lexical or referring to a whole prefix.
(define-type EnvReference (U EnvLexicalReference