whalesong/lexical-structs.rkt

55 lines
1.6 KiB
Racket

#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 Symbol ModuleVariable False))])
#:transparent)
(define-struct: ModuleVariable ([name : Symbol]
[module-path : Symbol])
#:transparent)
(define-struct: NamedBinding ([name : Symbol]
[parameter? : Boolean]
[boxed? : Boolean])
#:transparent)
(define-type ParseTimeEnvironmentEntry (U Prefix ;; a prefix
NamedBinding
False))
;; 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])
#:transparent)
(define-struct: EnvPrefixReference ([depth : Natural]
[pos : Natural])
#:transparent)
(define-struct: EnvWholePrefixReference ([depth : Natural])
#:transparent)
;; An environment reference is either lexical or referring to a whole prefix.
(define-type EnvReference (U EnvLexicalReference
EnvWholePrefixReference))