Support environment variable procedures.

typed-racket-doc/typed-racket/scribblings/reference/types.scrbl

@@ -266,6 +266,7 @@ These are not part of the numeric tower.
 @defidform[FSemaphore]
 @defidform[Will-Executor]
 @defidform[Pseudo-Random-Generator]
+@defidform[Environment-Variables]
 )]{
 These types represent primitive Racket data.
 

typed-racket-lib/typed-racket/base-env/base-env.rkt

@@ -2964,6 +2964,14 @@
  (->opt [(Un (-val #f) (-val 'subprocesses) -Thread)] -Fixnum)]
 
 ;; Section 15.7
+[environment-variables? (make-pred-ty -Environment-Variables)]
+[current-environment-variables (-Param -Environment-Variables)]
+[bytes-environment-variable-name? (asym-pred Univ B (-PS (-is-type 0 -Bytes) -tt))]
+[make-environment-variables (->* null -Bytes -Environment-Variables)]
+[environment-variables-ref (-> -Environment-Variables -Bytes (-opt -Bytes))]
+[environment-variables-set! (->opt -Environment-Variables -Bytes (-opt -Bytes) [(-> Univ)] Univ)]
+[environment-variables-names (-> -Environment-Variables  (-lst -Bytes))]
+[string-environment-variable-name? (asym-pred Univ B (-PS (-is-type 0 -) -tt))]
 [getenv (-> -String (Un -String (-val #f)))]
 [putenv (-> -String -String B)]
 

typed-racket-lib/typed-racket/base-env/base-types.rkt

@@ -160,6 +160,7 @@
 [Place-Channel -Place-Channel]
 [Place -Place]
 [Will-Executor -Will-Executor]
+[Environment-Variables -Environment-Variables]
 
 
 [Listof -Listof]

typed-racket-lib/typed-racket/types/abbrev.rkt

@@ -251,6 +251,8 @@
 (define/decl -Place-Channel (Un -Place -Base-Place-Channel))
 (define/decl -Will-Executor
   (make-Base 'Will-Executor #'will-executor? will-executor?))
+(define/decl -Environment-Variables
+  (make-Base 'Environment-Variables #'environment-variables? environment-variables?))
 
 ;; Paths
 (define/decl -car (make-CarPE))