1 files changed, 0 insertions, 57 deletions
diff --git a/stlc-let.rkt b/stlc-let.rkt
deleted file mode 100644
index 089f9d0..0000000
--- a/stlc-let.rkt
+++ /dev/null
@@ -1,57 +0,0 @@
-#lang racket
-(require "lib.rkt")
-
-;; The Simply-Typed Lambda Calculus, with let sugar and some base types
-
-;;      (interpret Expr Table[Sym, Expr]): Value
-(define (interpret expr)
-  (interpret-core (strip (desugar expr)) #hash()))
-(define (interpret-core expr Γ)
-  (match expr
-    ['sole 'sole]
-    [n #:when (natural? n) n]
-    [x #:when (dict-has-key? Γ x) (dict-ref Γ x)]
-    [`(λ ,x ,e) `(λ ,x ,e ,Γ)]
-    [`(,e1 ,e2)
-      (match (interpret-core e1 Γ)
-        [`(λ ,x ,e1 ,env) (interpret-core e1 (dict-set env x (interpret-core e2 Γ)))]
-        [e1 `(,e1 ,(interpret-core e2 Γ))])]
-    [e e]))
-
-;;      (check Expr Type Table[Sym, Type]): Bool
-(define (check expr with)
-  (check-core (desugar expr) with #hash()))
-(define (check-core expr with Γ)
-  (match with
-    [`(λ (,x : ,t) ,e)
-      (match with
-        [`(,t1 → ,t2)
-          (and (equal? t1 t) (check-core e t2 (dict-set Γ x t1)))]
-        [_ #f])]
-    [_ (equal? (infer-core expr Γ) with)]))
-
-;;      (infer Expr Table[Sym, Type]): Type
-(define (infer expr)
-  (infer-core (desugar expr) #hash()))
-(define (infer-core expr Γ)
-  (match expr
-    ['sole 'Unit]
-    [n #:when (natural? n) 'Nat]
-    [x #:when (dict-has-key? Γ x) (dict-ref Γ x)]
-    [`(λ (,x : ,t) ,e)
-      `(,t → ,(infer-core e (dict-set Γ x t)))]
-    [`(,e1 ,e2)
-      (match (infer-core e1 Γ)
-        [`(,t1 → ,t2)
-          (if (check-core e2 t1 Γ) t2
-            (err (format "inferred argument type ~a does not match arg ~a" t1 e2)))]
-        [t (err (format "expected → type on application body, got ~a" t))])]
-    [e (err (format "attempting to infer an unknown expression ~a" e))]))
-
-(provide interpret check infer)
-
-(require rackunit)
-(check-equal? (interpret '(λ x x)) '(λ x x #hash()))
-(check-equal? (interpret '((λ a a) (x y))) '(x y))
-(check-equal? (interpret '((λ a (x y)) (λ z z))) '(x y))
-(check-equal? (interpret '((λ a (a y)) x)) '(x y))