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author | JJ | 2024-07-29 19:47:19 +0000 |
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committer | JJ | 2024-07-29 19:47:19 +0000 |
commit | 83a1400957da57bf6930bab4b81af87f1851be5b (patch) | |
tree | ace9579033a9967893656e681ad938e8ac82f351 /base.rkt | |
parent | 17c9a9a1eb4b211b5b4260d7cdca598d14316ac3 (diff) |
split lib into lib and base; move tests to separate files & directory
Diffstat (limited to 'base.rkt')
-rw-r--r-- | base.rkt | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/base.rkt b/base.rkt new file mode 100644 index 0000000..c88a8ee --- /dev/null +++ b/base.rkt @@ -0,0 +1,78 @@ +#lang racket +(require "lib.rkt") +(provide (all-defined-out)) + +;; Base utility functions for working with the simply-typed lambda calculus + +;; Provides a pretty-print utility for terms in the simply-typed lambda calculus +;; (fmt Expr): String +(define (fmt expr) + (match expr + ['sole "⟨⟩"] + [`(λ ,x ,e) (format "λ~a.[~a]" x (fmt e))] + [`((λ ,x ,e1) ,e2) (format "~a = ~a; ~a" x (fmt e2) (fmt e1))] + [`(λ (,x : ,t) ,e) (format "~a: ~a; ~a" x (fmt t) (fmt e))] + [`((λ (,x : ,t) ,e1) ,e2) (format "~a: ~a; ~a = ~a; ~a" x (fmt t) x (fmt e2) (fmt e1))] + [`(λ ,x ,e ,env) (format "λ~a.[~a]" x (fmt e))] + [`(μ ,x ,t) (format "μ~a.~a" x (fmt t))] + [`(let (,x : ,t) ,e ,in) (format "~a: ~a; ~a = ~a; ~a" x (fmt t) x (fmt e) (fmt in))] + [`(let ,x ,e ,in) (format "~a = ~a; ~a" x (fmt e) (fmt in))] + [`(set ,x ,e ,in) (format "~a := ~a; ~a" x (fmt e) (fmt in))] + [`(,a → ,b) (format "(~a → ~a)" (fmt a) (fmt b))] + [`(,a → ,k ,b) (format "(~a →~a ~a)" (fmt a) k (fmt b))] + [`(Ref ,a) (format "Ref ~a" (fmt a))] + [`(new ,a) (format "new ~a" (fmt a))] + [`(! ,a) (format "!~a" (fmt a))] + [`(,a ,b) (format "(~a ~a)" (fmt a) (fmt b))] + [(hash-table (keys values) ...) + (format "{~a}" (foldl (λ (k v acc) (format "~a: ~a;" (fmt k) (fmt v))) "" keys values))] + [expr (format "~a" expr)])) + +;; Removes typing annotations and similar constructs, for interpretation +(define (strip expr) + (match expr + [`(,e : ,_) (strip e)] + [`(type ,_ ,_ ,e) (strip e)] + [`(fold ,_ ,e) `(fold ,(strip e))] + [`(unfold ,_ ,e) `(unfold ,(strip e))] + [`(,e ...) `(,@(map strip e))] + [e e])) + +;; Define aliases from higher-level constructs to their core forms +(define (desugar expr) + (match expr + ['⟨⟩ 'sole] + [`(ref ,e) (desugar `(new ,e))] + [`(deref ,e) (desugar `(! ,e))] + + ; set-with-continuation + [`(set ,e1 ,e2 ,in) + (desugar `(let (_ : Unit) (set ,e1 ,e2) ,in))] + + ; many forms of let. this lets us elide many typing annotations + [`(let (,id : (,a → ,k ,b)) (λ (,x : ,a) ,e) ,in) + (desugar `((λ (,id : (,a → ,k ,b)) ,in) (λ (,x : ,a) ,e)))] + [`(let (,id : (,a → ,k ,b)) (λ ,x ,e) ,in) + (desugar `((λ (,id : (,a → ,k ,b)) ,in) (λ (,x : ,a) ,e)))] + [`(let (,id : (,a → ,b)) (λ (,x : ,a) ,e) ,in) + (desugar `((λ (,id : (,a → ,b)) ,in) (λ (,x : ,a) ,e)))] + [`(let (,id : (,a → ,b)) (λ ,x ,e) ,in) + (desugar `((λ (,id : (,a → ,b)) ,in) (λ (,x : ,a) ,e)))] + [`(let ,x (,e : ,t) ,in) + (desugar `((λ (,x : ,t) ,in) (,e : ,t)))] + [`(let ,x ,e ,in) + (desugar `((λ ,x ,in) ,e))] + [`(let ,x ,e) + (desugar `(let ,x ,e sole))] + + ; letrec as let + fix + [`(letrec (,x : ,t) ,e ,in) + (desugar `(let (,x : ,t) (fix (λ (,x : ,t) ,e)) ,in))] + + [`(,e ...) `(,@(map desugar e))] + [e e])) + + ; [`(list ,exprs ...) + ; (foldr (λ (expr res) `(cons ,expr ,res)) 'nil)] + ; [`(type ,x ,type ,in) ; fails b/c types are not inferrable + ; (desugar `(let (,x : Type) ,type ,in))] |