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|
#| Copyright (c) Peter McGoron 2025
|
| Licensed under the Apache License, Version 2.0 (the "License");
| you may not use this file except in compliance with the License.
| You may obtain a copy of the License at
|
| http://www.apache.org/licenses/LICENSE-2.0
|
| Unless required by applicable law or agreed to in writing, software
| distributed under the License is distributed on an "AS IS" BASIS,
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
| See the License for the specific language governing permissions and
| limitations under the License.
|#
(define (curry-form form)
(cond
((and (pair? form)
(eq? (car form) 'lambda))
(list 'lambda (curry-form (cadr form))))
((and (pair? form)
(> (length form) 2))
(curry-form (cons (list (list-ref form 0)
(list-ref form 1))
(list-tail form 2))))
((pair? form)
(list (curry-form (list-ref form 0))
(curry-form (list-ref form 1))))
(else form)))
(define-syntax test-alpha
(syntax-rules ()
((test-alpha name (inputs ...) output)
(let-values (((global-map expanded-list)
(expand initial-environment
(list (empty-wrap (quote inputs)) ...))))
(test-equal name
(map curry-form (quote output))
(map (lambda (term)
(debruijnize global-map term '()))
expanded-list))))))
(define (test-expander)
(test-alpha "identity"
((lambda x x))
((lambda 0)))
(test-alpha "let-syntax of identifier"
((let-syntax ((λ lambda))
(λ x x))
(λ x x))
((lambda 0)
(λ x x)))
(test-alpha "define-syntax of identifier"
((define-syntax λ lambda)
(λ x x))
((lambda 0)))
(test-alpha "lexical renaming of keywords"
((lambda lambda (lambda lambda)))
((lambda (0 0))))
(test-alpha "simple syntax-rules"
((define-syntax let
(syntax-rules ()
((let ((name value)) body)
((lambda name body) value))))
(let ((x (f y))) (f x)))
(((lambda (f 0)) (f y))))
(test-alpha "syntax-rules with ellipsis"
((define-syntax let
(syntax-rules ()
((let ((name value)) body)
((lambda name body) value))))
(define-syntax or
(syntax-rules ()
((or) false)
((or x y ...)
(let ((tmp x))
(if tmp tmp (or y ...))))))
(or a tmp b))
(((lambda (if 0
0
((lambda (if 0
0
((lambda (if 0
0
false))
b))) tmp))) a)))
(test-alpha "splicing-let-syntax"
((splicing-let-syntax ((λ lambda))
(define-syntax lambda
(syntax-rules ()
((_ (name) body) (λ name body))
((_ (name rest ...) body)
(λ name (lambda (rest ...) body)))
((_ name body) (λ name body)))))
(lambda (x y) (x y)))
((lambda (lambda (1 0))))))
(define-syntax test-eval-alpha
(syntax-rules ()
((_ name (inputs ...) outputs)
(let-values (((expanded-list global-map)
(lceval (list (empty-wrap (quote inputs)) ...)
initial-environment)))
(test-equal name
(map curry-form (quote outputs))
(map (lambda (term)
(debruijnize global-map term '()))
expanded-list))))))
(define (test-eval)
(test-eval-alpha "identity evals to itself"
((lambda x x))
((lambda 0)))
(test-eval-alpha "identity applied to itself"
(((lambda x x) (lambda x x)))
((lambda 0)))
(test-eval-alpha "define returns nothing"
((define I (lambda x x)))
())
(test-eval-alpha "global environment lookup"
((define I (lambda x x))
I)
((lambda 0)))
(test-eval-alpha "K combinator, 1"
((define K (lambda x (lambda y x)))
(define I (lambda x x))
(K I I))
((lambda 0)))
(test-eval-alpha "K combinator, 2"
((define K (lambda x (lambda y x)))
(define I (lambda x x))
(K I K))
((lambda 0)))
(test-eval-alpha "K combinator, 3"
((define K (lambda x (lambda y x)))
(define I (lambda x x))
(K K I))
((lambda (lambda 1))))
(test-eval-alpha "define-syntax"
((define-syntax λ
(syntax-rules ()
((λ (x) body)
(lambda x body))
((λ (x y ...) body)
(lambda x (λ (y ...) body)))))
(define true (λ (x y) x))
(define false (λ (x y) y))
(false false true))
((lambda (lambda 1))))
(test-eval-alpha "normal order evaluation"
((define ω (lambda x (x x)))
(define K (lambda x (lambda y x)))
(K K (ω ω)))
((lambda (lambda 1)))))
(define (test-untyped-lambda-calculus)
(test-group "untyped lambda calculus"
(test-group "expander"
(test-expander))
(test-group "eval"
(test-eval))))
|
