1 665c255d 2023-08-04 jrmu ;; (define apply-in-underlying-scheme apply)
2 665c255d 2023-08-04 jrmu ;; (define eval-in-underlying-scheme eval)
4 665c255d 2023-08-04 jrmu (define (eval exp env)
5 665c255d 2023-08-04 jrmu (cond ((self-evaluating? exp) exp)
6 665c255d 2023-08-04 jrmu ((variable? exp) (lookup-variable-value exp env))
7 665c255d 2023-08-04 jrmu ((quoted? exp) (text-of-quotation exp))
8 665c255d 2023-08-04 jrmu ((assignment? exp) (eval-assignment exp env))
9 665c255d 2023-08-04 jrmu ((definition? exp) (eval-definition exp env))
10 665c255d 2023-08-04 jrmu ((if? exp) (eval-if exp env))
11 665c255d 2023-08-04 jrmu ((and? exp) (eval-and exp env))
12 665c255d 2023-08-04 jrmu ((or? exp) (eval-or exp env))
13 665c255d 2023-08-04 jrmu ((lambda? exp)
14 665c255d 2023-08-04 jrmu (make-procedure (lambda-parameters exp)
15 665c255d 2023-08-04 jrmu (lambda-body exp)
17 665c255d 2023-08-04 jrmu ((begin? exp)
18 665c255d 2023-08-04 jrmu (eval-sequence (begin-actions exp) env))
19 665c255d 2023-08-04 jrmu ((cond? exp) (eval (cond->if exp) env))
20 665c255d 2023-08-04 jrmu ((let? exp) (eval (let->combination exp) env))
21 665c255d 2023-08-04 jrmu ((application? exp)
22 665c255d 2023-08-04 jrmu (apply (eval (operator exp) env)
23 665c255d 2023-08-04 jrmu (list-of-values (operands exp) env)))
25 665c255d 2023-08-04 jrmu (error "Unknown expression type -- EVAL" exp))))
27 665c255d 2023-08-04 jrmu (define (apply procedure arguments)
28 665c255d 2023-08-04 jrmu (cond ((primitive-procedure? procedure)
29 665c255d 2023-08-04 jrmu (apply-primitive-procedure procedure arguments))
30 665c255d 2023-08-04 jrmu ((compound-procedure? procedure)
31 665c255d 2023-08-04 jrmu (eval-sequence
32 665c255d 2023-08-04 jrmu (procedure-body procedure)
33 665c255d 2023-08-04 jrmu (extend-environment
34 665c255d 2023-08-04 jrmu (procedure-parameters procedure)
36 665c255d 2023-08-04 jrmu (procedure-environment procedure))))
39 665c255d 2023-08-04 jrmu "Unknown procedure type -- APPLY" procedure))))
40 665c255d 2023-08-04 jrmu (define (list-of-values exps env)
41 665c255d 2023-08-04 jrmu (if (no-operands? exps)
43 665c255d 2023-08-04 jrmu (cons (eval (first-operand exps) env)
44 665c255d 2023-08-04 jrmu (list-of-values (rest-operands exps) env))))
46 665c255d 2023-08-04 jrmu (define (eval-if exp env)
47 665c255d 2023-08-04 jrmu (if (true? (eval (if-predicate exp) env))
48 665c255d 2023-08-04 jrmu (eval (if-consequent exp) env)
49 665c255d 2023-08-04 jrmu (eval (if-alternative exp) env)))
50 665c255d 2023-08-04 jrmu (define (eval-sequence exps env)
51 665c255d 2023-08-04 jrmu (cond ((last-exp? exps) (eval (first-exp exps) env))
52 665c255d 2023-08-04 jrmu (else (eval (first-exp exps) env)
53 665c255d 2023-08-04 jrmu (eval-sequence (rest-exps exps) env))))
54 665c255d 2023-08-04 jrmu (define (eval-assignment exp env)
55 665c255d 2023-08-04 jrmu (set-variable-value! (assignment-variable exp)
56 665c255d 2023-08-04 jrmu (eval (assignment-value exp) env)
59 665c255d 2023-08-04 jrmu (define (eval-definition exp env)
60 665c255d 2023-08-04 jrmu (define-variable! (definition-variable exp)
61 665c255d 2023-08-04 jrmu (eval (definition-value exp) env)
64 665c255d 2023-08-04 jrmu (define (self-evaluating? exp)
65 665c255d 2023-08-04 jrmu (cond ((number? exp) true)
66 665c255d 2023-08-04 jrmu ((string? exp) true)
67 665c255d 2023-08-04 jrmu (else false)))
68 665c255d 2023-08-04 jrmu (define (variable? exp) (symbol? exp))
69 665c255d 2023-08-04 jrmu (define (quoted? exp)
70 665c255d 2023-08-04 jrmu (tagged-list? exp 'quote))
72 665c255d 2023-08-04 jrmu (define (text-of-quotation exp) (cadr exp))
73 665c255d 2023-08-04 jrmu (define (tagged-list? exp tag)
74 665c255d 2023-08-04 jrmu (if (pair? exp)
75 665c255d 2023-08-04 jrmu (eq? (car exp) tag)
77 665c255d 2023-08-04 jrmu (define (assignment? exp)
78 665c255d 2023-08-04 jrmu (tagged-list? exp 'set!))
79 665c255d 2023-08-04 jrmu (define (assignment-variable exp) (cadr exp))
80 665c255d 2023-08-04 jrmu (define (assignment-value exp) (caddr exp))
81 665c255d 2023-08-04 jrmu (define (definition? exp)
82 665c255d 2023-08-04 jrmu (tagged-list? exp 'define))
83 665c255d 2023-08-04 jrmu (define (definition-variable exp)
84 665c255d 2023-08-04 jrmu (if (symbol? (cadr exp))
86 665c255d 2023-08-04 jrmu (caadr exp)))
87 665c255d 2023-08-04 jrmu (define (definition-value exp)
88 665c255d 2023-08-04 jrmu (if (symbol? (cadr exp))
90 665c255d 2023-08-04 jrmu (make-lambda (cdadr exp) ; formal parameters
91 665c255d 2023-08-04 jrmu (cddr exp)))) ; body
92 665c255d 2023-08-04 jrmu (define (lambda? exp) (tagged-list? exp 'lambda))
93 665c255d 2023-08-04 jrmu (define (lambda-parameters exp) (cadr exp))
94 665c255d 2023-08-04 jrmu (define (lambda-body exp) (cddr exp))
95 665c255d 2023-08-04 jrmu (define (make-lambda parameters body)
96 665c255d 2023-08-04 jrmu (cons 'lambda (cons parameters body)))
97 665c255d 2023-08-04 jrmu (define (if? exp) (tagged-list? exp 'if))
98 665c255d 2023-08-04 jrmu (define (if-predicate exp) (cadr exp))
99 665c255d 2023-08-04 jrmu (define (if-consequent exp) (caddr exp))
100 665c255d 2023-08-04 jrmu (define (if-alternative exp)
101 665c255d 2023-08-04 jrmu (if (not (null? (cdddr exp)))
102 665c255d 2023-08-04 jrmu (cadddr exp)
104 665c255d 2023-08-04 jrmu (define (make-if predicate consequent alternative)
105 665c255d 2023-08-04 jrmu (list 'if predicate consequent alternative))
106 665c255d 2023-08-04 jrmu (define (begin? exp) (tagged-list? exp 'begin))
107 665c255d 2023-08-04 jrmu (define (begin-actions exp) (cdr exp))
108 665c255d 2023-08-04 jrmu (define (last-exp? seq) (null? (cdr seq)))
109 665c255d 2023-08-04 jrmu (define (first-exp seq) (car seq))
110 665c255d 2023-08-04 jrmu (define (rest-exps seq) (cdr seq))
112 665c255d 2023-08-04 jrmu (define (sequence->exp seq)
113 665c255d 2023-08-04 jrmu (cond ((null? seq) seq)
114 665c255d 2023-08-04 jrmu ((last-exp? seq) (first-exp seq))
115 665c255d 2023-08-04 jrmu (else (make-begin seq))))
116 665c255d 2023-08-04 jrmu (define (make-begin seq) (cons 'begin seq))
117 665c255d 2023-08-04 jrmu (define (application? exp) (pair? exp))
118 665c255d 2023-08-04 jrmu (define (operator exp) (car exp))
119 665c255d 2023-08-04 jrmu (define (operands exp) (cdr exp))
120 665c255d 2023-08-04 jrmu (define (no-operands? ops) (null? ops))
121 665c255d 2023-08-04 jrmu (define (first-operand ops) (car ops))
122 665c255d 2023-08-04 jrmu (define (rest-operands ops) (cdr ops))
123 665c255d 2023-08-04 jrmu (define (cond? exp) (tagged-list? exp 'cond))
124 665c255d 2023-08-04 jrmu (define (cond-clauses exp) (cdr exp))
125 665c255d 2023-08-04 jrmu (define (cond-else-clause? clause)
126 665c255d 2023-08-04 jrmu (eq? (cond-predicate clause) 'else))
127 665c255d 2023-08-04 jrmu (define (cond-predicate clause) (car clause))
128 665c255d 2023-08-04 jrmu (define (cond-actions clause) (cdr clause))
129 665c255d 2023-08-04 jrmu (define (cond->if exp)
130 665c255d 2023-08-04 jrmu (expand-clauses (cond-clauses exp)))
132 665c255d 2023-08-04 jrmu (define (expand-clauses clauses)
133 665c255d 2023-08-04 jrmu (if (null? clauses)
134 665c255d 2023-08-04 jrmu 'false ; no else clause
135 665c255d 2023-08-04 jrmu (let ((first (car clauses))
136 665c255d 2023-08-04 jrmu (rest (cdr clauses)))
137 665c255d 2023-08-04 jrmu (if (cond-else-clause? first)
138 665c255d 2023-08-04 jrmu (if (null? rest)
139 665c255d 2023-08-04 jrmu (sequence->exp (cond-actions first))
140 665c255d 2023-08-04 jrmu (error "ELSE clause isn't last -- COND->IF"
142 665c255d 2023-08-04 jrmu (make-if (cond-predicate first)
143 665c255d 2023-08-04 jrmu (sequence->exp (cond-actions first))
144 665c255d 2023-08-04 jrmu (expand-clauses rest))))))
145 665c255d 2023-08-04 jrmu (define (true? x)
146 665c255d 2023-08-04 jrmu (not (eq? x false)))
147 665c255d 2023-08-04 jrmu (define (false? x)
148 665c255d 2023-08-04 jrmu (eq? x false))
149 665c255d 2023-08-04 jrmu (define (make-procedure parameters body env)
150 665c255d 2023-08-04 jrmu (list 'procedure parameters body env))
151 665c255d 2023-08-04 jrmu (define (compound-procedure? p)
152 665c255d 2023-08-04 jrmu (tagged-list? p 'procedure))
153 665c255d 2023-08-04 jrmu (define (procedure-parameters p) (cadr p))
154 665c255d 2023-08-04 jrmu (define (procedure-body p) (caddr p))
155 665c255d 2023-08-04 jrmu (define (procedure-environment p) (cadddr p))
156 665c255d 2023-08-04 jrmu (define (enclosing-environment env) (cdr env))
157 665c255d 2023-08-04 jrmu (define (first-frame env) (car env))
158 665c255d 2023-08-04 jrmu (define the-empty-environment '())
159 665c255d 2023-08-04 jrmu (define (make-frame variables values)
160 665c255d 2023-08-04 jrmu (cons variables values))
161 665c255d 2023-08-04 jrmu (define (frame-variables frame) (car frame))
162 665c255d 2023-08-04 jrmu (define (frame-values frame) (cdr frame))
163 665c255d 2023-08-04 jrmu (define (add-binding-to-frame! var val frame)
164 665c255d 2023-08-04 jrmu (set-car! frame (cons var (car frame)))
165 665c255d 2023-08-04 jrmu (set-cdr! frame (cons val (cdr frame))))
166 665c255d 2023-08-04 jrmu (define (extend-environment vars vals base-env)
167 665c255d 2023-08-04 jrmu (if (= (length vars) (length vals))
168 665c255d 2023-08-04 jrmu (cons (make-frame vars vals) base-env)
169 665c255d 2023-08-04 jrmu (if (< (length vars) (length vals))
170 665c255d 2023-08-04 jrmu (error "Too many arguments supplied" vars vals)
171 665c255d 2023-08-04 jrmu (error "Too few arguments supplied" vars vals))))
172 665c255d 2023-08-04 jrmu (define (lookup-variable-value var env)
173 665c255d 2023-08-04 jrmu (define (env-loop env)
174 665c255d 2023-08-04 jrmu (define (scan vars vals)
175 665c255d 2023-08-04 jrmu (cond ((null? vars)
176 665c255d 2023-08-04 jrmu (env-loop (enclosing-environment env)))
177 665c255d 2023-08-04 jrmu ((eq? var (car vars))
178 665c255d 2023-08-04 jrmu (car vals))
179 665c255d 2023-08-04 jrmu (else (scan (cdr vars) (cdr vals)))))
180 665c255d 2023-08-04 jrmu (if (eq? env the-empty-environment)
181 665c255d 2023-08-04 jrmu (error "Unbound variable" var)
182 665c255d 2023-08-04 jrmu (let ((frame (first-frame env)))
183 665c255d 2023-08-04 jrmu (scan (frame-variables frame)
184 665c255d 2023-08-04 jrmu (frame-values frame)))))
185 665c255d 2023-08-04 jrmu (env-loop env))
186 665c255d 2023-08-04 jrmu (define (set-variable-value! var val env)
187 665c255d 2023-08-04 jrmu (define (env-loop env)
188 665c255d 2023-08-04 jrmu (define (scan vars vals)
189 665c255d 2023-08-04 jrmu (cond ((null? vars)
190 665c255d 2023-08-04 jrmu (env-loop (enclosing-environment env)))
191 665c255d 2023-08-04 jrmu ((eq? var (car vars))
192 665c255d 2023-08-04 jrmu (set-car! vals val))
193 665c255d 2023-08-04 jrmu (else (scan (cdr vars) (cdr vals)))))
194 665c255d 2023-08-04 jrmu (if (eq? env the-empty-environment)
195 665c255d 2023-08-04 jrmu (error "Unbound variable -- SET!" var)
196 665c255d 2023-08-04 jrmu (let ((frame (first-frame env)))
197 665c255d 2023-08-04 jrmu (scan (frame-variables frame)
198 665c255d 2023-08-04 jrmu (frame-values frame)))))
199 665c255d 2023-08-04 jrmu (env-loop env))
200 665c255d 2023-08-04 jrmu (define (define-variable! var val env)
201 665c255d 2023-08-04 jrmu (let ((frame (first-frame env)))
202 665c255d 2023-08-04 jrmu (define (scan vars vals)
203 665c255d 2023-08-04 jrmu (cond ((null? vars)
204 665c255d 2023-08-04 jrmu (add-binding-to-frame! var val frame))
205 665c255d 2023-08-04 jrmu ((eq? var (car vars))
206 665c255d 2023-08-04 jrmu (set-car! vals val))
207 665c255d 2023-08-04 jrmu (else (scan (cdr vars) (cdr vals)))))
208 665c255d 2023-08-04 jrmu (scan (frame-variables frame)
209 665c255d 2023-08-04 jrmu (frame-values frame))))
210 665c255d 2023-08-04 jrmu (define (primitive-procedure? proc)
211 665c255d 2023-08-04 jrmu (tagged-list? proc 'primitive))
213 665c255d 2023-08-04 jrmu (define (primitive-implementation proc) (cadr proc))
214 665c255d 2023-08-04 jrmu (define primitive-procedures
215 665c255d 2023-08-04 jrmu (list (list 'car car)
216 665c255d 2023-08-04 jrmu (list 'cdr cdr)
217 665c255d 2023-08-04 jrmu (list 'cons cons)
218 665c255d 2023-08-04 jrmu (list 'null? null?)
219 665c255d 2023-08-04 jrmu (list '* *)
220 665c255d 2023-08-04 jrmu (list '/ /)
221 665c255d 2023-08-04 jrmu (list '+ +)
222 665c255d 2023-08-04 jrmu (list '- -)
223 665c255d 2023-08-04 jrmu (list '= =)
224 665c255d 2023-08-04 jrmu (list 'display display)))
225 665c255d 2023-08-04 jrmu (define (primitive-procedure-names)
227 665c255d 2023-08-04 jrmu primitive-procedures))
229 665c255d 2023-08-04 jrmu (define (primitive-procedure-objects)
230 665c255d 2023-08-04 jrmu (map (lambda (proc) (list 'primitive (cadr proc)))
231 665c255d 2023-08-04 jrmu primitive-procedures))
232 665c255d 2023-08-04 jrmu (define (apply-primitive-procedure proc args)
233 665c255d 2023-08-04 jrmu (apply-in-underlying-scheme
234 665c255d 2023-08-04 jrmu (primitive-implementation proc) args))
235 665c255d 2023-08-04 jrmu (define input-prompt ";;; M-Eval input:")
236 665c255d 2023-08-04 jrmu (define output-prompt ";;; M-Eval value:")
237 665c255d 2023-08-04 jrmu (define (driver-loop)
238 665c255d 2023-08-04 jrmu (prompt-for-input input-prompt)
239 665c255d 2023-08-04 jrmu (let ((input (read)))
240 665c255d 2023-08-04 jrmu (let ((output (eval input the-global-environment)))
241 665c255d 2023-08-04 jrmu (announce-output output-prompt)
242 665c255d 2023-08-04 jrmu (user-print output)))
243 665c255d 2023-08-04 jrmu (driver-loop))
244 665c255d 2023-08-04 jrmu (define (prompt-for-input string)
245 665c255d 2023-08-04 jrmu (newline) (newline) (display string) (newline))
247 665c255d 2023-08-04 jrmu (define (announce-output string)
248 665c255d 2023-08-04 jrmu (newline) (display string) (newline))
249 665c255d 2023-08-04 jrmu (define (user-print object)
250 665c255d 2023-08-04 jrmu (if (compound-procedure? object)
251 665c255d 2023-08-04 jrmu (display (list 'compound-procedure
252 665c255d 2023-08-04 jrmu (procedure-parameters object)
253 665c255d 2023-08-04 jrmu (procedure-body object)
254 665c255d 2023-08-04 jrmu '<procedure-env>))
255 665c255d 2023-08-04 jrmu (display object)))
256 665c255d 2023-08-04 jrmu (define (setup-environment)
257 665c255d 2023-08-04 jrmu (let ((initial-env
258 665c255d 2023-08-04 jrmu (extend-environment (primitive-procedure-names)
259 665c255d 2023-08-04 jrmu (primitive-procedure-objects)
260 665c255d 2023-08-04 jrmu the-empty-environment)))
261 665c255d 2023-08-04 jrmu (define-variable! 'true true initial-env)
262 665c255d 2023-08-04 jrmu (define-variable! 'false false initial-env)
263 665c255d 2023-08-04 jrmu initial-env))
264 665c255d 2023-08-04 jrmu (define the-global-environment (setup-environment))
266 665c255d 2023-08-04 jrmu (define (make-let vars vals body)
268 665c255d 2023-08-04 jrmu (cons (map (lambda (var val)
269 665c255d 2023-08-04 jrmu (list var val))
272 665c255d 2023-08-04 jrmu (define (let? exp)
273 665c255d 2023-08-04 jrmu (tagged-list? exp 'let))
274 665c255d 2023-08-04 jrmu (define (let-vars exp)
275 665c255d 2023-08-04 jrmu (map car (cadr exp)))
276 665c255d 2023-08-04 jrmu (define (let-vals exp)
277 665c255d 2023-08-04 jrmu (map cadr (cadr exp)))
278 665c255d 2023-08-04 jrmu (define (let-body exp)
279 665c255d 2023-08-04 jrmu (cddr exp))
280 665c255d 2023-08-04 jrmu (define (let->combination exp)
281 665c255d 2023-08-04 jrmu (make-application (make-lambda (let-vars exp) (let-body exp))
282 665c255d 2023-08-04 jrmu (let-vals exp)))
283 665c255d 2023-08-04 jrmu (define (make-application op args)
284 665c255d 2023-08-04 jrmu (cons op args))
286 665c255d 2023-08-04 jrmu (define (test-case actual expected)
288 665c255d 2023-08-04 jrmu (display "Actual: ")
289 665c255d 2023-08-04 jrmu (display actual)
291 665c255d 2023-08-04 jrmu (display "Expected: ")
292 665c255d 2023-08-04 jrmu (display expected)
295 665c255d 2023-08-04 jrmu (define (geval exp) ;; eval globally
296 665c255d 2023-08-04 jrmu (eval exp the-global-environment))
298 665c255d 2023-08-04 jrmu ;; Exercise 4.4. Recall the definitions of the special forms and and or from chapter 1:
300 665c255d 2023-08-04 jrmu ;; and: The expressions are evaluated from left to right. If any expression evaluates to false, false is returned; any remaining expressions are not evaluated. If all the expressions evaluate to true values, the value of the last expression is returned. If there are no expressions then true is returned.
302 665c255d 2023-08-04 jrmu ;; or: The expressions are evaluated from left to right. If any expression evaluates to a true value, that value is returned; any remaining expressions are not evaluated. If all expressions evaluate to false, or if there are no expressions, then false is returned.
304 665c255d 2023-08-04 jrmu ;; Install and and or as new special forms for the evaluator by defining appropriate syntax procedures and evaluation procedures eval-and and eval-or. Alternatively, show how to implement and and or as derived expressions.
306 665c255d 2023-08-04 jrmu (define (and? exp)
307 665c255d 2023-08-04 jrmu (tagged-list? exp 'and))
308 665c255d 2023-08-04 jrmu (define (and-clauses exp)
310 665c255d 2023-08-04 jrmu ;; (define (and->if exp)
311 665c255d 2023-08-04 jrmu ;; (define (expand-clauses clauses)
312 665c255d 2023-08-04 jrmu ;; (cond ((null? clauses) 'true)
313 665c255d 2023-08-04 jrmu ;; ((null? (cdr clauses)) (car clauses))
314 665c255d 2023-08-04 jrmu ;; (else (make-if (car clauses)
315 665c255d 2023-08-04 jrmu ;; (expand-clauses (cdr clauses))
316 665c255d 2023-08-04 jrmu ;; 'false))))
317 665c255d 2023-08-04 jrmu ;; (expand-clauses (and-clauses exp)))
318 665c255d 2023-08-04 jrmu (define (or? exp)
319 665c255d 2023-08-04 jrmu (tagged-list? exp 'or))
320 665c255d 2023-08-04 jrmu (define (or-clauses exp)
322 665c255d 2023-08-04 jrmu ;; the problem with this definition is that each clause will be evaluated twice; this is unacceptable if there are side effects
323 665c255d 2023-08-04 jrmu ;; (define (or->if exp)
324 665c255d 2023-08-04 jrmu ;; (define (expand-clauses clauses)
325 665c255d 2023-08-04 jrmu ;; (if (null? clauses)
327 665c255d 2023-08-04 jrmu ;; (make-if (car clauses)
328 665c255d 2023-08-04 jrmu ;; (car clauses)
329 665c255d 2023-08-04 jrmu ;; (expand-clauses (cdr clauses)))))
330 665c255d 2023-08-04 jrmu ;; (expand-clauses (or-clauses exp)))
333 665c255d 2023-08-04 jrmu ;; we can also install and/or as special forms
335 665c255d 2023-08-04 jrmu (define (eval-and exp env)
336 665c255d 2023-08-04 jrmu (define (eval-clauses clauses)
337 665c255d 2023-08-04 jrmu (cond ((null? clauses) true)
338 665c255d 2023-08-04 jrmu ((null? (cdr clauses)) (eval (car clauses) env))
339 665c255d 2023-08-04 jrmu (else (and (eval (car clauses) env)
340 665c255d 2023-08-04 jrmu (eval-clauses (cdr clauses))))))
341 665c255d 2023-08-04 jrmu (eval-clauses (and-clauses exp)))
342 665c255d 2023-08-04 jrmu (define (eval-or exp env)
343 665c255d 2023-08-04 jrmu (define (eval-clauses clauses)
344 665c255d 2023-08-04 jrmu (if (null? clauses)
346 665c255d 2023-08-04 jrmu (or (eval (car clauses) env)
347 665c255d 2023-08-04 jrmu (eval-clauses (cdr clauses)))))
348 665c255d 2023-08-04 jrmu (eval-clauses (or-clauses exp)))
350 665c255d 2023-08-04 jrmu ;; test-suite
352 665c255d 2023-08-04 jrmu ;; make-let
353 665c255d 2023-08-04 jrmu (test-case (geval (make-let '(x y) '(3 5) '((+ x y))))
357 665c255d 2023-08-04 jrmu (geval '(define x (+ 3 8)))
358 665c255d 2023-08-04 jrmu (test-case (geval '(and 0 true x)) 11)
359 665c255d 2023-08-04 jrmu (test-case (geval '(and 0 true x false)) false)
360 665c255d 2023-08-04 jrmu (test-case (geval '(and 0 true x (set! x -2) false)) false)
361 665c255d 2023-08-04 jrmu (test-case (geval 'x) -2)
362 665c255d 2023-08-04 jrmu (test-case (geval '(and 0 true x false (set! x -5))) false)
363 665c255d 2023-08-04 jrmu (test-case (geval 'x) -2)
364 665c255d 2023-08-04 jrmu (test-case (geval '(or false (set! x 25))) 'ok)
365 665c255d 2023-08-04 jrmu (test-case (geval 'x) 25)
366 665c255d 2023-08-04 jrmu (test-case (geval '(or (set! x 2) (set! x 4))) 'ok)
367 665c255d 2023-08-04 jrmu (test-case (geval 'x) 2)
368 665c255d 2023-08-04 jrmu (test-case (geval '(or false (set! x 25) true false)) 'ok)
369 665c255d 2023-08-04 jrmu (test-case (geval 'x) 25)
370 665c255d 2023-08-04 jrmu (test-case (geval '(or ((lambda (x) x) 5))) 5)
371 665c255d 2023-08-04 jrmu (test-case (geval '(or (begin (set! x (+ x 1)) x))) 26)
374 665c255d 2023-08-04 jrmu ;; all special forms
375 665c255d 2023-08-04 jrmu (test-case (geval '(begin 5 6)) 6)
376 665c255d 2023-08-04 jrmu (test-case (geval '10) 10)
377 665c255d 2023-08-04 jrmu (geval '(define x 3))
378 665c255d 2023-08-04 jrmu (test-case (geval 'x) 3)
379 665c255d 2023-08-04 jrmu (test-case (geval '(set! x -25)) 'ok)
380 665c255d 2023-08-04 jrmu (test-case (geval 'x) -25)
381 665c255d 2023-08-04 jrmu (geval '(define z (lambda (x y) (+ x (* x y)))))
382 665c255d 2023-08-04 jrmu (test-case (geval '(z 3 4)) 15)
383 665c255d 2023-08-04 jrmu (test-case (geval '(cond ((= x -2) 'x=-2)
384 665c255d 2023-08-04 jrmu ((= x -25) 'x=-25)
385 665c255d 2023-08-04 jrmu (else 'failed)))
387 665c255d 2023-08-04 jrmu (test-case (geval '(if true false true)) false)
388 665c255d 2023-08-04 jrmu (test-case (geval
389 665c255d 2023-08-04 jrmu '(let ((x 4) (y 7))
390 665c255d 2023-08-04 jrmu (+ x y (* x y))))
391 665c255d 2023-08-04 jrmu (+ 4 7 (* 4 7)))
393 665c255d 2023-08-04 jrmu ;; procedure definition and application
395 665c255d 2023-08-04 jrmu '(define (factorial n)
396 665c255d 2023-08-04 jrmu (if (= n 0)
398 665c255d 2023-08-04 jrmu (* n (factorial (- n 1))))))
399 665c255d 2023-08-04 jrmu (test-case (geval '(factorial 5)) 120)
