Difference between revisions of "Itty Bitty Programming Language Assignment"
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==Eval== | ==Eval== | ||
+ | {{RacketToImplement|eval|value?<br/>ensure-value?<br/>expand-environment<br/>eval-under-env|ibpl}} | ||
+ | |||
+ | <syntaxhighlight lang="racket"> | ||
+ | (struct closure (env function) #:transparent) | ||
+ | </syntaxhighlight> | ||
===value?=== | ===value?=== | ||
+ | IBPL expressions evaluate to Racket values. Valid value types are cons cells, integers, closures, and the null empty list. To be a valid value, a cons cell's car and cdr must be valid values. | ||
===ensure-value?=== | ===ensure-value?=== | ||
+ | <syntaxhighlight lang="racket"> | ||
+ | (define (ensure-value? v) | ||
+ | (if (value? v) v (error ("not a value: ~v" v)))) | ||
+ | </syntaxhighlight> | ||
===lookup-value-in-environment=== | ===lookup-value-in-environment=== | ||
<syntaxhighlight lang="racket"> | <syntaxhighlight lang="racket"> | ||
Line 43: | Line 53: | ||
===eval-under-env=== | ===eval-under-env=== | ||
+ | |||
+ | ===eval-exp=== | ||
+ | <syntaxhighlight lang="racket"> | ||
+ | (define (eval-exp e) | ||
+ | (eval-under-env e null)) | ||
+ | </syntaxhighlight> | ||
==Macros== | ==Macros== |
Revision as of 03:29, 6 March 2023
Contents
Credit
This assignment is based on MUPL by Dan Grossman and his team at UW.
Code To Investigate
Ast
(struct IdentifierExp (name) #:transparent)
(struct IntExp (value) #:transparent)
(struct AddExp (left_exp right_exp) #:transparent)
(struct IfGreaterExp (left_exp right_exp then_body_exp else_body_exp) #:transparent)
(struct NilExp () #:transparent)
(struct IsNilExp (exp) #:transparent)
(struct ConsExp (car_exp cdr_exp) #:transparent)
(struct CarOfConsExp (cons_exp) #:transparent)
(struct CdrOfConsExp (cons_exp) #:transparent)
(struct LetExp (binding_name binding_exp body_exp) #:transparent)
(struct FunctionExp (name_option parameter_name body_exp) #:transparent)
(struct CallExp (function_exp argument_exp) #:transparent)
Code To Implement
Warmup
file: | src/main/racket/ibpl/warmup.rkt | ![]() |
functions: | racket-integers->ibpl-IntExps ibpl-IntExps->racket-integers |
racket-integers->ibpl-IntExps
ibpl-IntExps->racket-integers
Eval
file: | src/main/racket/ibpl/eval.rkt | ![]() |
functions: | value? ensure-value? expand-environment eval-under-env |
(struct closure (env function) #:transparent)
value?
IBPL expressions evaluate to Racket values. Valid value types are cons cells, integers, closures, and the null empty list. To be a valid value, a cons cell's car and cdr must be valid values.
ensure-value?
(define (ensure-value? v)
(if (value? v) v (error ("not a value: ~v" v))))
lookup-value-in-environment
(struct entry (name value) #:transparent)
(define (lookup-value-in-environment env identifier-name)
(cond [(null? env) (error "unbound identifier during evaluation" identifier-name)]
[(equal? (entry-name (car env)) identifier-name) (entry-value (car env))]
[#t (lookup-value-in-environment (cdr env) identifier-name)]))
expand-environment
eval-under-env
eval-exp
(define (eval-exp e)
(eval-under-env e null))
Macros
IbIfNil
IbLet*
(struct binding (name exp) #:transparent)