Itty Bitty Programming Language Interpreter Assignment

In a series of assignments, we will build the Itty Bitty Programming Language (IBPL). The inspiration for these assignments is MUPL by Dan Grossman and his team at UW.

One can build an IBPL Abstract Syntax Tree (AST) with the following expressions:

Expressions

(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)

Values

int

• exact-integer?

the empty list

• null
• null?

the mighty cons cell

• cons
• cons?
• car
• cdr

closure

(struct closure (env function) #:transparent)

Utility

entry

Environments in IBPL will be stored as a list of entries. An entry is comprised of a name of type string and a value which is a value.

• string?
• value?

(struct entry (name value) #:transparent)

Code To Implement

file:	src/main/racket/ibpl/interpreter/interpreter.rkt
functions:	value? expand-environment evaluate

value?

(define (value? v)
        (error 'not-yet-implemented))

expand-environment

(define (expand-environment name value env)
        (error 'not-yet-implemented))

evaluate

(define (evaluate exp env)
  (if (expression? exp)
      (if (list? env)
          (ensure-value? 
                 (error 'not-yet-implemented))
          (raise-argument-error 'env "list?" env))
      (raise-argument-error 'exp "expression?" exp)))

Test

file:	test_interpreter.rkt	Test
source folder:	src/test/racket/ibpl/interpreter

note: ensure that you have removed all printing to receive credit for any assignment.