Part 3 50 Simple Lisp Interpreter Bison Flex Programming 1

Part 3 (50%) – Simple Lisp Interpreter (Bison & Flex Programming)

1. Design and implement the language for the following simple Lisp interpreter.

2. Language design and implementation

            2.1 number (of type double)

2.2 variable (atom)

Variable - the length of a variable-name can be up to 40 characters long

Support a symbol table to handle many variable entries (at least 100)

A variable is either undefined or to set for a number (type double).

2.3 list expression, for example,

(+ 1 2)

(+ 1.0 2.5)

(+ 1 2 3 4)

(+ (* 1 2) (- 3 4) )

2.4 setq statement to set a variable with a number (to be converted to double), for example,

(setq x 1.5)

2.5 lisp functions for basic arithmetic (+, -, *, /, 1+)

2.6 print function, for example, (print (+ a 10.2))

2.7 (exit) to terminate the program

            3. Try your program with the sample test cases.

1

2.5

(+ 1 2)

(+ 1.0 2.5)

(+ 1 2 3 4)

(+ (* 2 3) 1 (- 5 4))

(setq x 3)

(setq y 4)

(+   x    y)

            (setq z123456789 100.0)  

Solution

As per chegg policy I will be answering only tp 3 questions:

1)

(setq y 34.567)

(print y)

2)

(write-line (string \"Hello boy\"))

3)

(write (+ 1 2))
(terpri)
(write (+ 1.0 2.5))
(terpri)
(write ( + 1 2 3 4)
(terpri)
(write ( +(* 1 2) (- 3 4))