README.md
This is a compiler for a very lisp-like language based somewhat on scheme. The compiler is written in Racket and when run on a file, will output x86_64 instructions which you then run through NASM to make your executable. I've borrowed asm printer and expanded it to add support for new functionality.
Install Racket and NASM
sudo apt-get install racket nasm
To compile a program run racket compile-file.rkt example.srkt, and then run the output assembly through NASM.
Alternatively, run this command to create your executable:
racket compile-file.rkt example.srkt > example.s && nasm -f elf64 -g -o example.o example.s && ld example.o -o example-exe
You will find an example.srkt file in this repo containing all the examples below, which when compiled and run will print the respective outputs.
| Example Program | Description | Program Output |
|---|---|---|
(print "Hello World!") |
Prints the string and newline | Hello World! |
(print "Hello") (print "World!") |
Prints both strings with a newline after each | Hello\nWorld! |
(print (string-ref "Hello World!" 6)) |
Returns the 7th char (0 indexed) in the string | W |
(print (make-string 7 #\w)) |
Creates a string of 7 'w' chars | wwwwwww |
(print (integer? 6)) |
Checks if argument is an integer. This returns true | 2 |
(print (integer? #\b)) |
Checks if argument is an integer. This returns false | 0 |
(print (= (/ 8 4) 2)) |
Checks if 8 / 4 is equal to 2. This returns true |
2 |
(print (if (= (/ 8 4) 2) #t #f)) |
Checks if the condition (1st argument) is true, and it is so it evaluates the 2nd argument | 2 |
(print (if (< (* 8 8) 64) #t #f)) |
Checks if the condition (1st argument) is true, and it isn't so it evaluates the 3rd argument | 0 |
(print (abs -10)) |
Abolsute value of -10
|
10 |
(print (cond [(zero? 1) 2] [(zero? (sub1 1)) 4] [else 3])) |
Evaluates the conditions until one is true or the else is reached | 4 |
(print (if (zero? (if (zero? 0) 1 0)) (if (zero? 1) 1 2) 7)) |
Example of using expressions inside if statement 2nd and 3rd arguments | 7 |
(let ((x 7)) (print x)) |
Assigning the value 7 to the variable x and printing it |
7 |
(print (car (cons 1 2))) |
Creating a list and returning the 1st element | 1 |
(print (cdr (cons 1 2))) |
Creating a list and returning the last element | 2 |
supported types, keywords, and operations here:
type Token =
| Integer
| Char
| Boolean
| String
| '()
| `(variable ,Variable)
| `(keyword ,Keyword)
| `(prim ,Prim)
| 'lparen ;(
| 'rparen ;)
| 'lsquare ;[
| 'rsquare ;]
| 'eof ;end of file
type Variable = Symbol (other than 'let, 'cond, etc.)
type Keyword =
| 'let
| 'let*
| 'cond
| 'else
| 'if
| 'print
type Prim = Prim1 | Prim2 | '-
type Prim1 =
| 'add1
| 'sub1
| 'zero?
| 'abs
| 'integer->char
| 'char->integer
| 'char?
| 'boolean?
| 'integer?
| 'string?
| 'box?
| 'empty?
| 'cons?
| 'box
| 'unbox
| 'car
| 'cdr
| 'string-length
type Prim2 =
| 'cons
| 'make-string
| 'string-ref
| '=
| '<
| '<=
| 'char=?
| 'boolean=?
| '+
| '*
| '/