Glisp

Simple lisp implementation on Golang just for fun and self education.

Code examples

Factorial

(fn factorial [num]
    (if (eql num 1)
        num
        (mult
            (factorial (sub num 1))
            num)))
(print (factorial 10)) // 3628800

increment list items

(def arr (list 1 2 3 4 5 6 7 8 9))
(print arr) // 1 2 3 4 5 6 7 8 9

(fn inc [i] (sum i 1))
(def arr2 (map inc arr))
(print arr2) // 2 3 4 5 6 7 8 9 10

sum list items

(def nums (list 1 2 3 4 5))

(fn sumNums [nums]
    (if (eql (length nums) 1)
        (get 0 nums)
        (sum
            (sumNums (sublist nums 0 (sub (length nums) 2)))
            (get (sub (length nums) 1) nums))
))

(print (sumNums nums))

Usage

go build to build binary

./glisp run <filepath> run glisp code from the file

./glisp eval "<glisp_expression>" evaluate glisp expression from command line

Supported syntax

Operators

Calculus

operation	arguments	description	example
sum	2...N (num)	add N numbers	(sum 1 2 3) // 6
sub	2...N (num)	chain subtraction for N numbers	(sub 1 2 3) // -4
mult	2...N (num)	multiply N numbers	(mult 1 2 3) // 6
div	2...N (num)	add N numbers	(div 25 5 2) // 2.5
if	3 (bool, successValue, failValue)	if condition call successValue on true and failValue on false	(if true 5 2) // 5
def	2 (name, value)	define a variable	(def a 10) // 10
print	1 any	print arg to console log	(print "hello world") // hello world

Logical

operation	arguments	description	example
if	3 (bool, successValue, failValue)	if condition call successValue on true and failValue on false	(if true 5 2) // 5
eql	2 (v1, v2)	check if variables are equal, type including	(eql 10 10) // true (eql "10" 10) // false
more	2 (v1, v2)	check if v1 > v2	(more 10 5) // true
moreEq	2 (v1, v2)	check if v1 >= v2	(moreEq 10 10) // true

Defining

operation	arguments	description	example
def	2 (name, value)	define a variable	(def a 10) // 10
fn	3 (name, [args...], exp)	define a function	(fn inc [arg] (sum arg 1)) (inc 5) // 6

List

operation	arguments	description	example
list	0...N	create a list value	(list 1 2 3) // (1 2 3)
map	2 (fn, list)	you know map	(fn inc [arg] (sum arg 1)) (map inc (list 1 2 3)) // (2 3 4)

CMD

operation	arguments	description	example
print	1 any	print arg to console log	(print "hello world") // hello world

Nested expressions

(print (sum (div 100 2 (sum 2 3)) (sub (20 7 3)))) // 20

Variables

(def a 5)
(def b (mult a a))
(print (sum a b)) // 30

Contribution

Tests

go test -v ./...