Hello, I am Stan Marsh. This project is my toy interpreted language, common usage supported.

usage:

commandline mode:

stang

parse multiple sourcecode files

stang [filename...]

Note that in the latter mode, the program will exit if the result cannot be evaluated in 3 seconds.

examples:

1.data types

let a = 1
let b = 0.5
let c = true
let d = "hello"
let f = [1, 2, 3]
let g = {name:'stan'}
let h = function(x,y) { return x+y }
print(typeof a, typeof b, typeof c, typeof d, typeof e, typeof f, typeof g, typeof h)

output:

INTEGER, FLOAT, BOOLEAN, STRING, ERROR, ARRAY, HASH, FUNCTION

2.operation:

print(1+2.5)
print("stan"+"marsh"+1)
print(1||false)
print(!0&&true)

let a = 1
a = 2
print(--a)
delete a
print(a)

let h = {name:'stan', arr:[1,2,3]}
h['age'] = 8
delete h['arr'][0]
delete h['name']
print(h)

output:

3.5
stanmarsh1
true
true
1
2
0
0
Error: unknown identifier: 'a' is not defined
{arr:[1, 2, 3], name:stan}
8
1
stan
{age:8, arr:[null, 2, 3]}

The supported operators are:
+ - * / %
&& || !
+= -= *= /=
++(prefix, suffix) --(prefix, suffix)
== != > < >= <=
=(assign) =(define)
() for function call
[] for array or hash indexing
. for method call
typeof delete

note that in Stang, all expression has a return value.
The return value of the program is the return value of the last statement or the last 'return' statement, if that exists.

3.function

let f = function(x,f){
    return f(f(x))
}
f(2, function(x){return x*x})

output:

16

function is a first-class object in Stang.

4.control flow

let f = function(x) {
    if (x>0) {
        return true
    } else {
        return false
    }
}
for (let i=-5;i<=5;i+=2) {
    print(f(i))
}

let i = -5
while (true) {
    print(f(i))
    i += 2
    if (i>5) {
        break
    }
}

output:

false
false           
false           
true            
true            
true            
false           
false           
false           
true            
true            
true 

5.methods and builtin functions

print("stan,kyle".split(','))
print("stan".toUpper().toLower())

print(typeof string(0))
print(number("1.5")+2)

print(now())

let arr = [1,2,3]
arr.push(4)
print(arr.pop())
print(arr)

output:

[stan, kyle]
stan               
STRING             
3.5                
2022-03-30 04:35:06
4                  
[1, 2, 3]