Ensign Virtual Interpreted Language - first interpreter and a programming language I implemented. Ever.
Fuck if I know. Research? The entire thing is probably useless for advanced stuff.
Good question! I have no idea either. Probably using a text editor of sorts...
Import the project and...
using System.Threading.Tasks;
using EVIL;
using EVIL.Abstraction;
using Environment = EVIL.Environment;
class Program
{
private static Interpreter _interpreter;
private static Environment _environment;
private static readonly string _source = "fn main() { print(\"hello, world!\") }"
static async Task Main(string[] args)
{
_interpreter = new Interpreter();
_environment = new Environment(_interpreter);
_environment.LoadCoreRuntime();
_enviroment.RegisterBuiltIn("print", (interp, args) => {
Console.WriteLine(string.Join(' ', args.Select(x => x.AsString().String));
return DynValue.Zero;
});
await _interpreter.ExecuteAsync(_source, "main", new string[0]);
}
}No. But here's the gist:
Number, string, table, function.
Strings support basic control codes and unicode character inserts.
Numbers are double-precision floating point numbers, hexadecimal format integers are supported.
4. || and &&
3. >, <, >=, <=, == and !=
2. +, -, << and >>
1. *, /, &, |, ^ and %
@ - converts whatever's after it to a string representation
# - returns a variable's length - valid for strings and tables
? - returns a symbol's name
+ - addition (concatenation for strings)
- - subtraction
/ - division
* - multiplication
All arithmetic operators support compound versions of themselves (e.g. +=)
<< - shift left
>> - shift right
^ - XOR
& - AND
| - OR
~ - NOT
|| - Alternative
&& - Conjunction
> - greater than ('longer than' for strings)
< - lesser than ('shorter than' for strings)
>= greater than or equal to (analogous for string)
<= lesser than or equal to (analogous for string)
== equal to
!= not equal to
fn - define a function
for - c-style for-loop
each - foreach-loop
undef - undefine a previously defined symbol
while - while-loop
local - local variable definition
if - condition
elif - else-if
else - else
break - break out of a loop
skip - continue in normal languages
ret - return a value and finish function execution
true - interpreter alias for 1
false - interpreter alias for 0
exit - terminate script execution immediately
// All names functions must be top-level.
//
fn main(args) {
// lua-like count operator is present...
print("there are " + @#args)
// locals are valid only in the block defining it
local frac = 0.1234
local int = 100
// globals are valid throughout the script
some_gvar = 666
some_other_gvar = some_global_var << 2 // bitwise operators are present as in any C-like
some_gvar += 100
print_global() // won't work if executing top-down without entry-point, forward declarations not supported
for (local i = 0; i < 100; i++) {
if (i % 0 == 0 && i != 0) {
skip // same as continue in normal languages
}
if (i == 101) {
exit // terminates script execution immediately
}
if (i == 89) {
break // breaks out of the loop
}
print(@i)
local j = math.floor(i / 2)
while (j) { // anything non-zero is treated as truth, 'true' and 'false' are interpreter aliases for 1 and 0
// ? is 'nameof' operator, returns name of a variable in current scope...
print(?j + @j)
j--
}
}
// functions are 1st-class citizens
local f = fn(a, b) { ret a ^ b }
print(@f(10, 30))
// table initialization is supported...
local t = { 1, 2, "dog", f, f(13, 15) }
// you can iterate over tables...
each (k, v : t) {
sys.print(@k + ": " + @v)
}
local dog = t[2] // tables are 0-indexed...
local o = dog[1] // you can also index strings
// ret anywhere is optional and defaults to 0 if not present.
ret 0
}
fn add(a, b) { ret a + b }
fn print_global() {
// @ is unary operator meaning "whatever it is, i want it as a string"
print(@some_global_var)
}
// there's no namespace separation, dots are allowed in identifier names
fn util.thing() {
ret 69*0x420 // hex numbers are supported
}