feat: change behavior of bool builtin

examples/overview.aoc

@@ -175,8 +175,11 @@ float(1) // 1.0
 float("1.1") // 1.1
 float("asdf") // null
 
+// bool builtin does "is truthy" behavior, similar to if/else and loops
 bool(false) // false
 bool("true") // true
+bool("false") // true
+bool(0) //true
 
 floor(1.9) // 1.0
 ceil(1.1) // 2.0

runtime/src/builtin.rs

@@ -234,22 +234,7 @@ fn call_float(args: &[Object]) -> Result<Object, ErrorKind> {
 fn call_bool(args: &[Object]) -> Result<Object, ErrorKind> {
     validate_args_len(args, 1)?;
 
-    let res = match &args[0] {
-        Object::Boolean(bool) => *bool,
-        Object::String(str) => match str.parse() {
-            Ok(res) => res,
-            Err(_) => return Ok(Object::Null),
-        },
-
-        obj => {
-            return Err(ErrorKind::InvalidBuiltinArg {
-                builtin: Builtin::Bool,
-                data_type: obj.into(),
-            })
-        }
-    };
-
-    Ok(Object::Boolean(res))
+    Ok(Object::Boolean(args[0].is_truthy()))
 }
 
 fn call_round<F>(args: &[Object], round: F, builtin: Builtin) -> Result<Object, ErrorKind>

runtime/src/vm/test.rs

@@ -630,6 +630,10 @@ fn builtin() {
         ("char('a')", Ok(Object::Char(b'a'))),
         ("char(97)", Ok(Object::Char(b'a'))),
         ("char(10000)", Ok(Object::Char(16))),
+        // Bool (is truthy)
+        ("bool(0)", Ok(Object::Boolean(true))),
+        ("bool(\"false\")", Ok(Object::Boolean(true))),
+        ("bool(int(\"\"))", Ok(Object::Boolean(false))),
     ];
 
     for (input, expected) in tests {
@@ -654,18 +658,6 @@ fn builtin_float() {
     }
 }
 
-#[test]
-fn builtin_bool() {
-    let tests = [
-        ("bool(\"true\")", Object::Boolean(true)),
-        ("bool(\"false\")", Object::Boolean(false)),
-    ];
-
-    for (input, expected) in tests {
-        run_test(input, Ok(expected));
-    }
-}
-
 #[test]
 fn builtin_string() {
     let tests = [