Merge pull request #54 from rustysec/power_of

i64 and f64 exponent implementation

src/engine.rs

@@ -1418,6 +1418,9 @@ impl Engine {
         fn left_shift<T: Shl<T>>(x: T, y: T)   -> <T as Shl<T>>::Output { x.shl(y) }
         fn right_shift<T: Shr<T>>(x: T, y: T)   -> <T as Shr<T>>::Output { x.shr(y) }
         fn modulo<T: Rem<T>>(x: T, y: T)   -> <T as Rem<T>>::Output { x % y}
+        fn pow_i64_i64(x: i64, y: i64) -> i64 { x.pow(y as u32) }
+        fn pow_f64_f64(x: f64, y: f64) -> f64 { x.powf(y) }
+        fn pow_f64_i64(x: f64, y: i64) -> f64 { x.powi(y as i32) }
 
         reg_op!(engine, "+", add, i32, i64, u32, u64, f32, f64);
         reg_op!(engine, "-", sub, i32, i64, u32, u64, f32, f64);
@@ -1441,6 +1444,9 @@ impl Engine {
         reg_op!(engine, "<<", left_shift, i32, i64, u32, u64);
         reg_op!(engine, ">>", right_shift, i32, i64, u32, u64);
         reg_op!(engine, "%", modulo, i32, i64, u32, u64);
+        engine.register_fn("~", pow_i64_i64);
+        engine.register_fn("~", pow_f64_f64);
+        engine.register_fn("~", pow_f64_i64);
 
         reg_un!(engine, "-", neg, i32, i64, f32, f64);
         reg_un!(engine, "!", not, bool);

src/lib.rs

@@ -46,8 +46,8 @@ mod engine;
 mod fn_register;
 mod parser;
 
-//#[cfg(test)]
+#[cfg(test)]
-//mod tests;
+mod tests;
 
 pub use engine::{Engine, Scope, EvalAltResult};
 pub use fn_register::FnRegister;

src/parser.rs

@@ -170,6 +170,8 @@ pub enum Token {
     XOr,
     Modulo,
     ModuloEquals,
+    PowerOf,
+    PowerOfEquals,
     LexErr(LexError),
 }
 
@@ -223,7 +225,9 @@ impl Token {
             XOr              |
             Modulo           |
             ModuloEquals     |
-            Return => true,
+            Return           |
+            PowerOf          |
+            PowerOfEquals => true,
             _ => false,
         }
     }
@@ -252,7 +256,8 @@ impl Token {
             Pipe             |
             Or               |
             Ampersand        |
-            And => true,
+            And              |
+            PowerOf => true,
             _ => false,
         }
     }
@@ -701,7 +706,16 @@ impl<'a> TokenIterator<'a> {
                         }
                         _ => return Some(Token::Modulo)
                     }
+                },
+                '~' => {
+                    match self.char_stream.peek() {
+                        Some(&'=') => {
+                            self.char_stream.next();
+                            return Some(Token::PowerOfEquals);
                         }
+                        _ => return Some(Token::PowerOf)
+                    }
+                },
                 _x if _x.is_whitespace() => (),
                 _ => return Some(Token::LexErr(LexError::UnexpectedChar)),
             }
@@ -740,7 +754,8 @@ fn get_precedence(token: &Token) -> i32 {
         | Token::AndEquals
         | Token::OrEquals
         | Token::XOrEquals
-        | Token::ModuloEquals => 10,
+        | Token::ModuloEquals
+        | Token::PowerOfEquals => 10,
         Token::Or
         | Token::XOr
         | Token::Pipe  => 11,
@@ -755,7 +770,8 @@ fn get_precedence(token: &Token) -> i32 {
         Token::Plus
         | Token::Minus => 20,
         Token::Divide
-        | Token::Multiply => 40,
+        | Token::Multiply
+        | Token::PowerOf => 40,
         Token::LeftShift
         | Token::RightShift => 50,
         Token::Modulo => 60,
@@ -1033,7 +1049,15 @@ fn parse_binop<'a>(input: &mut Peekable<TokenIterator<'a>>,
                         Box::new(lhs_curr),
                         Box::new(Expr::FnCall("%".to_string(), vec![lhs_copy, rhs]))
                     )
-                }
+                },
+                Token::PowerOf => Expr::FnCall("~".to_string(), vec![lhs_curr, rhs]),
+                Token::PowerOfEquals => {
+                    let lhs_copy = lhs_curr.clone();
+                    Expr::Assignment(
+                        Box::new(lhs_curr),
+                        Box::new(Expr::FnCall("~".to_string(), vec![lhs_copy, rhs]))
+                    )
+                },
                 _ => return Err(ParseError::UnknownOperator),
             };
         }

src/tests/mod.rs

@@ -17,6 +17,7 @@ mod mismatched_op;
 mod not;
 mod number_literals;
 mod ops;
+mod power_of;
 mod string;
 mod unary_after_binary;
 mod unary_minus;

src/tests/power_of.rs

@@ -0,0 +1,27 @@
+use engine::Engine;
+
+#[test]
+fn test_power_of() {
+    let mut engine = Engine::new();
+
+    assert_eq!(engine.eval::<i64>("2 ~ 3").unwrap(), 8);
+    assert_eq!(engine.eval::<i64>("(-2 ~ 3)").unwrap(), -8);
+    assert_eq!(engine.eval::<f64>("2.2 ~ 3.3").unwrap(), 13.489468760533386_f64);
+    assert_eq!(engine.eval::<f64>("2.0~-2.0").unwrap(), 0.25_f64);
+    assert_eq!(engine.eval::<f64>("(-2.0~-2.0)").unwrap(), 0.25_f64);
+    assert_eq!(engine.eval::<f64>("(-2.0~-2)").unwrap(), 0.25_f64);
+    assert_eq!(engine.eval::<i64>("4~3").unwrap(), 64);
+}
+
+#[test]
+fn test_power_of_equals() {
+    let mut engine = Engine::new();
+
+    assert_eq!(engine.eval::<i64>("let x = 2; x ~= 3; x").unwrap(), 8);
+    assert_eq!(engine.eval::<i64>("let x = -2; x ~= 3; x").unwrap(), -8);
+    assert_eq!(engine.eval::<f64>("let x = 2.2; x ~= 3.3; x").unwrap(), 13.489468760533386_f64);
+    assert_eq!(engine.eval::<f64>("let x = 2.0; x ~= -2.0; x").unwrap(), 0.25_f64);
+    assert_eq!(engine.eval::<f64>("let x = -2.0; x ~= -2.0; x").unwrap(), 0.25_f64);
+    assert_eq!(engine.eval::<f64>("let x = -2.0; x ~= -2; x").unwrap(), 0.25_f64);
+    assert_eq!(engine.eval::<i64>("let x =4; x ~= 3; x").unwrap(), 64);
+}