Refactor and turn lib.cairo back into scaffold

exercism · Jul 3, 2024 · 1464a5b · 1464a5b
1 parent 01fd6d1
commit 1464a5b
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diff --git a/exercises/practice/rational-numbers/.meta/example.cairo b/exercises/practice/rational-numbers/.meta/example.cairo
@@ -6,28 +6,28 @@ use core::fmt::{Debug, Formatter, Error};
 #[derive(Drop, Debug, Copy)]
 struct Rational {
     numer: i128,
-    denom: i128,
+    denom: u128,
 }
 
 #[generate_trait]
 impl RationalImpl of RationalTrait {
     fn new(numer: i128, denom: i128) -> Rational {
         assert!(denom != 0, "denominator cannot be 0");
 
-        let numer_sign: i128 = if (numer < 0 && denom > 0) || (numer > 0 && denom < 0) {
+        let sign: i128 = if (numer < 0 && denom > 0) || (numer > 0 && denom < 0) {
             -1
         } else {
             1
         };
 
-        let numer_abs = abs(numer);
-        let denom_abs = abs(denom);
-        let gcd_num = gcd_two_numbers(numer_abs, denom_abs);
+        let numer = abs(numer);
+        let denom = abs(denom);
+        let gcd_num = gcd_two_numbers(numer, denom);
 
-        let mut numer_minif = to_i128(numer_abs / gcd_num) * numer_sign;
-        let denom_minif = to_i128(denom_abs / gcd_num);
+        let numer = to_i128(numer / gcd_num) * sign;
+        let denom = denom / gcd_num;
 
-        Rational { numer: numer_minif, denom: denom_minif }
+        Rational { numer, denom }
     }
 }
 
@@ -43,14 +43,14 @@ impl RationalPartialEq of PartialEq<Rational> {
 
 impl RationalNeg of Neg<Rational> {
     fn neg(a: Rational) -> Rational {
-        RationalTrait::new(a.numer * -1, a.denom)
+        RationalTrait::new(a.numer * -1, to_i128(a.denom))
     }
 }
 
 impl RationalAdd of Add<Rational> {
     fn add(lhs: Rational, rhs: Rational) -> Rational {
-        let numer = (lhs.numer * rhs.denom) + (lhs.denom * rhs.numer);
-        let denom = lhs.denom * rhs.denom;
+        let numer = (lhs.numer * to_i128(rhs.denom)) + (to_i128(lhs.denom) * rhs.numer);
+        let denom = to_i128(lhs.denom * rhs.denom);
         RationalTrait::new(numer, denom)
     }
 }
@@ -63,20 +63,20 @@ impl RationalSub of Sub<Rational> {
 
 impl RationalMul of Mul<Rational> {
     fn mul(lhs: Rational, rhs: Rational) -> Rational {
-        RationalTrait::new(lhs.numer * rhs.numer, lhs.denom * rhs.denom)
+        RationalTrait::new(lhs.numer * rhs.numer, to_i128(lhs.denom * rhs.denom))
     }
 }
 
 impl RationalDiv of Div<Rational> {
     fn div(lhs: Rational, rhs: Rational) -> Rational {
-        RationalTrait::new(lhs.numer * rhs.denom, lhs.denom * rhs.numer)
+        RationalTrait::new(lhs.numer * to_i128(rhs.denom), to_i128(lhs.denom) * rhs.numer)
     }
 }
 
 #[generate_trait]
 impl RationalAbs of RationalAbsTrait {
     fn abs(self: @Rational) -> Rational {
-        RationalTrait::new(to_i128(abs(*self.numer)), *self.denom)
+        RationalTrait::new(to_i128(abs(*self.numer)), to_i128(*self.denom))
     }
 }
 
@@ -88,23 +88,20 @@ impl RationalPow of RationalPowTrait {
         };
         // fast_power works only with unsigned integers
         let power_abs = abs(power);
-        let numer = abs(*self.numer);
-        let denom = to_u128(*self.denom);
         // determine the new number's sign
         let sign: i128 = if *self.numer < 0 && power_abs % 2 == 1 {
             -1
         } else {
             1
         };
 
+        let numer = to_i128(fast_power(abs(*self.numer), power_abs)) * sign;
+        let denom = to_i128(fast_power(*self.denom, power_abs));
+
         if power < 0 {
-            RationalTrait::new(
-                sign * to_i128(fast_power(denom, power_abs)), to_i128(fast_power(numer, power_abs))
-            )
+            RationalTrait::new(denom, numer)
         } else {
-            RationalTrait::new(
-                sign * to_i128(fast_power(numer, power_abs)), to_i128(fast_power(denom, power_abs))
-            )
+            RationalTrait::new(numer, denom)
         }
     }
 
@@ -114,7 +111,19 @@ impl RationalPow of RationalPowTrait {
         if power.numer < 0 {
             return 0;
         };
-        fast_nr_optimize(fast_power(*self, to_u128(power.numer)), to_u128(power.denom), 30)
+        fast_nr_optimize(fast_power(*self, to_u128(power.numer)), power.denom, 30)
+    }
+}
+
+// Enables printing i128 values in tests.
+// Note that this will soon be added to the core library.
+impl I128Debug of Debug<i128> {
+    fn fmt(self: @i128, ref f: Formatter) -> Result<(), Error> {
+        if *self < 0 {
+            f.buffer.append(@"-");
+        };
+        f.buffer.append(@format!("{}", abs(*self)));
+        Result::Ok(())
     }
 }
 
@@ -135,15 +144,5 @@ fn to_u128(n: i128) -> u128 {
     n.try_into().unwrap()
 }
 
-impl I128Debug of Debug<i128> {
-    fn fmt(self: @i128, ref f: Formatter) -> Result<(), Error> {
-        if *self < 0 {
-            f.buffer.append(@"-");
-        };
-        f.buffer.append(@format!("{}", abs(*self)));
-        Result::Ok(())
-    }
-}
-
 #[cfg(test)]
 mod tests;
diff --git a/exercises/practice/rational-numbers/src/lib.cairo b/exercises/practice/rational-numbers/src/lib.cairo
@@ -1,140 +1,75 @@
-use alexandria_math::gcd_of_n_numbers::gcd_two_numbers;
-use alexandria_math::fast_power::fast_power;
-use alexandria_math::fast_root::fast_nr_optimize;
 use core::fmt::{Debug, Formatter, Error};
 
-#[derive(Drop, Debug, Copy)]
-struct Rational {
-    numer: i128,
-    denom: u128,
-}
+#[derive(Drop, Debug)]
+struct Rational {}
 
 #[generate_trait]
 impl RationalImpl of RationalTrait {
     fn new(numer: i128, denom: i128) -> Rational {
-        assert!(denom != 0, "denominator cannot be 0");
-
-        let sign: i128 = if (numer < 0 && denom > 0) || (numer > 0 && denom < 0) {
-            -1
-        } else {
-            1
-        };
-
-        let numer = abs(numer);
-        let denom = abs(denom);
-        let gcd_num = gcd_two_numbers(numer, denom);
-
-        let numer = to_i128(numer / gcd_num) * sign;
-        let denom = denom / gcd_num;
-
-        Rational { numer, denom }
+        panic!()
     }
 }
 
 impl RationalPartialEq of PartialEq<Rational> {
     fn eq(lhs: @Rational, rhs: @Rational) -> bool {
-        lhs.numer == rhs.numer && lhs.denom == rhs.denom
+        panic!()
     }
 
     fn ne(lhs: @Rational, rhs: @Rational) -> bool {
-        !(lhs == rhs)
+        panic!()
     }
 }
 
 impl RationalNeg of Neg<Rational> {
     fn neg(a: Rational) -> Rational {
-        RationalTrait::new(a.numer * -1, to_i128(a.denom))
+        panic!()
     }
 }
 
 impl RationalAdd of Add<Rational> {
     fn add(lhs: Rational, rhs: Rational) -> Rational {
-        let numer = (lhs.numer * to_i128(rhs.denom)) + (to_i128(lhs.denom) * rhs.numer);
-        let denom = to_i128(lhs.denom * rhs.denom);
-        RationalTrait::new(numer, denom)
+        panic!()
     }
 }
 
 impl RationalSub of Sub<Rational> {
     fn sub(lhs: Rational, rhs: Rational) -> Rational {
-        lhs + (-rhs)
+        panic!()
     }
 }
 
 impl RationalMul of Mul<Rational> {
     fn mul(lhs: Rational, rhs: Rational) -> Rational {
-        RationalTrait::new(lhs.numer * rhs.numer, to_i128(lhs.denom * rhs.denom))
+        panic!()
     }
 }
 
 impl RationalDiv of Div<Rational> {
     fn div(lhs: Rational, rhs: Rational) -> Rational {
-        RationalTrait::new(lhs.numer * to_i128(rhs.denom), to_i128(lhs.denom) * rhs.numer)
+        panic!()
     }
 }
 
 #[generate_trait]
 impl RationalAbs of RationalAbsTrait {
     fn abs(self: @Rational) -> Rational {
-        RationalTrait::new(to_i128(abs(*self.numer)), to_i128(*self.denom))
+        panic!()
     }
 }
 
 #[generate_trait]
 impl RationalPow of RationalPowTrait {
     fn pow(self: @Rational, power: i128) -> Rational {
-        if *self.numer == 0 {
-            return *self;
-        };
-        // fast_power works only with unsigned integers
-        let power_abs = abs(power);
-        let numer = abs(*self.numer);
-        let denom = *self.denom;
-        // determine the new number's sign
-        let sign: i128 = if *self.numer < 0 && power_abs % 2 == 1 {
-            -1
-        } else {
-            1
-        };
-
-        if power < 0 {
-            RationalTrait::new(
-                sign * to_i128(fast_power(denom, power_abs)), to_i128(fast_power(numer, power_abs))
-            )
-        } else {
-            RationalTrait::new(
-                sign * to_i128(fast_power(numer, power_abs)), to_i128(fast_power(denom, power_abs))
-            )
-        }
+        panic!()
     }
 
     fn rpow(self: @u128, power: Rational) -> u128 {
-        // Cairo does not support floating point numbers, so a negative rational number
-        // will always return the result 0 (as 1 divided by any number is 0 in Cairo)
-        if power.numer < 0 {
-            return 0;
-        };
-        fast_nr_optimize(fast_power(*self, to_u128(power.numer)), power.denom, 30)
+        panic!()
     }
 }
 
-fn abs(n: i128) -> u128 {
-    let val = if n < 0 {
-        n * -1
-    } else {
-        n
-    };
-    to_u128(val)
-}
-
-fn to_i128(n: u128) -> i128 {
-    n.try_into().unwrap()
-}
-
-fn to_u128(n: i128) -> u128 {
-    n.try_into().unwrap()
-}
-
+// Enables printing i128 values in tests.
+// Note that this will soon be added to the core library.
 impl I128Debug of Debug<i128> {
     fn fmt(self: @i128, ref f: Formatter) -> Result<(), Error> {
         if *self < 0 {
@@ -145,5 +80,14 @@ impl I128Debug of Debug<i128> {
     }
 }
 
+fn abs(n: i128) -> u128 {
+    let val = if n < 0 {
+        n * -1
+    } else {
+        n
+    };
+    val.try_into().unwrap()
+}
+
 #[cfg(test)]
 mod tests;