From 8550be0ba2b68415a22a65ff72db4952630591d4 Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonyg@leastfixedpoint.com>
Date: Sat, 28 Aug 2021 17:01:59 +0200
Subject: [PATCH] Refactor SignedInteger conversions to be more comprehensive
 and less repetitive

---
 .../preserves/src/value/signed_integer.rs     | 125 +++++++++---------
 1 file changed, 65 insertions(+), 60 deletions(-)

diff --git a/implementations/rust/preserves/src/value/signed_integer.rs b/implementations/rust/preserves/src/value/signed_integer.rs
index 8b5e45f..9c753e5 100644
--- a/implementations/rust/preserves/src/value/signed_integer.rs
+++ b/implementations/rust/preserves/src/value/signed_integer.rs
@@ -81,29 +81,44 @@ impl SignedInteger {
     }
 }
 
-impl From<i32> for SignedInteger {
-    fn from(v: i32) -> Self {
-        SignedInteger(SignedIntegerRepr::I128(v.into()))
+//--
+
+macro_rules! map_integral_type_to_signed_integer {
+    ($iN:ident, $uN:ident) => {
+        impl From<$iN> for SignedInteger {
+            fn from(v: $iN) -> Self {
+                SignedInteger(SignedIntegerRepr::I128(v.into()))
+            }
+        }
+
+        impl From<$uN> for SignedInteger {
+            fn from(v: $uN) -> Self {
+                SignedInteger(SignedIntegerRepr::I128(v.into()))
+            }
+        }
+
+        impl TryFrom<&SignedInteger> for $iN {
+            type Error = ();
+            fn try_from(v: &SignedInteger) -> Result<Self, Self::Error> {
+                i128::try_from(v)?.try_into().map_err(|_| ())
+            }
+        }
+
+        impl TryFrom<&SignedInteger> for $uN {
+            type Error = ();
+            fn try_from(v: &SignedInteger) -> Result<Self, Self::Error> {
+                u128::try_from(v)?.try_into().map_err(|_| ())
+            }
+        }
     }
 }
 
-impl From<u32> for SignedInteger {
-    fn from(v: u32) -> Self {
-        SignedInteger(SignedIntegerRepr::I128(v.into()))
-    }
-}
+map_integral_type_to_signed_integer!(i8, u8);
+map_integral_type_to_signed_integer!(i16, u16);
+map_integral_type_to_signed_integer!(i32, u32);
+map_integral_type_to_signed_integer!(i64, u64);
 
-impl From<i64> for SignedInteger {
-    fn from(v: i64) -> Self {
-        SignedInteger(SignedIntegerRepr::I128(v.into()))
-    }
-}
-
-impl From<u64> for SignedInteger {
-    fn from(v: u64) -> Self {
-        SignedInteger(SignedIntegerRepr::I128(v.into()))
-    }
-}
+//--
 
 impl From<i128> for SignedInteger {
     fn from(v: i128) -> Self {
@@ -121,24 +136,6 @@ impl From<u128> for SignedInteger {
     }
 }
 
-impl From<BigInt> for SignedInteger {
-    fn from(v: BigInt) -> Self {
-        Self::from(Cow::Owned(v))
-    }
-}
-
-impl<'a> From<Cow<'a, BigInt>> for SignedInteger {
-    fn from(v: Cow<'a, BigInt>) -> Self {
-        if let Some(w) = v.to_i128() {
-            SignedInteger(SignedIntegerRepr::I128(w))
-        } else if let Some(w) = v.to_u128() {
-            SignedInteger(SignedIntegerRepr::U128(w))
-        } else {
-            SignedInteger(SignedIntegerRepr::Big(Box::new(v.into_owned())))
-        }
-    }
-}
-
 impl TryFrom<&SignedInteger> for i128 {
     type Error = ();
     fn try_from(v: &SignedInteger) -> Result<Self, Self::Error> {
@@ -161,13 +158,11 @@ impl TryFrom<&SignedInteger> for u128 {
     }
 }
 
-impl<'a> From<&'a SignedInteger> for Cow<'a, BigInt> {
-    fn from(v: &'a SignedInteger) -> Self {
-        match v.repr() {
-            SignedIntegerRepr::I128(i) => Cow::Owned(BigInt::from(*i)),
-            SignedIntegerRepr::U128(u) => Cow::Owned(BigInt::from(*u)),
-            SignedIntegerRepr::Big(n) => Cow::Borrowed(n),
-        }
+//--
+
+impl From<BigInt> for SignedInteger {
+    fn from(v: BigInt) -> Self {
+        Self::from(Cow::Owned(v))
     }
 }
 
@@ -181,31 +176,41 @@ impl<'a> From<&'a SignedInteger> for BigInt {
     }
 }
 
-impl TryFrom<&SignedInteger> for i32 {
-    type Error = ();
-    fn try_from(v: &SignedInteger) -> Result<Self, Self::Error> {
-        i128::try_from(v)?.try_into().map_err(|_| ())
+//--
+
+impl<'a> From<Cow<'a, BigInt>> for SignedInteger {
+    fn from(v: Cow<'a, BigInt>) -> Self {
+        if let Some(w) = v.to_i128() {
+            SignedInteger(SignedIntegerRepr::I128(w))
+        } else if let Some(w) = v.to_u128() {
+            SignedInteger(SignedIntegerRepr::U128(w))
+        } else {
+            SignedInteger(SignedIntegerRepr::Big(Box::new(v.into_owned())))
+        }
     }
 }
 
-impl TryFrom<&SignedInteger> for u32 {
-    type Error = ();
-    fn try_from(v: &SignedInteger) -> Result<Self, Self::Error> {
-        u128::try_from(v)?.try_into().map_err(|_| ())
+impl<'a> From<&'a SignedInteger> for Cow<'a, BigInt> {
+    fn from(v: &'a SignedInteger) -> Self {
+        match v.repr() {
+            SignedIntegerRepr::I128(i) => Cow::Owned(BigInt::from(*i)),
+            SignedIntegerRepr::U128(u) => Cow::Owned(BigInt::from(*u)),
+            SignedIntegerRepr::Big(n) => Cow::Borrowed(n),
+        }
     }
 }
 
-impl TryFrom<&SignedInteger> for i64 {
-    type Error = ();
-    fn try_from(v: &SignedInteger) -> Result<Self, Self::Error> {
-        i128::try_from(v)?.try_into().map_err(|_| ())
+//--
+
+impl From<isize> for SignedInteger {
+    fn from(v: isize) -> Self {
+        SignedInteger(SignedIntegerRepr::I128(v as i128))
     }
 }
 
-impl TryFrom<&SignedInteger> for u64 {
-    type Error = ();
-    fn try_from(v: &SignedInteger) -> Result<Self, Self::Error> {
-        u128::try_from(v)?.try_into().map_err(|_| ())
+impl From<usize> for SignedInteger {
+    fn from(v: usize) -> Self {
+        SignedInteger(SignedIntegerRepr::U128(v as u128))
     }
 }