core: Add abs functions for signed integer types

src/libcore/i16.rs

@@ -34,3 +34,8 @@ fn range(lo: i16, hi: i16, it: fn(i16)) {
 fn compl(i: i16) -> i16 {
     u16::compl(i as u16) as i16
 }
+
+#[doc = "Computes the absolute value"]
+fn abs(i: i16) -> i16 {
+    if negative(i) { -i } else { i }
+}

src/libcore/i32.rs

@@ -34,3 +34,8 @@ fn range(lo: i32, hi: i32, it: fn(i32)) {
 fn compl(i: i32) -> i32 {
     u32::compl(i as u32) as i32
 }
+
+#[doc = "Computes the absolute value"]
+fn abs(i: i32) -> i32 {
+    if negative(i) { -i } else { i }
+}

src/libcore/i64.rs

@@ -34,3 +34,8 @@ fn range(lo: i64, hi: i64, it: fn(i64)) {
 fn compl(i: i64) -> i64 {
     u64::compl(i as u64) as i64
 }
+
+#[doc = "Computes the absolute value"]
+fn abs(i: i64) -> i64 {
+    if negative(i) { -i } else { i }
+}

src/libcore/i8.rs

@@ -34,3 +34,8 @@ fn range(lo: i8, hi: i8, it: fn(i8)) {
 fn compl(i: i8) -> i8 {
     u8::compl(i as u8) as i8
 }
+
+#[doc = "Computes the absolute value"]
+fn abs(i: i8) -> i8 {
+    if negative(i) { -i } else { i }
+}

src/libcore/int.rs

@@ -191,6 +191,11 @@ fn compl(i: int) -> int {
     uint::compl(i as uint) as int
 }
 
+#[doc = "Computes the absolute value"]
+fn abs(i: int) -> int {
+    if negative(i) { -i } else { i }
+}
+
 #[test]
 fn test_from_str() {
     assert(from_str("0") == 0);