Expressions

examples/src/BitArith.jetl

@@ -0,0 +1,29 @@
+fun oneBit(index : Int) = 1 shl index
+
+fun setBit(x : Int, index : Int) = x or oneBit(index)
+fun unsetBit(x : Int, index : Int) = x and not(oneBit(index))
+
+fun getBit(x : Int, index : Int) = x and oneBit(index) != 0
+fun getBit(x : Int, index : Int) = (x shr index) shl 31 != 0
+
+fun countOnes(x : INumber) {
+  var result = 0
+  while (x != 0) {
+    result += x and 1
+    x = x ushr 1
+  }
+  result
+}
+
+fun mostSignificantBit(x : INumber) = (x and oneBit(x.bits - 1) != 0) as Int
+
+fun countOnes(x : INumber) = if (x == 0) 0 else mostSignificantBit(x) + countOnes(x shl 1)
+
+extension fun Int.matchMask(mask : Int) = this and mask == mask
+
+interface class INumber<T : this> : IComparable<T> {
+  val bits : Int
+  [operator] fun plus(other : T) : T
+  [operator] fun shl(bits : Int) : T
+  ...
+}