Merge: Annotation lateinit

[nit.git] / lib / standard / math.nit

diff --git a/lib/standard/math.nit b/lib/standard/math.nit
index 2b55dca..8b5fecb 100644 (file)
--- a/lib/standard/math.nit
+++ b/lib/standard/math.nit
@@ -47,7 +47,7 @@ redef class Int
        # Returns the square root of `self`
        #
        #     assert 16.sqrt == 4
-       fun sqrt: Int `{ return sqrt(recv); `}
+       fun sqrt: Int `{ return sqrt(self); `}
 
        # Returns the greatest common divisor of `self` and `o`
        #
@@ -158,7 +158,7 @@ redef class Float
        #     assert 12.0.abs == 12.0
        #     assert (-34.56).abs == 34.56
        #     assert -34.56.abs == -34.56
-       fun abs: Float `{ return fabs(recv); `}
+       fun abs: Float `{ return fabs(self); `}
 
        # Returns `self` raised at `e` power.
        #
@@ -186,13 +186,13 @@ redef class Float
        #     assert 1.9.ceil == 2.0
        #     assert 2.0.ceil == 2.0
        #     assert (-1.5).ceil == -1.0
-       fun ceil: Float `{ return ceil(recv); `}
+       fun ceil: Float `{ return ceil(self); `}
 
        #     assert 1.1.floor == 1.0
        #     assert 1.9.floor == 1.0
        #     assert 2.0.floor == 2.0
        #     assert (-1.5).floor == -2.0
-       fun floor: Float `{ return floor(recv); `}
+       fun floor: Float `{ return floor(self); `}
 
        # Rounds the value of a float to its nearest integer value
        #
@@ -241,6 +241,11 @@ end
 redef class Collection[ E ]
        # Return a random element form the collection
        # There must be at least one element in the collection
+       #
+       # ~~~
+       # var x = [1,2,3].rand
+       # assert x == 1 or x == 2 or x == 3
+       # ~~~
        fun rand: E
        do
                if is_empty then abort
@@ -252,6 +257,19 @@ redef class Collection[ E ]
                end
                abort
        end
+
+       # Return a new array made of elements in a random order.
+       #
+       # ~~~
+       # var a = [1,2,1].to_shuffle
+       # assert a == [1,1,2] or a == [1,2,1] or a == [2,1,1]
+       # ~~~
+       fun to_shuffle: Array[E]
+       do
+               var res = self.to_a
+               res.shuffle
+               return res
+       end
 end
 
 redef class SequenceRead[E]
@@ -263,6 +281,36 @@ redef class SequenceRead[E]
        end
 end
 
+redef class AbstractArray[E]
+       # Reorder randomly the elements in self.
+       #
+       # ~~~
+       # var a = new Array[Int]
+       #
+       # a.shuffle
+       # assert a.is_empty
+       #
+       # a.add 1
+       # a.shuffle
+       # assert a == [1]
+       #
+       # a.add 2
+       # a.shuffle
+       # assert a == [1,2] or a == [2,1]
+       # ~~~
+       #
+       # ENSURE self.shuffle.has_exactly(old(self))
+       fun shuffle
+       do
+               for i in [0..length[ do
+                       var j = i + (length-i).rand
+                       var tmp = self[i]
+                       self[i] = self[j]
+                       self[j] = tmp
+               end
+       end
+end
+
 redef class Sys
        init
        do