Merge pull request #2252 from natalie-lang/rb/integer-ceildiv

Implement Integer#ceildiv

spec/core/integer/ceildiv_spec.rb

@@ -0,0 +1,22 @@
+require_relative '../../spec_helper'
+
+describe "Integer#ceildiv" do
+  ruby_version_is '3.2' do
+    it "returns a quotient of division which is rounded up to the nearest integer" do
+      0.ceildiv(3).should eql(0)
+      1.ceildiv(3).should eql(1)
+      3.ceildiv(3).should eql(1)
+      4.ceildiv(3).should eql(2)
+
+      4.ceildiv(-3).should eql(-1)
+      -4.ceildiv(3).should eql(-1)
+      -4.ceildiv(-3).should eql(2)
+
+      3.ceildiv(1.2).should eql(3)
+      3.ceildiv(6/5r).should eql(3)
+
+      (10**100-11).ceildiv(10**99-1).should eql(10)
+      (10**100-9).ceildiv(10**99-1).should eql(11)
+    end
+  end
+end

src/integer.rb

@@ -9,8 +9,6 @@ def try_convert(n)
             raise TypeError, "can't convert #{n.class} to Integer (#{n.class}#to_int gives #{result.class})"
           end
         end
-      else
-        nil
       end
     end
   end
@@ -31,7 +29,7 @@ def digits(radix = 10)
     if radix < 0
       raise ArgumentError, 'negative radix'
     elsif radix < 2
-      raise ArgumentError, "invalid radix 0"
+      raise ArgumentError, 'invalid radix 0'
     end
 
     quotient = self
@@ -76,6 +74,10 @@ def fdiv(n)
     end
   end
 
+  def ceildiv(n)
+    -div(-n)
+  end
+
   def gcdlcm(n)
     [gcd(n), lcm(n)]
   end