Add JSON serialization to big number types

spec/std/json/serialization_spec.cr

@@ -408,6 +408,11 @@ describe "JSON serialization" do
       big.to_json.should eq("1234.567891011121314")
     end
 
+    pending_win32 "does for BigDecimal" do
+      big = BigDecimal.new("1234.567891011121314")
+      big.to_json.should eq("1234.567891011121314")
+    end
+
     it "does for UUID" do
       uuid = UUID.new("ee843b26-56d8-472b-b343-0b94ed9077ff")
       uuid.to_json.should eq("\"ee843b26-56d8-472b-b343-0b94ed9077ff\"")

spec/std/yaml/serialization_spec.cr

@@ -377,6 +377,11 @@ describe "YAML serialization" do
       BigFloat.from_yaml(big.to_yaml).should eq(big)
     end
 
+    pending_win32 "does for BigDecimal" do
+      big = BigDecimal.new("1234.567891011121314")
+      BigDecimal.from_yaml(big.to_yaml).should eq(big)
+    end
+
     it "does for Enum" do
       YAMLSpecEnum.from_yaml(YAMLSpecEnum::One.to_yaml).should eq(YAMLSpecEnum::One)
     end

src/big/json.cr

@@ -1,44 +1,104 @@
 require "json"
 require "big"
 
-def BigInt.new(pull : JSON::PullParser)
-  pull.read_int
-  BigInt.new(pull.raw_value)
-end
+class JSON::Builder
+  # Writes a big integer.
+  def number(number : BigInt)
+    scalar do
+      @io << number
+    end
+  end
 
-def BigInt.from_json_object_key?(key : String)
-  BigInt.new(key)
-rescue ArgumentError
-  nil
-end
+  # Writes a big float.
+  def number(number : BigFloat)
+    scalar do
+      @io << number
+    end
+  end
 
-def BigFloat.new(pull : JSON::PullParser)
-  pull.read_float
-  BigFloat.new(pull.raw_value)
+  # Writes a big decimal.
+  def number(number : BigDecimal)
+    scalar do
+      @io << number
+    end
+  end
 end
 
-def BigFloat.from_json_object_key?(key : String)
-  BigFloat.new(key)
-rescue ArgumentError
-  nil
+struct BigInt
+  def self.new(pull : JSON::PullParser)
+    pull.read_int
+    new(pull.raw_value)
+  end
+
+  def self.from_json_object_key?(key : String)
+    new(key)
+  rescue ArgumentError
+    nil
+  end
+
+  def to_json_object_key
+    to_s
+  end
+
+  def to_json(json : JSON::Builder)
+    json.number(self)
+  end
 end
 
-def BigDecimal.new(pull : JSON::PullParser)
-  case pull.kind
-  when .int?
-    pull.read_int
-    value = pull.raw_value
-  when .float?
-    pull.read_float
-    value = pull.raw_value
-  else
-    value = pull.read_string
-  end
-  BigDecimal.new(value)
+struct BigFloat
+  def self.new(pull : JSON::PullParser)
+    case pull.kind
+    when .int?
+      pull.read_int
+      value = pull.raw_value
+    else
+      pull.read_float
+      value = pull.raw_value
+    end
+    new(value)
+  end
+
+  def self.from_json_object_key?(key : String)
+    new(key)
+  rescue ArgumentError
+    nil
+  end
+
+  def to_json_object_key
+    to_s
+  end
+
+  def to_json(json : JSON::Builder)
+    json.number(self)
+  end
 end
 
-def BigDecimal.from_json_object_key?(key : String)
-  BigDecimal.new(key)
-rescue InvalidBigDecimalException
-  nil
+struct BigDecimal
+  def self.new(pull : JSON::PullParser)
+    case pull.kind
+    when .int?
+      pull.read_int
+      value = pull.raw_value
+    when .float?
+      pull.read_float
+      value = pull.raw_value
+    else
+      value = pull.read_string
+    end
+    new(value)
+  end
+
+  def self.from_json_object_key?(key : String)
+    new(key)
+  rescue InvalidBigDecimalException
+    nil
+  end
+
+  def to_json_object_key
+    to_s
+  end
+
+  def to_json(json : JSON::Builder)
+    json.number(self)
+  end
 end