Allow leading + in number strings

spec/std/big/big_decimal_spec.cr

@@ -177,6 +177,7 @@ describe BigDecimal do
   it "can be converted from other types" do
     1.to_big_d.should eq (BigDecimal.new(1))
     "1.5".to_big_d.should eq (BigDecimal.new(15, 1))
+    "+1.5".to_big_d.should eq (BigDecimal.new(15, 1))
     BigInt.new(15).to_big_d.should eq (BigDecimal.new(15, 0))
     1.5.to_big_d.should eq (BigDecimal.new(15, 1))
     1.5.to_big_f.to_big_d.should eq (BigDecimal.new(15, 1))

spec/std/big/big_float_spec.cr

@@ -11,6 +11,8 @@ describe "BigFloat" do
     it "new(String)" do
       bigfloat_of_integer_value.to_s.should eq(string_of_integer_value)
       bigfloat_of_float_value.to_s.should eq(string_of_float_value)
+      BigFloat.new("+#{string_of_integer_value}").to_s.should eq(string_of_integer_value)
+      BigFloat.new("-#{string_of_integer_value}").to_s.should eq("-#{string_of_integer_value}")
     end
 
     it "new(BigInt)" do

spec/std/big/big_int_spec.cr

@@ -22,6 +22,8 @@ describe "BigInt" do
 
   it "creates from string" do
     BigInt.new("12345678").to_s.should eq("12345678")
+    BigInt.new("+12345678").to_s.should eq("12345678")
+    BigInt.new("-12345678").to_s.should eq("-12345678")
   end
 
   it "raises if creates from string but invalid" do

src/big/big_decimal.cr

@@ -45,6 +45,9 @@ struct BigDecimal < Number
   #
   # Allows only valid number strings with an optional negative sign.
   def initialize(str : String)
+    # Strip leading '+' char to smooth out cases with strings like "+123"
+    str = str.lchop('+')
+
     raise InvalidBigDecimalException.new(str, "Zero size") if str.bytesize == 0
 
     # Check str's validity and find index of .

src/big/big_float.cr

@@ -13,6 +13,8 @@ struct BigFloat < Float
   end
 
   def initialize(str : String)
+    # Strip leading '+' char to smooth out cases with strings like "+123"
+    str = str.lchop('+')
     LibGMP.mpf_init_set_str(out @mpf, str, 10)
   end
 

src/big/big_int.cr

@@ -28,6 +28,8 @@ struct BigInt < Int
   # BigInt.new("1234567890ABCDEF", base: 16)           # => 1311768467294899695
   # ```
   def initialize(str : String, base = 10)
+    # Strip leading '+' char to smooth out cases with strings like "+123"
+    str = str.lchop('+')
     err = LibGMP.init_set_str(out @mpz, str, base)
     if err == -1
       raise ArgumentError.new("Invalid BigInt: #{str}")