Merge pull request #179 from faultyserver/nativelib/type_conversions

Closes #174. Implement various type conversions for primitive values

spec/myst/float_spec.mt

@@ -317,6 +317,58 @@ describe("Float#%") do
 end
 
 
+describe("Float#to_i") do
+  it("returns a new Integer representing the Float") do
+    assert(1.0.to_i).equals(1)
+    assert(100.0.to_i).equals(100)
+  end
+
+  it("truncates decimals to create the Integer") do
+    assert(1.4.to_i).equals(1)
+    assert(123.456.to_i).equals(123)
+  end
+
+  it("does not perform rounding when truncating") do
+    assert(1.7.to_i).equals(1)
+    assert(10.5.to_i).equals(10)
+  end
+
+  it("raises an error if the Float cannot fit into an Integer value") do
+    # This number is larger than the maximum storable in a 64-bit integer.
+    assert{ 9_223_372_036_854_775_810.0.to_i }.raises
+  end
+end
+
+
+describe("Float#round") do
+  it("returns a new Integer representing the Float") do
+    assert(1.0.round).equals(1)
+    assert(100.0.round).equals(100)
+  end
+
+  it("rounds to the nearest Integer") do
+    assert(1.4.round).equals(1)
+    assert(123.789.round).equals(124)
+  end
+
+  it("rounds .5 decimals to the higher nearest Integer") do
+    assert(1.5.round).equals(2)
+    assert(214.5.round).equals(215)
+  end
+
+  it("accurately rounds decimals around *.5") do
+    assert(100.49999.round).equals(100)
+    assert(100.50000.round).equals(101)
+    assert(100.50001.round).equals(101)
+  end
+
+  it("raises an error if the Float cannot fit into an Integer value") do
+    # This number is larger than the maximum storable in a 64-bit integer.
+    assert{ 9_223_372_036_854_775_810.0.round }.raises
+  end
+end
+
+
 describe("Float#to_s") do
   it("returns the string representation of the number") do
     assert(1.0.to_s).equals("1.0")

spec/myst/integer_spec.mt

@@ -346,6 +346,14 @@ describe("Integer#times") do
 end
 
 
+describe("Integer#to_f") do
+  it("returns a new Float representing the Integer") do
+    assert(1.to_f).equals(1.0)
+    assert(100.to_f).equals(100.0)
+  end
+end
+
+
 describe("Integer#to_s") do
   it("returns the string representation of the integer") do
     assert(1.to_s).equals("1")

spec/myst/string_spec.mt

@@ -137,6 +137,88 @@ describe("String#empty?") do
 end
 
 
+describe("String#to_i") do
+  it("returns the Integer represented in the String") do
+    assert("100".to_i).equals(100)
+  end
+
+  it("defaults to parsing in base 10") do
+    assert("1234567890".to_i).equals(1234567890)
+  end
+
+  it("allows whitespace on either side of the integer") do
+    assert("   100   ".to_i).equals(100)
+    assert("100   \t ".to_i).equals(100)
+    assert("   \t 100".to_i).equals(100)
+    assert("\n\n100\n\n".to_i).equals(100)
+  end
+
+  it("allows underscores in the integer value") do
+    assert("1_00_0".to_i).equals(1000)
+    assert("1_000".to_i).equals(1000)
+  end
+
+  it("allows prefixes to change the base") do
+    assert("0b10".to_i).equals(2)
+    assert("010".to_i).equals(8)
+    assert("0x10".to_i).equals(16)
+  end
+
+  it("raises an error if the string does not represent an integer") do
+    assert{ "hello".to_i }.raises
+  end
+
+  it("raises an error if the string contains a float value") do
+    assert{ "1.0".to_i }.raises
+  end
+
+  it("raises an error if the String contains extraneous characters after the integer") do
+    assert{ "100abc".to_i }.raises
+  end
+
+  describe("with a base argument") do
+    it("interprets the integer in the given base") do
+      assert("111".to_i(2)).equals(7)
+      assert("777".to_i(8)).equals(511)
+    end
+
+    it("expects the argument to be an Integer") do
+      assert{ "1".to_i(:f) }.raises
+    end
+  end
+end
+
+
+describe("String#to_f") do
+  it("returns the Float represented in the String") do
+    assert("100.123".to_f).equals(100.123)
+  end
+
+  it("defaults to parsing in base 10") do
+    assert("123450.6789".to_f).equals(123450.6789)
+  end
+
+  it("allows whitespace on either side of the Float") do
+    assert("   1.2   ".to_f).equals(1.2)
+    assert("1.2   \t ".to_f).equals(1.2)
+    assert("   \t 1.2".to_f).equals(1.2)
+    assert("\n\n1.2\n".to_f).equals(1.2)
+  end
+
+  it("can parse an integer value into a Float") do
+    assert("100".to_f).equals(100.0)
+  end
+
+  it("raises an error if the string does not represent an integer") do
+    assert{ "hello".to_f }.raises
+  end
+
+  it("raises an error if the String contains extraneous characters after the integer") do
+    assert{ "100abc".to_f }.raises
+  end
+end
+
+
 describe("String#to_s") do
   it("returns itself") do
     assert("".to_s).equals("")
@@ -146,13 +228,15 @@ describe("String#to_s") do
   end
 end
 
+
 describe("String#chars") do
   it("Returns a List with chars in a string") do
     assert("abc".chars).equals(["a", "b", "c"])
     assert("yay".chars).equals(["y", "a", "y"])
   end
 end
 
+
 describe("String#downcase") do
   it("returns a lowercased version of itself") do
     assert("HELLO".downcase).equals("hello")

src/myst/interpreter/native_lib/float.cr

@@ -47,6 +47,14 @@ module Myst
       end
     end
 
+    NativeLib.method :float_to_i, Float64 do
+      this.to_i64
+    end
+
+    NativeLib.method :float_round, Float64 do
+      this.round
+    end
+
     NativeLib.method :float_to_s, Float64 do
       this.to_s
     end
@@ -103,19 +111,21 @@ module Myst
       float_type = TType.new("Float", kernel.scope)
       float_type.instance_scope["type"] = float_type
 
-      NativeLib.def_instance_method(float_type, :+,     :float_add)
-      NativeLib.def_instance_method(float_type, :-,     :float_subtract)
-      NativeLib.def_instance_method(float_type, :*,     :float_multiply)
-      NativeLib.def_instance_method(float_type, :/,     :float_divide)
-      NativeLib.def_instance_method(float_type, :%,     :float_modulo)
-      NativeLib.def_instance_method(float_type, :==,    :float_eq)
-      NativeLib.def_instance_method(float_type, :!=,    :float_not_eq)
-      NativeLib.def_instance_method(float_type, :to_s,  :float_to_s)
-      NativeLib.def_instance_method(float_type, :negate,:float_negate)
-      NativeLib.def_instance_method(float_type, :<,     :float_lt)
-      NativeLib.def_instance_method(float_type, :<=,    :float_lte)
-      NativeLib.def_instance_method(float_type, :>,     :float_gt)
-      NativeLib.def_instance_method(float_type, :>=,    :float_gte)
+      NativeLib.def_instance_method(float_type, :+,       :float_add)
+      NativeLib.def_instance_method(float_type, :-,       :float_subtract)
+      NativeLib.def_instance_method(float_type, :*,       :float_multiply)
+      NativeLib.def_instance_method(float_type, :/,       :float_divide)
+      NativeLib.def_instance_method(float_type, :%,       :float_modulo)
+      NativeLib.def_instance_method(float_type, :==,      :float_eq)
+      NativeLib.def_instance_method(float_type, :!=,      :float_not_eq)
+      NativeLib.def_instance_method(float_type, :to_i,    :float_to_i)
+      NativeLib.def_instance_method(float_type, :round,   :float_round)
+      NativeLib.def_instance_method(float_type, :to_s,    :float_to_s)
+      NativeLib.def_instance_method(float_type, :negate,  :float_negate)
+      NativeLib.def_instance_method(float_type, :<,       :float_lt)
+      NativeLib.def_instance_method(float_type, :<=,      :float_lte)
+      NativeLib.def_instance_method(float_type, :>,       :float_gt)
+      NativeLib.def_instance_method(float_type, :>=,      :float_gte)
 
       float_type
     end

src/myst/interpreter/native_lib/integer.cr

@@ -50,6 +50,10 @@ module Myst
       end
     end
 
+    NativeLib.method :int_to_f, Int64 do
+      this.to_f64
+    end
+
     NativeLib.method :int_to_s, Int64 do
       this.to_s
     end
@@ -113,6 +117,7 @@ module Myst
       NativeLib.def_instance_method(integer_type, :%,     :int_modulo)
       NativeLib.def_instance_method(integer_type, :==,    :int_eq)
       NativeLib.def_instance_method(integer_type, :!=,    :int_not_eq)
+      NativeLib.def_instance_method(integer_type, :to_f,  :int_to_f)
       NativeLib.def_instance_method(integer_type, :to_s,  :int_to_s)
       NativeLib.def_instance_method(integer_type, :negate,:int_negate)
       NativeLib.def_instance_method(integer_type, :<,     :int_lt)

src/myst/interpreter/native_lib/string.cr

@@ -19,6 +19,23 @@ module Myst
       end
     end
 
+    NativeLib.method :string_to_i, String, base : Int64? do
+      begin
+        base = 10 if base.nil?
+        this.to_i64(base: base, whitespace: true, underscore: true, prefix: true, strict: true)
+      rescue ex : ArgumentError
+        __raise_runtime_error(ex.message.not_nil!)
+      end
+    end
+
+    NativeLib.method :string_to_f, String, base : Int64? do
+      begin
+        this.to_f64(whitespace: true, strict: true)
+      rescue ex : ArgumentError
+        __raise_runtime_error(ex.message.not_nil!)
+      end
+    end
+
     NativeLib.method :string_to_s, String do
       this
     end
@@ -117,6 +134,8 @@ module Myst
       NativeLib.def_instance_method(string_type, :==,        :string_eq)
       NativeLib.def_instance_method(string_type, :!=,        :string_not_eq)
       NativeLib.def_instance_method(string_type, :[],        :string_at)
+      NativeLib.def_instance_method(string_type, :to_i,      :string_to_i)
+      NativeLib.def_instance_method(string_type, :to_f,      :string_to_f)
       NativeLib.def_instance_method(string_type, :to_s,      :string_to_s)
       NativeLib.def_instance_method(string_type, :size,      :string_size)
       NativeLib.def_instance_method(string_type, :split,     :string_split)