Merge pull request #61 from shivam091/5.11.0

5.11.0

CHANGELOG.md

@@ -1,3 +1,12 @@
+## [5.11.0](https://github.com/shivam091/unit_measurements/compare/v5.10.0...v5.11.0) - 2023-11-11
+
+### What's new
+
+- Added `#systems` method to return unit systems within the unit group.
+- Added `#ratio` method to calculate the ratio between two units.
+
+----------
+
 ## [5.10.0](https://github.com/shivam091/unit_measurements/compare/v5.9.0...v5.10.0) - 2023-11-09
 
 ### What's new

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    unit_measurements (5.10.0)
+    unit_measurements (5.11.0)
       activesupport (~> 7.0)
 
 GEM

README.md

@@ -179,6 +179,13 @@ UnitMeasurements::Length.parse("1:2 km to m")
 #=> 500.0 m
 ```
 
+**Calculate the ratio between two units:**
+
+```ruby
+UnitMeasurements::Length.ratio("in", "ft")
+#=> "12.0 in/ft"
+```
+
 **Formatting measurement:**
 
 If you want to format the measurement to certain format, you can use `#to_fs` method.
@@ -239,6 +246,13 @@ UnitMeasurements::Length.unit_names_with_aliases
 #=> ["\"", "'", "feet", "foot", "ft", "in", "inch", "inches", "m", "meter", "meters", "metre", "metres", "mi", "mile", "miles", "yard", "yards", "yd"]
 ```
 
+**See list of unit systems defined within the unit group:**
+
+```ruby
+UnitMeasurements::Length.systems
+#=> ["metric", "imperial", "us_customary", "astronomical"]
+```
+
 **See list of units within the unit system:**
 
 You can use `#units_for` or `#units_for!` methods to find units within the unit system.

lib/unit_measurements/measurement.rb

@@ -243,7 +243,7 @@ class << self
       def_delegators :unit_group, :primitive, :units, :cache_file, :unit_names,
                      :unit_with_name_and_aliases, :unit_names_with_aliases,
                      :unit_for, :unit_for!, :defined?, :unit_or_alias?, :[],
-                     :units_for, :units_for!
+                     :units_for, :units_for!, :systems
 
       # Parses an input string and returns a +Measurement+ instance depending on
       # the input string. This method first normalizes the +input+ internally,
@@ -368,6 +368,40 @@ def clear_cache
         cached.clear_cache
       end
 
+      # Calculates the ratio between two units.
+      #
+      # This method takes a source unit and a target unit, and returns the ratio
+      # between them as a string representation.
+      #
+      # @example Calculating the ratio between 'in' and 'ft':
+      #   UnitMeasurements::Length.ratio("in", "ft")
+      #   => "12.0 in/ft"
+      #
+      #   UnitMeasurements::Length.ratio(UnitMeasurements::Length.unit_for("in"), "ft")
+      #   => "12.0 in/ft"
+      #
+      # @param [Unit|String|Symbol] source_unit
+      #   The source unit for the ratio calculation.
+      # @param [Unit|String|Symbol] target_unit
+      #   The target unit for the ratio calculation.
+      #
+      # @return [String] The ratio between the source and target units.
+      #
+      # @raise [UnitError]
+      #   If either the source unit or the target unit is not found in the unit group.
+      #
+      # @author {Harshal V. Ladhe}[https://shivam091.github.io/]
+      # @since 5.11.0
+      def ratio(source_unit, target_unit)
+        source_unit = source_unit.is_a?(Unit) ? source_unit : unit_for!(source_unit)
+        target_unit = target_unit.is_a?(Unit) ? target_unit : unit_for!(target_unit)
+
+        source_quantity = 1
+        target_quantity = new(source_quantity, target_unit).convert_to(source_unit).quantity
+
+        "#{target_quantity} #{source_unit}/#{target_unit}"
+      end
+
       private
 
       # @private

lib/unit_measurements/unit_group.rb

@@ -247,6 +247,22 @@ def units_for!(system_name)
       system_units
     end
 
+    # Returns an array of unit system names defined within the unit group.
+    #
+    # It scans through the units and compiles a list of unique system names.
+    #
+    # @example
+    #   UnitMeasurements::Length.systems
+    #   => ["metric", "imperial", "us_customary", "astronomical"]
+    #
+    # @return [Array<String>] An array of unit system names.
+    #
+    # @author {Harshal V. Ladhe}[https://shivam091.github.io/]
+    # @since 5.11.0
+    def systems
+      units.map { _1.system }.uniq
+    end
+
     private
 
     # @private

lib/unit_measurements/version.rb

@@ -4,5 +4,5 @@
 
 module UnitMeasurements
   # Current stable version.
-  VERSION = "5.10.0"
+  VERSION = "5.11.0"
 end

spec/unit_measurements/measurement_spec.rb

@@ -121,19 +121,19 @@
     context "when only quantity and source unit is provided" do
       it "parses scientific notations" do
         measurement = UnitMeasurements::Length.parse("4.3e12 m")
-        expect(measurement.quantity).to eq(4.3e12)
+        expect(measurement.quantity).to eq(4.3e+12)
         expect(measurement.unit).to eq(m)
 
         measurement = UnitMeasurements::Length.parse("4.3e12 m")
-        expect(measurement.quantity).to eq(4.3e12)
+        expect(measurement.quantity).to eq(4.3e+12)
         expect(measurement.unit).to eq(m)
 
         measurement = UnitMeasurements::Length.parse("4.3e12m")
-        expect(measurement.quantity).to eq(4.3e12)
+        expect(measurement.quantity).to eq(4.3e+12)
         expect(measurement.unit).to eq(m)
 
         measurement = UnitMeasurements::Length.new("4.3e12", "m")
-        expect(measurement.quantity).to eq(4.3e12)
+        expect(measurement.quantity).to eq(4.3e+12)
         expect(measurement.unit).to eq(m)
 
         expect(measurement.inspect).to eq("4300000000000.0 m")
@@ -307,27 +307,27 @@
     context "when quantity, source unit, and target unit is provided" do
       it "parses scientific notations" do
         measurement = UnitMeasurements::Length.parse("4.3e12 m to cm")
-        expect(measurement.quantity).to eq(0.43e15)
+        expect(measurement.quantity).to eq(4.3e+14)
         expect(measurement.unit).to eq(cm)
 
         measurement = UnitMeasurements::Length.parse("4.3e12 m to cm")
-        expect(measurement.quantity).to eq(0.43e15)
+        expect(measurement.quantity).to eq(4.3e+14)
         expect(measurement.unit).to eq(cm)
 
         measurement = UnitMeasurements::Length.parse("4.3e12m to cm")
-        expect(measurement.quantity).to eq(0.43e15)
+        expect(measurement.quantity).to eq(4.3e+14)
         expect(measurement.unit).to eq(cm)
 
         expect(measurement.inspect).to eq("430000000000000.0 cm")
       end
 
       it "parses fractions" do
         measurement = UnitMeasurements::Length.parse("1/4 m to cm")
-        expect(measurement.quantity).to eq(0.25e2)
+        expect(measurement.quantity).to eq(25)
         expect(measurement.unit).to eq(cm)
 
         measurement = UnitMeasurements::Length.parse("1/4 m to cm")
-        expect(measurement.quantity).to eq(0.25e2)
+        expect(measurement.quantity).to eq(25)
         expect(measurement.unit).to eq(cm)
 
         measurement = UnitMeasurements::Length.parse("1/4m to cm")
@@ -339,85 +339,85 @@
 
       it "parses fractions with special characters" do
         measurement = UnitMeasurements::Length.parse("⅜ m to cm")
-        expect(measurement.quantity).to eq(0.375e2)
+        expect(measurement.quantity).to eq(37.5)
         expect(measurement.unit).to eq(cm)
 
         measurement = UnitMeasurements::Length.parse("⅜ m to cm")
-        expect(measurement.quantity).to eq(0.375e2)
+        expect(measurement.quantity).to eq(37.5)
         expect(measurement.unit).to eq(cm)
 
         measurement = UnitMeasurements::Length.parse("⅜m to cm")
-        expect(measurement.quantity).to eq(0.375e2)
+        expect(measurement.quantity).to eq(37.5)
         expect(measurement.unit).to eq(cm)
       end
 
       it "parses mixed fractions" do
         measurement = UnitMeasurements::Length.parse("3 2/5 m to cm")
-        expect(measurement.quantity).to eq(0.34e3)
+        expect(measurement.quantity).to eq(340)
         expect(measurement.unit).to eq(cm)
 
         expect(measurement.inspect).to eq("340.0 cm")
       end
 
       it "parses mixed fractions with special characters" do
         measurement = UnitMeasurements::Length.parse("3⅜ m to cm")
-        expect(measurement.quantity).to eq(0.3375e3)
+        expect(measurement.quantity).to eq(337.5)
         expect(measurement.unit).to eq(cm)
 
         measurement = UnitMeasurements::Length.parse("3 ⅜ m to cm")
-        expect(measurement.quantity).to eq(0.3375e3)
+        expect(measurement.quantity).to eq(337.5)
         expect(measurement.unit).to eq(cm)
 
         measurement = UnitMeasurements::Length.parse("3⅜ m to cm")
-        expect(measurement.quantity).to eq(0.3375e3)
+        expect(measurement.quantity).to eq(337.5)
         expect(measurement.unit).to eq(cm)
 
         measurement = UnitMeasurements::Length.parse("3 ⅜ m to cm")
-        expect(measurement.quantity).to eq(0.3375e3)
+        expect(measurement.quantity).to eq(337.5)
         expect(measurement.unit).to eq(cm)
 
         measurement = UnitMeasurements::Length.parse("3⅜m to cm")
-        expect(measurement.quantity).to eq(0.3375e3)
+        expect(measurement.quantity).to eq(337.5)
         expect(measurement.unit).to eq(cm)
       end
 
       it "parses exponent symbols" do
         measurement = UnitMeasurements::Length.parse("10⁸ m to cm")
-        expect(measurement.quantity).to eq(0.108e5)
+        expect(measurement.quantity).to eq(10800)
         expect(measurement.unit).to eq(cm)
 
         measurement = UnitMeasurements::Length.parse("10e³ m to cm")
-        expect(measurement.quantity).to eq(0.1e7)
+        expect(measurement.quantity).to eq(1000000)
         expect(measurement.unit).to eq(cm)
 
         measurement = UnitMeasurements::Length.parse("10e⁺³ m to cm")
-        expect(measurement.quantity).to eq(0.1e7)
+        expect(measurement.quantity).to eq(1000000)
         expect(measurement.unit).to eq(cm)
 
         measurement = UnitMeasurements::Length.parse("10e+³ m to cm")
-        expect(measurement.quantity).to eq(0.1e7)
+        expect(measurement.quantity).to eq(1000000)
         expect(measurement.unit).to eq(cm)
 
         measurement = UnitMeasurements::Length.parse("10e⁻³ m to cm")
-        expect(measurement.quantity).to eq(0.1e1)
+        expect(measurement.quantity).to eq(1)
         expect(measurement.unit).to eq(cm)
 
         measurement = UnitMeasurements::Length.parse("10e-³ m to cm")
-        expect(measurement.quantity).to eq(0.1e1)
+        expect(measurement.quantity).to eq(1)
         expect(measurement.unit).to eq(cm)
       end
 
       it "parses decimals" do
         measurement = UnitMeasurements::Length.parse("2.1 m to cm")
-        expect(measurement.quantity).to eq(0.21e3)
+        expect(measurement.quantity).to eq(210)
         expect(measurement.unit).to eq(cm)
 
         measurement = UnitMeasurements::Length.parse("2.1 m to cm")
-        expect(measurement.quantity).to eq(0.21e3)
+        expect(measurement.quantity).to eq(210)
         expect(measurement.unit).to eq(cm)
 
         measurement = UnitMeasurements::Length.parse("2.1m to cm")
-        expect(measurement.quantity).to eq(0.21e3)
+        expect(measurement.quantity).to eq(210)
         expect(measurement.unit).to eq(cm)
 
         expect(measurement.inspect).to eq("210.0 cm")
@@ -433,15 +433,15 @@
 
       it "parses integers" do
         measurement = UnitMeasurements::Length.parse("1 m to cm")
-        expect(measurement.quantity).to eq(0.1e3)
+        expect(measurement.quantity).to eq(100)
         expect(measurement.unit).to eq(cm)
 
         expect(measurement.inspect).to eq("100.0 cm")
       end
 
       it "parses ratios" do
         measurement = UnitMeasurements::Length.parse("1:4 m to cm")
-        expect(measurement.quantity).to eq(0.25e2)
+        expect(measurement.quantity).to eq(25)
         expect(measurement.unit).to eq(cm)
       end
     end
@@ -457,4 +457,18 @@
       expect(cache.get("km", "m")).to be_nil
     end
   end
+
+  describe "#ratio" do
+    context "when the source unit and the target unit are strings" do
+      it "calculates the ratio" do
+        expect(UnitMeasurements::Length.ratio(:m, :cm)).to eq("0.01 m/cm")
+      end
+    end
+
+    context "when the source unit and the target unit are instance of Unit" do
+      it "calculates the ratio" do
+        expect(UnitMeasurements::Length.ratio(m, cm)).to eq("0.01 m/cm")
+      end
+    end
+  end
 end

spec/unit_measurements/unit_group_spec.rb

@@ -109,4 +109,10 @@
       end
     end
   end
+
+  describe "#systems" do
+    it "returns arrays of unit system names" do
+      expect(unit_group.systems).to eq(["metric"])
+    end
+  end
 end