bahaghari/lib: add isNumber and scale

subprojects/bahaghari/lib/default.nix

@@ -38,7 +38,8 @@ pkgs.lib.makeExtensible
     tinted-theming = callLibs ./tinted-theming.nix;
 
     inherit (self.trivial) importYAML toYAML toBaseDigitsWithGlyphs
-      generateGlyphSet generateConversionTable generateBaseDigitType clamp;
+      generateGlyphSet generateConversionTable generateBaseDigitType clamp
+      isNumber scale;
 
     inherit (self.hex) isHexString;
     inherit (self.math) abs pow percentage;

subprojects/bahaghari/lib/trivial.nix

@@ -160,4 +160,39 @@ rec {
   */
   clamp = min: max: value:
     lib.min max (lib.max min value);
+
+  /* Given a value, check if it's a number type.
+
+     Type: isNumber :: Number -> bool
+
+     Example:
+       isNumber 3.0
+       => true
+
+       isNumber 653
+       => true
+
+       isNumber true
+       => false
+  */
+  isNumber = v:
+    lib.isInt v || lib.isFloat v;
+
+  /* Given an initial range of integers, scale the given number with its own
+     set of range.
+
+     Type: scale :: Attrs -> Number -> Number
+
+     Example:
+       scale { inMin = 0; inMax = 15; outMin = 0; outMax = 255; } 4
+       => 68
+
+       scale { inMin = 0; inMax = 15; outMin = 0; outMax = 255; } (-4)
+       => -68
+
+       scale { inMin = 0; inMax = 15; outMin = 0; outMax = 255; } 15
+       => 255
+  */
+  scale = { inMin, inMax, outMin, outMax }: v:
+    ((v - inMin) * (outMax - outMin)) / ((inMax - inMin) + outMin);
 }

subprojects/bahaghari/tests/lib/trivial/default.nix

@@ -225,4 +225,39 @@ lib.runTests {
     expr = self.trivial.clamp 1 10 453;
     expected = 10;
   };
+
+  testNumberScale = {
+    expr = self.trivial.scale { inMin = 0; inMax = 15; outMin = 0; outMax = 255; } 15;
+    expected = 255;
+  };
+
+  testNumberScale2 = {
+    expr = self.trivial.scale { inMin = 0; inMax = 15; outMin = 0; outMax = 255; } 4;
+    expected = 68;
+  };
+
+  testNumberScale3 = {
+    expr = self.trivial.scale { inMin = 0; inMax = 15; outMin = 0; outMax = 255; } (-4);
+    expected = (-68);
+  };
+
+  testIsNumber1 = {
+    expr = self.trivial.isNumber 3;
+    expected = true;
+  };
+
+  testIsNumber2 = {
+    expr = self.trivial.isNumber 4.09;
+    expected = true;
+  };
+
+  testIsNumber3 = {
+    expr = self.trivial.isNumber "HELLO";
+    expected = false;
+  };
+
+  testIsNumber4 = {
+    expr = self.trivial.isNumber true;
+    expected = false;
+  };
 }