bahaghari/lib: add floor and ceil for math subset

Even though they're already available from the builtins, we still want
the library subset to feel consistent.

subprojects/bahaghari/lib/default.nix

@@ -48,5 +48,6 @@ pkgs.lib.makeExtensible
       isNumber scale;
 
     inherit (self.hex) isHexString;
-    inherit (self.math) abs pow percentage factorial round round' summate product;
+    inherit (self.math) abs pow percentage factorial floor ceil round round'
+      summate product;
   })

subprojects/bahaghari/lib/math.nix

@@ -4,6 +4,10 @@
 { pkgs, lib, self }:
 
 rec {
+  # We have the rounding functions here anyways so we may as well include the
+  # rest of the decimal place changing functions here for consistency.
+  inherit (builtins) floor ceil;
+
   pi = 3.141592653589793238462643383279502884197;
   e = 2.7182818284590452353602874713527;
 
@@ -173,7 +177,7 @@ rec {
       nearest = pow 10.0 tens;
       difference = number / nearest;
     in
-      builtins.floor (difference + 0.5) * nearest;
+      floor (difference + 0.5) * nearest;
 
   /* Adds all of the given items on the list starting from a sum of zero.
 

subprojects/bahaghari/tests/lib/math.nix

@@ -81,6 +81,26 @@ lib.runTests {
     expected = 0;
   };
 
+  testMathFloor = {
+    expr = self.math.floor 3.467;
+    expected = 3;
+  };
+
+  testMathFloor2 = {
+    expr = self.math.floor 3.796;
+    expected = 3;
+  };
+
+  testMathCeil = {
+    expr = self.math.ceil 3.469;
+    expected = 4;
+  };
+
+  testMathCeil2 = {
+    expr = self.math.ceil 3.796;
+    expected = 4;
+  };
+
   testMathRoundDown = {
     expr = self.math.round 2.3;
     expected = 2;