Merge pull request #22 from ianrose/gh21-floating-point-warning

Adds floating point warn

_typesettings.scss

@@ -81,10 +81,18 @@ $ms-up2: $ms-up1 * $ms-ratio; // [5]
 $ms-up3: $ms-up2 * $ms-ratio; // [6]
 $ms-up4: $ms-up3 * $ms-ratio; // [7]
 
+// Warning text for when an integer is not used in rhythm functions
+$not-integer-txt: ' value breaks vertical rhythm. Use an interger (whole number) for $lines.';
+
 //==============================================================================
 // Helper function(s)
 //==============================================================================
 
+// Check if value is an integer and returns true or false
+@function is-int($number) {
+  @return type-of($number) == number and floor(abs($number)) == abs($number);
+}
+
 // Returns a number without a unit. For example 16px becomes 16
 @function stripUnits($number) {
   @return $number / ($number * 0 + 1);
@@ -98,12 +106,18 @@ $ms-up4: $ms-up3 * $ms-ratio; // [7]
 // Returns an EM value that is a multiple of our defined base vertical unit. For
 // example 3 becomes 1.125em
 @function emRhythm($lines: $base-vertical-unit, $font-size: $base-em-font-size) {
+  @if is-int($lines) == false {
+    @warn  #{$lines} + $not-integer-txt;
+  }
   @return (stripUnits($lines) * stripUnits($base-vertical-unit)) / (stripUnits($font-size) * stripUnits($base-font-size)) + 0em;
 }
 
 // Returns a unitless number that is a multiple of our defined base vertical unit.
 // For example 3 becomes 1.125
 @function unitlessRhythm($lines: $base-line-multi, $font-size: $base-em-font-size) {
+  @if is-int($lines) == false {
+    @warn #{$lines} + $not-integer-txt;
+  }
   @return ($lines * stripUnits($base-vertical-unit)) / (stripUnits($font-size) * stripUnits($base-font-size));
 }
 

test/test.css

@@ -158,3 +158,6 @@ hr {
   border-top-style: solid;
   border-top-width: 1px;
   padding-top: 1.4375em; }
+
+.div {
+  margin-bottom: 0.45em; }

test/test.scss

@@ -1 +1,5 @@
-@import "../typesettings";
+@import "../typesettings";
+
+.div {
+  margin-bottom: emRhythm(1.2);
+}