Merge pull request #578 from kohler/middle

Handle \middle.

test/katex-spec.js

@@ -1042,6 +1042,26 @@ describe("A left/right parser", function() {
         var normalEmpty = "\\Bigl .";
         expect(normalEmpty).toParse();
     });
+
+    it("should handle \\middle", function() {
+        var normalMiddle = "\\left( \\dfrac{x}{y} \\middle| \\dfrac{y}{z} \\right)";
+        expect(normalMiddle).toParse();
+    });
+
+    it("should handle multiple \\middles", function() {
+        var multiMiddle = "\\left( \\dfrac{x}{y} \\middle| \\dfrac{y}{z} \\middle/ \\dfrac{z}{q} \\right)";
+        expect(multiMiddle).toParse();
+    });
+
+    it("should handle nested \\middles", function() {
+        var nestedMiddle = "\\left( a^2 \\middle| \\left( b \\middle/ c \\right) \\right)";
+        expect(nestedMiddle).toParse();
+    });
+
+    it("should error when \\middle is not in \\left...\\right", function() {
+        var unmatchedMiddle = "(\\middle|\\dfrac{x}{y})";
+        expect(unmatchedMiddle).toNotParse();
+    });
 });
 
 describe("A begin/end parser", function() {

test/screenshotter/ss_data.yaml

@@ -72,6 +72,7 @@ Kern:
 Lap: ab\llap{f}cd\rlap{g}h
 LeftRight: \left( x^2 \right) \left\{ x^{x^{x^{x^x}}} \right.
 LeftRightListStyling: a+\left(x+y\right)-x
+LeftRightMiddle: \left( x^2 \middle/ \right) \left\{ x^{x^{x^{x^x}}} \middle/ y \right.
 LeftRightStyleSizing: |
     +\left\{\rule{0.1em}{1em}\right.
     x^{+\left\{\rule{0.1em}{1em}\right.