Move infix operator handling into functions/genfrac.js. (#1328)

src/functions.js

@@ -118,32 +118,6 @@ defineFunction("xArrow", [
     };
 });
 
-// Infix generalized fractions
-defineFunction("infix", ["\\over", "\\choose", "\\atop"], {
-    numArgs: 0,
-    infix: true,
-}, function(context) {
-    let replaceWith;
-    switch (context.funcName) {
-        case "\\over":
-            replaceWith = "\\frac";
-            break;
-        case "\\choose":
-            replaceWith = "\\binom";
-            break;
-        case "\\atop":
-            replaceWith = "\\\\atopfrac";
-            break;
-        default:
-            throw new Error("Unrecognized infix genfrac command");
-    }
-    return {
-        type: "infix",
-        replaceWith: replaceWith,
-        token: context.token,
-    };
-});
-
 // Row and line breaks
 import "./functions/cr";
 

src/functions/genfrac.js

@@ -251,3 +251,36 @@ defineFunction({
         return node;
     },
 });
+
+// Infix generalized fractions -- these are not rendered directly, but replaced
+// immediately by one of the variants above.
+defineFunction({
+    type: "infix",
+    names: ["\\over", "\\choose", "\\atop"],
+    props: {
+        numArgs: 0,
+        infix: true,
+    },
+    handler(context) {
+        let replaceWith;
+        switch (context.funcName) {
+            case "\\over":
+                replaceWith = "\\frac";
+                break;
+            case "\\choose":
+                replaceWith = "\\binom";
+                break;
+            case "\\atop":
+                replaceWith = "\\\\atopfrac";
+                break;
+            default:
+                throw new Error("Unrecognized infix genfrac command");
+        }
+        return {
+            type: "infix",
+            replaceWith: replaceWith,
+            token: context.token,
+        };
+    },
+});
+