Merge pull request #314 from JeffEverett/limits_and_nolimits

Add support for \limits and \nolimits controls

src/Parser.js

@@ -254,7 +254,18 @@ Parser.prototype.parseAtom = function(pos, mode) {
         // Lex the first token
         var lex = this.lexer.lex(currPos, mode);
 
-        if (lex.text === "^") {
+        if (lex.text === "\\limits" || lex.text === "\\nolimits") {
+            // We got a limit control
+            if (!base || base.result.type !== "op") {
+                throw new ParseError("Limit controls must follow a math operator",
+                    this.lexer, currPos);
+            }
+            else {
+                var limits = lex.text == "\\limits";
+                base.result.value.limits = limits;
+                currPos = lex.position;
+            }
+        } else if (lex.text === "^") {
             // We got a superscript start
             if (superscript) {
                 throw new ParseError(

test/katex-spec.js

@@ -360,6 +360,40 @@ describe("A subscript and superscript tree-builder", function() {
     });
 });
 
+describe("A parser with limit controls", function() {
+    it("should fail when the limit control is not preceded by an op node", function() {
+        expect("3\\nolimits_2^2").toNotParse();
+        expect("\\sqrt\\limits_2^2").toNotParse();
+        expect("45 +\\nolimits 45").toNotParse();
+    });
+
+    it("should parse when the limit control directly follows an op node", function() {
+        expect("\\int\\limits_2^2 3").toParse();
+        expect("\\sum\\nolimits_3^4 4").toParse();
+    });
+
+    it("should parse when the limit control is in the sup/sub area of an op node", function() {
+        expect("\\int_2^2\\limits").toParse();
+        expect("\\int^2\\nolimits_2").toParse();
+        expect("\\int_2\\limits^2").toParse();
+    });
+
+    it("should allow multiple limit controls in the sup/sub area of an op node", function() {
+        expect("\\int_2\\nolimits^2\\limits 3").toParse();
+        expect("\\int\\nolimits\\limits_2^2").toParse();
+        expect("\\int\\limits\\limits\\limits_2^2").toParse();
+    });
+
+    it("should have the rightmost limit control determine the limits property " +
+        "of the preceding op node", function() {
+            var parsedInput = getParsed("\\int\\nolimits\\limits_2^2");
+            expect(parsedInput[0].value.base.value.limits).toBe(true);
+
+            parsedInput = getParsed("\\int\\limits_2\\nolimits^2");
+            expect(parsedInput[0].value.base.value.limits).toBe(false);
+    });
+});
+
 describe("A group parser", function() {
     it("should not fail", function() {
         expect("{xy}").toParse();

test/screenshotter/ss_data.json

@@ -20,6 +20,7 @@
     "LeftRight": "http://localhost:7936/test/screenshotter/test.html?m=\\left( x^2 \\right) \\left\\{ x^{x^{x^{x^x}}} \\right.",
     "LeftRightListStyling": "http://localhost:7936/test/screenshotter/test.html?m=a+\\left(x+y\\right)-x",
     "LeftRightStyleSizing": "http://localhost:7936/test/screenshotter/test.html?m=+\\left\\{\\rule{0.1em}{1em}\\right.x^{+\\left\\{\\rule{0.1em}{1em}\\right.x^{+\\left\\{\\rule{0.1em}{1em}\\right.}}",
+    "LimitControls": "http://localhost:7936/test/screenshotter/test.html?m=\\displaystyle\\int\\limits_2^3 3x^2\\,dx + \\sum\\nolimits^n_{i=1}i",
     "NestedFractions": "http://localhost:7936/test/screenshotter/test.html?m=\\dfrac{\\frac{a}{b}}{\\frac{c}{d}}\\dfrac{\\dfrac{a}{b}}{\\dfrac{c}{d}}\\frac{\\frac{a}{b}}{\\frac{c}{d}}",
     "NullDelimiterInteraction": "http://localhost:7936/test/screenshotter/test.html?m=a \\bigl. + 2 \\quad \\left. + a \\right)",
     "OpLimits": "http://localhost:7936/test/screenshotter/test.html?m={\\sin_2^2 \\lim_2^2 \\int_2^2 \\sum_2^2}{\\displaystyle \\lim_2^2 \\int_2^2 \\intop_2^2 \\sum_2^2}",