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Fix bug in khan-exercise.js where appropriate modules are not loaded …
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…as users navigate to new exercises via tutorial-nav

Summary:
This fixes two bugs:
    1. First, with khan-exercise.js. Essentially, the modules of all loaded exercises, instead of the current exercise, were being used in runModules(), which executes the functions of the form $.fn["module"], $.fn["moduleLoad"], and $.fn["moduleCleanup"]. As a result, the current exercise was compiled using modules for all loaded exercises. This bug had not been found earlier b/c matrix-input is pretty unique right now in visibly modifying the answer area & b/c the matrices tutorial contains both exercises that use and don't use it. This bug was probably slowing down fairly lightweight exercises that were in the same tutorial as heavy exercises (ex: using the word-problems package), since they were running $.fn["word-problemsLoad"] on every newProblem event.
    2. Make sure matrix-input events are not attached again when each hint is requested.

There is room for improvement for whoever is brave enough to dive into this crazy mess of code.

Test Plan:
Devappserver:
    1. Visit /math/algebra/algebra-matrices/e/scalar_matrix_multiplication
    2. Navigate to "matrix dimensions" via tutorial nav
    3. Observe that the matrix input braces do not appear in the answer area

Exercise land:
    1. Visit scalar_matrix_multiplication.html and matrix_dimensions.html
    2. Observe that nothing's visibly changed

Reviewers: eater

Reviewed By: eater

CC: marcia, desmond

Differential Revision: http://phabricator.khanacademy.org/D938
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Stephanie H. Chang committed Nov 21, 2012
1 parent ebfcd74 commit 8a389e5
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Showing 5 changed files with 114 additions and 26 deletions.
10 changes: 6 additions & 4 deletions exercises/matrix_inverse_2x2.html
View file
Expand Up @@ -8,10 +8,12 @@
<body>
<div class="exercise">

<div class="vars" data-ensure="DET !== 0">
<var id="DIM">2</var>
<var id="MAT">makeMatrix(randRange(-2, 5, DIM, DIM))</var>
<var id="DET">matrixDet(MAT)</var>
<div class="vars">
<div data-ensure="DET !== 0">
<var id="DIM">2</var>
<var id="MAT">makeMatrix(randRange(-2, 5, DIM, DIM))</var>
<var id="DET">matrixDet(MAT)</var>
</div>
<var id="SOLN_MAT">matrixInverse(MAT)</var>
<var id="PADDED_SOLN_MAT">matrixPad(SOLN_MAT, 3, 3)</var>
<var id="PRETTY_SOLN_MAT">
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10 changes: 6 additions & 4 deletions exercises/matrix_inverse_3x3.html
View file
Expand Up @@ -8,10 +8,12 @@
<body>
<div class="exercise">

<div class="vars" data-ensure="DET !== 0">
<var id="DIM">3</var>
<var id="MAT">makeMatrix(randRange(-2, 5, DIM, DIM))</var>
<var id="DET">matrixDet(MAT)</var>
<div class="vars">
<div data-ensure="DET !== 0">
<var id="DIM">3</var>
<var id="MAT">makeMatrix(randRange(-2, 5, DIM, DIM))</var>
<var id="DET">matrixDet(MAT)</var>
</div>
<var id="SOLN_MAT">matrixInverse(MAT)</var>
<var id="PADDED_SOLN_MAT">matrixPad(SOLN_MAT, 3, 3)</var>
<var id="PRETTY_SOLN_MAT">
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55 changes: 46 additions & 9 deletions khan-exercise.js
View file
Expand Up @@ -302,8 +302,20 @@ var Khan = (function() {

// The main Khan Module
var Khan = {

// Modules currently in use
modules: {},

// Map from exercise filename to a string of required modules
// (data-require). These module names are used in runModules(), where
// $.fn["module-name"], $.fn["module-nameLoad"], and
// $.fn["module-nameCleanup"] are called.
exerciseModulesMap: {},

// Used to retrieve required modules list for current exercise from
// exerciseModulesMap
currExerciseFilename: "",

// So modules can use file paths properly
urlBase: urlBase,

Expand Down Expand Up @@ -353,6 +365,26 @@ var Khan = (function() {
warn("You should " + enableFontDownload + " to improve the appearance of math expressions.", true);
},

resetModules: function(modules) {
Khan.modules = {};

if (testMode) {
Khan.require(["../jquery-ui", "../jquery.qtip"]);
}

// Base modules required for every problem
Khan.require(["answer-types", "tmpl", "underscore", "jquery.adhesion", "hints", "calculator"]);

if (modules) {
Khan.require(modules);
}

if (testMode && !modules) {
modules = document.documentElement.getAttribute("data-require");
Khan.require(modules);
}
},

require: function(mods) {
if (mods == null) {
return;
Expand Down Expand Up @@ -743,14 +775,7 @@ var Khan = (function() {
// Actually load the scripts. This is getting evaluated when the file is loaded.
Khan.loadScripts(scripts, function() {

if (testMode) {
Khan.require(["../jquery-ui", "../jquery.qtip"]);
}

// Base modules required for every problem
Khan.require(["answer-types", "tmpl", "underscore", "jquery.adhesion", "hints", "calculator"]);

Khan.require(document.documentElement.getAttribute("data-require"));
Khan.resetModules();

// Initialize to an empty jQuery set
exercises = jQuery();
Expand Down Expand Up @@ -963,6 +988,10 @@ var Khan = (function() {
exerciseFile = exerciseId + ".html";
}

// Store the filename of the current exercise for use as an
// index for setting/getting values from the exerciseModulesMap
Khan.currExerciseFilename = exerciseFile;

function finishRender() {

// Get all problems of this exercise type...
Expand Down Expand Up @@ -1206,6 +1235,9 @@ var Khan = (function() {

debugLog("added inline styles");

// Reset modules to only those required by the current exercise
Khan.resetModules(Khan.exerciseModulesMap[Khan.currExerciseFilename]);

// Run the main method of any modules
problem.runModules(problem, "Load");
debugLog("done with runModules Load");
Expand Down Expand Up @@ -2959,7 +2991,12 @@ var Khan = (function() {
requires = requires[2];
}

Khan.require(requires);
// Store the module requirements in exerciseModulesMap
Khan.exerciseModulesMap[fileName] = requires;

// Calling resetModules here is necessary for populating
// Khan.modules immediately so that required scripts can be fetched
Khan.resetModules(requires);

// Extract contents from various tags and save them up for parsing when
// actually showing this particular exercise.
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35 changes: 32 additions & 3 deletions utils/matrix-input.js
View file
Expand Up @@ -34,6 +34,8 @@ $.extend(KhanUtil, {

matrixInput: {

eventsAttached: false,

containerEl: null,
bracketEls: null,
cells: null,
Expand Down Expand Up @@ -92,6 +94,12 @@ $.extend(KhanUtil, {
this.bracketEls = [left, right];
},

removeBrackets: function() {
_.each(this.bracketEls, function(bracketEl) {
$(bracketEl).remove();
});
},

indexToRow: function(i) {
return Math.floor(i / this.COLS);
},
Expand Down Expand Up @@ -306,18 +314,39 @@ $.extend(KhanUtil, {

render: function() {
this.positionBrackets();
},

cleanup: function() {
this.removeBrackets();
}
}
});

$.fn["matrix-input"] = function() {
$.fn["matrix-inputLoad"] = function() {
if (KhanUtil.matrixInput.eventsAttached) {
return;
}

$(Khan).on("newProblem", function() {
$(Khan).on("newProblem.matrix-input", function() {
KhanUtil.matrixInput.init();
});

$(Khan).on("showGuess", function() {
$(Khan).on("showGuess.matrix-input", function() {
KhanUtil.matrixInput.setMaxValsFromScratch();
KhanUtil.matrixInput.render();
});

KhanUtil.matrixInput.eventsAttached = true;
};

$.fn["matrix-inputCleanup"] = function() {
if (!KhanUtil.matrixInput.eventsAttached) {
return;
}

KhanUtil.matrixInput.cleanup();
$(Khan).off("newProblem.matrix-input");
$(Khan).off("showGuess.matrix-input");

KhanUtil.matrixInput.eventsAttached = false;
};
30 changes: 24 additions & 6 deletions utils/matrix.js
View file
@@ -1,14 +1,24 @@
$.extend(KhanUtil, {
// To add two 2-dimensional matrices, use
// deepZipWith(2, function(a, b) { return a + b; }, matrixA, matrixB);
deepZipWith: function deepZipWith(depth, fn) {
deepZipWith: function(depth, fn) {
var arrays = [].slice.call(arguments, 2);

// if any of the "array" arguments to deepZipWith are null, return null
var hasNullValue = _.any(arrays, function(array) {
if (array === null) {
return true;
}
});
if (hasNullValue) {
return null;
}

if (depth === 0) {
return fn.apply(null, arrays);
} else {
return _.map(_.zip.apply(_, arrays), function(els) {
return deepZipWith.apply(this, [depth - 1, fn].concat(els));
return KhanUtil.deepZipWith.apply(this, [depth - 1, fn].concat(els));
});
}
},
Expand Down Expand Up @@ -73,6 +83,10 @@ $.extend(KhanUtil, {
var args = Array.prototype.slice.call(arguments);
mat = KhanUtil.deepZipWith.apply(this, [2].concat(args));

if (!mat) {
return null;
}

var table = _.map(mat, function(row, i) {
return row.join(" & ");
}).join(" \\\\ ");
Expand Down Expand Up @@ -209,7 +223,7 @@ $.extend(KhanUtil, {
var c = mat.r;

if (!r || !c) {
return undefined;
return null;
}

var matT = [];
Expand Down Expand Up @@ -237,7 +251,7 @@ $.extend(KhanUtil, {

// determinant is only defined for a square matrix
if (mat.r !== mat.c) {
return undefined;
return null;
}

var a, b, c, d, e, f, g, h, k, det;
Expand Down Expand Up @@ -344,13 +358,13 @@ $.extend(KhanUtil, {

// if determinant is undefined or 0, inverse does not exist
if (!det) {
return undefined;
return null;
}

var adj = KhanUtil.matrixAdj(mat);

if (!adj) {
return undefined;
return null;
}

var inv = KhanUtil.deepZipWith(2, function(val) {
Expand All @@ -376,6 +390,10 @@ $.extend(KhanUtil, {
* @return {result of makeMatrix}
*/
matrixPad: function(mat, rows, cols, padVal) {
if (!mat) {
return null;
}

mat = KhanUtil.makeMatrix(mat);
matP = KhanUtil.matrixCopy(mat);

Expand Down

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