scribble-math/MJLite.js
Ben Alpert 29949b500a Make clearNode screaming-fast-er
Reviewers: xymostech

Reviewed By: xymostech

Differential Revision: http://phabricator.benalpert.com/D35
2013-07-05 21:24:39 -07:00

110 lines
3.4 KiB
JavaScript

var MJLite = (function() {
var buildExpression = function(expression) {
return _.map(expression, function(ex, i) {
var prev = i > 0 ? expression[i-1] : null;
return buildGroup(ex, prev);
});
};
var makeSpan = function(className, children) {
var span = document.createElement("span");
span.className = className;
if (_.isArray(children)) {
_.each(children, function(v) {
span.appendChild(v);
});
} else if (children) {
span.appendChild(children);
}
return span;
};
var buildGroup = function(group, prev) {
if (group.type === "ord") {
return makeSpan("mord", mathit(group.value));
} else if (group.type === "bin") {
var className = "mbin";
if (prev == null || prev.type === "bin" || prev.type === "open") {
group.type = "ord";
className = "mord";
}
return makeSpan(className, textit(group.value));
} else if (group.type === "sup") {
var sup = makeSpan("msup", buildExpression(group.value.sup));
return makeSpan("mord", buildExpression(group.value.base).concat(sup));
} else if (group.type === "sub") {
var sub = makeSpan("msub", buildExpression(group.value.sub, sub));
return makeSpan("mord", buildExpression(group.value.base, elem).concat(sub));
} else if (group.type === "supsub") {
var sup = makeSpan("msup", buildExpression(group.value.sup, sup));
var sub = makeSpan("msub", buildExpression(group.value.sub, sub));
var supsub = makeSpan("msupsub", [sup, sub]);
return makeSpan("mord", buildExpression(group.value.base, elem).concat(supsub));
} else if (group.type === "open") {
return makeSpan("mopen", textit(group.value));
} else if (group.type === "close") {
return makeSpan("mclose", textit(group.value));
} else if (group.type === "frac") {
var numer = makeSpan("mfracnum", buildExpression(group.value.numer, numer));
var mid = makeSpan("mfracmid", makeSpan());
var denom = makeSpan("mfracden", buildExpression(group.value.denom, denom));
return makeSpan("mord mfrac", [numer, mid, denom]);
} else {
console.log("Unknown type:", group.type);
}
};
var charLookup = {
'*': '\u2217',
'-': '\u2212',
'cdot': '\u22C5',
'lvert': '|',
'rvert': '|'
};
var textit = function(value) {
if (value in charLookup) {
value = charLookup[value];
}
return document.createTextNode(value);
};
var mathit = function(value) {
var text = textit(value);
if (/[a-zA-Z]/.test(value)) {
return makeSpan("mathit", text);
} else {
return text;
}
};
var clearNode = function(node) {
if ("textContent" in node) {
node.textContent = "";
} else {
node.innerText = "";
}
};
var process = function(toParse, baseElem) {
var tree = parser.parse(toParse);
clearNode(baseElem);
_.each(buildExpression(tree), function(elem) {
baseElem.appendChild(elem);
});
};
return {
process: process
};
})();