Implement cases environment
See issue #278. Although the official definition makes use of @{…} notation, we use custom spacing instead, since that seems easier for now.
This commit is contained in:
Martin von Gagern
parent
7f1b53cbfd
commit
758bdba31e
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@ -511,7 +511,9 @@ var groupTypes = {
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// Vertical spacing
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var baselineskip = 12 * pt; // see size10.clo
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var arraystretch = 1; // factor, see lttab.dtx
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// Default \arraystretch from lttab.dtx
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// TODO(gagern): may get redefined once we have user-defined macros
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var arraystretch = utils.deflt(group.value.arraystretch, 1);
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var arrayskip = arraystretch * baselineskip;
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var arstrutHeight = 0.7 * arrayskip; // \strutbox in ltfsstrc.dtx and
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var arstrutDepth = 0.3 * arrayskip; // \@arstrutbox in lttab.dtx
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@ -565,14 +567,19 @@ var groupTypes = {
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body[r] = outrow;
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}
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var offset = totalHeight / 2 + fontMetrics.metrics.axisHeight;
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var colalign = group.value.colalign || [];
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var coldescriptions = group.value.cols || [];
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var cols = [];
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var colsep;
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for (c = 0; c < nc; ++c) {
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var coldescr = coldescriptions[c] || {};
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var sepwidth;
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if (c > 0 || group.value.hskipBeforeAndAfter) {
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colsep = makeSpan(["arraycolsep"], []);
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colsep.style.width = arraycolsep + "em";
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cols.push(colsep);
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sepwidth = utils.deflt(coldescr.pregap, arraycolsep);
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if (sepwidth !== 0) {
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colsep = makeSpan(["arraycolsep"], []);
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colsep.style.width = sepwidth + "em";
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cols.push(colsep);
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}
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}
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var col = [];
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for (r = 0; r < nr; ++r) {
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@ -588,13 +595,16 @@ var groupTypes = {
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}
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col = buildCommon.makeVList(col, "individualShift", null, options);
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col = makeSpan(
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["col-align-" + (colalign[c] || "c")],
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["col-align-" + (coldescr.align || "c")],
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[col]);
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cols.push(col);
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if (c < nc - 1 || group.value.hskipBeforeAndAfter) {
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colsep = makeSpan(["arraycolsep"], []);
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colsep.style.width = arraycolsep + "em";
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cols.push(colsep);
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sepwidth = utils.deflt(coldescr.postgap, arraycolsep);
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if (sepwidth !== 0) {
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colsep = makeSpan(["arraycolsep"], []);
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colsep.style.width = sepwidth + "em";
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cols.push(colsep);
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}
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}
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}
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body = makeSpan(["mtable"], cols);
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@ -1,3 +1,4 @@
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var fontMetrics = require("./fontMetrics");
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var parseData = require("./parseData");
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var ParseError = require("./ParseError");
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@ -66,10 +67,12 @@ var environmentDefinitions = [
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var parser = this;
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// Currently only supports alignment, no separators like | yet.
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colalign = colalign.value.map ? colalign.value : [colalign];
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colalign = colalign.map(function(node) {
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var cols = colalign.map(function(node) {
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var ca = node.value;
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if ("lcr".indexOf(ca) !== -1) {
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return ca;
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return {
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align: ca
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};
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}
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throw new ParseError(
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"Unknown column alignment: " + node.value,
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@ -77,7 +80,7 @@ var environmentDefinitions = [
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});
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var res = {
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type: "array",
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colalign: colalign,
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cols: cols,
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hskipBeforeAndAfter: true // \@preamble in lttab.dtx
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};
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res = parseArray(parser, pos, mode, res);
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@ -111,8 +114,36 @@ var environmentDefinitions = [
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}
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return res;
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}
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}
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},
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// A cases environment (in amsmath.sty) is almost equivalent to
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// \def\arraystretch{1.2}%
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// \left\{\begin{array}{@{}l@{\quad}l@{}} … \end{array}\right.
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{
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names: ["cases"],
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handler: function(pos, mode, envName) {
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var res = {
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type: "array",
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arraystretch: 1.2,
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cols: [{
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align: "l",
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pregap: 0,
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postgap: fontMetrics.metrics.quad
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}, {
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align: "l",
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pregap: 0,
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postgap: 0
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}]
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};
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res = parseArray(this, pos, mode, res);
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res.result = new ParseNode("leftright", {
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body: [res.result],
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left: "\\{",
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right: "."
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}, mode);
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return res;
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}
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}
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];
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module.exports = (function() {
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@ -31,6 +31,13 @@ var contains = function(list, elem) {
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return indexOf(list, elem) !== -1;
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};
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/**
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* Provide a default value if a setting is undefined
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*/
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var deflt = function(setting, defaultIfUndefined) {
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return setting === undefined ? defaultIfUndefined : setting;
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};
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// hyphenate and escape adapted from Facebook's React under Apache 2 license
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var uppercase = /([A-Z])/g;
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@ -89,6 +96,7 @@ function clearNode(node) {
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module.exports = {
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contains: contains,
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deflt: deflt,
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escape: escape,
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hyphenate: hyphenate,
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indexOf: indexOf,
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@ -1310,7 +1310,17 @@ describe("An array environment", function() {
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it("should accept a single alignment character", function() {
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var parse = getParsed("\\begin{array}r1\\\\20\\end{array}");
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expect(parse[0].type).toBe("array");
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expect(parse[0].value.colalign).toEqual(["r"]);
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expect(parse[0].value.cols).toEqual([{align:"r"}]);
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});
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});
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describe("A cases environment", function() {
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it("should parse its input", function() {
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expect("f(a,b)=\\begin{cases}a+1&\\text{if }b\\text{ is odd}\\\\" +
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"a&\\text{if }b=0\\\\a-1&\\text{otherwise}\\end{cases}")
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.toParse();
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});
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});
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BIN
test/screenshotter/images/Cases-firefox.png
Normal file
BIN
test/screenshotter/images/Cases-firefox.png
Normal file
Binary file not shown.
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After Width: | Height: | Size: 35 KiB |
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@ -4,6 +4,7 @@
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"Baseline": "http://localhost:7936/test/screenshotter/test.html?m=a+b-c\\cdot d/e",
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"BasicTest": "http://localhost:7936/test/screenshotter/test.html?m=a",
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"BinomTest": "http://localhost:7936/test/screenshotter/test.html?m=\\dbinom{a}{b}\\tbinom{a}{b}^{\\binom{a}{b}+17}",
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"Cases": "http://localhost:7936/test/screenshotter/test.html?m=f(a,b)=\\begin{cases}a+1%26\\text{if }b\\text{ is odd}\\\\a%26\\text{if }b=0\\\\a-1%26\\text{otherwise}\\end{cases}",
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"Colors": "http://localhost:7936/test/screenshotter/test.html?m=\\blue{a}\\color{%230f0}{b}\\color{red}{c}",
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"DeepFontSizing": "http://localhost:7936/test/screenshotter/test.html?m=a^{\\big| x^{\\big(}}_{\\Big\\uparrow} + i^{i^{\\Huge x}_y}_{\\Huge z} + \\dfrac{\\Huge x}{y}",
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"DelimiterSizing": "http://localhost:7936/test/screenshotter/test.html?m=\\bigl\\uparrow\\Bigl\\downarrow\\biggl\\updownarrow\\Biggl\\Uparrow\\Biggr\\Downarrow\\biggr\\langle\\Bigr\\}\\bigr\\rfloor",
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