commit c951df4269eb0b72826f803b218e6fa7c19c78e5
parent 9d3cdf694c33ee008af9508481d316d78cce329a
Author: Eddie Kohler <ekohler@gmail.com>
Date: Mon, 21 Nov 2016 14:02:24 -0500
Fix #4.
Post-process the list of atoms after they are created, changing
binary operators to ordinary atoms according to the TeXbook's
rules. This makes the `prev` argument redundant, so drop it.
This commit assumes that the math class (mop/mbin/mrel/etc.) comes
first in the `classes` list, if present. Add a TODO to change the
signature of `makeSpan/makeSymbol` to enforce this invariant.
Diffstat:
6 files changed, 99 insertions(+), 74 deletions(-)
diff --git a/src/buildCommon.js b/src/buildCommon.js
@@ -36,6 +36,8 @@ var mainitLetters = [
* classes to be attached to the node.
*
* TODO: make argument order closer to makeSpan
+ * TODO: add a separate argument for math class (e.g. `mop`, `mbin`), which
+ * should if present come first in `classes`.
*/
var makeSymbol = function(value, fontFamily, mode, options, classes) {
// Replace the value with its replaced value from symbol.js
@@ -183,6 +185,8 @@ var sizeElementFromChildren = function(elem) {
*
* TODO: Ensure that `options` is always provided (currently some call sites
* don't pass it).
+ * TODO: add a separate argument for math class (e.g. `mop`, `mbin`), which
+ * should if present come first in `classes`.
*/
var makeSpan = function(classes, children, options) {
var span = new domTree.span(classes, children, options);
diff --git a/src/buildHTML.js b/src/buildHTML.js
@@ -21,27 +21,52 @@ var isSpace = function(node) {
return node instanceof domTree.span && node.classes[0] === "mspace";
};
+// Binary atoms (first class `mbin`) change into ordinary atoms (`mord`)
+// depending on their surroundings. See TeXbook pg. 442-446, Rules 5 and 6,
+// and the text before Rule 19.
+
+var isBin = function(node) {
+ return node && node.classes[0] === "mbin";
+};
+
+var isBinLeftCanceller = function(node, isRealGroup) {
+ // TODO: This code assumes that a node's math class is the first element
+ // of its `classes` array. A later cleanup should ensure this, for
+ // instance by changing the signature of `makeSpan`.
+ if (node) {
+ return utils.contains(["mbin", "mopen", "mrel", "mop", "mpunct"],
+ node.classes[0]);
+ } else {
+ return isRealGroup;
+ }
+};
+
+var isBinRightCanceller = function(node, isRealGroup) {
+ if (node) {
+ return utils.contains(["mrel", "mclose", "mpunct"], node.classes[0]);
+ } else {
+ return isRealGroup;
+ }
+};
+
/**
* Take a list of nodes, build them in order, and return a list of the built
- * nodes. This function handles the `prev` node correctly, and passes the
- * previous element from the list as the prev of the next element, ignoring
- * spaces. documentFragments are flattened into their contents, so the
- * returned list contains no fragments.
+ * nodes. documentFragments are flattened into their contents, so the
+ * returned list contains no fragments. `isRealGroup` is true if `expression`
+ * is a real group (no atoms will be added on either side), as opposed to
+ * a partial group (e.g. one created by \color).
*/
-var buildExpression = function(expression, options, prev) {
+var buildExpression = function(expression, options, isRealGroup) {
// Parse expressions into `groups`.
var groups = [];
for (var i = 0; i < expression.length; i++) {
var group = expression[i];
- var output = buildGroup(group, options, prev);
+ var output = buildGroup(group, options);
if (output instanceof domTree.documentFragment) {
Array.prototype.push.apply(groups, output.children);
} else {
groups.push(output);
}
- if (!isSpace(output)) {
- prev = group;
- }
}
// At this point `groups` consists entirely of `symbolNode`s and `span`s.
@@ -68,6 +93,15 @@ var buildExpression = function(expression, options, prev) {
Array.prototype.push.apply(groups, spaces);
}
+ // Binary operators change to ordinary symbols in some contexts.
+ for (i = 0; i < groups.length; i++) {
+ if (isBin(groups[i])
+ && (isBinLeftCanceller(groups[i - 1], isRealGroup)
+ || isBinRightCanceller(groups[i + 1], isRealGroup))) {
+ groups[i].classes[0] = "mord";
+ }
+ }
+
return groups;
};
@@ -215,81 +249,63 @@ var makeNullDelimiter = function(options) {
*/
var groupTypes = {};
-groupTypes.mathord = function(group, options, prev) {
+groupTypes.mathord = function(group, options) {
return buildCommon.makeOrd(group, options, "mathord");
};
-groupTypes.textord = function(group, options, prev) {
+groupTypes.textord = function(group, options) {
return buildCommon.makeOrd(group, options, "textord");
};
-groupTypes.bin = function(group, options, prev) {
- var className = "mbin";
- // Pull out the most recent element. Do some special handling to find
- // things at the end of a \color group. Note that we don't use the same
- // logic for ordgroups (which count as ords).
- var prevAtom = prev;
- while (prevAtom && prevAtom.type === "color") {
- var atoms = prevAtom.value.value;
- prevAtom = atoms[atoms.length - 1];
- }
- // See TeXbook pg. 442-446, Rules 5 and 6, and the text before Rule 19.
- // Here, we determine whether the bin should turn into an ord. We
- // currently only apply Rule 5.
- if (!prev || utils.contains(["mbin", "mopen", "mrel", "mop", "mpunct"],
- getTypeOfGroup(prevAtom))) {
- group.type = "textord";
- className = "mord";
- }
-
+groupTypes.bin = function(group, options) {
return buildCommon.mathsym(
- group.value, group.mode, options, [className]);
+ group.value, group.mode, options, ["mbin"]);
};
-groupTypes.rel = function(group, options, prev) {
+groupTypes.rel = function(group, options) {
return buildCommon.mathsym(
group.value, group.mode, options, ["mrel"]);
};
-groupTypes.open = function(group, options, prev) {
+groupTypes.open = function(group, options) {
return buildCommon.mathsym(
group.value, group.mode, options, ["mopen"]);
};
-groupTypes.close = function(group, options, prev) {
+groupTypes.close = function(group, options) {
return buildCommon.mathsym(
group.value, group.mode, options, ["mclose"]);
};
-groupTypes.inner = function(group, options, prev) {
+groupTypes.inner = function(group, options) {
return buildCommon.mathsym(
group.value, group.mode, options, ["minner"]);
};
-groupTypes.punct = function(group, options, prev) {
+groupTypes.punct = function(group, options) {
return buildCommon.mathsym(
group.value, group.mode, options, ["mpunct"]);
};
-groupTypes.ordgroup = function(group, options, prev) {
+groupTypes.ordgroup = function(group, options) {
return makeSpan(
["mord", options.style.cls()],
- buildExpression(group.value, options.reset()),
+ buildExpression(group.value, options.reset(), true),
options
);
};
-groupTypes.text = function(group, options, prev) {
+groupTypes.text = function(group, options) {
return makeSpan(["mord", "text", options.style.cls()],
- buildExpression(group.value.body, options.reset()),
+ buildExpression(group.value.body, options.reset(), true),
options);
};
-groupTypes.color = function(group, options, prev) {
+groupTypes.color = function(group, options) {
var elements = buildExpression(
group.value.value,
options.withColor(group.value.color),
- prev
+ false
);
// \color isn't supposed to affect the type of the elements it contains.
@@ -299,14 +315,14 @@ groupTypes.color = function(group, options, prev) {
return new buildCommon.makeFragment(elements);
};
-groupTypes.supsub = function(group, options, prev) {
+groupTypes.supsub = function(group, options) {
// Superscript and subscripts are handled in the TeXbook on page
// 445-446, rules 18(a-f).
// Here is where we defer to the inner group if it should handle
// superscripts and subscripts itself.
if (shouldHandleSupSub(group.value.base, options)) {
- return groupTypes[group.value.base.type](group, options, prev);
+ return groupTypes[group.value.base.type](group, options);
}
var base = buildGroup(group.value.base, options.reset());
@@ -427,7 +443,7 @@ groupTypes.supsub = function(group, options, prev) {
options);
};
-groupTypes.genfrac = function(group, options, prev) {
+groupTypes.genfrac = function(group, options) {
// Fractions are handled in the TeXbook on pages 444-445, rules 15(a-e).
// Figure out what style this fraction should be in based on the
// function used
@@ -566,7 +582,7 @@ groupTypes.genfrac = function(group, options, prev) {
options);
};
-groupTypes.array = function(group, options, prev) {
+groupTypes.array = function(group, options) {
var r;
var c;
var nr = group.value.body.length;
@@ -730,7 +746,7 @@ groupTypes.array = function(group, options, prev) {
return makeSpan(["mord"], [body], options);
};
-groupTypes.spacing = function(group, options, prev) {
+groupTypes.spacing = function(group, options) {
if (group.value === "\\ " || group.value === "\\space" ||
group.value === " " || group.value === "~") {
// Spaces are generated by adding an actual space. Each of these
@@ -749,7 +765,7 @@ groupTypes.spacing = function(group, options, prev) {
}
};
-groupTypes.llap = function(group, options, prev) {
+groupTypes.llap = function(group, options) {
var inner = makeSpan(
["inner"], [buildGroup(group.value.body, options.reset())]);
var fix = makeSpan(["fix"], []);
@@ -757,7 +773,7 @@ groupTypes.llap = function(group, options, prev) {
["llap", options.style.cls()], [inner, fix], options);
};
-groupTypes.rlap = function(group, options, prev) {
+groupTypes.rlap = function(group, options) {
var inner = makeSpan(
["inner"], [buildGroup(group.value.body, options.reset())]);
var fix = makeSpan(["fix"], []);
@@ -765,12 +781,12 @@ groupTypes.rlap = function(group, options, prev) {
["rlap", options.style.cls()], [inner, fix], options);
};
-groupTypes.op = function(group, options, prev) {
+groupTypes.op = function(group, options) {
// Operators are handled in the TeXbook pg. 443-444, rule 13(a).
var supGroup;
var subGroup;
var hasLimits = false;
- if (group.type === "supsub" ) {
+ if (group.type === "supsub") {
// If we have limits, supsub will pass us its group to handle. Pull
// out the superscript and subscript and set the group to the op in
// its base.
@@ -930,7 +946,7 @@ groupTypes.op = function(group, options, prev) {
}
};
-groupTypes.katex = function(group, options, prev) {
+groupTypes.katex = function(group, options) {
// The KaTeX logo. The offsets for the K and a were chosen to look
// good, but the offsets for the T, E, and X were taken from the
// definition of \TeX in TeX (see TeXbook pg. 356)
@@ -957,7 +973,7 @@ groupTypes.katex = function(group, options, prev) {
["mord", "katex-logo"], [k, a, t, e, x], options);
};
-groupTypes.overline = function(group, options, prev) {
+groupTypes.overline = function(group, options) {
// Overlines are handled in the TeXbook pg 443, Rule 9.
var style = options.style;
@@ -985,7 +1001,7 @@ groupTypes.overline = function(group, options, prev) {
return makeSpan(["mord", "overline"], [vlist], options);
};
-groupTypes.underline = function(group, options, prev) {
+groupTypes.underline = function(group, options) {
// Underlines are handled in the TeXbook pg 443, Rule 10.
var style = options.style;
@@ -1011,7 +1027,7 @@ groupTypes.underline = function(group, options, prev) {
return makeSpan(["mord", "underline"], [vlist], options);
};
-groupTypes.sqrt = function(group, options, prev) {
+groupTypes.sqrt = function(group, options) {
// Square roots are handled in the TeXbook pg. 443, Rule 11.
var style = options.style;
@@ -1110,12 +1126,12 @@ groupTypes.sqrt = function(group, options, prev) {
}
};
-groupTypes.sizing = function(group, options, prev) {
+groupTypes.sizing = function(group, options) {
// Handle sizing operators like \Huge. Real TeX doesn't actually allow
// these functions inside of math expressions, so we do some special
// handling.
var inner = buildExpression(group.value.value,
- options.withSize(group.value.size), prev);
+ options.withSize(group.value.size), false);
// Compute the correct maxFontSize.
var style = options.style;
@@ -1141,7 +1157,7 @@ groupTypes.sizing = function(group, options, prev) {
return buildCommon.makeFragment(inner);
};
-groupTypes.styling = function(group, options, prev) {
+groupTypes.styling = function(group, options) {
// Style changes are handled in the TeXbook on pg. 442, Rule 3.
// Figure out what style we're changing to.
@@ -1157,7 +1173,7 @@ groupTypes.styling = function(group, options, prev) {
// Build the inner expression in the new style.
var inner = buildExpression(
- group.value.value, newOptions, prev);
+ group.value.value, newOptions, false);
// Add style-resetting classes to the inner list. Handle nested changes.
for (var i = 0; i < inner.length; i++) {
@@ -1174,12 +1190,12 @@ groupTypes.styling = function(group, options, prev) {
return new buildCommon.makeFragment(inner);
};
-groupTypes.font = function(group, options, prev) {
+groupTypes.font = function(group, options) {
var font = group.value.font;
- return buildGroup(group.value.body, options.withFont(font), prev);
+ return buildGroup(group.value.body, options.withFont(font));
};
-groupTypes.delimsizing = function(group, options, prev) {
+groupTypes.delimsizing = function(group, options) {
var delim = group.value.value;
if (delim === ".") {
@@ -1196,9 +1212,9 @@ groupTypes.delimsizing = function(group, options, prev) {
options);
};
-groupTypes.leftright = function(group, options, prev) {
+groupTypes.leftright = function(group, options) {
// Build the inner expression
- var inner = buildExpression(group.value.body, options.reset());
+ var inner = buildExpression(group.value.body, options.reset(), true);
var innerHeight = 0;
var innerDepth = 0;
@@ -1247,7 +1263,7 @@ groupTypes.leftright = function(group, options, prev) {
["minner", style.cls()], inner, options);
};
-groupTypes.rule = function(group, options, prev) {
+groupTypes.rule = function(group, options) {
// Make an empty span for the rule
var rule = makeSpan(["mord", "rule"], [], options);
var style = options.style;
@@ -1290,7 +1306,7 @@ groupTypes.rule = function(group, options, prev) {
return rule;
};
-groupTypes.kern = function(group, options, prev) {
+groupTypes.kern = function(group, options) {
// Make an empty span for the rule
var rule = makeSpan(["mord", "rule"], [], options);
var style = options.style;
@@ -1310,7 +1326,7 @@ groupTypes.kern = function(group, options, prev) {
return rule;
};
-groupTypes.accent = function(group, options, prev) {
+groupTypes.accent = function(group, options) {
// Accents are handled in the TeXbook pg. 443, rule 12.
var base = group.value.base;
var style = options.style;
@@ -1337,7 +1353,7 @@ groupTypes.accent = function(group, options, prev) {
// Rerender the supsub group with its new base, and store that
// result.
supsubGroup = buildGroup(
- supsub, options.reset(), prev);
+ supsub, options.reset());
}
// Build the base group
@@ -1419,11 +1435,11 @@ groupTypes.accent = function(group, options, prev) {
}
};
-groupTypes.phantom = function(group, options, prev) {
+groupTypes.phantom = function(group, options) {
var elements = buildExpression(
group.value.value,
options.withPhantom(),
- prev
+ false
);
// \phantom isn't supposed to affect the elements it contains.
@@ -1436,14 +1452,14 @@ groupTypes.phantom = function(group, options, prev) {
* function for it. It also handles the interaction of size and style changes
* between parents and children.
*/
-var buildGroup = function(group, options, prev) {
+var buildGroup = function(group, options) {
if (!group) {
return makeSpan();
}
if (groupTypes[group.type]) {
// Call the groupTypes function
- var groupNode = groupTypes[group.type](group, options, prev);
+ var groupNode = groupTypes[group.type](group, options);
var multiplier;
// If the style changed between the parent and the current group,
@@ -1483,7 +1499,7 @@ var buildHTML = function(tree, options) {
tree = JSON.parse(JSON.stringify(tree));
// Build the expression contained in the tree
- var expression = buildExpression(tree, options);
+ var expression = buildExpression(tree, options, true);
var body = makeSpan(["base", options.style.cls()], expression, options);
// Add struts, which ensure that the top of the HTML element falls at the
diff --git a/src/buildMathML.js b/src/buildMathML.js
@@ -470,7 +470,7 @@ groupTypes.rlap = function(group, options) {
return node;
};
-groupTypes.phantom = function(group, options, prev) {
+groupTypes.phantom = function(group, options) {
var inner = buildExpression(group.value.value, options);
return new mathMLTree.MathNode("mphantom", inner);
};
diff --git a/test/screenshotter/images/BinCancellation-chrome.png b/test/screenshotter/images/BinCancellation-chrome.png
Binary files differ.
diff --git a/test/screenshotter/images/BinCancellation-firefox.png b/test/screenshotter/images/BinCancellation-firefox.png
Binary files differ.
diff --git a/test/screenshotter/ss_data.yaml b/test/screenshotter/ss_data.yaml
@@ -26,6 +26,11 @@ Arrays: |
ArrayType: 1\begin{array}{c}2\\3\end{array}4
Baseline: a+b-c\cdot d/e
BasicTest: a
+BinCancellation: |
+ \begin{array}{ccc}
+ +1 & 1+ & 1+1 \\
+ 1++1 & 3\times) & 1+,
+ \end{array}
BinomTest: \dbinom{a}{b}\tbinom{a}{b}^{\binom{a}{b}+17}
BoldSpacing: \mathbf{A}^2+\mathbf{B}_3*\mathscr{C}'
Cases: |
