content: Handle KaTeX math, with a rough preview #472
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I assume we want to resolve this CZO thread before I review this. (edit: as discussed in the office, I'll read the code; we don't expect the visual design changes to change much of it.) |
lib/model/content.dart
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| if (greatgrand.localName != 'semantics') return null; | ||
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| if (greatgrand.nodes.isEmpty) return null; | ||
| final child4 = greatgrand.nodes.last; |
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In order to name the last child child4, do we want to assert that there are four children? (er, or 5 children, if we count from 0?)
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Hmm, that's not the meaning I intended with this name. Definitely could use some changes to make it clearer, then!
I don't expect a fixed number of children here, of the <semantics> element. In particular if you look at your example below, or at the example in the test cases, it has two children — an <mrow> and then the <annotation> — but I figure it's probably not always an <mrow>, and may not always be just one sibling before the <annotation>.
Maybe a better name would be descendant4. It's the child of greatgrand, which is the great-grandchild of katexElement, the third generation down from katexElement; so this one is the fourth generation down.
The first name I started typing for it was greatgreat, but I figured that looks too similar to greatgrand. Could also say greatgreatgrand, I guess — or maybe greatGrand and greatGreatGrand would be the proper camel-casing.
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Maybe a better name would be
descendant4.
Sure, that sounds good.
lib/model/content.dart
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| @@ -792,6 +894,16 @@ class _ZulipContentParser { | |||
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| if (localName == 'p' && classes.isEmpty) { | |||
| // Oddly, the way a math block gets encoded in Zulip HTML is inside a <p>. | |||
| if (element.nodes case [dom.Element(localName: 'span') && var child]) { | |||
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Hmm, I'm seeing a block-quoted math block with more than one child inside the <p>. The HTML has the expected span and then <br>\n.
https://chat.zulip.org/#narrow/stream/7-test-here/topic/Chris/near/1714716
````quote
```math
1 + 1
```
````
"<blockquote>\n<p><span class=\"katex-display\"><span class=\"katex\"><span class=\"katex-mathml\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\" display=\"block\"><semantics><mrow><mn>1</mn><mo>+</mo><mn>1</mn></mrow><annotation encoding=\"application/x-tex\">1 + 1</annotation></semantics></math></span><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"strut\" style=\"height:0.7278em;vertical-align:-0.0833em;\"></span><span class=\"mord\">1</span><span class=\"mspace\" style=\"margin-right:0.2222em;\"></span><span class=\"mbin\">+</span><span class=\"mspace\" style=\"margin-right:0.2222em;\"></span></span><span class=\"base\"><span class=\"strut\" style=\"height:0.6444em;\"></span><span class=\"mord\">1</span></span></span></span></span><br>\n</p>\n</blockquote>"
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Good find, thanks! I'll handle that, and also take this as a sign I should do some broader experimenting.
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Revision pushed! PTAL. In addition to the review items above, I changed the visual design to the one more people preferred in that thread. (Screenshots updated.) |
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Hmm, CI shows a test failure in a MathBlock content widget test. |
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Oops, thanks — fixed. |
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Thanks, LGTM! Merging. |
Fixes: #359
See discussion on visual design: https://chat.zulip.org/#narrow/stream/48-mobile/topic/TeX.20in.20Flutter.20app/near/1710839
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