Fix export of multi-line labels

CITATION.cff

@@ -7,7 +7,7 @@ authors:
     given-names: Nathanael
     orcid: https://orcid.org/0000-0002-4092-7930
 url: https://q.uiver.app/
-version: 1.5.0
-date-released: 2024-04-12
+version: 1.5.1
+date-released: 2024-05-01
 repository-code: https://github.com/varkor/quiver
 license: MIT

package/quiver.sty

@@ -4,7 +4,7 @@
 % This package is currently a wrapper around the `tikz-cd` package, importing necessary TikZ
 % libraries, and defining a new TikZ style for curves of a fixed height.
 %
-% Version: 1.5.0
+% Version: 1.5.1
 % Authors:
 % - varkor (https://github.com/varkor)
 % - AndréC (https://tex.stackexchange.com/users/138900/andr%C3%A9c)

src/quiver.js

@@ -370,9 +370,17 @@ QuiverImportExport.tikz_cd = new class extends QuiverImportExport {
         const simple_label = /^[a-zA-Z0-9\\]+$/;
 
         // Adapt a label to be appropriate for TikZ output, by surrounding it in curly brackets when
-        // necessary, and using `\shortstack` for newlines.
+        // necessary, and using `\array` for newlines.
         const format_label = (label) => {
-            return !simple_label.test(label) ? `{${label}}` : label;
+            if (label.includes("\\\\")) {
+                // The label may contain a newline. In this case, we place the label inside a table,
+                // which is permitted to contain newlines.
+                return `\\begin{array}{c} ${label} \\end{array}`;
+            }
+            if (!simple_label.test(label)) {
+                return `{${label}}`;
+            }
+            return label;
         };
 
         // We handle the export in two stages: vertices and edges. These are fundamentally handled

src/ui.js

@@ -3,7 +3,7 @@
 /// Various parameters.
 Object.assign(CONSTANTS, {
     /// The current quiver version.
-    VERSION: "1.5.0",
+    VERSION: "1.5.1",
     /// When the `quiver.sty` package was last modified.
     PACKAGE_VERSION: "2021/01/11",
     /// We currently only support n-cells for (n ≤ 4). This restriction is not technical: it can be