From 724619b0efc5937b4fba974769cea7fa6049dffc Mon Sep 17 00:00:00 2001
From: Robin Stocker <robin@nibor.org>
Date: Mon, 22 Jan 2024 22:46:33 +1100
Subject: [PATCH] Use Setext heading if necessary
---
.../markdown/CoreMarkdownNodeRenderer.java | 47 +++++++++++++++++++
.../renderer/markdown/MarkdownRenderer.java | 2 +-
.../markdown/MarkdownRendererTest.java | 3 ++
.../markdown/SpecMarkdownRendererTest.java | 2 +-
4 files changed, 52 insertions(+), 2 deletions(-)
diff --git a/commonmark/src/main/java/org/commonmark/renderer/markdown/CoreMarkdownNodeRenderer.java b/commonmark/src/main/java/org/commonmark/renderer/markdown/CoreMarkdownNodeRenderer.java
index a135d73e..dbaa9a47 100644
--- a/commonmark/src/main/java/org/commonmark/renderer/markdown/CoreMarkdownNodeRenderer.java
+++ b/commonmark/src/main/java/org/commonmark/renderer/markdown/CoreMarkdownNodeRenderer.java
@@ -13,6 +13,10 @@ import java.util.Set;
/**
* The node renderer that renders all the core nodes (comes last in the order of node renderers).
+ * <p>
+ * Note that while sometimes it would be easier to record what kind of syntax was used on parsing (e.g. ATX vs Setext
+ * heading), this renderer is intended to also work for documents that were created by directly creating
+ * {@link Node Nodes} instead. So in order to support that, it sometimes needs to do a bit more work.
*/
public class CoreMarkdownNodeRenderer extends AbstractVisitor implements NodeRenderer {
@@ -211,11 +215,34 @@ public class CoreMarkdownNodeRenderer extends AbstractVisitor implements NodeRen
@Override
public void visit(Heading heading) {
+ if (heading.getLevel() <= 2) {
+ LineBreakVisitor lineBreakVisitor = new LineBreakVisitor();
+ heading.accept(lineBreakVisitor);
+ boolean isMultipleLines = lineBreakVisitor.hasLineBreak();
+
+ if (isMultipleLines) {
+ // Setext headings: Can have multiple lines, but only level 1 or 2
+ visitChildren(heading);
+ writer.line();
+ if (heading.getLevel() == 1) {
+ // Note that it would be nice to match the length of the contents instead of just using 3, but that's
+ // not easy.
+ writer.write("===");
+ } else {
+ writer.write("---");
+ }
+ writer.block();
+ return;
+ }
+ }
+
+ // ATX headings: Can't have multiple lines, but up to level 6.
for (int i = 0; i < heading.getLevel(); i++) {
writer.write('#');
}
writer.write(' ');
visitChildren(heading);
+
writer.block();
}
@@ -392,4 +419,24 @@ public class CoreMarkdownNodeRenderer extends AbstractVisitor implements NodeRen
number = orderedList.getStartNumber();
}
}
+
+ private static class LineBreakVisitor extends AbstractVisitor {
+ private boolean lineBreak = false;
+
+ public boolean hasLineBreak() {
+ return lineBreak;
+ }
+
+ @Override
+ public void visit(SoftLineBreak softLineBreak) {
+ super.visit(softLineBreak);
+ lineBreak = true;
+ }
+
+ @Override
+ public void visit(HardLineBreak hardLineBreak) {
+ super.visit(hardLineBreak);
+ lineBreak = true;
+ }
+ }
}
diff --git a/commonmark/src/main/java/org/commonmark/renderer/markdown/MarkdownRenderer.java b/commonmark/src/main/java/org/commonmark/renderer/markdown/MarkdownRenderer.java
index 4dc8dbff..4dee17ed 100644
--- a/commonmark/src/main/java/org/commonmark/renderer/markdown/MarkdownRenderer.java
+++ b/commonmark/src/main/java/org/commonmark/renderer/markdown/MarkdownRenderer.java
@@ -14,7 +14,7 @@ import java.util.List;
* <p>
* Note that it does not currently attempt to preserve the exact syntax of the original input Markdown (if any):
* <ul>
- * <li>Headings are always output as ATX headings for simplicity</li>
+ * <li>Headings are output as ATX headings if possible (multi-line headings need Setext headings)</li>
* <li>Escaping might be over-eager, e.g. a plain {@code *} might be escaped
* even though it doesn't need to be in that particular context</li>
* </ul>
diff --git a/commonmark/src/test/java/org/commonmark/renderer/markdown/MarkdownRendererTest.java b/commonmark/src/test/java/org/commonmark/renderer/markdown/MarkdownRendererTest.java
index f6ce1b4e..05a253fd 100644
--- a/commonmark/src/test/java/org/commonmark/renderer/markdown/MarkdownRendererTest.java
+++ b/commonmark/src/test/java/org/commonmark/renderer/markdown/MarkdownRendererTest.java
@@ -28,6 +28,9 @@ public class MarkdownRendererTest {
assertRoundTrip("##### foo\n");
assertRoundTrip("###### foo\n");
+ assertRoundTrip("Foo\nbar\n===\n");
+ assertRoundTrip("[foo\nbar](/url)\n===\n");
+
assertRoundTrip("# foo\n\nbar\n");
}
diff --git a/commonmark/src/test/java/org/commonmark/renderer/markdown/SpecMarkdownRendererTest.java b/commonmark/src/test/java/org/commonmark/renderer/markdown/SpecMarkdownRendererTest.java
index 4e9396e7..1dd06441 100644
--- a/commonmark/src/test/java/org/commonmark/renderer/markdown/SpecMarkdownRendererTest.java
+++ b/commonmark/src/test/java/org/commonmark/renderer/markdown/SpecMarkdownRendererTest.java
@@ -62,7 +62,7 @@ public class SpecMarkdownRendererTest {
System.out.println();
}
- int expectedPassed = 622;
+ int expectedPassed = 625;
assertTrue("Expected at least " + expectedPassed + " examples to pass but was " + passes.size(), passes.size() >= expectedPassed);
}
--
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