Add strikethrough markdown support

Since it's inlined, the extension is added directly to the core module.
JetBrains · Mar 21, 2024 · c0a4392 · c0a4392
1 parent 93d7e26
commit c0a4392
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Showing 10 changed files with 95 additions and 8 deletions.
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
@@ -16,6 +16,7 @@ poko = "0.13.1"
 
 [libraries]
 commonmark-core = { module = "org.commonmark:commonmark", version.ref = "commonmark" }
+commonmark-extGfmStrikethrough = { module = "org.commonmark:commonmark-ext-gfm-strikethrough", version.ref = "commonmark" }
 
 filePicker = { module = "com.darkrockstudios:mpfilepicker", version = "3.1.0" }
 

diff --git a/markdown/README.md b/markdown/README.md
@@ -11,13 +11,13 @@ Currently supports the [CommonMark 0.31.2](https://spec.commonmark.org/0.31.2/)
 Additional supported Markdown, via extensions:
 
 * Alerts ([GitHub Flavored Markdown][alerts-specs]) — see [`extension-gfm-alerts`](extension-gfm-alerts)
+* Strikethrough(builtin) ([GitHub Flavored Markdown](https://github.github.com/gfm/#strikethrough-extension-))
 
 [alerts-specs]: https://github.com/orgs/community/discussions/16925
 
 On the roadmap, but not currently supported — in no particular order:
 
 * Tables ([GitHub Flavored Markdown](https://github.github.com/gfm/#tables-extension-))
-* Strikethrough ([GitHub Flavored Markdown](https://github.github.com/gfm/#strikethrough-extension-))
 * Image loading (via [Coil 3](https://coil-kt.github.io/coil/upgrading_to_coil3/))
 * Auto-linking ([GitHub Flavored Markdown](https://github.github.com/gfm/#autolinks-extension-))
 * Task list items ([GitHub Flavored Markdown](https://github.github.com/gfm/#task-list-items-extension-))

diff --git a/markdown/core/api/core.api b/markdown/core/api/core.api
@@ -370,12 +370,12 @@ public class org/jetbrains/jewel/markdown/rendering/DefaultMarkdownBlockRenderer
 }
 
 public final class org/jetbrains/jewel/markdown/rendering/DefaultStylingKt {
-	public static final fun dark (Lorg/jetbrains/jewel/markdown/rendering/InlinesStyling$Companion;Landroidx/compose/ui/text/TextStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Z)Lorg/jetbrains/jewel/markdown/rendering/InlinesStyling;
+	public static final fun dark (Lorg/jetbrains/jewel/markdown/rendering/InlinesStyling$Companion;Landroidx/compose/ui/text/TextStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Z)Lorg/jetbrains/jewel/markdown/rendering/InlinesStyling;
 	public static final fun dark (Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Code$Companion;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Code$Indented;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Code$Fenced;)Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Code;
 	public static final fun dark (Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$Companion;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H1;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H2;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H3;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H4;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H5;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H6;)Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading;
 	public static final fun dark (Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$List$Companion;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$List$Ordered;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$List$Unordered;)Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$List;
 	public static final fun dark (Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Paragraph$Companion;Lorg/jetbrains/jewel/markdown/rendering/InlinesStyling;)Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Paragraph;
-	public static synthetic fun dark$default (Lorg/jetbrains/jewel/markdown/rendering/InlinesStyling$Companion;Landroidx/compose/ui/text/TextStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;ZILjava/lang/Object;)Lorg/jetbrains/jewel/markdown/rendering/InlinesStyling;
+	public static synthetic fun dark$default (Lorg/jetbrains/jewel/markdown/rendering/InlinesStyling$Companion;Landroidx/compose/ui/text/TextStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;ZILjava/lang/Object;)Lorg/jetbrains/jewel/markdown/rendering/InlinesStyling;
 	public static synthetic fun dark$default (Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Code$Companion;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Code$Indented;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Code$Fenced;ILjava/lang/Object;)Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Code;
 	public static synthetic fun dark$default (Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$Companion;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H1;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H2;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H3;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H4;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H5;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H6;ILjava/lang/Object;)Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading;
 	public static synthetic fun dark$default (Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$List$Companion;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$List$Ordered;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$List$Unordered;ILjava/lang/Object;)Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$List;
@@ -410,12 +410,12 @@ public final class org/jetbrains/jewel/markdown/rendering/DefaultStylingKt {
 	public static synthetic fun dark-pI2OzKA$default (Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$BlockQuote$Companion;Landroidx/compose/foundation/layout/PaddingValues;FJLandroidx/compose/ui/graphics/PathEffect;IJILjava/lang/Object;)Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$BlockQuote;
 	public static final fun default-1Fc8zlc (Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Image$Companion;Landroidx/compose/ui/Alignment;Landroidx/compose/ui/layout/ContentScale;Landroidx/compose/foundation/layout/PaddingValues;Landroidx/compose/ui/graphics/Shape;JFJ)Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Image;
 	public static synthetic fun default-1Fc8zlc$default (Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Image$Companion;Landroidx/compose/ui/Alignment;Landroidx/compose/ui/layout/ContentScale;Landroidx/compose/foundation/layout/PaddingValues;Landroidx/compose/ui/graphics/Shape;JFJILjava/lang/Object;)Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Image;
-	public static final fun light (Lorg/jetbrains/jewel/markdown/rendering/InlinesStyling$Companion;Landroidx/compose/ui/text/TextStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Z)Lorg/jetbrains/jewel/markdown/rendering/InlinesStyling;
+	public static final fun light (Lorg/jetbrains/jewel/markdown/rendering/InlinesStyling$Companion;Landroidx/compose/ui/text/TextStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Z)Lorg/jetbrains/jewel/markdown/rendering/InlinesStyling;
 	public static final fun light (Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Code$Companion;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Code$Indented;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Code$Fenced;)Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Code;
 	public static final fun light (Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$Companion;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H1;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H2;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H3;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H4;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H5;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H6;)Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading;
 	public static final fun light (Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$List$Companion;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$List$Ordered;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$List$Unordered;)Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$List;
 	public static final fun light (Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Paragraph$Companion;Lorg/jetbrains/jewel/markdown/rendering/InlinesStyling;)Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Paragraph;
-	public static synthetic fun light$default (Lorg/jetbrains/jewel/markdown/rendering/InlinesStyling$Companion;Landroidx/compose/ui/text/TextStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;ZILjava/lang/Object;)Lorg/jetbrains/jewel/markdown/rendering/InlinesStyling;
+	public static synthetic fun light$default (Lorg/jetbrains/jewel/markdown/rendering/InlinesStyling$Companion;Landroidx/compose/ui/text/TextStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;ZILjava/lang/Object;)Lorg/jetbrains/jewel/markdown/rendering/InlinesStyling;
 	public static synthetic fun light$default (Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Code$Companion;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Code$Indented;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Code$Fenced;ILjava/lang/Object;)Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Code;
 	public static synthetic fun light$default (Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$Companion;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H1;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H2;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H3;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H4;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H5;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading$H6;ILjava/lang/Object;)Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$Heading;
 	public static synthetic fun light$default (Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$List$Companion;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$List$Ordered;Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$List$Unordered;ILjava/lang/Object;)Lorg/jetbrains/jewel/markdown/rendering/MarkdownStyling$List;
@@ -463,13 +463,14 @@ public final class org/jetbrains/jewel/markdown/rendering/InlineMarkdownRenderer
 public final class org/jetbrains/jewel/markdown/rendering/InlinesStyling {
 	public static final field $stable I
 	public static final field Companion Lorg/jetbrains/jewel/markdown/rendering/InlinesStyling$Companion;
-	public fun <init> (Landroidx/compose/ui/text/TextStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Z)V
+	public fun <init> (Landroidx/compose/ui/text/TextStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Landroidx/compose/ui/text/SpanStyle;Z)V
 	public fun equals (Ljava/lang/Object;)Z
 	public final fun getEmphasis ()Landroidx/compose/ui/text/SpanStyle;
 	public final fun getInlineCode ()Landroidx/compose/ui/text/SpanStyle;
 	public final fun getInlineHtml ()Landroidx/compose/ui/text/SpanStyle;
 	public final fun getLink ()Landroidx/compose/ui/text/SpanStyle;
 	public final fun getRenderInlineHtml ()Z
+	public final fun getStrikethrough ()Landroidx/compose/ui/text/SpanStyle;
 	public final fun getStrongEmphasis ()Landroidx/compose/ui/text/SpanStyle;
 	public final fun getTextStyle ()Landroidx/compose/ui/text/TextStyle;
 	public fun hashCode ()I

diff --git a/markdown/core/build.gradle.kts b/markdown/core/build.gradle.kts
@@ -8,6 +8,7 @@ plugins {
 dependencies {
     compileOnly(projects.ui)
     api(libs.commonmark.core)
+    api(libs.commonmark.extGfmStrikethrough)
 
     testImplementation(compose.desktop.uiTestJUnit4)
     testImplementation(projects.ui)

diff --git a/markdown/core/src/main/kotlin/org/jetbrains/jewel/markdown/processing/MarkdownProcessor.kt b/markdown/core/src/main/kotlin/org/jetbrains/jewel/markdown/processing/MarkdownProcessor.kt
@@ -1,5 +1,7 @@
 package org.jetbrains.jewel.markdown.processing
 
+import org.commonmark.ext.gfm.strikethrough.Strikethrough
+import org.commonmark.ext.gfm.strikethrough.StrikethroughExtension
 import org.commonmark.node.BlockQuote
 import org.commonmark.node.BulletList
 import org.commonmark.node.Code
@@ -46,11 +48,16 @@ public class MarkdownProcessor(private val extensions: List<MarkdownProcessorExt
 
     public constructor(vararg extensions: MarkdownProcessorExtension) : this(extensions.toList())
 
+    private val strikethroughExtension = StrikethroughExtension.create()
+
     private val commonMarkParser =
-        Parser.builder().extensions(extensions.map { it.parserExtension }).build()
+        Parser.builder()
+            .extensions(listOf(strikethroughExtension))
+            .extensions(extensions.map { it.parserExtension }).build()
 
     private val textContentRenderer =
         TextContentRenderer.builder()
+            .extensions(listOf(strikethroughExtension))
             .extensions(extensions.map { it.textRendererExtension })
             .build()
 
@@ -216,6 +223,12 @@ public class MarkdownProcessor(private val extensions: List<MarkdownProcessorExt
                     append(child.closingDelimiter)
                 }
 
+                is Strikethrough -> {
+                    append(child.openingDelimiter)
+                    appendInlineMarkdownFrom(child)
+                    append(child.closingDelimiter)
+                }
+
                 is Code -> append(child.literal.asInlineCodeString())
                 is Link -> appendLink(child, allowLinks)
 

diff --git a/...e/src/main/kotlin/org/jetbrains/jewel/markdown/rendering/DefaultInlineMarkdownRenderer.kt b/...e/src/main/kotlin/org/jetbrains/jewel/markdown/rendering/DefaultInlineMarkdownRenderer.kt
@@ -7,6 +7,8 @@ import androidx.compose.ui.text.ExperimentalTextApi
 import androidx.compose.ui.text.SpanStyle
 import androidx.compose.ui.text.UrlAnnotation
 import androidx.compose.ui.text.buildAnnotatedString
+import org.commonmark.ext.gfm.strikethrough.Strikethrough
+import org.commonmark.ext.gfm.strikethrough.StrikethroughExtension
 import org.commonmark.node.Block
 import org.commonmark.node.Code
 import org.commonmark.node.Emphasis
@@ -30,11 +32,16 @@ public open class DefaultInlineMarkdownRenderer(rendererExtensions: List<Markdow
 
     public constructor(vararg extensions: MarkdownProcessorExtension) : this(extensions.toList())
 
+    private val strikethroughExtension = StrikethroughExtension.create()
+
     private val commonMarkParser =
-        Parser.builder().extensions(rendererExtensions.map { it.parserExtension }).build()
+        Parser.builder()
+            .extensions(listOf(strikethroughExtension))
+            .extensions(rendererExtensions.map { it.parserExtension }).build()
 
     private val plainTextRenderer =
         TextContentRenderer.builder()
+            .extensions(listOf(strikethroughExtension))
             .extensions(rendererExtensions.map { it.textRendererExtension })
             .build()
 
@@ -70,6 +77,10 @@ public open class DefaultInlineMarkdownRenderer(rendererExtensions: List<Markdow
                     withStyles(styling.strongEmphasis, child) { appendInlineMarkdownFrom(it, styling) }
                 }
 
+                is Strikethrough -> {
+                    withStyles(styling.strikethrough, child) { appendInlineMarkdownFrom(it, styling) }
+                }
+
                 is Code -> {
                     withStyles(styling.inlineCode, child) { append(it.literal) }
                 }

diff --git a/markdown/core/src/main/kotlin/org/jetbrains/jewel/markdown/rendering/DefaultStyling.kt b/markdown/core/src/main/kotlin/org/jetbrains/jewel/markdown/rendering/DefaultStyling.kt
@@ -596,6 +596,7 @@ public fun InlinesStyling.Companion.light(
         textStyle.copy(color = Color(0xFF0969DA), textDecoration = TextDecoration.Underline).toSpanStyle(),
     emphasis: SpanStyle = textStyle.copy(fontStyle = FontStyle.Italic).toSpanStyle(),
     strongEmphasis: SpanStyle = textStyle.copy(fontWeight = FontWeight.Bold).toSpanStyle(),
+    strikethrough: SpanStyle = textStyle.copy(textDecoration = TextDecoration.LineThrough).toSpanStyle().copy(),
     inlineHtml: SpanStyle = textStyle.toSpanStyle(),
     renderInlineHtml: Boolean = false,
 ): InlinesStyling =
@@ -605,6 +606,7 @@ public fun InlinesStyling.Companion.light(
         link,
         emphasis,
         strongEmphasis,
+        strikethrough,
         inlineHtml,
         renderInlineHtml,
     )
@@ -625,6 +627,7 @@ public fun InlinesStyling.Companion.dark(
             .toSpanStyle(),
     emphasis: SpanStyle = textStyle.copy(fontStyle = FontStyle.Italic).toSpanStyle(),
     strongEmphasis: SpanStyle = textStyle.copy(fontWeight = FontWeight.Bold).toSpanStyle(),
+    strikethrough: SpanStyle = textStyle.copy(textDecoration = TextDecoration.LineThrough).toSpanStyle().copy(),
     inlineHtml: SpanStyle = textStyle.toSpanStyle(),
     renderInlineHtml: Boolean = false,
 ): InlinesStyling =
@@ -634,6 +637,7 @@ public fun InlinesStyling.Companion.dark(
         link,
         emphasis,
         strongEmphasis,
+        strikethrough,
         inlineHtml,
         renderInlineHtml,
     )
diff --git a/markdown/core/src/main/kotlin/org/jetbrains/jewel/markdown/rendering/MarkdownStyling.kt b/markdown/core/src/main/kotlin/org/jetbrains/jewel/markdown/rendering/MarkdownStyling.kt
@@ -288,6 +288,7 @@ public class InlinesStyling(
     public val link: SpanStyle,
     public val emphasis: SpanStyle,
     public val strongEmphasis: SpanStyle,
+    public val strikethrough: SpanStyle,
     public val inlineHtml: SpanStyle,
     public val renderInlineHtml: Boolean,
 ) {

diff --git a/...src/test/kotlin/org/jetbrains/jewel/markdown/MarkdownProcessorDocumentParsingExtraTest.kt b/...src/test/kotlin/org/jetbrains/jewel/markdown/MarkdownProcessorDocumentParsingExtraTest.kt
@@ -61,4 +61,56 @@ class MarkdownProcessorDocumentParsingExtraTest {
          */
         parsed.assertEquals(paragraph("*_*foo *bar* a*_*"))
     }
+
+    @Test
+    fun `should parse gfm spec example 491 correctly (Strikethrough)`() {
+        val parsed = processor.processMarkdownDocument("~~Hi~~ Hello, ~~there~~ world!")
+
+        /*
+         * Expected HTML:
+         * <p><del>Hi</del> Hello, <del>there</del> world!</p>
+         */
+        parsed.assertEquals(paragraph("~~Hi~~ Hello, ~~there~~ world\\!"))
+    }
+
+    @org.junit.Ignore("Strikethrough is any text wrapped in a pair of one tildes, but our implementation assumes two")
+    @Test
+    fun `should parse gfm spec example 491b correctly (Strikethrough)`() {
+        val parsed = processor.processMarkdownDocument("~there~ world!")
+
+        parsed.assertEquals(paragraph("~there~ world\\!"))
+    }
+
+    /** As with regular emphasis delimiters, a new paragraph will cause strikethrough parsing to cease */
+    @Test
+    fun `should parse gfm spec example 492 correctly (Strikethrough)`() {
+        val parsed = processor.processMarkdownDocument(
+            """
+            |This ~~has a
+            |
+            |new paragraph~~.
+            """.trimMargin(),
+        )
+
+        /*
+         * Expected HTML:
+         * <p>This ~~has a</p>
+         * <p>new paragraph~~.</p>
+         */
+        parsed.assertEquals(
+            paragraph("This \\~\\~has a"),
+            paragraph("new paragraph\\~\\~."),
+        )
+    }
+
+    @Test
+    fun `should parse gfm spec example 493 correctly (Strikethrough)`() {
+        val parsed = processor.processMarkdownDocument("This will ~~~not~~~ strike.")
+
+        /*
+         * Expected HTML:
+         * <p>This will ~~~not~~~ strike.</p>
+         */
+        parsed.assertEquals(paragraph("This will \\~\\~\\~not\\~\\~\\~ strike."))
+    }
 }
diff --git a/settings.gradle.kts b/settings.gradle.kts
@@ -37,6 +37,7 @@ include(
     ":int-ui:int-ui-standalone",
     ":markdown:core",
     ":markdown:extension-gfm-alerts",
+    ":markdown:commonmark-extensions",
     ":samples:ide-plugin",
     ":samples:standalone",
     ":ui",
@@ -49,3 +50,5 @@ gradleEnterprise {
         termsOfServiceAgree = "yes"
     }
 }
+include("markdown:commonmark-extensions")
+findProject(":markdown:commonmark-extensions")?.name = "commonmark-extensions"