Add support for GFM strikethrough

1 files changed, 387 insertions, 0 deletions

diff --git a/tests/gfm_strikethrough.rs b/tests/gfm_strikethrough.rs
new file mode 100644
index 0000000..f39be07
--- /dev/null
+++ b/tests/gfm_strikethrough.rs
@@ -0,0 +1,387 @@
+extern crate micromark;
+use micromark::{micromark, micromark_with_options, Constructs, Options};
+use pretty_assertions::assert_eq;
+
+#[test]
+fn gfm_strikethrough() {
+    let gfm = Options {
+        constructs: Constructs::gfm(),
+        ..Options::default()
+    };
+
+    assert_eq!(
+        micromark("a ~b~ c"),
+        "<p>a ~b~ c</p>",
+        "should ignore strikethrough by default"
+    );
+
+    assert_eq!(
+        micromark_with_options("a ~b~", &gfm),
+        "<p>a <del>b</del></p>",
+        "should support strikethrough w/ one tilde"
+    );
+
+    assert_eq!(
+        micromark_with_options("a ~~b~~", &gfm),
+        "<p>a <del>b</del></p>",
+        "should support strikethrough w/ two tildes"
+    );
+
+    assert_eq!(
+        micromark_with_options("a ~~~b~~~", &gfm),
+        "<p>a ~~~b~~~</p>",
+        "should not support strikethrough w/ three tildes"
+    );
+
+    assert_eq!(
+        micromark_with_options("a \\~~~b~~ c", &gfm),
+        "<p>a ~<del>b</del> c</p>",
+        "should support strikethrough after an escaped tilde"
+    );
+
+    assert_eq!(
+        micromark_with_options("a ~~b ~~c~~ d~~ e", &gfm),
+        "<p>a <del>b <del>c</del> d</del> e</p>",
+        "should support nested strikethrough"
+    );
+
+    assert_eq!(
+        micromark_with_options("a ~-1~ b", &gfm),
+        "<p>a <del>-1</del> b</p>",
+        "should open if preceded by whitespace and followed by punctuation"
+    );
+
+    assert_eq!(
+        micromark_with_options("a ~b.~ c", &gfm),
+        "<p>a <del>b.</del> c</p>",
+        "should close if preceded by punctuation and followed by whitespace"
+    );
+
+    assert_eq!(
+        micromark_with_options("~b.~.", &gfm),
+        "<p><del>b.</del>.</p>",
+        "should close if preceded and followed by punctuation"
+    );
+
+    assert_eq!(
+        micromark_with_options(
+            r###"
+# Balanced
+
+a ~one~ b
+
+a ~~two~~ b
+
+a ~~~three~~~ b
+
+a ~~~~four~~~~ b
+
+# Unbalanced
+
+a ~one/two~~ b
+
+a ~one/three~~~ b
+
+a ~one/four~~~~ b
+
+***
+
+a ~~two/one~ b
+
+a ~~two/three~~~ b
+
+a ~~two/four~~~~ b
+
+***
+
+a ~~~three/one~ b
+
+a ~~~three/two~~ b
+
+a ~~~three/four~~~~ b
+
+***
+
+a ~~~~four/one~ b
+
+a ~~~~four/two~~ b
+
+a ~~~~four/three~~~ b
+
+## Multiple
+
+a ~one b one~ c one~ d
+
+a ~one b two~~ c one~ d
+
+a ~one b one~ c two~~ d
+
+a ~~two b two~~ c two~~ d
+
+a ~~two b one~ c two~~ d
+
+a ~~two b two~~ c one~ d
+"###,
+            &gfm
+        ),
+        r###"<h1>Balanced</h1>
+<p>a <del>one</del> b</p>
+<p>a <del>two</del> b</p>
+<p>a ~~~three~~~ b</p>
+<p>a ~~~~four~~~~ b</p>
+<h1>Unbalanced</h1>
+<p>a ~one/two~~ b</p>
+<p>a ~one/three~~~ b</p>
+<p>a ~one/four~~~~ b</p>
+<hr />
+<p>a ~~two/one~ b</p>
+<p>a ~~two/three~~~ b</p>
+<p>a ~~two/four~~~~ b</p>
+<hr />
+<p>a ~~~three/one~ b</p>
+<p>a ~~~three/two~~ b</p>
+<p>a ~~~three/four~~~~ b</p>
+<hr />
+<p>a ~~~~four/one~ b</p>
+<p>a ~~~~four/two~~ b</p>
+<p>a ~~~~four/three~~~ b</p>
+<h2>Multiple</h2>
+<p>a <del>one b one</del> c one~ d</p>
+<p>a <del>one b two~~ c one</del> d</p>
+<p>a <del>one b one</del> c two~~ d</p>
+<p>a <del>two b two</del> c two~~ d</p>
+<p>a <del>two b one~ c two</del> d</p>
+<p>a <del>two b two</del> c one~ d</p>
+"###,
+        "should handle balance like GitHub"
+    );
+
+    assert_eq!(
+        micromark_with_options(
+            r###"
+# Flank
+
+a oneRight~ b oneRight~ c oneRight~ d
+
+a oneRight~ b oneRight~ c ~oneLeft d
+
+a oneRight~ b ~oneLeft c oneRight~ d
+
+a ~oneLeft b oneRight~ c oneRight~ d
+
+a ~oneLeft b oneRight~ c ~oneLeft d
+
+a ~oneLeft b ~oneLeft c oneRight~ d
+
+a ~oneLeft b ~oneLeft c ~oneLeft d
+
+***
+
+a twoRight~~ b twoRight~~ c twoRight~~ d
+
+a twoRight~~ b twoRight~~ c ~~twoLeft d
+
+a twoRight~~ b ~~twoLeft c twoRight~~ d
+
+a ~~twoLeft b twoRight~~ c twoRight~~ d
+
+a ~~twoLeft b twoRight~~ c ~~twoLeft d
+
+a ~~twoLeft b ~~twoLeft c twoRight~~ d
+
+a ~~twoLeft b ~~twoLeft c ~~twoLeft d
+"###,
+            &gfm
+        ),
+        r###"<h1>Flank</h1>
+<p>a oneRight~ b oneRight~ c oneRight~ d</p>
+<p>a oneRight~ b oneRight~ c ~oneLeft d</p>
+<p>a oneRight~ b <del>oneLeft c oneRight</del> d</p>
+<p>a <del>oneLeft b oneRight</del> c oneRight~ d</p>
+<p>a <del>oneLeft b oneRight</del> c ~oneLeft d</p>
+<p>a ~oneLeft b <del>oneLeft c oneRight</del> d</p>
+<p>a ~oneLeft b ~oneLeft c ~oneLeft d</p>
+<hr />
+<p>a twoRight~~ b twoRight~~ c twoRight~~ d</p>
+<p>a twoRight~~ b twoRight~~ c ~~twoLeft d</p>
+<p>a twoRight~~ b <del>twoLeft c twoRight</del> d</p>
+<p>a <del>twoLeft b twoRight</del> c twoRight~~ d</p>
+<p>a <del>twoLeft b twoRight</del> c ~~twoLeft d</p>
+<p>a ~~twoLeft b <del>twoLeft c twoRight</del> d</p>
+<p>a ~~twoLeft b ~~twoLeft c ~~twoLeft d</p>
+"###,
+        "should handle flanking like GitHub"
+    );
+
+    assert_eq!(
+        micromark_with_options(
+            r###"
+# Interlpay
+
+## Interleave with attention
+
+a ~~two *emphasis* two~~ b
+
+a ~~two **strong** two~~ b
+
+a *marker ~~two marker* two~~ b
+
+a ~~two *marker two~~ marker* b
+
+## Interleave with links
+
+a ~~two [resource](#) two~~ b
+
+a ~~two [reference][#] two~~ b
+
+a [label start ~~two label end](#) two~~ b
+
+a ~~two [label start two~~ label end](#) b
+
+a ~~two [label start ~one one~ label end](#) two~~ b
+
+a ~one [label start ~~two two~~ label end](#) one~ b
+
+a ~one [label start ~one one~ label end](#) one~ b
+
+a ~~two [label start ~~two two~~ label end](#) two~~ b
+
+[#]: #
+
+## Interleave with code (text)
+
+a ~~two `code` two~~ b
+
+a ~~two `code two~~` b
+
+a `code start ~~two code end` two~~ b
+
+a ~~two `code start two~~ code end` b
+
+a ~~two `code start ~one one~ code end` two~~ b
+
+a ~one `code start ~~two two~~ code end` one~ b
+
+a ~one `code start ~one one~ code end` one~ b
+
+a ~~two `code start ~~two two~~ code end` two~~ b
+
+## Emphasis/strong/strikethrough interplay
+
+a ***~~xxx~~*** zzz
+
+b ***xxx***zzz
+
+c **xxx**zzz
+
+d *xxx*zzz
+
+e ***~~xxx~~***yyy
+
+f **~~xxx~~**yyy
+
+g *~~xxx~~*yyy
+
+h ***~~xxx~~*** zzz
+
+i **~~xxx~~** zzz
+
+j *~~xxx~~* zzz
+
+k ~~~**xxx**~~~ zzz
+
+l ~~~xxx~~~zzz
+
+m ~~xxx~~zzz
+
+n ~xxx~zzz
+
+o ~~~**xxx**~~~yyy
+
+p ~~**xxx**~~yyy
+
+r ~**xxx**~yyy
+
+s ~~~**xxx**~~~ zzz
+
+t ~~**xxx**~~ zzz
+
+u ~**xxx**~ zzz
+"###,
+            &gfm
+        ),
+        r###"<h1>Interlpay</h1>
+<h2>Interleave with attention</h2>
+<p>a <del>two <em>emphasis</em> two</del> b</p>
+<p>a <del>two <strong>strong</strong> two</del> b</p>
+<p>a <em>marker ~~two marker</em> two~~ b</p>
+<p>a <del>two *marker two</del> marker* b</p>
+<h2>Interleave with links</h2>
+<p>a <del>two <a href="#">resource</a> two</del> b</p>
+<p>a <del>two <a href="#">reference</a> two</del> b</p>
+<p>a <a href="#">label start ~~two label end</a> two~~ b</p>
+<p>a ~~two <a href="#">label start two~~ label end</a> b</p>
+<p>a <del>two <a href="#">label start <del>one one</del> label end</a> two</del> b</p>
+<p>a <del>one <a href="#">label start <del>two two</del> label end</a> one</del> b</p>
+<p>a <del>one <a href="#">label start <del>one one</del> label end</a> one</del> b</p>
+<p>a <del>two <a href="#">label start <del>two two</del> label end</a> two</del> b</p>
+<h2>Interleave with code (text)</h2>
+<p>a <del>two <code>code</code> two</del> b</p>
+<p>a ~~two <code>code two~~</code> b</p>
+<p>a <code>code start ~~two code end</code> two~~ b</p>
+<p>a ~~two <code>code start two~~ code end</code> b</p>
+<p>a <del>two <code>code start ~one one~ code end</code> two</del> b</p>
+<p>a <del>one <code>code start ~~two two~~ code end</code> one</del> b</p>
+<p>a <del>one <code>code start ~one one~ code end</code> one</del> b</p>
+<p>a <del>two <code>code start ~~two two~~ code end</code> two</del> b</p>
+<h2>Emphasis/strong/strikethrough interplay</h2>
+<p>a <em><strong><del>xxx</del></strong></em> zzz</p>
+<p>b <em><strong>xxx</strong></em>zzz</p>
+<p>c <strong>xxx</strong>zzz</p>
+<p>d <em>xxx</em>zzz</p>
+<p>e <em><strong><del>xxx</del></strong></em>yyy</p>
+<p>f <strong><del>xxx</del></strong>yyy</p>
+<p>g <em><del>xxx</del></em>yyy</p>
+<p>h <em><strong><del>xxx</del></strong></em> zzz</p>
+<p>i <strong><del>xxx</del></strong> zzz</p>
+<p>j <em><del>xxx</del></em> zzz</p>
+<p>k ~~~<strong>xxx</strong>~~~ zzz</p>
+<p>l ~~~xxx~~~zzz</p>
+<p>m <del>xxx</del>zzz</p>
+<p>n <del>xxx</del>zzz</p>
+<p>o ~~~<strong>xxx</strong>~~~yyy</p>
+<p>p ~~<strong>xxx</strong>~~yyy</p>
+<p>r ~<strong>xxx</strong>~yyy</p>
+<p>s ~~~<strong>xxx</strong>~~~ zzz</p>
+<p>t <del><strong>xxx</strong></del> zzz</p>
+<p>u <del><strong>xxx</strong></del> zzz</p>
+"###,
+        "should handle interplay like GitHub"
+    );
+
+    assert_eq!(
+        micromark_with_options(
+            "a ~b~ ~~c~~ d",
+            &Options {
+                constructs: Constructs::gfm(),
+                gfm_strikethrough_single_tilde: false,
+                ..Options::default()
+            }
+        ),
+        "<p>a ~b~ <del>c</del> d</p>",
+        "should not support strikethrough w/ one tilde if `singleTilde: false`"
+    );
+
+    assert_eq!(
+        micromark_with_options(
+            "a ~b~ ~~c~~ d",
+            &Options {
+                constructs: Constructs::gfm(),
+                gfm_strikethrough_single_tilde: true,
+                ..Options::default()
+            }
+        ),
+        "<p>a <del>b</del> <del>c</del> d</p>",
+        "should support strikethrough w/ one tilde if `singleTilde: true`"
+    );
+}