Filter paragraphbreaks only needs core

askama/src/filters/alloc.rs

@@ -149,65 +149,6 @@ fn flush_linebreaksbr(dest: &mut (impl fmt::Write + ?Sized), s: &str) -> fmt::Re
     dest.write_str(&s.replace('\n', "<br/>"))
 }
 
-/// Replaces only paragraph breaks in plain text with appropriate HTML
-///
-/// A new line followed by a blank line becomes a paragraph break `<p>`.
-/// Paragraph tags only wrap content; empty paragraphs are removed.
-/// No `<br/>` tags are added.
-///
-/// ```
-/// # #[cfg(feature = "code-in-doc")] {
-/// # use askama::Template;
-/// /// ```jinja
-/// /// {{ lines|paragraphbreaks }}
-/// /// ```
-/// #[derive(Template)]
-/// #[template(ext = "html", in_doc = true)]
-/// struct Example<'a> {
-///     lines: &'a str,
-/// }
-///
-/// assert_eq!(
-///     Example { lines: "Foo\nBar\n\nBaz" }.to_string(),
-///     "<p>Foo\nBar</p><p>Baz</p>"
-/// );
-/// # }
-/// ```
-#[inline]
-pub fn paragraphbreaks<S: fmt::Display>(
-    source: S,
-) -> Result<HtmlSafeOutput<Paragraphbreaks<S>>, Infallible> {
-    Ok(HtmlSafeOutput(Paragraphbreaks(source)))
-}
-
-pub struct Paragraphbreaks<S>(S);
-
-impl<S: fmt::Display> fmt::Display for Paragraphbreaks<S> {
-    #[inline]
-    fn fmt(&self, dest: &mut fmt::Formatter<'_>) -> fmt::Result {
-        let mut buffer;
-        flush_paragraphbreaks(dest, try_to_str!(self.0 => buffer))
-    }
-}
-
-impl<S: FastWritable> FastWritable for Paragraphbreaks<S> {
-    #[inline]
-    fn write_into<W: fmt::Write + ?Sized>(
-        &self,
-        dest: &mut W,
-        values: &dyn crate::Values,
-    ) -> crate::Result<()> {
-        let mut buffer = String::new();
-        self.0.write_into(&mut buffer, values)?;
-        Ok(flush_paragraphbreaks(dest, &buffer)?)
-    }
-}
-
-fn flush_paragraphbreaks(dest: &mut (impl fmt::Write + ?Sized), s: &str) -> fmt::Result {
-    let linebroken = s.replace("\n\n", "</p><p>").replace("<p></p>", "");
-    write!(dest, "<p>{linebroken}</p>")
-}
-
 /// Converts to lowercase
 ///
 /// ```
@@ -609,24 +550,6 @@ mod tests {
         );
     }
 
-    #[test]
-    fn test_paragraphbreaks() {
-        assert_eq!(
-            paragraphbreaks("Foo\nBar Baz").unwrap().to_string(),
-            "<p>Foo\nBar Baz</p>"
-        );
-        assert_eq!(
-            paragraphbreaks("Foo\nBar\n\nBaz").unwrap().to_string(),
-            "<p>Foo\nBar</p><p>Baz</p>"
-        );
-        assert_eq!(
-            paragraphbreaks("Foo\n\n\n\n\nBar\n\nBaz")
-                .unwrap()
-                .to_string(),
-            "<p>Foo</p><p>\nBar</p><p>Baz</p>"
-        );
-    }
-
     #[test]
     fn test_lower() {
         assert_eq!(lower("Foo").unwrap().to_string(), "foo");

askama/src/filters/core.rs

@@ -641,41 +641,94 @@ impl<'a> fmt::Write for WordCountWriter<'a> {
 /// # }
 /// ```
 #[inline]
-pub fn linebreaks<S: fmt::Display>(source: S) -> Result<HtmlSafeOutput<Linebreaks<S>>, Infallible> {
-    Ok(HtmlSafeOutput(Linebreaks(source)))
+pub fn linebreaks<S: fmt::Display>(
+    source: S,
+) -> Result<HtmlSafeOutput<NewlineCounting<S>>, Infallible> {
+    Ok(HtmlSafeOutput(NewlineCounting {
+        source,
+        one: "<br/>",
+    }))
 }
 
-pub struct Linebreaks<S>(S);
+/// Replaces only paragraph breaks in plain text with appropriate HTML
+///
+/// A new line followed by a blank line becomes a paragraph break `<p>`.
+/// Paragraph tags only wrap content; empty paragraphs are removed.
+/// No `<br/>` tags are added.
+///
+/// ```
+/// # #[cfg(feature = "code-in-doc")] {
+/// # use askama::Template;
+/// /// ```jinja
+/// /// {{ lines|paragraphbreaks }}
+/// /// ```
+/// #[derive(Template)]
+/// #[template(ext = "html", in_doc = true)]
+/// struct Example<'a> {
+///     lines: &'a str,
+/// }
+///
+/// assert_eq!(
+///     Example { lines: "Foo\nBar\n\nBaz" }.to_string(),
+///     "<p>Foo\nBar</p><p>Baz</p>"
+/// );
+/// # }
+/// ```
+#[inline]
+pub fn paragraphbreaks<S: fmt::Display>(
+    source: S,
+) -> Result<HtmlSafeOutput<NewlineCounting<S>>, Infallible> {
+    Ok(HtmlSafeOutput(NewlineCounting { source, one: "\n" }))
+}
 
-impl<S: fmt::Display> fmt::Display for Linebreaks<S> {
+pub struct NewlineCounting<S> {
+    source: S,
+    one: &'static str,
+}
+
+impl<S> NewlineCounting<S> {
+    #[inline]
+    fn run<'a, F, W, E>(&self, dest: &'a mut W, inner: F) -> Result<(), E>
+    where
+        W: fmt::Write + ?Sized,
+        F: FnOnce(&mut NewlineCountingFormatter<'a, W>) -> Result<(), E>,
+        E: From<fmt::Error>,
+    {
+        let mut formatter = NewlineCountingFormatter {
+            dest,
+            counter: -1,
+            one: self.one,
+        };
+        formatter.dest.write_str("<p>")?;
+        inner(&mut formatter)?;
+        formatter.dest.write_str("</p>")?;
+        Ok(())
+    }
+}
+
+impl<S: fmt::Display> fmt::Display for NewlineCounting<S> {
     fn fmt(&self, dest: &mut fmt::Formatter<'_>) -> fmt::Result {
-        dest.write_str("<p>")?;
-        let mut formatter = LinebreakFormatter { dest, counter: -1 };
-        write!(formatter, "{}", self.0)?;
-        formatter.dest.write_str("</p>")
+        self.run(dest, |f| write!(f, "{}", self.source))
     }
 }
 
-impl<S: FastWritable> FastWritable for Linebreaks<S> {
+impl<S: FastWritable> FastWritable for NewlineCounting<S> {
     fn write_into<W: fmt::Write + ?Sized>(
         &self,
         dest: &mut W,
         values: &dyn crate::Values,
     ) -> crate::Result<()> {
-        dest.write_str("<p>")?;
-        let mut formatter = LinebreakFormatter { dest, counter: -1 };
-        self.0.write_into(&mut formatter, values)?;
-        dest.write_str("</p>")?;
-        Ok(())
+        self.run(dest, |f| self.source.write_into(f, values))
     }
 }
 
-struct LinebreakFormatter<'a, W: ?Sized> {
+struct NewlineCountingFormatter<'a, W: ?Sized> {
     dest: &'a mut W,
     counter: isize,
+    one: &'static str,
 }
 
-impl<W: fmt::Write + ?Sized> fmt::Write for LinebreakFormatter<'_, W> {
+impl<W: fmt::Write + ?Sized> fmt::Write for NewlineCountingFormatter<'_, W> {
     fn write_str(&mut self, s: &str) -> fmt::Result {
         if s.is_empty() {
             return Ok(());
@@ -693,7 +746,7 @@ impl<W: fmt::Write + ?Sized> fmt::Write for LinebreakFormatter<'_, W> {
             if !line.is_empty() {
                 match replace(&mut self.counter, if has_eol { 1 } else { 0 }) {
                     ..=0 => {}
-                    1 => self.dest.write_str("<br/>")?,
+                    1 => self.dest.write_str(self.one)?,
                     2.. => self.dest.write_str("</p><p>")?,
                 }
                 self.dest.write_str(line)?;
@@ -827,4 +880,22 @@ mod tests {
             "<p>Foo<br/>Bar</p><p>Baz</p>"
         );
     }
+
+    #[test]
+    fn test_paragraphbreaks() {
+        assert_eq!(
+            paragraphbreaks("Foo\nBar Baz").unwrap().to_string(),
+            "<p>Foo\nBar Baz</p>"
+        );
+        assert_eq!(
+            paragraphbreaks("Foo\nBar\n\nBaz").unwrap().to_string(),
+            "<p>Foo\nBar</p><p>Baz</p>"
+        );
+        assert_eq!(
+            paragraphbreaks("Foo\n\n\n\n\nBar\n\nBaz")
+                .unwrap()
+                .to_string(),
+            "<p>Foo</p><p>Bar</p><p>Baz</p>"
+        );
+    }
 }

askama/src/filters/mod.rs

@@ -25,11 +25,12 @@ mod urlencode;
 
 #[cfg(feature = "alloc")]
 pub use self::alloc::{
-    capitalize, fmt, format, linebreaksbr, lower, lowercase, paragraphbreaks, title, titlecase,
-    trim, upper, uppercase,
+    capitalize, fmt, format, linebreaksbr, lower, lowercase, title, titlecase, trim, upper,
+    uppercase,
 };
 pub use self::core::{
-    PluralizeCount, center, join, linebreaks, pluralize, reject, reject_with, truncate, wordcount,
+    PluralizeCount, center, join, linebreaks, paragraphbreaks, pluralize, reject, reject_with,
+    truncate, wordcount,
 };
 pub use self::escape::{
     AutoEscape, AutoEscaper, Escaper, Html, HtmlSafe, HtmlSafeOutput, MaybeSafe, Safe, Text,

askama_derive/src/generator/filter.rs

@@ -323,9 +323,8 @@ impl<'a> Generator<'a, '_> {
         ctx: &Context<'_>,
         buf: &mut Buffer,
         args: &[WithSpan<'a, Expr<'a>>],
-        node: Span<'_>,
+        _node: Span<'_>,
     ) -> Result<DisplayWrap, CompileError> {
-        ensure_filter_has_feature_alloc(ctx, "paragraphbreaks", node)?;
         self.visit_linebreaks_filters(ctx, buf, "paragraphbreaks", args)
     }
 

book/src/filters.md

@@ -346,11 +346,6 @@ hello<br />world<br /><br />from<br />askama
 ### paragraphbreaks
 [#paragraphbreaks]: #paragraphbreaks
 
-<blockquote class="right" style="padding:0.5ex 1ex; margin:0 0 1ex 1ex; font-size:80%">
-enabled by <code>"alloc"</code><br/>
-enabled by <code>"default"</code>
-</blockquote>
-
 ```jinja
 {{ text_to_break | paragraphbreaks }}
 ```

testing/tests/filter_block.rs

@@ -302,11 +302,9 @@ fn filter_nested_filter_blocks() {
     };
     assert_eq!(
         template.render().unwrap(),
-        r"[
-<P>HELLO &</P><P>GOODBYE!
-</P>
-<P>HELLO &</P><P>GOODBYE!
-</P>]
+        "[
+<P>HELLO &</P><P>GOODBYE!</P>
+<P>HELLO &</P><P>GOODBYE!</P>]
 2"
     );
 }