fix(latex): tokenize piton PitonInputFile like lstinputlisting

docs/orgmode/reference/config.org

@@ -187,14 +187,15 @@ Adding =algorithm= stops reflow of that environment.
 
 String array of extra command names tokenized like the built-in verb command before sentence split.
 The next character after the name is the delimiter.
-Built-in names are =verb=, =lstinline=, =lstinputlisting=, =spverb=, =mintinline=, =inputminted=, =mint=, fancyvrb =Verb= / =Verb*= / =SaveVerb= / =VerbatimInput= / =BVerbatimInput= / =LVerbatimInput=, piton.sty =\piton=, and tools/verbatim.sty =\verbatiminput=; =lstinline= still accepts optional =[...]= and ={...}=.
+Built-in names are =verb=, =lstinline=, =lstinputlisting=, =spverb=, =mintinline=, =inputminted=, =mint=, fancyvrb =Verb= / =Verb*= / =SaveVerb= / =VerbatimInput= / =BVerbatimInput= / =LVerbatimInput=, piton.sty =\piton= / =\PitonInputFile=, and tools/verbatim.sty =\verbatiminput=; =lstinline= still accepts optional =[...]= and ={...}=.
 =mintinline= / =mint= take optional =[...]=, a ={lang}= argument, then a delimiter or ={...}= body.
 =\inputminted= takes the same optional =[...]= and ={lang}= then a required ={filename}=; following flush prose stays on its own line.
 =SaveVerb= takes optional =[...]=, a ={name}= argument, then the same delimiter body as =Verb=.
 =\piton|...|= is verb-like (interior =.!?%= stay one token); =\piton{...}= stays one token via the generic command argument.
 =\lstinputlisting= takes optional =[...]= then a required ={filename}=; following flush prose stays on its own line.
 =\VerbatimInput= / =\BVerbatimInput= / =\LVerbatimInput= take optional =[...]= then a required ={filename}=; following flush prose stays on its own line.
 =\verbatiminput= / =\verbatiminput*= take a required ={filename}=; following flush prose stays on its own line.
+=\PitonInputFile= takes optional =<...>= / =[...]= then a required ={filename}=; following flush prose stays on its own line.
 Adding another name keeps that command's delimited body atomic and treats an inner =%= as content, not a comment.
 
 * Code-block sections (=[code.<lang>]=)

docs/orgmode/reference/formats.org

@@ -135,12 +135,13 @@ These tokens within prose are not split across lines:
 - piton.sty =Piton= is a built-in code region (verbatim listing env)
 - Extra names from =[latex].verbatim_envs= are code regions too
 - Body follows the same comment-reflow and optional =--format-code= rules as other formats when language is known (=minted= / =minted*= language arg, =lstlisting= / =lstlisting*= =language== option)
-- Inline =\verb= / =\lstinline= / =\spverb= / =\mintinline= / =\mint= / fancyvrb =\Verb= / =\Verb*= / =\SaveVerb= / =\VerbatimInput= / =\BVerbatimInput= / =\LVerbatimInput= / piton.sty =\piton= / listings.sty =\lstinputlisting= / minted.sty =\inputminted= / tools/verbatim.sty =\verbatiminput= (and extra =[latex].verbatim_commands=) stay atomic; inner =.!?%= do not split or comment.
+- Inline =\verb= / =\lstinline= / =\spverb= / =\mintinline= / =\mint= / fancyvrb =\Verb= / =\Verb*= / =\SaveVerb= / =\VerbatimInput= / =\BVerbatimInput= / =\LVerbatimInput= / piton.sty =\piton= / =\PitonInputFile= / listings.sty =\lstinputlisting= / minted.sty =\inputminted= / tools/verbatim.sty =\verbatiminput= (and extra =[latex].verbatim_commands=) stay atomic; inner =.!?%= do not split or comment.
   =\piton|...|= is verb-like; =\piton{...}= stays one token via the generic command argument
   =\lstinputlisting= / =\lstinputlisting*= take optional =[...]= then a ={filename}=; a flush following sentence stays on its own line
   =\inputminted= / =\inputminted*= take optional =[...]=, ={lang}=, then a ={filename}=; a flush following sentence stays on its own line
   =\VerbatimInput= / =\BVerbatimInput= / =\LVerbatimInput= take optional =[...]= then a ={filename}=; a flush following sentence stays on its own line
   =\verbatiminput= / =\verbatiminput*= take a ={filename}=; a flush following sentence stays on its own line
+  =\PitonInputFile= takes optional =<...>=, optional =[...]=, then a ={filename}=; a flush following sentence stays on its own line
 
 *** Prose regions (reflowed)
 :PROPERTIES:

src/config.rs

@@ -49,7 +49,7 @@ pub struct FormatOverrides {
     pub structure_envs: Vec<String>,
     /// Extra LaTeX command names tokenized like `\verb` before split.
     /// Meaningful under `[latex]` only. Missing or empty keeps
-    /// verb/lstinline/lstinputlisting/spverb/mintinline/inputminted/mint/Verb/SaveVerb/VerbatimInput/piton/verbatiminput.
+    /// verb/lstinline/lstinputlisting/spverb/mintinline/inputminted/mint/Verb/SaveVerb/VerbatimInput/piton/verbatiminput/PitonInputFile.
     pub verbatim_commands: Vec<String>,
 }
 

src/lib.rs

@@ -147,7 +147,7 @@ pub struct FormatConfig {
     /// to `NON_PROSE_ENVS`. Empty keeps the built-in list.
     pub latex_structure_envs: Vec<String>,
     /// Extra LaTeX command names tokenized like `\verb` before split.
-    /// Empty keeps verb/lstinline/lstinputlisting/spverb/mintinline/inputminted/mint/Verb/SaveVerb/VerbatimInput/piton/verbatiminput.
+    /// Empty keeps verb/lstinline/lstinputlisting/spverb/mintinline/inputminted/mint/Verb/SaveVerb/VerbatimInput/piton/verbatiminput/PitonInputFile.
     pub latex_verbatim_commands: Vec<String>,
 }
 

src/parser/latex.rs

@@ -503,7 +503,7 @@ impl LatexParser {
     /// inside `\verb` / `\lstinline` / `\spverb` / `\mintinline` / `\mint` /
     /// `\Verb` / `\SaveVerb` / `\piton` / `\lstinputlisting` /
     /// `\inputminted` / `\verbatiminput` / `\VerbatimInput` /
-    /// configured verbatim commands.
+    /// `\PitonInputFile` / configured verbatim commands.
     fn unescaped_percent(&self, line: &str) -> Option<usize> {
         unescaped_percent_with(line, &self.extra_verbatim_commands)
     }
@@ -877,7 +877,7 @@ fn find_tex_cs(line: &str, from: usize, cs: &str) -> Option<usize> {
 /// `\iffalse` in ordinary TeX, skipping `\verb` / `\lstinline` /
 /// `\spverb` / `\mintinline` / `\mint` / `\inputminted` / `\Verb` /
 /// `\SaveVerb` / `\piton` / `\lstinputlisting` / `\verbatiminput` /
-/// `\VerbatimInput` spans.
+/// `\VerbatimInput` / `\PitonInputFile` spans.
 fn find_iffalse_at(line: &str, from: usize, extra_cmds: &[String]) -> Option<usize> {
     let bytes = line.as_bytes();
     let mut i = from;
@@ -941,6 +941,19 @@ fn find_fancyvrb_input_at(
     find_leftover_cmd_at(line, from, extra_cmds, fancyvrb_input_cs_at)
 }
 
+/// Leftover piton.sty `\PitonInputFile` (optional `<...>`, optional
+/// `[...]`, required `{file}`; `d < > O { } m`; GitHub #406). Other
+/// verb spans are skipped so `\verb|\PitonInputFile{x}|` is not
+/// stolen. Walk stops at an unescaped `%` so a comment is not a
+/// command tail.
+fn find_pitoninputfile_at(
+    line: &str,
+    from: usize,
+    extra_cmds: &[String],
+) -> Option<(usize, usize)> {
+    find_leftover_cmd_at(line, from, extra_cmds, pitoninputfile_cs_at)
+}
+
 fn find_leftover_cmd_at(
     line: &str,
     from: usize,
@@ -1013,6 +1026,16 @@ fn fancyvrb_input_cs_at(line: &str, at: usize) -> bool {
     false
 }
 
+fn pitoninputfile_cs_at(line: &str, at: usize) -> bool {
+    let Some(tail) = line.get(at..).and_then(|s| s.strip_prefix('\\')) else {
+        return false;
+    };
+    let Some(after) = tail.strip_prefix("PitonInputFile") else {
+        return false;
+    };
+    !after.starts_with(|c: char| c.is_ascii_alphabetic())
+}
+
 struct ParseState<'a> {
     input: &'a str,
     parser: &'a LatexParser,
@@ -1704,6 +1727,9 @@ impl<'a> ParseState<'a> {
                     .or_else(|| {
                         find_fancyvrb_input_at(code, i, &self.parser.extra_verbatim_commands)
                     })
+                    .or_else(|| {
+                        find_pitoninputfile_at(code, i, &self.parser.extra_verbatim_commands)
+                    })
             {
                 self.append_item_or_prose(line.start + i, &code[i..start]);
                 self.push_structure(ByteSpan::new(
@@ -2875,6 +2901,184 @@ Some text.
         assert_eq!(format_text(&minted_out, &latex_cfg()).unwrap(), minted_out);
     }
 
+    /// Ticket fixture (GitHub #406): piton.sty `\PitonInputFile{file}`
+    /// is one leftover command. Following flush prose does not join the
+    /// command line. `After.` / `Next.` still split. Optional `[...]`
+    /// and `d < >` stay atomic. Piton env, `\piton`, `\verbatiminput`,
+    /// and fancyvrb `\VerbatimInput` unchanged.
+    #[test]
+    fn pitoninputfile_does_not_join_following_prose() {
+        use crate::format_text;
+
+        let input = concat!(
+            "Before. Next.\n",
+            "\\PitonInputFile{foo.py}\n",
+            "After. Next.\n",
+        );
+        let regions = LatexParser::default().parse(input);
+        assert!(
+            regions.iter().any(|r| matches!(
+                r,
+                Region::Structure(s) if s.contains(r"\PitonInputFile{foo.py}")
+            )),
+            "PitonInputFile must stay one Structure command, got: {regions:?}"
+        );
+        assert!(
+            !regions.iter().any(|r| matches!(
+                r,
+                Region::Prose(p) if p.contains(r"\PitonInputFile{foo.py}")
+            )),
+            "PitonInputFile must not leak into Prose, got: {regions:?}"
+        );
+        assert!(
+            regions.iter().any(|r| matches!(
+                r,
+                Region::Prose(p) if p.contains("After.") && p.contains("Next.")
+            )),
+            "After. / Next. must stay Prose, got: {regions:?}"
+        );
+        let out = format_text(input, &latex_cfg()).unwrap();
+        assert!(
+            out.contains("\\PitonInputFile{foo.py}\n"),
+            "PitonInputFile must stay one atomic command, got:\n{out}"
+        );
+        assert!(
+            !out.contains("\\PitonInputFile{foo.py} After."),
+            "following flush prose must not join the command line, got:\n{out}"
+        );
+        assert!(
+            out.contains("Before.\nNext."),
+            "prose before PitonInputFile must still split, got:\n{out}"
+        );
+        assert!(
+            out.contains("After.\nNext."),
+            "prose after PitonInputFile must still split, got:\n{out}"
+        );
+        assert_eq!(format_text(&out, &latex_cfg()).unwrap(), out);
+
+        let opts = concat!(
+            "Before. Next.\n",
+            "\\PitonInputFile[language=python]{foo.py}\n",
+            "After. Next.\n",
+        );
+        let opts_out = format_text(opts, &latex_cfg()).unwrap();
+        assert!(
+            opts_out.contains("\\PitonInputFile[language=python]{foo.py}\n"),
+            "PitonInputFile optional args must stay atomic, got:\n{opts_out}"
+        );
+        assert!(
+            !opts_out.contains("\\PitonInputFile[language=python]{foo.py} After."),
+            "optional-arg PitonInputFile must not join following prose, got:\n{opts_out}"
+        );
+        assert!(
+            opts_out.contains("After.\nNext."),
+            "prose after optional-arg PitonInputFile must still split, got:\n{opts_out}"
+        );
+
+        let range = concat!(
+            "Before. Next.\n",
+            "\\PitonInputFile<1-10>[language=python]{foo.py}\n",
+            "After. Next.\n",
+        );
+        let range_out = format_text(range, &latex_cfg()).unwrap();
+        assert!(
+            range_out.contains("\\PitonInputFile<1-10>[language=python]{foo.py}\n"),
+            "PitonInputFile d<> plus optional args must stay atomic, got:\n{range_out}"
+        );
+        assert!(
+            !range_out.contains("\\PitonInputFile<1-10>[language=python]{foo.py} After."),
+            "d<> PitonInputFile must not join following prose, got:\n{range_out}"
+        );
+        assert!(
+            range_out.contains("After.\nNext."),
+            "prose after d<> PitonInputFile must still split, got:\n{range_out}"
+        );
+
+        let angle = concat!(
+            "Before. Next.\n",
+            "\\PitonInputFile<python>{foo.py}\n",
+            "After. Next.\n",
+        );
+        let angle_out = format_text(angle, &latex_cfg()).unwrap();
+        assert!(
+            angle_out.contains("\\PitonInputFile<python>{foo.py}\n"),
+            "PitonInputFile standalone angle must stay atomic, got:\n{angle_out}"
+        );
+        assert!(
+            !angle_out.contains("\\PitonInputFile<python>{foo.py} After."),
+            "standalone-angle PitonInputFile must not join following prose, got:\n{angle_out}"
+        );
+        assert!(
+            angle_out.contains("After.\nNext."),
+            "prose after standalone-angle PitonInputFile must still split, got:\n{angle_out}"
+        );
+
+        let piton_env = concat!(
+            "\\begin{Piton}\n",
+            "First line. Second line.\n",
+            "\\end{Piton}\n",
+            "After the block. Next.\n",
+        );
+        let piton_env_out = format_text(piton_env, &latex_cfg()).unwrap();
+        assert!(
+            piton_env_out.contains("\\begin{Piton}\nFirst line. Second line.\n\\end{Piton}"),
+            "Piton env must stay a code env, got:\n{piton_env_out}"
+        );
+        assert!(
+            piton_env_out.contains("After the block.\nNext."),
+            "prose after Piton env must still split, got:\n{piton_env_out}"
+        );
+
+        let piton_cmd = "See \\piton|done. Next| here. After.\n";
+        let piton_cmd_out = format_text(piton_cmd, &latex_cfg()).unwrap();
+        assert!(
+            piton_cmd_out.contains("See \\piton|done. Next| here.\nAfter."),
+            "\\piton must stay intact and still split, got:\n{piton_cmd_out}"
+        );
+
+        let verb_in = concat!(
+            "Before. Next.\n",
+            "\\verbatiminput{foo.py}\n",
+            "After. Next.\n",
+        );
+        let verb_out = format_text(verb_in, &latex_cfg()).unwrap();
+        assert!(
+            verb_out.contains("\\verbatiminput{foo.py}\n"),
+            "verbatiminput must stay unchanged, got:\n{verb_out}"
+        );
+        assert!(
+            !verb_out.contains("\\verbatiminput{foo.py} After."),
+            "verbatiminput must not join following prose, got:\n{verb_out}"
+        );
+        assert!(
+            verb_out.contains("After.\nNext."),
+            "prose after verbatiminput must still split, got:\n{verb_out}"
+        );
+
+        let fancy = concat!(
+            "Before. Next.\n",
+            "\\VerbatimInput{foo.py}\n",
+            "After. Next.\n",
+        );
+        let fancy_out = format_text(fancy, &latex_cfg()).unwrap();
+        assert!(
+            fancy_out.contains("\\VerbatimInput{foo.py}\n"),
+            "VerbatimInput must stay unchanged, got:\n{fancy_out}"
+        );
+        assert!(
+            !fancy_out.contains("\\VerbatimInput{foo.py} After."),
+            "VerbatimInput must not join following prose, got:\n{fancy_out}"
+        );
+        assert!(
+            !fancy_out.contains("\\PitonInputFile"),
+            "PitonInputFile walker must not rewrite VerbatimInput, got:\n{fancy_out}"
+        );
+        assert!(
+            fancy_out.contains("After.\nNext."),
+            "prose after VerbatimInput must still split, got:\n{fancy_out}"
+        );
+    }
+
     /// Ticket fixture (GitHub #245): minted `\mintinline{lang}|body|` is
     /// one token; following `Next sentence.` still splits.
     #[test]