1 files changed, 78 insertions, 13 deletions

diff --git a/src/html.rs b/src/html.rs
index 7237258..b39872b 100644
--- a/src/html.rs
+++ b/src/html.rs
@@ -72,7 +72,7 @@ impl HtmlPage {
 }
 
 /// Parse Markdown text into an HTML element.
-pub fn parse(markdown: &str) -> Result<Element, HtmlError> {
+pub fn parse(filename: &Path, markdown: &str) -> Result<Element, HtmlError> {
     let mut options = Options::empty();
     options.insert(Options::ENABLE_HEADING_ATTRIBUTES);
     options.insert(Options::ENABLE_STRIKETHROUGH);
@@ -85,7 +85,7 @@ pub fn parse(markdown: &str) -> Result<Element, HtmlError> {
     for (event, loc) in p {
         trace!("event {:?}", event);
         let (line, col) = linecol.get(loc.start);
-        let loc = Location::new(line, col);
+        let loc = Location::new(filename, line, col);
         match event {
             Event::Start(tag) => match tag {
                 Tag::Paragraph => stack.push_tag(ElementTag::P, loc),
@@ -162,7 +162,7 @@ pub fn parse(markdown: &str) -> Result<Element, HtmlError> {
                     let s = as_plain_text(e.children());
                     trace!("paragraph text: {:?}", s);
                     if s.starts_with(": ") || s.contains("\n: ") {
-                        return Err(HtmlError::DefinitionList(loc.line, loc.col));
+                        return Err(HtmlError::DefinitionList(loc));
                     }
                     stack.append_child(Content::Elt(e));
                 }
@@ -254,8 +254,12 @@ impl Element {
     }
 
     /// Get location.
-    pub fn location(&self) -> &Option<Location> {
-        &self.loc
+    pub fn location(&self) -> Location {
+        if let Some(loc) = &self.loc {
+            loc.clone()
+        } else {
+            Location::unknown()
+        }
     }
 
     fn set_block_attributes(&mut self, block_attrs: Vec<BlockAttr>) {
@@ -543,15 +547,76 @@ impl Content {
 }
 
 /// Location of element in source file.
-#[derive(Debug, Clone, Copy)]
-pub struct Location {
-    line: usize,
-    col: usize,
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub enum Location {
+    /// A known location.
+    Known {
+        /// Name of file.
+        filename: PathBuf,
+        /// Line in file.
+        line: usize,
+        /// Column in line.
+        col: usize,
+    },
+    /// An unknown location.
+    Unknown,
 }
 
 impl Location {
-    fn new(line: usize, col: usize) -> Self {
-        Self { line, col }
+    fn new(filename: &Path, line: usize, col: usize) -> Self {
+        Self::Known {
+            filename: filename.into(),
+            line,
+            col,
+        }
+    }
+
+    /// Create an unknown location.
+    pub fn unknown() -> Self {
+        Self::Unknown
+    }
+
+    /// Report name of source file from where this element comes from.
+    pub fn filename(&self) -> &Path {
+        if let Self::Known {
+            filename,
+            line: _,
+            col: _,
+        } = self
+        {
+            filename
+        } else {
+            Path::new("")
+        }
+    }
+
+    /// Report row and column in source where this element comes from.
+    pub fn rowcol(&self) -> (usize, usize) {
+        if let Self::Known {
+            filename: _,
+            line,
+            col,
+        } = self
+        {
+            (*line, *col)
+        } else {
+            (0, 0)
+        }
+    }
+}
+
+impl std::fmt::Display for Location {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
+        if let Self::Known {
+            filename,
+            line,
+            col,
+        } = self
+        {
+            write!(f, "{}:{}:{}", filename.display(), line, col)
+        } else {
+            write!(f, "(unknown location)")
+        }
     }
 }
 
@@ -616,8 +681,8 @@ pub enum HtmlError {
 
     /// Input contains an attempt to use a definition list in
     /// Markdown.
-    #[error("attempt to use definition lists in Markdown: line {0}, column {1}")]
-    DefinitionList(usize, usize),
+    #[error("attempt to use definition lists in Markdown: {0}")]
+    DefinitionList(Location),
 
     /// String formatting error. This is likely a programming error.
     #[error("string formatting error: {0}")]