1 files changed, 66 insertions, 7 deletions

diff --git a/src/ast.rs b/src/ast.rs
index 012e05a..bc3547d 100644
--- a/src/ast.rs
+++ b/src/ast.rs
@@ -89,6 +89,12 @@ impl<'a> Document {
     {
         let mut ast: Pandoc = serde_json::from_str(json)?;
         let meta = Metadata::new(basedir, &ast)?;
+        let mut linter = LintingVisitor::default();
+        linter.walk_pandoc(&mut ast);
+        if !linter.issues.is_empty() {
+            // Currently we can't really return more than one error so return one
+            return Err(linter.issues.remove(0));
+        }
         let files = DataFiles::new(&mut ast);
         Ok(Document::new(markdowns, ast, meta, files))
     }
@@ -970,11 +976,8 @@ pub struct DataFile {
 }
 
 impl DataFile {
-    fn new(filename: &str, contents: &str) -> DataFile {
-        DataFile {
-            filename: filename.to_string(),
-            contents: contents.to_string(),
-        }
+    fn new(filename: String, contents: String) -> DataFile {
+        DataFile { filename, contents }
     }
 
     pub fn filename(&self) -> &str {
@@ -1010,8 +1013,18 @@ impl MutVisitor for DataFiles {
             match block {
                 Block::CodeBlock(attr, contents) => {
                     if is_class(attr, "file") {
-                        self.files
-                            .push(DataFile::new(&get_filename(attr), &contents));
+                        let add_newline = match find_attr_kv(&attr, "add-newline").next() {
+                            None | Some("auto") => !contents.ends_with('\n'),
+                            Some("yes") => true,
+                            Some("no") => false,
+                            _ => unreachable!(),
+                        };
+                        let contents = if add_newline {
+                            format!("{}\n", contents)
+                        } else {
+                            contents.clone()
+                        };
+                        self.files.push(DataFile::new(get_filename(attr), contents));
                     }
                 }
                 _ => {
@@ -1070,6 +1083,41 @@ impl MutVisitor for BlockClassVisitor {
     }
 }
 
+#[derive(Default)]
+struct LintingVisitor {
+    issues: Vec<SubplotError>,
+}
+
+impl MutVisitor for LintingVisitor {
+    fn visit_vec_block(&mut self, vec_block: &mut Vec<Block>) {
+        for block in vec_block {
+            match block {
+                Block::CodeBlock(attr, _) => {
+                    if is_class(attr, "file") {
+                        let newlines: Vec<_> = find_attr_kv(&attr, "add-newline").collect();
+                        match newlines.len() {
+                            0 => {}
+                            1 => match newlines[0].to_ascii_lowercase().as_ref() {
+                                "auto" | "yes" | "no" => {}
+                                _ => self.issues.push(SubplotError::UnrecognisedAddNewline(
+                                    get_filename(&attr),
+                                    newlines[0].to_owned(),
+                                )),
+                            },
+                            _ => self.issues.push(SubplotError::RepeatedAddNewlineAttribute(
+                                get_filename(&attr),
+                            )),
+                        }
+                    }
+                }
+                _ => {
+                    self.visit_block(block);
+                }
+            }
+        }
+    }
+}
+
 /// Get the base directory given the name of the markdown file.
 ///
 /// All relative filename, such as bindings files, are resolved
@@ -1081,3 +1129,14 @@ pub fn get_basedir_from(filename: &Path) -> Result<PathBuf> {
     };
     Ok(dirname)
 }
+
+/// Utility function to find key/value pairs from an attribute
+fn find_attr_kv<'a>(attr: &'a Attr, key: &'static str) -> impl Iterator<Item = &'a str> {
+    attr.2.iter().flat_map(move |(key_, value)| {
+        if key == key_ {
+            Some(value.as_ref())
+        } else {
+            None
+        }
+    })
+}