1 files changed, 48 insertions, 50 deletions

diff --git a/src/md.rs b/src/md.rs
index 15fe57a..f43b462 100644
--- a/src/md.rs
+++ b/src/md.rs
@@ -1,34 +1,62 @@
 //! A parsed Markdown document.
 
 use crate::{
-    parse_scenario_snippet, visitor, Bindings, EmbeddedFiles, LintingVisitor, Scenario,
-    ScenarioStep, Style, SubplotError, Warning, YamlMetadata,
+    parse_scenario_snippet, Bindings, EmbeddedFiles, Scenario, ScenarioStep, Style, SubplotError,
+    Warning, YamlMetadata,
 };
 use log::trace;
 use pandoc_ast::{Map, MetaValue, MutVisitor, Pandoc};
 use serde_yaml::{Mapping, Value};
+use std::cell::RefCell;
 use std::collections::HashSet;
-use std::convert::TryFrom;
 use std::path::{Path, PathBuf};
 
+mod panhelper;
+mod typeset;
+
+mod visitor;
+use visitor::LintingVisitor;
+
 /// A parsed Markdown document.
 #[derive(Debug)]
 pub struct Markdown {
-    pandoc: Pandoc,
+    pandoc: RefCell<Pandoc>,
 }
 
 impl Markdown {
-    fn new(pandoc: Pandoc) -> Self {
-        Self { pandoc }
+    /// Load a Markdown file.
+    pub fn load_file(filename: &Path) -> Result<Self, SubplotError> {
+        trace!("parsing file as markdown: {}", filename.display());
+        let mut pandoc = pandoc::new();
+        pandoc.add_input(&filename);
+        pandoc.set_input_format(
+            pandoc::InputFormat::Markdown,
+            vec![pandoc::MarkdownExtension::Citations],
+        );
+        pandoc.set_output_format(pandoc::OutputFormat::Json, vec![]);
+        pandoc.set_output(pandoc::OutputKind::Pipe);
+
+        // Add external Pandoc filters.
+        crate::policy::add_citeproc(&mut pandoc);
+
+        let json = match pandoc.execute().map_err(SubplotError::Pandoc)? {
+            pandoc::PandocOutput::ToBuffer(o) => o,
+            _ => return Err(SubplotError::NotJson),
+        };
+
+        let ast: Pandoc = serde_json::from_str(&json).map_err(SubplotError::AstJson)?;
+        Ok(Self::new(ast))
     }
 
-    fn pandoc(&mut self) -> &mut Pandoc {
-        &mut self.pandoc
+    fn new(pandoc: Pandoc) -> Self {
+        Self {
+            pandoc: RefCell::new(pandoc),
+        }
     }
 
     /// Set document metadata from subplot.
     pub fn set_metadata(&mut self, meta: &YamlMetadata) {
-        self.pandoc.meta = to_pandoc_meta(meta);
+        self.pandoc.borrow_mut().meta = to_pandoc_meta(meta);
     }
 
     /// JSON representation of Pandoc AST.
@@ -38,17 +66,17 @@ impl Markdown {
     }
 
     /// Find problems.
-    pub fn lint(&mut self) -> Vec<SubplotError> {
+    pub fn lint(&self) -> Vec<SubplotError> {
         let mut linter = LintingVisitor::default();
-        linter.walk_pandoc(self.pandoc());
+        linter.walk_pandoc(&mut self.pandoc.borrow_mut());
         linter.issues
     }
 
     /// Find included images.
-    pub fn images(&mut self) -> Vec<PathBuf> {
+    pub fn images(&self) -> Vec<PathBuf> {
         let mut names = vec![];
         let mut visitor = visitor::ImageVisitor::new();
-        visitor.walk_pandoc(self.pandoc());
+        visitor.walk_pandoc(&mut self.pandoc.borrow_mut());
         for x in visitor.images().iter() {
             names.push(x.to_path_buf());
         }
@@ -56,31 +84,28 @@ impl Markdown {
     }
 
     /// Find classes used for fenced blocks.
-    pub fn block_classes(&mut self) -> HashSet<String> {
+    pub fn block_classes(&self) -> HashSet<String> {
         let mut visitor = visitor::BlockClassVisitor::default();
-        // Irritatingly we can't immutably visit the AST for some reason
-        // This clone() is expensive and unwanted, but I'm not sure how
-        // to get around it for now
-        visitor.walk_pandoc(self.pandoc());
+        visitor.walk_pandoc(&mut self.pandoc.borrow_mut());
         visitor.classes
     }
 
     /// Typeset.
     pub fn typeset(&mut self, style: Style, bindings: &Bindings) -> Vec<Warning> {
         let mut visitor = visitor::TypesettingVisitor::new(style, bindings);
-        visitor.walk_pandoc(self.pandoc());
+        visitor.walk_pandoc(&mut self.pandoc.borrow_mut());
         visitor.warnings().warnings().to_vec()
     }
 
     /// Find scenarios.
-    pub fn scenarios(&mut self) -> Result<Vec<Scenario>, SubplotError> {
+    pub fn scenarios(&self) -> Result<Vec<Scenario>, SubplotError> {
         trace!(
             "Metadata::scenarios: looking for scenarios: {:#?}",
             self.pandoc
         );
 
         let mut visitor = visitor::StructureVisitor::new();
-        visitor.walk_pandoc(self.pandoc());
+        visitor.walk_pandoc(&mut self.pandoc.borrow_mut());
         trace!(
             "Metadata::scenarios: visitor found {} elements: {:#?}",
             visitor.elements.len(),
@@ -102,9 +127,9 @@ impl Markdown {
     }
 
     /// Find embedded files.
-    pub fn embedded_files(&mut self) -> EmbeddedFiles {
+    pub fn embedded_files(&self) -> EmbeddedFiles {
         let mut files = EmbeddedFiles::default();
-        files.walk_pandoc(self.pandoc());
+        files.walk_pandoc(&mut self.pandoc.borrow_mut());
         files
     }
 }
@@ -209,33 +234,6 @@ fn meta_path_bufs(v: &[PathBuf]) -> MetaValue {
     MetaValue::MetaList(v.iter().map(|p| meta_path_buf(p)).collect())
 }
 
-impl TryFrom<&Path> for Markdown {
-    type Error = SubplotError;
-
-    fn try_from(filename: &Path) -> Result<Self, Self::Error> {
-        trace!("parsing file as markdown: {}", filename.display());
-        let mut pandoc = pandoc::new();
-        pandoc.add_input(&filename);
-        pandoc.set_input_format(
-            pandoc::InputFormat::Markdown,
-            vec![pandoc::MarkdownExtension::Citations],
-        );
-        pandoc.set_output_format(pandoc::OutputFormat::Json, vec![]);
-        pandoc.set_output(pandoc::OutputKind::Pipe);
-
-        // Add external Pandoc filters.
-        crate::policy::add_citeproc(&mut pandoc);
-
-        let json = match pandoc.execute().map_err(SubplotError::Pandoc)? {
-            pandoc::PandocOutput::ToBuffer(o) => o,
-            _ => return Err(SubplotError::NotJson),
-        };
-
-        let ast: Pandoc = serde_json::from_str(&json).map_err(SubplotError::AstJson)?;
-        Ok(Self::new(ast))
-    }
-}
-
 fn extract_scenario(e: &[visitor::Element]) -> Result<(Option<Scenario>, usize), SubplotError> {
     if e.is_empty() {
         // If we get here, it's a programming error.