1 files changed, 87 insertions, 0 deletions
diff --git a/src/engine.rs b/src/engine.rs
new file mode 100644
index 00000000..f7d820e8
--- /dev/null
+++ b/src/engine.rs
@@ -0,0 +1,87 @@
+//! Core typesetting engine.
+
+use std::fmt;
+use crate::parsing::{SyntaxTree, Node};
+use crate::doc::{Document, Style, Page, Text, TextCommand};
+use crate::font::Font;
+
+
+/// A type that can be typesetted into a document.
+pub trait Typeset {
+    /// Generate a document from self.
+    fn typeset(self) -> TypeResult<Document>;
+}
+
+impl Typeset for SyntaxTree<'_> {
+    fn typeset(self) -> TypeResult<Document> {
+        Engine::new(self).typeset()
+    }
+}
+
+/// Result type used for parsing.
+type TypeResult<T> = std::result::Result<T, TypesetError>;
+
+/// Errors occuring in the process of typesetting.
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct TypesetError {
+    message: String,
+}
+
+impl fmt::Display for TypesetError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.write_str(&self.message)
+    }
+}
+
+
+/// Transforms an abstract syntax tree into a document.
+#[derive(Debug, Clone)]
+struct Engine<'s> {
+    tree: SyntaxTree<'s>,
+}
+
+impl<'s> Engine<'s> {
+    /// Create a new generator from a syntax tree.
+    fn new(tree: SyntaxTree<'s>) -> Engine<'s> {
+        Engine { tree }
+    }
+
+    /// Generate the abstract document.
+    fn typeset(&mut self) -> TypeResult<Document> {
+        let style = Style::default();
+
+        // Load font defined by style
+        let font_family = style.font_families.first().unwrap();
+        let program = std::fs::read(format!("../fonts/{}-Regular.ttf", font_family)).unwrap();
+        let font = Font::new(program).unwrap();
+
+        let mut text = String::new();
+        for node in &self.tree.nodes {
+            match node {
+                Node::Space if !text.is_empty() => text.push(' '),
+                Node::Space | Node::Newline => (),
+                Node::Word(word) => text.push_str(word),
+
+                Node::ToggleItalics | Node::ToggleBold | Node::ToggleMath => unimplemented!(),
+                Node::Func(_) => unimplemented!(),
+            }
+        }
+
+        let page = Page {
+            width: style.paper_size[0],
+            height: style.paper_size[1],
+            text: vec![Text {
+                commands: vec![
+                    TextCommand::Move(style.margins[0], style.paper_size[1] - style.margins[1]),
+                    TextCommand::SetFont(0, style.font_size),
+                    TextCommand::Text(text)
+                ]
+            }],
+        };
+
+        Ok(Document {
+            pages: vec![page],
+            fonts: vec![font],
+        })
+    }
+}