[fine] Type checking bones

fine/build.rs

@@ -5,10 +5,12 @@ use std::path::{Path, PathBuf};
 
 fn generate_test_for_file(path: PathBuf) -> String {
     let contents = fs::read_to_string(&path).expect("Unable to read input");
+    let display_path = path.display().to_string();
 
     let mut concrete_stuff: Option<String> = None;
 
     // Start iterating over lines and processing directives....
+    let mut type_assertions = Vec::new();
     let mut lines = contents.lines();
     while let Some(line) = lines.next() {
         let line = match line.strip_prefix("//") {
@@ -29,11 +31,23 @@ fn generate_test_for_file(path: PathBuf) -> String {
                 concrete.push_str("\n");
             }
             concrete_stuff = Some(concrete);
+        } else if let Some(line) = line.strip_prefix("type:") {
+            let (pos, expected) = line
+                .trim()
+                .split_once(' ')
+                .expect("Mal-formed type expectation");
+            let pos: usize = pos
+                .trim()
+                .parse()
+                .expect(&format!("Unable to parse position '{pos}'"));
+            let expected = expected.trim();
+            type_assertions.push(quote! {
+                crate::assert_type_at(&_tree, &_lines, #pos, #expected, #display_path);
+            });
         }
     }
 
     let concrete_comparison = if let Some(concrete) = concrete_stuff {
-        let display_path = path.display().to_string();
         quote! {
             crate::assert_concrete(&_tree, #concrete, #display_path)
         }
@@ -46,6 +60,7 @@ fn generate_test_for_file(path: PathBuf) -> String {
         fn #name() {
             let (_tree, _lines) = fine::parser::parse(#contents);
             #concrete_comparison;
+            #(#type_assertions)*
         }
     };