[fine] Re-work compiler main, checking is everything

fine/src/lib.rs

@@ -1,4 +1,32 @@
+use std::fs;
+
+use parser::parse;
+use semantics::{check, Semantics};
+
 pub mod compiler;
 pub mod parser;
 pub mod semantics;
 pub mod tokens;
+pub mod vm;
+
+pub fn process_file(file: &str) {
+    let source = match fs::read_to_string(file) {
+        Ok(c) => c,
+        Err(e) => {
+            eprintln!("Unable to read file {file}: {e}");
+            return;
+        }
+    };
+
+    // What am I doing here?
+    let (tree, lines) = parse(&source);
+    let semantics = Semantics::new(&tree, &lines);
+    check(&semantics);
+
+    // OK now there might be errors.
+    let mut errors = semantics.snapshot_errors();
+    errors.reverse();
+    for e in errors {
+        eprintln!("{file}: {}:{}: {}", e.start.0, e.start.1, e.message);
+    }
+}