cl-interpret: Write an example for driving the interpreter

compiler/cl-interpret/examples/conlang-run.rs

@@ -0,0 +1,55 @@
+//! A bare-minimum harness to evaluate a Conlang program
+
+use std::{error::Error, path::PathBuf};
+
+use cl_interpret::{convalue::ConValue, env::Environment};
+use cl_lexer::Lexer;
+use cl_parser::{inliner::ModuleInliner, Parser};
+
+fn main() -> Result<(), Box<dyn Error>> {
+    let mut args = std::env::args();
+
+    let prog = args.next().unwrap();
+    let Some(path) = args.next().map(PathBuf::from) else {
+        println!("Usage: {prog} `file.cl` [ args... ]");
+        return Ok(());
+    };
+
+    let parent = path.parent().unwrap_or("".as_ref());
+
+    let code = std::fs::read_to_string(&path)?;
+    let code = Parser::new(Lexer::new(&code)).file()?;
+    let code = match ModuleInliner::new(parent).inline(code) {
+        Ok(code) => code,
+        Err((code, ioerrs, perrs)) => {
+            for (p, err) in ioerrs {
+                eprintln!("{}:{err}", p.display());
+            }
+            for (p, err) in perrs {
+                eprintln!("{}:{err}", p.display());
+            }
+            code
+        }
+    };
+
+    let mut env = Environment::new();
+    env.eval(&code)?;
+
+    let main = "main".into();
+    if env.get(main).is_ok() {
+        let args = args
+            .flat_map(|arg| {
+                Parser::new(Lexer::new(&arg))
+                    .expr()
+                    .map(|arg| env.eval(&arg))
+            })
+            .collect::<Result<Vec<_>, _>>()?;
+
+        match env.call(main, &args)? {
+            ConValue::Empty => {}
+            retval => println!("{retval}"),
+        }
+    }
+
+    Ok(())
+}