Implement simple cli

src/interpreter.rs

@@ -1,6 +1,6 @@
 use std::collections::HashMap;
 
-use crate::parser::{Expr, BinOpType, UnOpType, Ast, Stmt};
+use crate::{parser::{Expr, BinOpType, UnOpType, Ast, Stmt, parse}, lexer::lex};
 
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum Value {
@@ -18,6 +18,18 @@ impl Interpreter {
         Self { vartable }
     }
 
+    pub fn run_text(&mut self, code: &str, print_tokens: bool, print_ast: bool) {
+        let tokens = lex(code);
+        if print_tokens {
+            println!("Tokens: {:?}", tokens);
+        }
+        let ast = parse(tokens);
+        if print_ast {
+            println!("Ast:\n{:#?}", ast);
+        }
+        self.run(ast);
+    }
+
     pub fn run(&mut self, prog: Ast) {
         for stmt in prog.prog {
             match stmt {

src/main.rs

@@ -1,23 +1,52 @@
-use nek_lang::{lexer::lex, parser::parse, interpreter::Interpreter};
+use std::{env::args, io::Write};
 
+use nek_lang::interpreter::Interpreter;
+
+#[derive(Debug, Default)]
+struct CliConfig {
+    print_tokens: bool,
+    print_ast: bool,
+    interactive: bool,
+    file: Option<String>,
+}
 
 fn main() {
+    let mut cfg = CliConfig::default();
 
-    let mut code = String::new();
-
-    std::io::stdin().read_line(&mut code).unwrap();
-    let code = code.trim();
-
-    let tokens = lex(&code);
-
-    println!("Tokens: {:?}\n", tokens);
-
-    let ast = parse(tokens);
-
-    println!("Ast: {:#?}\n", ast);
+    for arg in args().skip(1) {
+        match arg.as_str() {
+            "--tokens" | "-t" => cfg.print_tokens = true,
+            "--ast" | "-a" => cfg.print_ast = true,
+            "--interactive" | "-i" => cfg.interactive = true,
+            file if cfg.file.is_none() => cfg.file = Some(file.to_string()),
+            _ => panic!("Invalid argument: '{}'", arg),
+        }
+    }
 
     let mut interpreter = Interpreter::new();
 
-    interpreter.run(ast);
+    if let Some(file) = &cfg.file {
+        let code = std::fs::read_to_string(file).expect(&format!("File not found: '{}'", file));
+        interpreter.run_text(&code, cfg.print_tokens, cfg.print_ast);
+    }
 
+    if cfg.interactive || cfg.file.is_none() {
+
+        let mut code = String::new();
+
+        loop {
+            print!(">> ");
+            std::io::stdout().flush().unwrap();
+
+            code.clear();
+            std::io::stdin().read_line(&mut code).unwrap();
+            let code = code.trim();
+
+            if code == "exit" {
+                break;
+            }
+
+            interpreter.run_text(&code, cfg.print_tokens, cfg.print_ast);
+        }
+    }
 }