From 124ffd883f9745ff7a92bf9ce942adbe28a73420 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Emmanuel=20Beno=C3=AEt?= <tseeker@nocternity.net>
Date: Fri, 30 Dec 2022 16:56:21 +0100
Subject: [PATCH] Error handler in separate module + basic scanner module

---
 src/errors.rs  | 23 +++++++++++++++++++++++
 src/main.rs    | 37 ++++++++-----------------------------
 src/scanner.rs | 31 +++++++++++++++++++++++++++++++
 3 files changed, 62 insertions(+), 29 deletions(-)
 create mode 100644 src/errors.rs
 create mode 100644 src/scanner.rs

diff --git a/src/errors.rs b/src/errors.rs
new file mode 100644
index 0000000..14e724b
--- /dev/null
+++ b/src/errors.rs
@@ -0,0 +1,23 @@
+/// Error handler. Can be used to print error messages; will also retain the
+/// current error status.
+#[derive(Default, Debug)]
+pub struct ErrorHandler {
+    had_error: bool,
+}
+
+impl ErrorHandler {
+    /// Check whether this handler reported an error.
+    pub fn had_error(&self) -> bool {
+        self.had_error
+    }
+
+    /// Report an error.
+    pub fn error(&mut self, line: usize, message: &str) {
+        self.report(line, "", message)
+    }
+
+    fn report(&mut self, line: usize, pos: &str, message: &str) {
+        self.had_error = true;
+        println!("[line {line}] Error{pos}: {message}")
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 637f4ad..2bd696a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,3 +1,5 @@
+mod errors;
+mod scanner;
 mod tokens;
 
 use std::{
@@ -6,40 +8,17 @@ use std::{
     process::ExitCode,
 };
 
-/// Error handler. Can be used to print error messages; will also retain the
-/// current error status.
-#[derive(Default, Debug)]
-struct ErrorHandler {
-    had_error: bool,
-}
-
-impl ErrorHandler {
-    /// Check whether this handler reported an error.
-    pub fn had_error(&self) -> bool {
-        self.had_error
-    }
-
-    /// Report an error.
-    pub fn error(&mut self, line: usize, message: &str) {
-        self.report(line, "", message)
-    }
-
-    fn report(&mut self, line: usize, pos: &str, message: &str) {
-        self.had_error = true;
-        println!("[line {line}] Error{pos}: {message}")
-    }
-}
+use errors::ErrorHandler;
+use scanner::Scanner;
 
 /// Execute a script.
-fn run(_source: String) -> ErrorHandler {
-    let error_handler = ErrorHandler::default();
-    /*
+fn run(source: String) -> ErrorHandler {
+    let mut error_handler = ErrorHandler::default();
     let scanner = Scanner::new(source);
-    let tokens = scanner.scan_tokens();
+    let tokens = scanner.scan_tokens(&mut error_handler);
     for token in tokens {
-        println!("{}", token);
+        println!("{:#?}", token);
     }
-    */
     error_handler
 }
 
diff --git a/src/scanner.rs b/src/scanner.rs
new file mode 100644
index 0000000..820d682
--- /dev/null
+++ b/src/scanner.rs
@@ -0,0 +1,31 @@
+use crate::ErrorHandler;
+
+use super::tokens::Token;
+
+/// The scanner's state, including the source it is scanning.
+pub struct Scanner {
+    source: String,
+    tokens: Vec<Token>,
+    start: usize,
+    current: usize,
+    line: usize,
+}
+
+impl Scanner {
+    /// Initialize a scanner by specifying the source code to scan.
+    pub fn new(source: String) -> Scanner {
+        Scanner{
+            source: source,
+            tokens: Vec::new(),
+            start: 0,
+            current: 0,
+            line: 1,
+        }
+    }
+
+    /// Scan the source code, generating the list of tokens and returning it.
+    /// The scanner itself is destroyed once the process is complete.
+    pub fn scan_tokens(self, err_hdl: &mut ErrorHandler) -> Vec<Token> {
+        self.tokens
+    }
+}