feat: finish scanning section of the book

src/lib.rs

@@ -4,6 +4,7 @@ use std::{
     io::{self, Write},
 };
 
+use scanner::Scanner;
 use token::Token;
 
 mod scanner;
@@ -13,24 +14,37 @@ mod utils;
 pub fn run_file(path: &str) -> Result<(), Box<dyn Error>> {
     let file = fs::read_to_string(path)?;
 
+    run(&file);
     Ok(())
 }
 
 pub fn run(src: &str) {
-    let tokens: Vec<Token> = Vec::new();
+    let mut scanner = Scanner::new(src.to_string());
+    let tokens = scanner.scan_tokens();
+
+    match tokens {
+        Err(ref errors) => {
+            for err in errors {
+                report(err.line, "", &err.msg);
+            }
+        }
+        Ok(_) => {
+            for token in tokens.unwrap() {
+                println!("{}", token);
+            }
+        }
+    }
 }
 
 pub fn run_prompt() -> Result<(), Box<dyn Error>> {
     let stdin = io::stdin();
     let input = &mut String::new();
-    print!("> ");
-    io::stdout().flush()?;
     loop {
         input.clear();
-        let _ = stdin.read_line(input)?;
-
         print!("> ");
         io::stdout().flush()?;
+        stdin.read_line(input)?;
+        run(input);
     }
 }
 
@@ -40,12 +54,6 @@ pub struct RloxError {
     line: usize,
 }
 
-impl RloxError {
+pub fn report(line: usize, location: &str, message: &str) {
-    pub fn error(line: i32, message: &str) {
-        report(line, "", message);
-    }
-}
-
-pub fn report(line: i32, location: &str, message: &str) {
     eprintln!("[line {line}] Error {location}: {message}");
 }

src/scanner.rs

@@ -16,7 +16,7 @@ pub struct Scanner {
 }
 
 impl Scanner {
-    fn new(source: String) -> Self {
+    pub fn new(source: String) -> Self {
         // the reason for using unsafe here is to have the ability to use utf-8 symbols
         // rust doesn't allow having both the iterator and iterable inside one
         // structure(understandably so bcs of reference invalidation)
@@ -35,7 +35,7 @@ impl Scanner {
 
     // this is so awful for me to write. This function needs to be not mutable in theory and it
     // could be accomplished. TODO!
-    fn scan_tokens(&mut self) -> Result<&Vec<Token>, Vec<RloxError>> {
+    pub fn scan_tokens(&mut self) -> Result<&Vec<Token>, Vec<RloxError>> {
         let mut errors = Vec::new();
         while self.peek().is_some() {
             self.start = self.current;
@@ -94,10 +94,11 @@ impl Scanner {
             }
             '/' => self.add_token(TokenType::Slash),
             '"' => error = self.string(),
-            '0'..='9' => self.number(),
             ' ' | '\r' | '\t' => (),
             '\n' => self.line += 1,
 
+            '0'..='9' => self.number(),
+            'a'..='z' | 'A'..='Z' | '_' => self.identifier(),
             _ => {
                 error = Err(RloxError {
                     msg: "Unexpected character".to_string(),
@@ -200,6 +201,45 @@ impl Scanner {
 
         self.add_token_literal(TokenType::Number, Some(LiteralType::Number(number)));
     }
+
+    fn identifier(&mut self) {
+        while self.peek().is_some_and(is_alpha_numeric) {
+            self.advance();
+        }
+
+        let text_value = self.source.slice(self.start..self.current);
+        if let Some(identified_token) = get_identified_keyword(text_value) {
+            return self.add_token(identified_token);
+        }
+
+        self.add_token(TokenType::Identifier);
+    }
+}
+
+fn is_alpha_numeric(chr: char) -> bool {
+    matches!(chr ,'0'..='9'| '_' | 'a'..='z'|'A'..='Z')
+}
+
+fn get_identified_keyword(identifier: &str) -> Option<TokenType> {
+    match identifier {
+        "and" => Some(TokenType::And),
+        "class" => Some(TokenType::Class),
+        "else" => Some(TokenType::Else),
+        "false" => Some(TokenType::False),
+        "for" => Some(TokenType::For),
+        "fun" => Some(TokenType::Fun),
+        "if" => Some(TokenType::If),
+        "nil" => Some(TokenType::Nil),
+        "or" => Some(TokenType::OR),
+        "print" => Some(TokenType::Print),
+        "return" => Some(TokenType::Return),
+        "super" => Some(TokenType::Super),
+        "this" => Some(TokenType::This),
+        "true" => Some(TokenType::True),
+        "var" => Some(TokenType::Var),
+        "while" => Some(TokenType::While),
+        _ => None,
+    }
 }
 
 #[cfg(test)]
@@ -312,7 +352,7 @@ mod tests {
     fn correct_fractional_number_scan() {
         let value = r#"
             // number test
-            123.456"#
+            123.aaa"#
             .to_string();
 
         let mut scanner = Scanner::new(value);