Refactor and scan grouping signs

src/lexic/mod.rs

@@ -4,6 +4,15 @@ use super::token::{self, Token};
 
 type Chars = Vec<char>;
 
+pub enum LexResult {
+    // A token was scanned
+    Some(Token, usize),
+    // No token was found, but there was no error (EOF)
+    None(usize),
+    Err(String),
+}
+
+
 /// Scans and returns all the tokens in the input String
 pub fn get_tokens(input: &String) -> Result<Vec<Token>, String> {
     let chars: Vec<char> = input.chars().into_iter().collect();
@@ -12,14 +21,14 @@ pub fn get_tokens(input: &String) -> Result<Vec<Token>, String> {
 
     while has_input(&chars, current_pos) {
         match next_token(&chars, current_pos) {
-            Ok((Some(token), next_pos)) => {
+            LexResult::Some(token, next_pos) => {
                 results.push(token);
                 current_pos = next_pos;
             },
-            Ok((None, next_pos)) => {
+            LexResult::None(next_pos) => {
                 current_pos = next_pos;
             },
-            Err(reason) => return Err(reason),
+            LexResult::Err(reason) => return Err(reason),
         }
     }
 
@@ -27,12 +36,12 @@ pub fn get_tokens(input: &String) -> Result<Vec<Token>, String> {
     Ok(results)
 }
 
-fn next_token(chars: &Chars, current_pos: usize) -> Result<(Option<Token>, usize),String> {
+fn next_token(chars: &Chars, current_pos: usize) -> LexResult {
     let next_char = peek(chars, current_pos);
 
-    // If EOF is reached return nothing
+    // If EOF is reached return nothing but the current position
     if next_char == '\0' {
-        return Ok((None, current_pos))
+        return LexResult::None(current_pos)
     }
 
     // Handle whitespace recursively
@@ -41,20 +50,19 @@ fn next_token(chars: &Chars, current_pos: usize) -> Result<(Option<Token>, usize
     }
 
     // Test number
-    if utils::is_digit(next_char) {
+    None
-        match scanner::number(chars, current_pos) {
+        .or_else(|| {
-            Ok((token, next_pos)) => Ok((Some(token), next_pos)),
+            scanner::number(next_char, chars, current_pos)
-            Err(reason) => Err(reason),
+        })
-        }
+        .or_else(|| {
-    }
+            scanner::operator(next_char, chars, current_pos)
-    // Test operator
+        })
-    else if utils::is_operator(next_char) {
+        .or_else(|| {
-        let (token, next_pos) = scanner::operator(chars, current_pos);
+            scanner::grouping_sign(next_char, chars, current_pos)
-        Ok((Some(token), next_pos))
+        })
-    }
+        .unwrap_or_else(|| {
-    else {
+            LexResult::Err(format!("Unrecognized character: {}", next_char))
-        Err(format!("Unrecognized character: {}", next_char))
+        })
-    }
 }
 
 fn peek(input: &Chars, pos: usize) -> char {
@@ -103,11 +111,11 @@ mod tests {
         assert_eq!(4, chars.len());
         assert!(has_input(&chars, 0));
 
-        match next_token(&chars, 0).unwrap() {
+        match next_token(&chars, 0) {
-            (Some(t), _) => {
+            LexResult::Some(t, _) => {
                 assert_eq!("126", t.value)
             },
-            (None, _) => {
+            _ => {
                 panic!()
             }
         }
@@ -116,7 +124,7 @@ mod tests {
     /// Should scan numbers
     #[test]
     fn number_test() {
-        let input = String::from("126 278.98 0.282398");
+        let input = String::from("126 278.98 0.282398 1789e+1 239.3298e-103");
         let tokens = get_tokens(&input).unwrap();
 
         let t1 = tokens.get(0).unwrap();
@@ -130,10 +138,39 @@ mod tests {
         let t3 = tokens.get(2).unwrap();
         assert_eq!(TokenType::Number, t3.token_type);
         assert_eq!("0.282398", t3.value);
-        /*
+        
-        assert_eq!("1798e+1", tokens.get(3).unwrap().value);
+        assert_eq!("1789e+1", tokens.get(3).unwrap().value);
         assert_eq!("239.3298e-103", tokens.get(4).unwrap().value);
         assert_eq!(TokenType::EOF, tokens.get(5).unwrap().token_type);
-        */
+    }
+
+    #[test]
+    fn grouping_sign_test() {
+        let input = String::from("( ) { } [ ]");
+        let tokens = get_tokens(&input).unwrap();
+
+        let t = tokens.get(0).unwrap();
+        assert_eq!(TokenType::LeftParen, t.token_type);
+        assert_eq!("(", t.value);
+
+        let t = tokens.get(1).unwrap();
+        assert_eq!(TokenType::RightParen, t.token_type);
+        assert_eq!(")", t.value);
+
+        let t = tokens.get(2).unwrap();
+        assert_eq!(TokenType::LeftBrace, t.token_type);
+        assert_eq!("{", t.value);
+
+        let t = tokens.get(3).unwrap();
+        assert_eq!(TokenType::RightBrace, t.token_type);
+        assert_eq!("}", t.value);
+
+        let t = tokens.get(4).unwrap();
+        assert_eq!(TokenType::LeftBracket, t.token_type);
+        assert_eq!("[", t.value);
+
+        let t = tokens.get(5).unwrap();
+        assert_eq!(TokenType::RightBracket, t.token_type);
+        assert_eq!("]", t.value);
     }
 }

src/lexic/scanner/mod.rs

@@ -1,12 +1,53 @@
-use super::token::Token;
+use super::{token::{TokenType, self}, utils, LexResult};
 
 mod number;
 mod operator;
 
-pub fn number(chars: &Vec<char>, start_pos: usize) -> Result<(Token, usize), String> {
+/// Attempts to scan a number. Returns None to be able to chain other scanner
-    number::scan(chars, start_pos)
+pub fn number(c: char, chars: &Vec<char>, start_pos: usize) -> Option<LexResult> {
+    if utils::is_digit(c) {
+        match number::scan(chars, start_pos) {
+            Ok((token, next_pos)) => {
+                Some(LexResult::Some(token, next_pos))
+            },
+            Err(reason) => {
+                Some(LexResult::Err(reason))
+            },
+        }
+    }
+    else {
+        None
+    }
 }
 
-pub fn operator(chars: &Vec<char>, start_pos: usize) -> (Token, usize) {
+
-    operator::scan(chars, start_pos)
+/// Attempts to scan an operator. Returns None to be able to chain other scanner
+pub fn operator(c: char, chars: &Vec<char>, start_pos: usize) -> Option<LexResult> {
+    if utils::is_operator(c) {
+        Some(operator::scan(chars, start_pos))
+    }
+    else {
+        None
+    }
+}
+
+
+/// Attempts to scan a grouping sign. Returns None to be able to chain other scanner
+pub fn grouping_sign(c: char, _: &Vec<char>, start_pos: usize) -> Option<LexResult> {
+    let token_type = match c {
+        '(' => TokenType::LeftParen,
+        ')' => TokenType::RightParen,
+        '[' => TokenType::LeftBracket,
+        ']' => TokenType::RightBracket,
+        '{' => TokenType::LeftBrace,
+        '}' => TokenType::RightBrace,
+        _ => return None,
+    };
+
+    let token = token::new_grouping_sign(
+        c.to_string(), 
+        start_pos as i32, 
+        token_type,
+    );
+    Some(LexResult::Some(token, start_pos + 1))
 }

src/lexic/scanner/operator.rs

@@ -1,25 +1,26 @@
-use crate::lexic::{token::{Token, self}, utils};
+use crate::lexic::{token::{Token, self}, utils, LexResult};
 
 
 /// Function to scan an operator
 /// 
 /// This function assumes the character at `start_pos` is an operator
-pub fn scan(chars: &Vec<char>, start_pos: usize) -> (Token, usize) {
+pub fn scan(chars: &Vec<char>, start_pos: usize) -> LexResult {
     scan_impl(chars, start_pos, String::from(""))
 }
 
-pub fn scan_impl(chars: &Vec<char>, start_pos: usize, current: String) -> (Token, usize) {
+pub fn scan_impl(chars: &Vec<char>, start_pos: usize, current: String) -> LexResult {
-    let next_char = chars.get(start_pos);
+    match chars.get(start_pos) {
-
+        Some(c) if utils::is_operator(*c) => {
-    if let Some(c) = next_char {
+            scan_impl(chars, start_pos + 1, utils::str_append(current, *c))
-        if utils::is_operator(*c) {
+        },
-            return scan_impl(chars, start_pos + 1, utils::str_append(current, *c))
+        _ => {
+            LexResult::Some(token::new_operator(current, start_pos as i32), start_pos)
+        }
     }
 }
 
-    // Return current value
+
-    (token::new_operator(current, start_pos as i32), start_pos)
+
-}
 
 #[cfg(test)]
 mod tests {
@@ -59,11 +60,14 @@ mod tests {
         for op in operators {
             let input = str_to_vec(op);
             let start_pos = 0;
-            let (token, next) = scan(&input, start_pos);
+            match scan(&input, start_pos) {
-
+                LexResult::Some(token, next) => {
                     assert_eq!(1, next);
                     assert_eq!(TokenType::Operator, token.token_type);
                     assert_eq!(op, token.value);
+                },
+                _ => panic!()
+            }
         }
     }
 
@@ -91,11 +95,14 @@ mod tests {
         for op in operators {
             let input = str_to_vec(op);
             let start_pos = 0;
-            let (token, next) = scan(&input, start_pos);
+            match scan(&input, start_pos) {
-
+                LexResult::Some(token, next) => {
                     assert_eq!(2, next);
                     assert_eq!(TokenType::Operator, token.token_type);
                     assert_eq!(op, token.value);
+                },
+                _ => panic!()
+            }
         }
     }
 }

src/lexic/utils.rs

@@ -18,3 +18,7 @@ pub fn is_operator(c: char) -> bool {
              || c == '&' || c == '?' || c == '<' || c == '>' 
              || c == '^' || c == '.' || c == ':'
 }
+
+pub fn is_grouping_sign(c: char) -> bool {
+    c == '(' || c == ')' || c == '{' || c == '}' || c == '[' || c == ']'
+}

src/token.rs

@@ -5,7 +5,6 @@ pub enum TokenType {
     Comment,
     Number,
     String,
-    Unit,
     Operator,
     LeftParen,
     RightParen,
@@ -52,3 +51,7 @@ pub fn new_operator(value: String, position: i32) -> Token {
         position
     }
 }
+
+pub fn new_grouping_sign(value: String, position: i32, token_type: TokenType) -> Token {
+    Token {token_type, value, position}
+}