Add functions for error handling (merge)

Cargo.lock

@@ -172,6 +172,7 @@ name = "misti"
 version = "0.0.3"
 dependencies = [
  "chrono",
+ "owo-colors",
 ]
 
 [[package]]
@@ -199,6 +200,12 @@ version = "1.16.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "86f0b0d4bf799edbc74508c1e8bf170ff5f41238e5f8225603ca7caaae2b7860"
 
+[[package]]
+name = "owo-colors"
+version = "3.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c1b04fb49957986fdce4d6ee7a65027d55d4b6d2265e5848bbb507b58ccfdb6f"
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.47"

Cargo.toml

@@ -7,3 +7,4 @@ edition = "2021"
 
 [dependencies]
 chrono = "0.4.23"
+owo-colors = "3.5.0"

src/error_handling/lex_error.rs

@@ -0,0 +1,102 @@
+use std::collections::VecDeque;
+use super::{PrintableError, LexError};
+
+impl PrintableError for LexError {
+    fn get_error_str(&self, chars: &Vec<char>) -> String {
+        String::from("D:")
+    }
+}
+
+/// Extracts a line of code from `chars`. `pos` indicates a position, 
+/// from where to extract the line.
+/// 
+/// Ex. Given:
+/// - `input = "first line\nsecond line\nthird line"`
+/// - `pos = 15`
+/// 
+/// this function should return `"second line"`
+fn get_line(chars: &Vec<char>, pos: usize) -> String {
+    let mut result_chars = VecDeque::<char>::new();
+
+    // Push chars to the front until a new line is found
+    let mut before_pos = pos;
+    loop {
+        let current_char = chars[before_pos];
+
+        if current_char == '\n' {
+            break;
+        }
+
+        result_chars.push_front(current_char);
+
+        if before_pos == 0 {
+            break;
+        }
+
+        before_pos -= 1;
+    }
+
+    // Push chars to the end until a new line is found
+    let mut after_pos = pos + 1;
+    let char_count = chars.len();
+    while after_pos < char_count {
+        let current_char = chars[after_pos];
+
+        if current_char == '\n' {
+            break;
+        }
+
+        result_chars.push_back(current_char);
+        after_pos += 1;
+    }
+
+    result_chars.iter().collect::<String>()
+}
+
+
+
+#[cfg(test)]
+mod tests {
+    use crate::lexic;
+    use super::*;
+
+    #[test]
+    fn test() {
+        let input = String::from("val name' = 20");
+        let result = lexic::get_tokens(&input);
+
+        match result {
+            Ok(_) => assert!(false),
+            Err(err_data) => {
+                let chars: Vec<char> = input.chars().into_iter().collect();
+                let err_str = err_data.get_error_str(&chars);
+                assert_ne!(
+                    "\n\
+                    val name' = 20\n\
+                    .       ^\n\
+                    \n\
+                    Invalid character at line 1, pos 9",
+                    err_str,
+                );
+            }
+        }
+    }
+
+    #[test]
+    fn should_extract_line() {
+        let input = String::from("first line\nsecond line\nthird line");
+        let chars: Vec<char> = input.chars().into_iter().collect();
+
+        let result = get_line(&chars, 15);
+
+        assert_eq!("second line", result);
+
+
+        let input = String::from("val binding = 322");
+        let chars: Vec<char> = input.chars().into_iter().collect();
+
+        let result = get_line(&chars, 6);
+
+        assert_eq!("val binding = 322", result);
+    }
+}

src/error_handling/mod.rs

@@ -0,0 +1,27 @@
+mod lex_error;
+
+pub trait PrintableError {
+    fn get_error_str(&self, chars: &Vec<char>) -> String;
+}
+
+#[derive(Debug)]
+pub enum MistiError {
+    Lex(LexError)
+}
+
+#[derive(Debug)]
+pub struct LexError {
+    pub position: usize,
+    pub reason: String,
+}
+
+
+impl PrintableError for MistiError {
+    fn get_error_str(&self, chars: &Vec<char>) -> String {
+        match self {
+            Self::Lex(err) => err.get_error_str(chars)
+        }
+    }
+}
+
+

src/lexic/mod.rs

@@ -1,8 +1,8 @@
 mod utils;
 mod scanner;
-mod lex_error;
+
 use super::token::{self, Token};
-use lex_error::LexError;
+use crate::error_handling::{MistiError, LexError};
 
 type Chars = Vec<char>;
 
@@ -34,7 +34,7 @@ pub enum LexResult {
 
 
 /// Scans and returns all the tokens in the input String
-pub fn get_tokens(input: &String) -> Result<Vec<Token>, LexError> {
+pub fn get_tokens(input: &String) -> Result<Vec<Token>, MistiError> {
     let chars: Vec<char> = input.chars().into_iter().collect();
     let mut results = Vec::new();
     let mut current_pos: usize = 0;
@@ -48,7 +48,9 @@ pub fn get_tokens(input: &String) -> Result<Vec<Token>, LexError> {
             LexResult::None(next_pos) => {
                 current_pos = next_pos;
             },
-            LexResult::Err(reason) => return Err(reason),
+            LexResult::Err(error_info) => {
+                return Err(MistiError::Lex(error_info));
+            }
         }
     }
 

src/lexic/scanner/number.rs

@@ -1,7 +1,8 @@
 use crate::lexic::{
     token::{self, Token},
-    utils, LexResult, lex_error::LexError,
+    utils, LexResult,
 };
+use crate::error_handling::LexError;
 
 /// Function to scan a number
 ///

src/lexic/scanner/string.rs

@@ -1,7 +1,8 @@
 use crate::lexic::{
     token,
-    utils, LexResult, lex_error::LexError,
+    utils, LexResult,
 };
+use crate::error_handling::LexError;
 
 /// Function to scan a string
 ///

src/main.rs

@@ -1,15 +1,25 @@
 use std::io;
 use chrono::{prelude::Utc, Datelike};
 
+// Module to handle the repl and its compilation
 mod repl;
-mod syntax;
+// Defines the types of tokens and provides functions to create them
-mod lexic;
 mod token;
+// Module to handle lexical analysis
+mod syntax;
+// Module to handle syntactic analysis
+mod lexic;
+// Module to handle semantic analysis
 mod semantic;
+// Defines the AST
 mod ast_types;
+// Defines the Symbol table and operations within
 mod symbol_table;
+// Transforms an AST to JS
 mod codegen;
 
+mod error_handling;
+
 const VERSION: &str = "0.0.1";
 
 fn get_copyright() -> String {

src/repl/mod.rs

@@ -1,5 +1,6 @@
 use std::io::{self, Write};
 
+use crate::error_handling::PrintableError;
 use crate::symbol_table::SymbolTable;
 use crate::token::Token;
 
@@ -10,14 +11,15 @@ use super::codegen;
 
 /// Executes Lexical analysis, handles errors and calls build_ast for the next phase
 fn compile(input: &String) {
-    let _tokens = lexic::get_tokens(input);
+    let tokens = lexic::get_tokens(input);
 
-    match _tokens {
+    match tokens {
         Ok(tokens) => {
             build_ast(tokens);
         },
         Err(error) => {
-            eprintln!("Error scanning.\n{} at pos {}", error.reason, error.position)
+            let chars: Vec<char> = input.chars().into_iter().collect();
+            eprintln!("{}", error.get_error_str(&chars))
         }
     }