diff --git a/test.sl b/program.trv
similarity index 97%
rename from test.sl
rename to program.trv
index 6af6c8d..28e349b 100644
--- a/test.sl
+++ b/program.trv
@@ -5,7 +5,7 @@ func is_greater_than_44(params : Integer) -> Integer {
   if x > 44 is True then {
     1
   }
-  else if not {
+  else {
     0
   }
 }
diff --git a/src/lexer/lexer.rs b/src/lexer/lexer.rs
new file mode 100644
index 0000000..3d24724
--- /dev/null
+++ b/src/lexer/lexer.rs
@@ -0,0 +1,284 @@
+use std::{any::Any, string};
+
+use crate::lexer::token::{Token, TokenType};
+
+
+
+#[derive(Debug)]
+pub struct Lexer {
+    input: Vec<char>,
+    position: usize,
+    line: usize,
+    column: usize
+}
+
+impl Lexer {
+    pub fn new(input: String) -> Self{
+        Self {
+            input:input.chars().collect(),
+            position: 0,
+            line: 1,
+            column: 1,
+        }
+    }
+    pub fn tokenize(&mut self) -> Vec<Token> {
+        let mut tokens: Vec<Token> = Vec::new();
+        while let Some(ch) = self.current_char() {
+            match ch {
+                ' ' | '\t' => {
+                    self.advance();
+                }
+
+                '\n' => {
+                    self.advance_line();
+                }
+                'A'..='Z' | 'a'..='z' | '_' => {
+                    tokens.push(self.read_identifier(ch));
+                }
+                '0' ..= '9' => {
+                    tokens.push(self.read_number(ch));
+                }
+                '=' => {
+                    tokens.push(self.assign_or_equals());
+                }
+                ':' => {
+                    tokens.push(self.simple_token(TokenType::Colon));
+                }
+                '+' => {
+                    tokens.push(self.simple_token(TokenType::Plus));
+                }
+                '-' => {
+                    tokens.push(self.minus_or_arrow());
+                }
+                '*' => {
+                    tokens.push(self.simple_token(TokenType::Multiply));
+                }
+                '{' => {
+                    tokens.push(self.simple_token(TokenType::LeftBrace));
+                }
+                '}' => {
+                    tokens.push(self.simple_token(TokenType::RightBrace));
+                }
+                '(' => {
+                    tokens.push(self.simple_token(TokenType::LeftParen));
+                }
+                ')' => {
+                    tokens.push(self.simple_token(TokenType::RightParen));
+                }
+                '>' =>{
+                    tokens.push(self.simple_token(TokenType::GreaterThan));
+                }
+                '<' =>{
+                    tokens.push(self.simple_token(TokenType::LessThan));
+                }
+                ';' =>{
+                    tokens.push(self.simple_token(TokenType::Semicolon));                    
+                }
+                '"' => {
+                    tokens.push(self.read_string_literal());
+                }
+                ',' => {
+                    tokens.push(self.simple_token(TokenType::Comma));
+                }
+                '#' => {
+                    self.read_comment();
+                }
+                _ => panic!("Suuuper wrongdog in here, unexpected char '{}' at {}:{}", ch, self.line, self.column),
+            }
+        }
+        tokens
+    }
+    fn current_char(&self) -> Option<char> {
+        self.input.get(self.position).copied()
+    }
+
+    fn advance(&mut self) {
+        self.position += 1;
+        self.column += 1;
+    }
+
+    fn advance_line(&mut self) {
+        self.position += 1;
+        self.line += 1;
+        self.column = 1;
+    }
+
+    fn simple_token(&mut self, token_type: TokenType) -> Token {
+        let start_col_num = self.column;
+        self.advance();
+        Token::new(token_type, self.line, start_col_num)
+        
+    }
+    fn assign_or_equals(&mut self) -> Token{
+        let original_col = self.column;
+        self.advance();
+        if self.current_char().unwrap() == '=' {
+            Token::new(TokenType::Equals, self.line, original_col)
+        } else {
+            Token::new(TokenType::Assign, self.line, original_col)
+        }
+    }
+    fn minus_or_arrow(&mut self) -> Token {
+        let original_col = self.column;
+        self.advance();
+        if self.current_char().unwrap() == '>' {
+            Token::new(TokenType::Arrow, self.line, original_col)
+        } else {
+            Token::new(TokenType::Minus, self.line, original_col)
+        }
+    }
+    fn read_comment(&mut self) {
+        while let Some(ch) = self.current_char(){
+            match ch{
+                '\n' => {
+                    break;
+                }
+                _ => {
+                    self.advance();
+                }
+            }
+        }
+    }
+    fn read_number(&mut self, first_ch: char) -> Token {
+        let mut num_string: String = "".to_string();
+        let start_col_num :usize= self.column;
+        num_string.push(first_ch);
+        self.advance();
+        while let Some(ch) = self.current_char() {
+            match ch {
+                '0'..='9' =>{
+                    num_string.push(ch);
+                    self.advance();
+                }
+                _ => {
+                    break;
+                }
+            }
+        }
+        let num = num_string.parse::<i64>().unwrap();
+        Token::new(TokenType::IntegerLiteral(num), self.line, start_col_num)
+    }
+
+    fn read_string_literal(&mut self) -> Token{
+        let mut the_litteral: String = "".to_string();
+        let start_col_num: usize = self.column;
+        the_litteral.push('"');
+        self.advance();
+        while let Some(ch) = self.current_char(){
+            match ch {
+                '"' => {
+                    the_litteral.push(ch);
+                    self.advance();
+                    break;
+                }
+                _ => {
+                    the_litteral.push(ch);
+                    self.advance();
+                }
+            }
+        }
+        Token::new(TokenType::StringLiteral(the_litteral), self.line, start_col_num)
+    }
+
+    fn read_identifier(&mut self, first_ch: char) -> Token {
+        let mut name:String  = "".to_string();
+        let start_col_num: usize = self.column;
+        name.push(first_ch);
+        self.advance();
+        while let Some(ch) = self.current_char() {
+            match ch {
+                'A'..='Z' | 'a'..='z' | '_' => {
+                    name.push(ch);
+                    self.advance();
+                }
+                _ => {
+                    break;
+                }
+            }
+        }
+        self.give_keyword_or_literal_token(name.as_mut_str(), self.line, start_col_num)
+    }
+    fn give_keyword_or_literal_token(&mut self, name: &str, line: usize, col: usize) -> Token{
+        match name {
+            "let"    => Token::new(TokenType::Let, line, col),
+            "func"   => Token::new(TokenType::Func, line, col),
+            "if"     => Token::new(TokenType::If, line, col),
+            "then"   => Token::new(TokenType::Then, line, col),
+            "else"   => Token::new(TokenType::Else, line, col),
+            "not"    => Token::new(TokenType::Not, line, col),
+            "while"  => Token::new(TokenType::While, line, col),
+            "print"  => Token::new(TokenType::Print, line, col),
+            "do"     => Token::new(TokenType::Do, line, col),
+            "is"     => Token::new(TokenType::Is, line, col),
+            "Integer"=> Token::new(TokenType::Integer, line, col),
+            "Boolean"=> Token::new(TokenType::Boolean, line, col),
+            "True"   => Token::new(TokenType::True, line, col),
+            "False"  => Token::new(TokenType::False, line, col),
+            "Eof"    => Token::new(TokenType::Eof, line, col),
+            _        => Token::new(TokenType::Identifier(name.to_string()), line, col),
+        }
+    }
+}
+impl PartialEq for Lexer {
+    fn eq(&self, other: &Self) -> bool {
+        self.input == other.input &&
+        self.position == other.position &&
+        self.column == other.column &&
+        self.line == other.line
+    }
+}
+mod tests{
+    use crate::lexer::{lexer::Lexer, token::{Token, TokenType}};
+    #[test]
+    fn new_creates_lexer_correctly(){
+        let actual = Lexer::new("a = 2".to_string());
+
+        let expected = Lexer {
+            input: vec!['a', ' ', '=', ' ', '2'],
+            position: 0,
+            line: 1,
+            column: 1,
+        };
+
+        assert_eq!(actual, expected);
+    }
+    #[test]
+    fn tokenize_works_as_intended(){
+        let mut lex: Lexer = Lexer::new("abc_def = 2".to_string()); 
+        let actual_token_vec: Vec<Token> = lex.tokenize();
+
+        let expected: Vec<Token> = vec![
+            Token::new(TokenType::Identifier("abc_def".to_string()), 1, 1), 
+            Token::new(TokenType::Assign, 1, 9), 
+            Token::new(TokenType::IntegerLiteral(2), 1, 11),
+        ];
+
+        assert_eq!(actual_token_vec, expected);
+    }
+    #[test]
+    fn reading_comments_tokenize_lexer_line_col_are_correct(){
+        let mut lex: Lexer = Lexer::new("#abc_def = 2\n".to_string()); 
+        lex.tokenize();
+        assert_eq!((lex.line, lex.column), (2,1));
+    }
+    #[test]
+    fn reading_comments_tokenize_returns_empty_vector(){
+        let mut lex: Lexer = Lexer::new("#abc_def = 2\n".to_string()); 
+        let actual_token_vec: Vec<Token> = lex.tokenize();
+
+        let expected: Vec<Token> = vec![];
+
+        assert_eq!(actual_token_vec, expected);
+    }
+    #[test]
+    fn read_string_literal_makes_correct_token(){
+        let mut lex: Lexer = Lexer::new("\"test\"".to_string()); 
+        let actual_token_vec: Vec<Token> = lex.tokenize();
+
+        let expected: Vec<Token> = vec![
+            Token::new(TokenType::StringLiteral("\"test\"".to_string()), 1, 1)
+        ];
+
+        assert_eq!(actual_token_vec, expected);
+    }
+}
\ No newline at end of file
diff --git a/src/lexer/mod.rs b/src/lexer/mod.rs
new file mode 100644
index 0000000..325f721
--- /dev/null
+++ b/src/lexer/mod.rs
@@ -0,0 +1,2 @@
+pub mod token;
+pub mod lexer;
\ No newline at end of file
diff --git a/src/lexer/token.rs b/src/lexer/token.rs
new file mode 100644
index 0000000..d3c7e0a
--- /dev/null
+++ b/src/lexer/token.rs
@@ -0,0 +1,73 @@
+#[derive(Debug, Clone, PartialEq)]
+pub enum TokenType {
+    // Keywords
+    Func,
+    Let,
+    If,
+    Then,
+    Else,
+    Not,
+    While,
+    Print,
+    Do,
+    Is,
+
+    // Types
+    Integer,
+    Boolean,
+
+    // Literals
+    True,
+    False,
+    IntegerLiteral(i64),
+    StringLiteral(String),
+
+    // Identifiers
+    Identifier(String),
+
+    // Operators
+    Colon,       // :
+    Arrow,       // ->
+    Assign,      // =
+    GreaterThan, // >
+    LessThan, // <
+    Equals,      // ==
+    Plus,        // +
+    Minus,       // -
+    Multiply,    // *
+
+    // Punctuation
+    LeftParen,  // (
+    RightParen, // )
+    LeftBrace,  // {
+    RightBrace, // }
+    Comma,      // ,
+    Semicolon,  // ;
+
+    // Special
+    Eof,
+}
+
+#[derive(Debug, Clone)]
+pub struct Token {
+    pub token_type: TokenType,
+    pub line: usize,
+    pub column: usize,
+}
+
+impl Token {
+    pub fn new(token_type: TokenType, line: usize, column: usize) -> Self {
+        Token {
+            token_type,
+            line,
+            column,
+        }
+    }
+}
+impl PartialEq for Token {
+    fn eq(&self, other: &Self) -> bool {
+        self.token_type == other.token_type &&
+        self.line == other.line &&
+        self.column == other.column
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index c97fc64..ef90e80 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,27 @@
+mod lexer;
+
+use std::env;
+use std::fs;
+
+use lexer::lexer::Lexer; // adjust if needed
+
 fn main() {
-    println!("Hello, world!");
+    let args: Vec<String> = env::args().collect();
+
+    if args.len() < 3 {
+        eprintln!("Usage: triviC <filename>");
+        std::process::exit(1);
+    }
+
+    let filename = &args[2];
+
+    let source = fs::read_to_string(filename)
+        .expect("Failed to read file");
+
+    let mut lexer = Lexer::new(source);
+    let _tokens = lexer.tokenize();
+
+    println!("Lexing completed successfully.");
 }
 
 #[cfg(test)]
diff --git a/src/semantic/mod.rs b/src/semantic/mod.rs
new file mode 100644
index 0000000..3533058
--- /dev/null
+++ b/src/semantic/mod.rs
@@ -0,0 +1,2 @@
+pub mod Type;
+pub mod SymbolTable;
\ No newline at end of file
diff --git a/src/semantic/symbol_table.rs b/src/semantic/symbol_table.rs
new file mode 100644
index 0000000..815f864
--- /dev/null
+++ b/src/semantic/symbol_table.rs
@@ -0,0 +1,11 @@
+use std::collections::HashMap;
+pub struct Symbol {
+    symbol_type: Type,
+    scope_level: usize,
+    //perchance we need to add some more info, for functions (return types, param names)
+}
+
+pub struct SymbolTable {
+    scopes: Vec<HashMap<String, Symbol>>, 
+    //key = name i figured, so no "name" property in Symbol struct
+}
\ No newline at end of file
diff --git a/src/semantic/types.rs b/src/semantic/types.rs
new file mode 100644
index 0000000..da7232b
--- /dev/null
+++ b/src/semantic/types.rs
@@ -0,0 +1,5 @@
+#[derive(Debug, Clone, PartialEq)]
+pub enum Type {
+    Integer,
+    Boolean,
+}