building parser

hello-world.fddl

@@ -1,3 +1,3 @@
 func main() {
-	print(`hello, world in fddl`);
+	print("hello, world in fddl");
 }

hello.fddl

@@ -0,0 +1,5 @@
+!test
+
+func main() {
+	print("Hello World");
+}

readme.md

@@ -27,11 +27,20 @@ To start experimenting with fddl, you can run it in two ways:
 cargo run
 ```
 
-### Run a fddl Script
+### Parse a fddl Script
 ```sh
 cargo run path/to/script.fddl
 ```
 
+## Running the Project
+
+Make sure your project compiles and the tests pass:
+
+```bash
+cargo build
+cargo test
+```
+
 ---
 
 ## Examples
@@ -77,7 +86,7 @@ fddl is very much a work in progress, with lots of planned improvements and addi
   - [ ] Currently a placeholder. Implement parsing for function calls, expressions, etc.
 
 - **Compiler**: 
-  - [ ] Currently a placeholder. Implement the compiler to execute parsed code.
+  - [ ] Currently a placeholder. Implement the compiler to compile parsed code.
 
 - **Comments**:
   - [x] Added support for single-line and documentation comments.
@@ -85,26 +94,14 @@ fddl is very much a work in progress, with lots of planned improvements and addi
   - [ ] Implement document building comments.
 
 - **Error Handling**: 
-  - [ ] Replace basic error reporting with a more robust error handling mechanism.
+  - [ ] Replace `stderr` with a more robust error handling mechanism.
-
-- **String Interpolation**: 
-  - [ ] Implement string interpolation using backticks with `$variable` syntax.
 
 - **Testing**: 
-  - [x] Added initial lexer tests. 
+  - [x] Added initial `lexer` tests. 
   - [ ] Expand tests to cover more syntax and edge cases.
 
 ---
 
-## Running the Project
-
-Make sure your project compiles and the tests pass:
-
-```bash
-cargo build
-cargo test
-```
-
 ## License
 
 This project is licensed under the MIT License.

src/lexer/lexer.rs

@@ -23,7 +23,12 @@ impl Lexer {
         while !self.is_at_end() {
             self.start = self.current;
             if let Some(token) = self.scan_token() {
-                tokens.push(token);
+                if matches!(token, Token::Error(_)) {
+                    tokens.push(token);
+                    break;
+                } else {
+                    tokens.push(token);
+                }
             }
         }
 
@@ -71,7 +76,7 @@ impl Lexer {
                 if self.match_char('=') {
                     Some(Token::BangEqual)
                 } else {
-                    None // Or handle as an error or another token if needed
+                    Some(Token::Error(format!("Unexpected character '{}'", c)))
                 }
             },
             '=' => {
@@ -111,7 +116,7 @@ impl Lexer {
             // Any other character
             _ => {
                 eprintln!("Unexpected character '{}' on line {}", c, self.line);
-                None
+                Some(Token::Error(format!("Unexpected character '{}'", c)))
             }
         }
     }
@@ -238,6 +243,8 @@ impl Lexer {
             "print" => Token::Print,
             "pub" => Token::Pub,
             "sym" => Token::Sym,
+            "module" => Token::Module,
+            "import" => Token::Import,
             _ => Token::Identifier(text),
         };
 

src/lexer/token.rs

@@ -43,9 +43,14 @@ pub enum Token {
     Print,
     Pub,
     Sym,
+    Module,
+    Import,
 
     // Comments
     Comment(String),
 
+    // Errors
+    Error(String),
+
     EOF,
 }

src/parser/ast.rs

@@ -1,9 +1,47 @@
-// placeholder for ast defintions
-
 pub enum Expression {
-    // Define expression types
+    Literal(Literal),
+    Variable(String),
+    Binary(Box<Expression>, Operator, Box<Expression>),
+    Unary(Operator, Box<Expression>),
+    Grouping(Box<Expression>),
+    Assignment(String, Box<Expression>),
+    FunctionCall(Box<Expression>, Vec<Expression>),
+}
+
+pub enum Literal {
+    Number(f64),
+    String(String),
+    Boolean(bool),
+    Nil,
+}
+
+pub enum Operator {
+    Plus,
+    Minux,
+    Multiply,
+    Divide,
+    Greater,
+    Less,
+    GreaterEqual,
+    LessEqual,
+    EqualEqual,
+    NotEqual,
+    AlmostEqual,
+    Almost,
 }
 
 pub enum Statement {
-    // Define statement types
+    ExpressionStatement(Expression),
+    PrintStatement(Expression),
+    VariableDeclaration(String, Option<Expression>),
+    Block(Vec<Statement>),
+    IfStatement(Expression, Box<Statement>, Option<Box<Statement>>),
+    WhileStatement(Expression, Box<Statement>),
+    ForStatement(Box<Statement>, Expression, Box<Statement>, Box<Statement>),
+    FunctionDeclaration {
+        name: String,
+        params: Vec<String>,
+        body: Vec<Statement>,
+    },
+    ReturnStatement(Option<Expression>),
 }

src/parser/parser.rs

@@ -0,0 +1,66 @@
+use crate::lexer::token::Token;
+
+pub struct Parser {
+    tokens: Vec<Token>,
+    current: usize,
+}
+
+impl Parser {
+    fn parse_statement(&mut self) -> Option<Statement> {
+        if self.match_token(Token::Print) {
+            self.parse_print_statement()
+        }
+    }
+
+
+    pub fn new(tokens: Vec<Token>) -> Self {
+        Parser {
+            tokens,
+            current: 0,
+        }
+    }
+
+    fn current_token(&self) -> &Token {
+        &self.tokens[self.current]
+    }
+
+    fn peek(&self) -> &Token {
+        &self.tokens[self.current + 1]
+    }
+
+    fn is_at_end(&self) -> bool {
+        matches!(self.current_token(), Token::EOF)
+    }
+
+    fn advance(&mut self) -> &Token {
+        if !self.is_at_end() {
+            self.current += 1;
+        }
+        self.current_token()
+    }
+
+    fn match_token(&mut self, expected: Token) -> bool {
+        if self.current_token() == &expected {
+            self.advance();
+            true
+        } else {
+            false
+        }
+    }
+
+    fn previous_token(&self) -> &Token {
+        &self.tokens[self.current - 1]
+    }
+}
+
+fn main() {
+    let source = String::from("let x = 10;");
+    let mut lexer = Lexer::new(source);
+    let tokens = lexer.scan_tokens();
+    let mut parser = Parser::new(tokens);
+
+    while !parser.is_at_end() {
+        println!("{:?}", parser.current_token());
+        parser.advance();
+    }
+}