Basic parsing framework

src/main.rs

@@ -11,7 +11,7 @@ use simplerepl::{REPL, ReplState};
 use tokenizer::tokenize;
 mod tokenizer;
 
-use parser::parse;
+use parser::{parse, ParseResult};
 mod parser;
 
 fn main() {
@@ -64,10 +64,14 @@ fn repl_handler(input: &str, state: &mut InterpreterState) -> String {
         println!("Tokens: {:?}", tokens);
     }
 
+    let ast = match parse(&tokens, &[]) {
+        Ok(ast) => ast,
+        Err(err) => return err.msg
+    };
+
     if state.show_parse {
-        println!("not implemented")
+        println!("AST: {:?}", ast);
     }
 
-    let ast = parse(&tokens);
-    format!("{:?}", tokens)
+    format!("{:?}", ast)
 }

src/parser.rs

@@ -1,11 +1,52 @@
 use tokenizer::Token;
 
+#[derive(Debug, Clone)]
+pub enum ASTNode {
+    ExprNode(Expression),
+    FuncNode(Function),
+}
+
+#[derive(Debug, Clone)]
+pub struct Function {
+    pub prototype: Prototype,
+    pub body: Expression
+}
+
+#[derive(Debug, Clone)]
+pub struct Prototype {
+    pub name: String,
+    pub args: Vec<String>
+}
+
+#[derive(Debug, Clone)]
+pub enum Expression {
+    Literal(f64),
+    Variable(String),
+    BinExp(String, Box<Expression>, Box<Expression>),
+    Call(String, Vec<Expression>),
+}
+
+pub type AST = Vec<ASTNode>;
+
+//TODO make this support incomplete parses
+pub type ParseResult<T> = Result<T, ParseError>;
+
 #[derive(Debug)]
-pub struct ParseResult {
-    msg: i32
+pub struct ParseError {
+    pub msg: String
 }
 
-pub fn parse(tokens: &[Token]) -> ParseResult {
-
-    ParseResult { msg: 0 }
+impl ParseError {
+    fn new<T>(msg: &str) -> ParseResult<T> {
+        Err(ParseError { msg: msg.to_string() })
+    }
 }
+
+pub fn parse(tokens: &[Token], parsed_tree: &[ASTNode]) -> ParseResult<AST> {
+
+    let rest = tokens.to_vec().reverse();
+    let mut ast = parsed_tree.to_vec();
+
+    ParseError::new("Parsing not implemented")
+}
+