Starting to do if statement parsing
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169e662049
commit
edf100b583
@ -11,7 +11,8 @@ pub enum AST {
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Number(f64),
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BinOp(Box<AST>, Box<AST>, Box<AST>),
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Binding(String, Box<AST>),
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Statements(Vec<AST>)
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Statements(Vec<AST>),
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IfStatement(Box<AST>, Box<AST>, Option<Box<AST>>)
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}
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pub enum ParseResult {
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@ -120,9 +121,28 @@ fn let_expression(input: &mut Tokens) -> ParseResult {
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}
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fn expression(input: &mut Tokens) -> ParseResult {
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ParseResult::Err("dame".to_string())
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let lookahead = input.peek().map(|i| i.clone());
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println!("{:?}", lookahead);
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match lookahead {
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Some(&Keyword(Kw::If)) => {
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input.next();
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ParseResult::Ok( AST::IfStatement(
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Box::new(AST::Number(1.0)),
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Box::new(AST::Number(2.0)),
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None))
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},
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_ => ParseResult::Err("error in expression()".to_string())
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}
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}
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/*
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fn if_expression(input: &mut Tokens) -> ParseResult {
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}
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*/
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fn rhs(input: &mut Tokens) -> ParseResult {
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let next = input.next();
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if let Some(&Identifier(ref value)) = next {
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@ -92,9 +92,9 @@ pub fn tokenize(input: &str) -> Vec<Token> {
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}
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fn handle_identifier(identifier: String) -> Token {
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if identifier == "let" {
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return Token::Keyword(Kw::Let);
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match &identifier[..] {
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"let" => Token::Keyword(Kw::Let),
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"if" => Token::Keyword(Kw::If),
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_ => Token::Identifier(identifier)
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}
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return Token::Identifier(identifier);
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}
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