basic if expression
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0e4469fa58
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@ -122,26 +122,36 @@ fn let_expression(input: &mut Tokens) -> ParseResult {
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fn expression(input: &mut Tokens) -> ParseResult {
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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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if_expression(input)
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},
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_ => ParseResult::Err("error in expression()".to_string())
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_ => rhs(input)
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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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expect!(Keyword(Kw::If), input);
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let if_clause = match expression(input) {
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err@ParseResult::Err(_) => return err,
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ParseResult::Ok(ast) => ast
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};
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expect!(Keyword(Kw::Then), input);
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let then_clause = match expression(input) {
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err@ParseResult::Err(_) => return err,
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ParseResult::Ok(ast) => ast
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};
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expect!(Keyword(Kw::End), input);
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ParseResult::Ok( AST::IfStatement(
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Box::new(if_clause),
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Box::new(then_clause),
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None))
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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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