Parsing statement blocks works

This commit is contained in:
greg 2015-07-24 02:05:15 -07:00
parent bfa16fd6fb
commit 329c521964

View File

@ -10,7 +10,8 @@ pub enum AST {
LangString(String),
Number(f64),
BinOp(Box<AST>, Box<AST>, Box<AST>),
Binding(String, Box<AST>)
Binding(String, Box<AST>),
Statements(Vec<AST>)
}
pub enum ParseResult {
@ -51,14 +52,48 @@ pub fn parse(input: Vec<Token>) -> ParseResult {
let mut tokens: Tokens = input.iter().peekable();
if let ParseResult::Ok(ast) = let_expression(&mut tokens) {
expect!(EOF, &mut tokens);
return ParseResult::Ok(ast);
match statements(&mut tokens) {
ok@ParseResult::Ok(_) => {
expect!(EOF, &mut tokens);
ok
},
err@ParseResult::Err(_) => err
}
return ParseResult::Err("Bad parse".to_string());
}
fn statements(input: &mut Tokens) -> ParseResult {
let mut statements = Vec::new();
let initial_statement = statement(input);
match initial_statement {
ParseResult::Ok(ast) => {
statements.push(ast);
loop {
let lookahead = input.peek().map(|i| i.clone());
if let Some(&Separator) = lookahead {
input.next();
if let ParseResult::Ok(ast_next) = statement(input) {
statements.push(ast_next);
} else {
return ParseResult::Err("bad thing happened".to_string());
}
} else {
break;
}
}
},
err@ParseResult::Err(_) => {
return err;
}
}
return ParseResult::Ok(AST::Statements(statements));
}
fn statement(input: &mut Tokens) -> ParseResult {
let_expression(input)
}
fn let_expression(input: &mut Tokens) -> ParseResult {
expect!(Keyword(Kw::Let), input);
@ -84,5 +119,5 @@ fn let_expression(input: &mut Tokens) -> ParseResult {
}
}
return ParseResult::Err("Bad parse".to_string());
return ParseResult::Err("Bad parse in let_expression()".to_string());
}