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Fill out support for operators

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jonathandturner
2016-03-01 09:40:48 -05:00
parent 02935fd8cf
commit 419781cfb6
5 changed files with 331 additions and 439 deletions
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68
src/parser.rs
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@@ -46,13 +46,12 @@ pub enum Stmt { If(Box<Expr>, Box<Stmt>), While(Box<Expr>, Box<Stmt>), Var(Strin
Block(Box<Vec<Stmt>>), Expr(Box<Expr>) }
#[derive(Debug)]
pub enum Expr { IntConst(i32), Identifier(String), Plus(Box<Expr>, Box<Expr>), Minus(Box<Expr>, Box<Expr>),
Multiply(Box<Expr>, Box<Expr>), Divide(Box<Expr>, Box<Expr>), Call(String, Box<Vec<Expr>>),
Assignment(Box<Expr>, Box<Expr>), True, False }
pub enum Expr { IntConst(i32), Identifier(String), Call(String, Box<Vec<Expr>>), Assignment(Box<Expr>, Box<Expr>), True, False }
#[derive(Debug)]
pub enum Token { Int(i32), Id(String), LCurly, RCurly, LParen, RParen, LSquare, RSquare,
Plus, Minus, Multiply, Divide, Semicolon, Colon, Comma, Equals, True, False, Var, If, While }
Plus, Minus, Multiply, Divide, Semicolon, Colon, Comma, Equals, True, False, Var, If, While,
LessThan, GreaterThan, Bang, LessThanEqual, GreaterThanEqual, EqualTo, NotEqualTo, Pipe, Or, Ampersand, And }
pub struct TokenIterator<'a> {
char_stream: Peekable<Chars<'a>>
@@ -128,7 +127,42 @@ impl<'a> Iterator for TokenIterator<'a> {
';' => { return Some(Token::Semicolon); },
':' => { return Some(Token::Colon); },
',' => { return Some(Token::Comma); },
'=' => { return Some(Token::Equals); },
'=' => {
match self.char_stream.peek() {
Some(&'=') => {self.char_stream.next(); return Some(Token::EqualTo); },
_ => { return Some(Token::Equals); }
}
},
'<' => {
match self.char_stream.peek() {
Some(&'=') => {self.char_stream.next(); return Some(Token::LessThanEqual); },
_ => { return Some(Token::LessThan); }
}
}
'>' => {
match self.char_stream.peek() {
Some(&'=') => {self.char_stream.next(); return Some(Token::GreaterThanEqual); },
_ => { return Some(Token::GreaterThan); }
}
},
'!' => {
match self.char_stream.peek() {
Some(&'=') => {self.char_stream.next(); return Some(Token::NotEqualTo); },
_ => { return Some(Token::Bang); }
}
},
'|' => {
match self.char_stream.peek() {
Some(&'|') => {self.char_stream.next(); return Some(Token::Or); },
_ => { return Some(Token::Pipe); }
}
},
'&' => {
match self.char_stream.peek() {
Some(&'&') => {self.char_stream.next(); return Some(Token::And); },
_ => { return Some(Token::Ampersand); }
}
},
' ' | '\n' | '\r' => (),
_ => return None
}
@@ -145,6 +179,14 @@ pub fn lex<'a>(input: &'a String) -> TokenIterator<'a> {
fn get_precedence(token: &Token) -> i32 {
match *token {
Token::Equals => 10,
Token::Or => 11,
Token::And => 12,
Token::LessThan => 15,
Token::LessThanEqual => 15,
Token::GreaterThan => 15,
Token::GreaterThanEqual => 15,
Token::EqualTo => 15,
Token::NotEqualTo => 15,
Token::Plus => 20,
Token::Minus => 20,
Token::Multiply => 40,
@@ -238,11 +280,19 @@ fn parse_binop<'a>(input: &mut Peekable<TokenIterator<'a>>, prec: i32, lhs: Expr
}
lhs_curr = match op_token {
Token::Plus => Expr::Plus(Box::new(lhs_curr), Box::new(rhs)),
Token::Minus => Expr::Minus(Box::new(lhs_curr), Box::new(rhs)),
Token::Multiply => Expr::Multiply(Box::new(lhs_curr), Box::new(rhs)),
Token::Divide => Expr::Divide(Box::new(lhs_curr), Box::new(rhs)),
Token::Plus => Expr::Call("+".to_string(), Box::new(vec![lhs_curr, rhs])),
Token::Minus => Expr::Call("-".to_string(), Box::new(vec![lhs_curr, rhs])),
Token::Multiply => Expr::Call("*".to_string(), Box::new(vec![lhs_curr, rhs])),
Token::Divide => Expr::Call("/".to_string(), Box::new(vec![lhs_curr, rhs])),
Token::Equals => Expr::Assignment(Box::new(lhs_curr), Box::new(rhs)),
Token::EqualTo => Expr::Call("==".to_string(), Box::new(vec![lhs_curr, rhs])),
Token::NotEqualTo => Expr::Call("!=".to_string(), Box::new(vec![lhs_curr, rhs])),
Token::LessThan => Expr::Call("<".to_string(), Box::new(vec![lhs_curr, rhs])),
Token::LessThanEqual => Expr::Call("<=".to_string(), Box::new(vec![lhs_curr, rhs])),
Token::GreaterThan => Expr::Call(">".to_string(), Box::new(vec![lhs_curr, rhs])),
Token::GreaterThanEqual => Expr::Call(">=".to_string(), Box::new(vec![lhs_curr, rhs])),
Token::Or => Expr::Call("||".to_string(), Box::new(vec![lhs_curr, rhs])),
Token::And => Expr::Call("&&".to_string(), Box::new(vec![lhs_curr, rhs])),
_ => return Err(ParseError::UnknownOperator)
};
}