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Start adding support for dotted expressions

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This commit is contained in:
jonathandturner
2016-03-07 15:39:02 -05:00
parent fbf81ff651
commit 72c23ad7ca
2 changed files with 196 additions and 102 deletions
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36
src/parser.rs
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@@ -43,7 +43,6 @@ pub enum ParseError {
MissingRCurly,
MalformedCallExpr,
VarExpectsIdentifier,
ExpectedMethodInvocation,
FnMissingName,
FnMissingParams
}
@@ -59,7 +58,6 @@ impl Error for ParseError {
ParseError::MissingRCurly => "Expected '}'",
ParseError::MalformedCallExpr => "Call contains bad expression",
ParseError::VarExpectsIdentifier => "'var' expects the name of a variable",
ParseError::ExpectedMethodInvocation => "Expected method call after '.'",
ParseError::FnMissingName => "Function declaration is missing name",
ParseError::FnMissingParams => "Function declaration is missing parameters"
}
@@ -89,7 +87,7 @@ pub enum Stmt { If(Box<Expr>, Box<Stmt>), IfElse(Box<Expr>, Box<Stmt>, Box<Stmt>
#[derive(Debug, Clone)]
pub enum Expr { IntConst(i32), Identifier(String), StringConst(String), FnCall(String, Box<Vec<Expr>>),
MethodCall(String, String, Box<Vec<Expr>>), Assignment(Box<Expr>, Box<Expr>), True, False }
Assignment(Box<Expr>, Box<Expr>), Dot(Box<Expr>, Box<Expr>), True, False }
#[derive(Debug)]
pub enum Token { IntConst(i32), Identifier(String), StringConst(String), LCurly, RCurly, LParen, RParen, LSquare, RSquare,
@@ -343,6 +341,7 @@ fn get_precedence(token: &Token) -> i32 {
Token::Minus => 20,
Token::Divide => 40,
Token::Multiply => 40,
Token::Period => 100,
_ => -1
}
}
@@ -357,18 +356,6 @@ fn parse_paren_expr<'a>(input: &mut Peekable<TokenIterator<'a>>) -> Result<Expr,
}
fn parse_ident_expr<'a>(id: String, input: &mut Peekable<TokenIterator<'a>>) -> Result<Expr, ParseError> {
let id2 = match input.peek() {
Some(&Token::Period) => {
input.next();
match input.next() {
Some(Token::Identifier(ref s)) => {
s.clone()
}
_ => return Err(ParseError::ExpectedMethodInvocation)
}
},
_ => String::new()
};
match input.peek() {
Some(&Token::LParen) => {input.next();},
_ => return Ok(Expr::Identifier(id))
@@ -379,12 +366,7 @@ fn parse_ident_expr<'a>(id: String, input: &mut Peekable<TokenIterator<'a>>) ->
match input.peek() {
Some(&Token::RParen) => {
input.next();
if id2 == "" {
return Ok(Expr::FnCall(id, Box::new(args)))
}
else {
return Ok(Expr::MethodCall(id, id2, Box::new(args)))
}
return Ok(Expr::FnCall(id, Box::new(args)))
},
_ => ()
}
@@ -400,12 +382,7 @@ fn parse_ident_expr<'a>(id: String, input: &mut Peekable<TokenIterator<'a>>) ->
match input.peek() {
Some(&Token::RParen) => {
input.next();
if id2 == "" {
return Ok(Expr::FnCall(id, Box::new(args)))
}
else {
return Ok(Expr::MethodCall(id, id2, Box::new(args)))
}
return Ok(Expr::FnCall(id, Box::new(args)))
},
Some(&Token::Comma) => (),
_ => return Err(ParseError::MalformedCallExpr)
@@ -459,6 +436,10 @@ fn parse_binop<'a>(input: &mut Peekable<TokenIterator<'a>>, prec: i32, lhs: Expr
if curr_prec < next_prec {
rhs = try!(parse_binop(input, curr_prec+1, rhs));
}
else if curr_prec >= 100 {
//Always bind right to left for precedence over 100
rhs = try!(parse_binop(input, curr_prec, rhs));
}
lhs_curr = match op_token {
Token::Plus => Expr::FnCall("+".to_string(), Box::new(vec![lhs_curr, rhs])),
@@ -466,6 +447,7 @@ fn parse_binop<'a>(input: &mut Peekable<TokenIterator<'a>>, prec: i32, lhs: Expr
Token::Multiply => Expr::FnCall("*".to_string(), Box::new(vec![lhs_curr, rhs])),
Token::Divide => Expr::FnCall("/".to_string(), Box::new(vec![lhs_curr, rhs])),
Token::Equals => Expr::Assignment(Box::new(lhs_curr), Box::new(rhs)),
Token::Period => Expr::Dot(Box::new(lhs_curr), Box::new(rhs)),
Token::EqualTo => Expr::FnCall("==".to_string(), Box::new(vec![lhs_curr, rhs])),
Token::NotEqualTo => Expr::FnCall("!=".to_string(), Box::new(vec![lhs_curr, rhs])),
Token::LessThan => Expr::FnCall("<".to_string(), Box::new(vec![lhs_curr, rhs])),