Fix struct literals in if expressions

With special case-ing, sigh :( Also will need to do this for match
expressions but I'll cross that bridge when I come to it
This commit is contained in:
greg 2018-02-11 22:10:21 -08:00
parent 4d0bfa2a52
commit f7e88c7cab
1 changed files with 43 additions and 12 deletions

View File

@ -284,12 +284,10 @@ type_names := ε | type_name (, type_name)*
type_params := '<' type_name (, type_name)* '>'
expression := precedence_expr type_anno+
precedence_expr := prefix_expr
prefix_expr := prefix_op primary
prefix_op := '+' | '-' | '!' | '~'
primary := literal | paren_expr | if_expr | match_expr | for_expr | identifier_expr
paren_expr := LParen paren_inner RParen
paren_inner := (expression ',')*
identifier_expr := named_struct | call_expr | index_expr | IDENTIFIER
@ -348,12 +346,22 @@ pub struct ParseRecord {
struct Parser {
tokens: TokenIter,
parse_record: Vec<ParseRecord>,
parse_level: u32
parse_level: u32,
restrictions: ParserRestrictions,
}
struct ParserRestrictions {
no_struct_literal: bool
}
impl Parser {
fn new(input: Vec<Token>) -> Parser {
Parser { tokens: input.into_iter().peekable(), parse_record: vec![], parse_level: 0 }
Parser {
tokens: input.into_iter().peekable(),
parse_record: vec![],
parse_level: 0,
restrictions: ParserRestrictions { no_struct_literal: false }
}
}
fn peek(&mut self) -> TokenType {
@ -812,19 +820,25 @@ impl Parser {
parse_method!(paren_expr(&mut self) -> ParseResult<Expression> {
use self::ExpressionType::*;
let mut inner = delimited!(self, LParen, '(', expression, Comma, RParen, ')');
match inner.len() {
0 => Ok(Expression(TupleLiteral(vec![]), None)),
1 => Ok(inner.pop().unwrap()),
_ => Ok(Expression(TupleLiteral(inner), None)),
}
let old_struct_value = self.restrictions.no_struct_literal;
self.restrictions.no_struct_literal = false;
let output = (|| {
let mut inner = delimited!(self, LParen, '(', expression, Comma, RParen, ')');
match inner.len() {
0 => Ok(Expression(TupleLiteral(vec![]), None)),
1 => Ok(inner.pop().unwrap()),
_ => Ok(Expression(TupleLiteral(inner), None)),
}
})();
self.restrictions.no_struct_literal = old_struct_value;
output
});
parse_method!(identifier_expr(&mut self) -> ParseResult<Expression> {
use self::ExpressionType::*;
let identifier = self.identifier()?;
Ok(match self.peek() {
LCurlyBrace => {
LCurlyBrace if !self.restrictions.no_struct_literal => {
let fields = self.record_block()?;
Expression(Value(identifier, fields), None)
},
@ -866,7 +880,12 @@ impl Parser {
parse_method!(if_expr(&mut self) -> ParseResult<Expression> {
expect!(self, Keyword(Kw::If), "'if'");
let condition = self.expression()?;
let condition = (|| {
self.restrictions.no_struct_literal = true;
let x = self.expression();
self.restrictions.no_struct_literal = false;
x
})()?;
let then_clause = self.block()?;
let else_clause = self.else_clause()?;
Ok(Expression(ExpressionType::IfExpression(Box::new(condition), then_clause, else_clause), None))
@ -1243,6 +1262,18 @@ mod parse_tests {
exprstatement!(Value(rc!(b), vec![]))],
Some(vec![exprstatement!(Value(rc!(c), vec![]))])))])
);
parse_test!("if a { b } else { c }", AST(vec![exprstatement!(
IfExpression(Box::new(ex!(val!("a"))),
vec![exprstatement!(val!("b"))],
Some(vec![exprstatement!(val!("c"))])))]));
parse_test!("if (A {a: 1}) { b } else { c }", AST(vec![exprstatement!(
IfExpression(Box::new(ex!(Value(rc!(A), vec![(rc!(a), ex!(IntLiteral(1)))]))),
vec![exprstatement!(val!("b"))],
Some(vec![exprstatement!(val!("c"))])))]));
parse_error!("if A {a: 1} { b } else { c }");
}
#[test]