Add object parsing and tests

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

src/syn/parser.rs

@@ -9,6 +9,7 @@ const BASE_EXPR_START: &[TokenKind] = &[
     TokenKind::LParen,
     TokenKind::LBracket,
     TokenKind::LBrace,
+    TokenKind::ObjBrace,
 ];
 
 const UN_EXPR_START: &[TokenKind] = &[TokenKind::Plus, TokenKind::Minus, TokenKind::Bang];
@@ -61,6 +62,15 @@ impl<'t> Parser<'t> {
     }
 }
 
+////////////////////////////////////////////////////////////////////////////////
+// Statement parsing
+////////////////////////////////////////////////////////////////////////////////
+impl<'t> Parser<'t> {
+    pub fn next_stmt(&mut self) -> Result<Stmt> {
+        todo!()
+    }
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // Expression parsing
 ////////////////////////////////////////////////////////////////////////////////
@@ -165,7 +175,17 @@ impl<'t> Parser<'t> {
                 }
                 .into()
             }
-            TokenKind::LBrace => todo!(),
+            TokenKind::LBrace => todo!("TODO body expressions"),
+            TokenKind::ObjBrace => {
+                let prev_skip = self.set_skip_newlines(true)?;
+                let object = self.next_obj_list()?;
+                let end_token = self.expect_token_kind(TokenKind::RBrace, "end of object (right curly brace)")?;
+                let span = token.span().union(end_token.span());
+                Expr::Base(BaseExpr {
+                    kind: BaseExprKind::Object(object),
+                    span,
+                })
+            }
             TokenKind::LParen => {
                 let prev_skip = self.set_skip_newlines(true)?;
                 let first = self.next_expr()?;
@@ -175,7 +195,7 @@ impl<'t> Parser<'t> {
                     self.set_skip_newlines(prev_skip)?;
                     let end_token = self.expect_token_kind(TokenKind::RParen, "end of tuple")?;
 
-                    let span = first.span().union(end_token.span());
+                    let span = token.span().union(end_token.span());
                     list.insert(0, first);
                     Expr::Base(
                         BaseExpr {
@@ -212,6 +232,28 @@ impl<'t> Parser<'t> {
         Ok(list_items)
     }
 
+    /// Parses the tail of a `BaseExprKind::Object` expression.
+    ///
+    /// This function expects that the initial object brace `%{` has already been eaten.
+    fn next_obj_list(&mut self) -> Result<Vec<(Expr, Expr)>> {
+        let mut object = Vec::new();
+
+        // Parses this pattern:
+        // ( key EQ value ( COMMA key = value )* COMMA? )?
+        while !self.is_token_kind(TokenKind::RBrace) {
+            let key = self.next_expr()?;
+            self.expect_token_kind(TokenKind::Eq, "equals sign for object item")?;
+            let value = self.next_expr()?;
+            object.push((key, value));
+
+            // match a comma, otherwise exit the loop
+            if self.match_token_kind(TokenKind::Comma)?.is_none() {
+                break;
+            }
+        }
+        Ok(object)
+    }
+
     ////////////////////////////////////////////////////////////////////////////////
     // Token matching functions
     ////////////////////////////////////////////////////////////////////////////////
@@ -220,13 +262,19 @@ impl<'t> Parser<'t> {
         let mut next_token = self.lexer.next_token()?;
 
         if self.is_skip_newlines() {
-            while next_token.map(|t| t.kind() == TokenKind::Newline).unwrap_or(false) {
+            while next_token
+                .map(|t| t.kind() == TokenKind::Newline)
+                .unwrap_or(false)
+            {
                 next_token = self.lexer.next_token()?;
             }
 
             if self.is_token_kind(TokenKind::Newline) {
                 self.curr_token = next_token;
-                while next_token.map(|t| t.kind() == TokenKind::Newline).unwrap_or(false) {
+                while next_token
+                    .map(|t| t.kind() == TokenKind::Newline)
+                    .unwrap_or(false)
+                {
                     next_token = self.lexer.next_token()?;
                 }
             }
@@ -485,9 +533,7 @@ mod test {
         test_parser!(
             Parser::try_from("(:sym,)").unwrap(),
             next_expr,
-            base_expr(BaseExprKind::Tuple(vec![
+            base_expr(BaseExprKind::Tuple(vec![base_expr(BaseExprKind::Sym),]))
-                base_expr(BaseExprKind::Sym),
-            ]))
         );
 
         test_parser!(
@@ -497,6 +543,26 @@ mod test {
         );
     }
 
+    #[test]
+    fn test_object_expr() {
+        test_parser!(
+            Parser::try_from(
+                r#"%{
+                    :sym = value,
+                    key = "value",
+                    "lit" = 1,
+                }"#
+            )
+            .unwrap(),
+            next_expr,
+            base_expr(BaseExprKind::Object(vec![
+                    (base_expr(BaseExprKind::Sym), base_expr(BaseExprKind::Ident)),
+                    (base_expr(BaseExprKind::Ident), base_expr(BaseExprKind::Str)),
+                    (base_expr(BaseExprKind::Str), base_expr(BaseExprKind::Num)),
+            ]))
+        );
+    }
+
     #[test]
     fn test_bin_expr() {
         test_parser!(
@@ -613,26 +679,30 @@ mod test {
     #[test]
     fn test_multiline_exprs() {
         test_parser!(
-            Parser::try_from(r"[
+            Parser::try_from(
+                r"[
                 1,
                 x,
                 ['value', :value],
                 :sym
-            ]").unwrap(),
+            ]"
+            )
+            .unwrap(),
             next_expr,
             base_expr(BaseExprKind::List(vec![
                 base_expr(BaseExprKind::Num),
                 base_expr(BaseExprKind::Ident),
                 base_expr(BaseExprKind::List(vec![
-                        base_expr(BaseExprKind::Str),
+                    base_expr(BaseExprKind::Str),
-                        base_expr(BaseExprKind::Sym),
+                    base_expr(BaseExprKind::Sym),
                 ])),
                 base_expr(BaseExprKind::Sym),
             ]))
         );
 
         test_parser!(
-            Parser::try_from(r"(
+            Parser::try_from(
+                r"(
                 1,
                 x,
                 [
@@ -640,26 +710,31 @@ mod test {
                     'value',
                 ],
                 :sym
-            )").unwrap(),
+            )"
+            )
+            .unwrap(),
             next_expr,
             base_expr(BaseExprKind::Tuple(vec![
                 base_expr(BaseExprKind::Num),
                 base_expr(BaseExprKind::Ident),
                 base_expr(BaseExprKind::List(vec![
-                        base_expr(BaseExprKind::Sym),
+                    base_expr(BaseExprKind::Sym),
-                        base_expr(BaseExprKind::Str),
+                    base_expr(BaseExprKind::Str),
                 ])),
                 base_expr(BaseExprKind::Sym),
             ]))
         );
 
         test_parser!(
-            Parser::try_from(r"(
+            Parser::try_from(
+                r"(
                 + 1
                 + 2
                 + 3
                 + 4
-            )").unwrap(),
+            )"
+            )
+            .unwrap(),
             next_expr,
             bin_expr(
                 un_expr(UnOp::Plus, base_expr(BaseExprKind::Num)),
@@ -677,29 +752,30 @@ mod test {
         );
 
         test_parser!(
-            Parser::try_from(r"(
+            Parser::try_from(
+                r"(
                 + 1
                 + 2
                 + 3
                 + 4
                 ,
-            )").unwrap(),
+            )"
+            )
+            .unwrap(),
             next_expr,
-            base_expr(BaseExprKind::Tuple(vec![
+            base_expr(BaseExprKind::Tuple(vec![bin_expr(
+                un_expr(UnOp::Plus, base_expr(BaseExprKind::Num)),
+                BinOp::Plus,
                 bin_expr(
-                    un_expr(UnOp::Plus, base_expr(BaseExprKind::Num)),
+                    base_expr(BaseExprKind::Num),
                     BinOp::Plus,
                     bin_expr(
                         base_expr(BaseExprKind::Num),
                         BinOp::Plus,
-                        bin_expr(
+                        base_expr(BaseExprKind::Num)
-                            base_expr(BaseExprKind::Num),
-                            BinOp::Plus,
-                            base_expr(BaseExprKind::Num)
-                        )
                     )
                 )
-            ]))
+            )]))
         );
     }
 }