Parse closures

src/parse/ast.rs

@@ -50,7 +50,7 @@ pub enum Expr<'a> {
 
     // Pattern Matching
     When(&'a [(Loc<Pattern<'a>>, Loc<Expr<'a>>)]),
-    Closure(&'a (&'a [Loc<Pattern<'a>>], Loc<Expr<'a>>)),
+    Closure(&'a (Loc<Vec<'a, Loc<Pattern<'a>>>>, Loc<Expr<'a>>)),
     // /// basically Assign(Vec<(Loc<Pattern>, Loc<Expr>)>, Loc<Expr>)
     // Assign(&'a (&'a [(Loc<Pattern<'a>>, Loc<Expr<'a>>)], Loc<Expr<'a>>)),
 
@@ -87,9 +87,9 @@ pub enum Pattern<'a> {
     // Identifier
     Identifier(&'a str),
 
-    // Variant
-    Variant(&'a VariantName),
-    AppliedVariant(&'a (Loc<&'a VariantName>, [Loc<Pattern<'a>>])),
+    // Variant, optionally qualified
+    Variant(&'a [&'a str], &'a VariantName),
+    Apply(&'a (Loc<&'a Pattern<'a>>, [Loc<Pattern<'a>>])),
 
     // Literal
     IntLiteral(i64),
@@ -205,7 +205,7 @@ fn pattern_size() {
         // better performance, due to more data structures being inlinable,
         // and therefore having fewer pointers to chase. This seems worth
         // investigating as well.
-        std::mem::size_of::<usize>() * 4
+        std::mem::size_of::<usize>() * 5
     );
 }
 

src/parse/mod.rs

@@ -17,7 +17,7 @@ use parse::blankspace::{space0, space0_around, space0_before, space1_before};
 use parse::ident::{ident, Ident};
 use parse::number_literal::number_literal;
 use parse::parser::{
-    and, attempt, between, char, either, loc, map, map_with_arena, one_of2, one_of4, one_of8,
+    and, attempt, between, char, either, loc, map, map_with_arena, one_of2, one_of4, one_of9,
     one_or_more, optional, sep_by0, skip_first, skip_second, string, unexpected, unexpected_eof,
     Either, ParseResult, Parser, State,
 };
@@ -36,11 +36,12 @@ fn loc_parse_expr_body_without_operators<'a>(
     arena: &'a Bump,
     state: State<'a>,
 ) -> ParseResult<'a, Located<Expr<'a>>> {
-    one_of8(
+    one_of9(
         loc_parenthetical_expr(min_indent),
         loc(string_literal()),
         loc(number_literal()),
         loc(record_literal(min_indent)),
+        loc(closure(min_indent)),
         loc(list_literal(min_indent)),
         loc(when(min_indent)),
         loc(conditional(min_indent)),
@@ -156,8 +157,24 @@ fn loc_function_arg<'a>(min_indent: u16) -> impl Parser<'a, Located<Expr<'a>>> {
 }
 
 fn closure<'a>(min_indent: u16) -> impl Parser<'a, Expr<'a>> {
-    map(skip_first(char('\\'), one_or_more(loc_closure_param(min_indent))),
-        |params
+    map_with_arena(
+        skip_first(
+            char('\\'),
+            and(
+                loc(one_or_more(space0_around(
+                    loc_closure_param(min_indent),
+                    min_indent,
+                ))),
+                skip_first(
+                    string("->"),
+                    space0_before(
+                        loc(move |arena, state| parse_expr(min_indent, arena, state)),
+                        min_indent,
+                    ),
+                ),
+            ),
+        ),
+        |arena, (params, loc_body)| Expr::Closure(arena.alloc((params, loc_body))),
     )
 }
 

src/parse/parser.rs

@@ -907,3 +907,65 @@ where
         }
     }
 }
+
+pub fn one_of9<'a, P1, P2, P3, P4, P5, P6, P7, P8, P9, A>(
+    p1: P1,
+    p2: P2,
+    p3: P3,
+    p4: P4,
+    p5: P5,
+    p6: P6,
+    p7: P7,
+    p8: P8,
+    p9: P9,
+) -> impl Parser<'a, A>
+where
+    P1: Parser<'a, A>,
+    P2: Parser<'a, A>,
+    P3: Parser<'a, A>,
+    P4: Parser<'a, A>,
+    P5: Parser<'a, A>,
+    P6: Parser<'a, A>,
+    P7: Parser<'a, A>,
+    P8: Parser<'a, A>,
+    P9: Parser<'a, A>,
+{
+    move |arena: &'a Bump, state: State<'a>| {
+        let original_attempting = state.attempting;
+
+        match p1.parse(arena, state) {
+            valid @ Ok(_) => valid,
+            Err((_, state)) => match p2.parse(arena, state) {
+                valid @ Ok(_) => valid,
+                Err((_, state)) => match p3.parse(arena, state) {
+                    valid @ Ok(_) => valid,
+                    Err((_, state)) => match p4.parse(arena, state) {
+                        valid @ Ok(_) => valid,
+                        Err((_, state)) => match p5.parse(arena, state) {
+                            valid @ Ok(_) => valid,
+                            Err((_, state)) => match p6.parse(arena, state) {
+                                valid @ Ok(_) => valid,
+                                Err((_, state)) => match p7.parse(arena, state) {
+                                    valid @ Ok(_) => valid,
+                                    Err((_, state)) => match p8.parse(arena, state) {
+                                        valid @ Ok(_) => valid,
+                                        Err((_, state)) => match p9.parse(arena, state) {
+                                            valid @ Ok(_) => valid,
+                                            Err((fail, state)) => Err((
+                                                Fail {
+                                                    attempting: original_attempting,
+                                                    ..fail
+                                                },
+                                                state,
+                                            )),
+                                        },
+                                    },
+                                },
+                            },
+                        },
+                    },
+                },
+            },
+        }
+    }
+}