From 9c4b84ce33ea6ac7fe0f1b00ee5c67718643a34a Mon Sep 17 00:00:00 2001
From: Jakub Doka <jakub.doka2@gmail.com>
Date: Sun, 22 Dec 2024 20:43:49 +0100
Subject: [PATCH] fixing the precedence regarding slice ranges

Signed-off-by: Jakub Doka <jakub.doka2@gmail.com>
---
 lang/src/parser.rs | 69 +++++++++++++++++++++++++---------------------
 1 file changed, 38 insertions(+), 31 deletions(-)

diff --git a/lang/src/parser.rs b/lang/src/parser.rs
index 5bf4e181..50359391 100644
--- a/lang/src/parser.rs
+++ b/lang/src/parser.rs
@@ -490,15 +490,6 @@ impl<'a, 'b> Parser<'a, 'b> {
                 },
                 body: self.ptr_expr()?,
             },
-            T::Range => E::Range {
-                pos: token.start,
-                start: None,
-                end: if matches!(self.token.kind, TokenKind::RBrack) {
-                    None
-                } else {
-                    Some(self.ptr_expr()?)
-                },
-            },
             T::Ctor => self.ctor(pos, None),
             T::Tupl => self.tupl(pos, None, ListKind::Tuple),
             T::Arr => self.tupl(pos, None, ListKind::Array),
@@ -570,14 +561,7 @@ impl<'a, 'b> Parser<'a, 'b> {
                 let token = self.token;
                 if matches!(
                     token.kind,
-                    T::LParen
-                        | T::Ctor
-                        | T::Dot
-                        | T::Tupl
-                        | T::Arr
-                        | T::LBrack
-                        | T::Colon
-                        | T::Range
+                    T::LParen | T::Ctor | T::Dot | T::Tupl | T::Arr | T::LBrack | T::Colon
                 ) {
                     self.next();
                 }
@@ -593,20 +577,43 @@ impl<'a, 'b> Parser<'a, 'b> {
                     T::Arr => self.tupl(token.start, Some(expr), ListKind::Array),
                     T::LBrack => E::Index {
                         base: self.arena.alloc(expr),
-                        index: {
-                            let index = self.expr()?;
-                            self.expect_advance(T::RBrack)?;
-                            self.arena.alloc(index)
-                        },
-                    },
-                    T::Range => E::Range {
-                        pos: token.start,
-                        start: Some(self.arena.alloc(expr)),
-                        end: if matches!(self.token.kind, TokenKind::RBrack) {
-                            None
-                        } else {
-                            Some(self.ptr_expr()?)
-                        },
+                        index: self.arena.alloc({
+                            if self.advance_if(T::Range) {
+                                let pos = self.token.start;
+                                if self.advance_if(T::RBrack) {
+                                    Expr::Range { pos, start: None, end: None }
+                                } else {
+                                    let res = Expr::Range {
+                                        pos,
+                                        start: None,
+                                        end: Some(self.ptr_expr()?),
+                                    };
+                                    self.expect_advance(T::RBrack)?;
+                                    res
+                                }
+                            } else {
+                                let start = self.expr()?;
+
+                                let pos = self.token.start;
+                                if self.advance_if(T::Range) {
+                                    let start = self.arena.alloc(start);
+                                    if self.advance_if(T::RBrack) {
+                                        Expr::Range { pos, start: Some(start), end: None }
+                                    } else {
+                                        let res = Expr::Range {
+                                            pos,
+                                            start: Some(start),
+                                            end: Some(self.ptr_expr()?),
+                                        };
+                                        self.expect_advance(T::RBrack)?;
+                                        res
+                                    }
+                                } else {
+                                    self.expect_advance(T::RBrack)?;
+                                    start
+                                }
+                            }
+                        }),
                     },
                     T::Colon => E::BinOp {
                         left: {