From d5d98b67a83944d72a5c0f8e8e2f43aeee667122 Mon Sep 17 00:00:00 2001
From: Marmare314 <49279081+Marmare314@users.noreply.github.com>
Date: Tue, 25 Apr 2023 11:22:12 +0200
Subject: Destructuring assign (#703)

---
 src/syntax/parser.rs | 45 +++++++++++++++++++++++++++++----------------
 1 file changed, 29 insertions(+), 16 deletions(-)

(limited to 'src/syntax/parser.rs')

diff --git a/src/syntax/parser.rs b/src/syntax/parser.rs
index 389cf026..0bbf77e2 100644
--- a/src/syntax/parser.rs
+++ b/src/syntax/parser.rs
@@ -725,7 +725,16 @@ fn with_paren(p: &mut Parser) {
         p.assert(SyntaxKind::Arrow);
         code_expr(p);
         kind = SyntaxKind::Closure;
+    } else if p.at(SyntaxKind::Eq) && kind != SyntaxKind::Parenthesized {
+        // TODO: add warning if p.at(SyntaxKind::Eq) && kind == SyntaxKind::Parenthesized
+
+        validate_destruct_pattern(p, m, false);
+        p.wrap(m, SyntaxKind::Destructuring);
+        p.assert(SyntaxKind::Eq);
+        code_expr(p);
+        kind = SyntaxKind::DestructAssignment;
     }
+
     match kind {
         SyntaxKind::Array => validate_array(p, m),
         SyntaxKind::Dict => validate_dict(p, m),
@@ -866,7 +875,7 @@ fn pattern(p: &mut Parser) -> PatternKind {
     let m = p.marker();
     if p.at(SyntaxKind::LeftParen) {
         let kind = collection(p, false);
-        validate_destruct_pattern(p, m);
+        validate_destruct_pattern(p, m, true);
 
         if kind == SyntaxKind::Parenthesized {
             PatternKind::Ident
@@ -1184,7 +1193,7 @@ fn validate_args(p: &mut Parser, m: Marker) {
     }
 }
 
-fn validate_destruct_pattern(p: &mut Parser, m: Marker) {
+fn validate_destruct_pattern(p: &mut Parser, m: Marker, forbid_expressions: bool) {
     let mut used_spread = false;
     let mut used = HashSet::new();
     for child in p.post_process(m) {
@@ -1206,7 +1215,7 @@ fn validate_destruct_pattern(p: &mut Parser, m: Marker) {
 
                 if within.kind() == SyntaxKind::Dots {
                     continue;
-                } else if within.kind() != SyntaxKind::Ident {
+                } else if forbid_expressions && within.kind() != SyntaxKind::Ident {
                     within.convert_to_error(eco_format!(
                         "expected identifier, found {}",
                         within.kind().name(),
@@ -1231,15 +1240,17 @@ fn validate_destruct_pattern(p: &mut Parser, m: Marker) {
                     child.make_erroneous();
                 }
 
-                let Some(within) = child.children_mut().last_mut() else { return };
-                if within.kind() != SyntaxKind::Ident
-                    && within.kind() != SyntaxKind::Underscore
-                {
-                    within.convert_to_error(eco_format!(
-                        "expected identifier, found {}",
-                        within.kind().name(),
-                    ));
-                    child.make_erroneous();
+                if forbid_expressions {
+                    let Some(within) = child.children_mut().last_mut() else { return };
+                    if within.kind() != SyntaxKind::Ident
+                        && within.kind() != SyntaxKind::Underscore
+                    {
+                        within.convert_to_error(eco_format!(
+                            "expected identifier, found {}",
+                            within.kind().name(),
+                        ));
+                        child.make_erroneous();
+                    }
                 }
             }
             SyntaxKind::LeftParen
@@ -1247,10 +1258,12 @@ fn validate_destruct_pattern(p: &mut Parser, m: Marker) {
             | SyntaxKind::Comma
             | SyntaxKind::Underscore => {}
             kind => {
-                child.convert_to_error(eco_format!(
-                    "expected identifier or destructuring sink, found {}",
-                    kind.name()
-                ));
+                if forbid_expressions {
+                    child.convert_to_error(eco_format!(
+                        "expected identifier or destructuring sink, found {}",
+                        kind.name()
+                    ));
+                }
             }
         }
     }
-- 
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