feat: destructuring of structs and messages

CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Docs: the `description` property to the frontmatter of the each page for better SEO: PR [#916](https://github.com/tact-lang/tact/pull/916)
 - Docs: Google Analytics tags per every page: PR [#921](https://github.com/tact-lang/tact/pull/921)
 - Ability to specify a compile-time method ID expression for getters: PR [#922](https://github.com/tact-lang/tact/pull/922) and PR [#932](https://github.com/tact-lang/tact/pull/932)
+- Destructuring of structs and messages: PR [#856](https://github.com/tact-lang/tact/pull/856)
 
 ### Changed
 

src/generator/writers/writeFunction.ts

@@ -465,6 +465,26 @@ export function writeStatement(
 
             return;
         }
+        case "statement_destruct": {
+            const t = getExpType(ctx.ctx, f.expression);
+            if (t.kind !== "ref") {
+                throwInternalCompilerError(
+                    `invalid destruct expression kind: ${t.kind}`,
+                    f.expression.loc,
+                );
+            }
+            const ty = getType(ctx.ctx, t.name);
+            const ids = ty.fields.map((field) => {
+                const id = f.identifiers.get(field.name);
+                return id === undefined || isWildcard(id[1])
+                    ? "_"
+                    : funcIdOf(id[1]);
+            });
+            ctx.append(
+                `var (${ids.join(", ")}) = ${writeCastedExpression(f.expression, t, ctx)};`,
+            );
+            return;
+        }
     }
 
     throw Error("Unknown statement kind");