lvalue subroutines

Author: fglock

FEATURE_MATRIX.md

@@ -144,7 +144,7 @@
 - ❌  **Subroutine signatures**: Formal parameters are not implemented.
 - ❌  **Inline "constant" subroutines optimization**: Optimization for inline constants is not yet implemented.
 - ❌  **Subroutine attributes**: Subroutine attributes are not yet supported.
-- ❌  **`lvalue` subroutines**: Subroutines with attribute `:lvalue` are not yet supported.
+- ✔️   **`lvalue` subroutines**: Subroutines with attribute `:lvalue` are supported.
 - ❌  **Lexical subroutines**: Subroutines declared `my`, `state`, or `our` are not yet supported.
 - ✔️   **CORE namespace**: `CORE` is implemented.
 - ❌  **CORE::GLOBAL namespace**: `CORE::GLOBAL` is not implemented.

MILESTONES.md

@@ -85,6 +85,7 @@
   - Added v-strings.
   - Added Infinity, -Infinity, NaN.
   - Added `\N{name}` operator for named characters in double quoted strings and in regex.
+  - Added lvalue subroutines.
   - CI/CD runs in Ubuntu and Windows
   - Work in progress:
     - `state` variables.

src/main/java/org/perlonjava/codegen/LValueVisitor.java

@@ -48,6 +48,11 @@ public void visit(BinaryOperatorNode node) {
             case "substr":
                 context = RuntimeContextType.SCALAR;
                 break;
+            case "(":
+                // l-value subroutine call
+                // XXX TODO - check for lvalue attribute
+                context = RuntimeContextType.SCALAR;
+                break;
             default:
                 context = RuntimeContextType.VOID;  // Not an L-value
         }

src/test/resources/subroutine.pl

@@ -109,3 +109,7 @@ package Other {
 $result = &$ref_to_sub;
 print "not " if $result ne "<reference test>"; say "ok # reference to subroutine with &$ref_to_sub reused @_ and returned '$result'";
 
+# lvalue subroutine
+sub lv :lvalue { $result }
+lv = 13;
+print "not " if $result ne "13"; say "ok # lvalue subroutine call is assignable";