Merge pull request #191 from Shopify/Alex/translate-local-vars

Implement Prism -> Sorbet translation for local variables

Author: egiurleo

parser/prism/Translator.cc

@@ -282,6 +282,25 @@ std::unique_ptr<parser::Node> Translator::translate(pm_node_t *node) {
 
             return make_unique<parser::Kwrestarg>(parser.translateLocation(loc), gs.enterNameUTF8(name));
         }
+        case PM_LOCAL_VARIABLE_READ_NODE: {
+            auto localVarReadNode = reinterpret_cast<pm_local_variable_read_node *>(node);
+            pm_location_t *loc = &localVarReadNode->base.location;
+
+            std::string_view name = parser.resolveConstant(localVarReadNode->name);
+
+            return make_unique<parser::LVar>(parser.translateLocation(loc), gs.enterNameUTF8(name));
+        }
+        case PM_LOCAL_VARIABLE_WRITE_NODE: {
+            auto localVarWriteNode = reinterpret_cast<pm_local_variable_write_node *>(node);
+            pm_location_t *loc = &localVarWriteNode->base.location;
+            pm_location_t *nameLoc = &localVarWriteNode->name_loc;
+
+            auto name = parser.resolveConstant(localVarWriteNode->name);
+            auto lhs = make_unique<parser::LVarLhs>(parser.translateLocation(nameLoc), gs.enterNameUTF8(name));
+            auto rhs = translate(localVarWriteNode->value);
+
+            return make_unique<parser::Assign>(parser.translateLocation(loc), std::move(lhs), std::move(rhs));
+        }
         case PM_MODULE_NODE: { // Modules declarations, like `module A::B::C; ...; end`
             auto moduleNode = reinterpret_cast<pm_module_node *>(node);
             pm_location_t *loc = &moduleNode->base.location;
@@ -620,9 +639,7 @@ std::unique_ptr<parser::Node> Translator::translate(pm_node_t *node) {
         case PM_LOCAL_VARIABLE_AND_WRITE_NODE:
         case PM_LOCAL_VARIABLE_OPERATOR_WRITE_NODE:
         case PM_LOCAL_VARIABLE_OR_WRITE_NODE:
-        case PM_LOCAL_VARIABLE_READ_NODE:
         case PM_LOCAL_VARIABLE_TARGET_NODE:
-        case PM_LOCAL_VARIABLE_WRITE_NODE:
         case PM_MATCH_LAST_LINE_NODE:
         case PM_MATCH_PREDICATE_NODE:
         case PM_MATCH_REQUIRED_NODE:

test/prism_regression/local_variables.parse-tree.exp

@@ -0,0 +1,31 @@
+Begin {
+  stmts = [
+    Assign {
+      lhs = LVarLhs {
+        name = <U local_variable1>
+      }
+      rhs = Integer {
+        val = "123"
+      }
+    }
+    Assign {
+      lhs = LVarLhs {
+        name = <U local_variable2>
+      }
+      rhs = Send {
+        receiver = NULL
+        method = <U this_is_a_method_call>
+        args = [
+        ]
+      }
+    }
+    Assign {
+      lhs = LVarLhs {
+        name = <U local_variable2>
+      }
+      rhs = LVar {
+        name = <U local_variable1>
+      }
+    }
+  ]
+}

test/prism_regression/local_variables.rb

@@ -0,0 +1,8 @@
+# typed: true
+
+local_variable1 = 123
+
+local_variable2 = this_is_a_method_call
+#                 ^^^^^^^^^^^^^^^^^^^^^ error: Method `this_is_a_method_call` does not exist on `T.class_of(<root>)`
+
+local_variable2 = local_variable1 # should parse as local variable lookup