Implement data_changevariableby

Author: adazem009

src/dev/blocks/variableblocks.cpp

@@ -25,6 +25,7 @@ void VariableBlocks::registerBlocks(IEngine *engine)
 {
     engine->addCompileFunction(this, "data_variable", &compileVariable);
     engine->addCompileFunction(this, "data_setvariableto", &compileSetVariableTo);
+    engine->addCompileFunction(this, "data_changevariableby", &compileChangeVariableBy);
 }
 
 CompilerValue *VariableBlocks::compileVariable(Compiler *compiler)
@@ -50,3 +51,17 @@ CompilerValue *VariableBlocks::compileSetVariableTo(Compiler *compiler)
 
     return nullptr;
 }
+
+CompilerValue *VariableBlocks::compileChangeVariableBy(Compiler *compiler)
+{
+    Field *varField = compiler->field("VARIABLE");
+    Variable *var = static_cast<Variable *>(varField->valuePtr().get());
+    assert(var);
+
+    if (var) {
+        CompilerValue *value = compiler->createAdd(compiler->addVariableValue(var), compiler->addInput("VALUE"));
+        compiler->createVariableWrite(var, value);
+    }
+
+    return nullptr;
+}

src/dev/blocks/variableblocks.h

@@ -18,6 +18,7 @@ class VariableBlocks : public IExtension
     private:
         static CompilerValue *compileVariable(Compiler *compiler);
         static CompilerValue *compileSetVariableTo(Compiler *compiler);
+        static CompilerValue *compileChangeVariableBy(Compiler *compiler);
 };
 
 } // namespace libscratchcpp

test/dev/blocks/variable_blocks_test.cpp

@@ -77,3 +77,35 @@ TEST_F(VariableBlocksTest, SetVariableTo)
     ASSERT_EQ(var1->value(), "test");
     ASSERT_EQ(var2->value(), 123);
 }
+
+TEST_F(VariableBlocksTest, ChangeVariableBy)
+{
+    auto target = std::make_shared<Sprite>();
+    auto var1 = std::make_shared<Variable>("", "", 835.21);
+    target->addVariable(var1);
+    auto var2 = std::make_shared<Variable>("", "", "Hello world");
+    target->addVariable(var2);
+    ScriptBuilder builder(m_extension.get(), m_engine, target);
+
+    builder.addBlock("data_changevariableby");
+    builder.addEntityField("VARIABLE", var1);
+    builder.addValueInput("VALUE", "5.12");
+
+    builder.addBlock("data_changevariableby");
+    builder.addEntityField("VARIABLE", var2);
+    builder.addValueInput("VALUE", -2.5);
+
+    builder.build();
+
+    builder.run();
+    ASSERT_EQ(var1->value(), 840.33);
+    ASSERT_EQ(var2->value(), -2.5);
+
+    builder.run();
+    ASSERT_EQ(var1->value(), 845.45);
+    ASSERT_EQ(var2->value(), -5);
+
+    builder.run();
+    ASSERT_EQ(var1->value(), 850.57);
+    ASSERT_EQ(var2->value(), -7.5);
+}