Update docs

Author: adazem009

docs/Block sections.md

@@ -1,30 +1,152 @@
 \page extensions Extensions
 
-An extension is a group of block sections (see [Block sections](blockSections.html)).
+An extension is a group of Scratch blocks, for example motion blocks.
 
 ## Creating an extension
 To create a custom extension, subclass \link libscratchcpp::IExtension IExtension \endlink and override
 \link libscratchcpp::IExtension::name() name() \endlink and \link libscratchcpp::IExtension::description() description() \endlink
-functions to return the name and the description of the extension.
-
-There's also an \link libscratchcpp::IExtension::includeByDefault() includeByDefault() \endlink function which returns `true`
-if the extension is intended to be hidden from the block palette and included in a Scratch project by default.
-
-The default implementation returns `false`.
+functions to return the name and the description of the extension. Then override \link libscratchcpp::IExtension::registerBlocks() registerBlocks() \endlink
+where you'll register the compile functions for blocks.
 
 It's recommended to use the libscratchcpp namespace like this in your extension class:
 ```cpp
 using namespace libscratchcpp;
 ```
 
-### Registering block sections
-Block sections can be registered by overriding the \link libscratchcpp::IExtension::registerSections() registerSections() \endlink function:
+### Adding blocks
+See the [Scratch Wiki](https://en.scratch-wiki.info/wiki/Scratch_File_Format#Blocks) for more information about blocks.
+
+Scratch projects are compiled by the \link libscratchcpp::Compiler Compiler \endlink class.
+To add a block, you have to let the compiler know how to compile it.
+Start by defining a **compile function**.
+For example, the compile function for a `hello world` block would look like this:
+```cpp
+class MyExtension : public IExtension {
+    public:
+        ...
+        static void compileHelloWorld(Compiler *compiler);
+        static unsigned int helloWorld(VirtualMachine *vm);
+};
+
+void MySection::compileHelloWorld(Compiler *compiler) {
+    compiler->addFunctionCall(&helloWorld);
+}
+
+unsigned int MySection::helloWorld(VirtualMachine *vm) {
+    std::cout << "Hello, world!" << std::endl;
+    return 0;
+}
+```
+\note Make sure the functions are **static**.
+
+Register the compile function using the \link libscratchcpp::IEngine::addCompileFunction() addCompileFunction() \endlink method in link libscratchcpp::IExtension::registerBlocks() registerBlocks() \endlink:
+```cpp
+MyExtension::registerBlocks(IEngine *engine) {
+    engine->addCompileFunction(this, "myextension_helloworld", &MySection::compileHelloWorld);
+}
+```
+Where `myextension_helloworld` is the opcode of the `hello world` block.
+
+### Adding inputs
+To add inputs, create an `Inputs` enumeration in your extension:
+```hpp
+class MyExtension : public IExtension {
+    enum Inputs {
+        TEXT
+    };
+    ...
+};
+```
+Then add inputs in link libscratchcpp::IExtension::registerBlocks() registerBlocks() \endlink:
+```cpp
+MyExtension::registerBlocks(IEngine *engine) {
+    ...
+    engine->addInput(this, "TEXT", TEXT);
+}
+```
+The compiler will assign the input name with the `TEXT` ID. In this case, the ID is 0 because it's the first member of the enumeration.
+
+To add the input to the compiled code, call the \link libscratchcpp::Compiler::addInput() addInput() \endlink function:
+```cpp
+void MyExtension::compileHelloWorld(Compiler *compiler) {
+    compiler->addInput(TEXT);
+    compiler->addFunctionCall(&helloWorld);
+}
+```
+
+The value of the input can be read during runtime using the \link libscratchcpp::VirtualMachine::getInput() getInput() \endlink function:
+```cpp
+unsigned int MyExtension::helloWorld(VirtualMachine *vm) {
+    std::cout << "Hello, " << vm->getInput(0, 1)->toString() << "!" << std::endl;
+    return 1;
+}
+```
+\note The order of the inputs is the same as in the compile function. Do not use the `Inputs` enumeration in runtime functions.
+
+```cpp
+vm->getInput(0, 1)
+```
+The first argument is the index of the input and the second argument is the amount of inputs.
+\note Make sure to return the amount of inputs in the `helloWorld` function.
+
+### Adding fields
+**Fields** are drop-down menus into which one cannot drop a reporter.
+Fields have a predefined set of values.
+```cpp
+class MyExtension : public IExtension {
+    ...
+    enum Fields {
+        ANIMAL
+    };
+
+    enum FieldValues {
+        Cat,
+        Dog
+    };
+    ...
+};
+
+MyExtension::registerBlocks(IEngine *engine) {
+    ...
+    engine->addField(this, "ANIMAL", ANIMAL);
+    engine->addFieldValue(this, "Cat", Cat);
+    engine->addFieldValue(this, "Dog", Dog);
+}
+```
+
+Because fields are handled at compile time, you can read them from the compile function:
 ```cpp
-void MyExtension::registerSections(IEngine *engine) {
-    engine->registerSection(std::make_shared<MySection>());
+void MyExtension::compileHelloWorld(Compiler *compiler) {
+    int id = compiler->field(ANIMAL)->specialValueId();
+
+    switch(id) {
+        case Cat:
+            compiler->addFunctionCall(&helloCat);
+            break;
+
+        case Dog:
+            compiler->addFunctionCall(&helloDog);
+            break;
+
+        default:
+            break;
+    }
+}
+
+unsigned int MySection::helloCat(VirtualMachine *vm) {
+    std::cout << "Hello, cat!" << std::endl;
+    return 0;
+}
+
+unsigned int MySection::helloDog(VirtualMachine *vm) {
+    std::cout << "Hello, dog!" << std::endl;
+    return 0;
 }
 ```
-See the [Block sections](blockSections.html) page for instructions on how to create a block section.
+\note Don't confuse \link libscratchcpp::Field::specialValueId() specialValueId() \endlink with \link libscratchcpp::Field::valueId() valueId() \endlink
+because \link libscratchcpp::Field::valueId() valueId() \endlink stores the ID of the block, variable, list or broadcast selected in the dropdown list.
+
+To get a pointer to the block, variable, list or broadcast selected in the dropdown list, use \link libscratchcpp::Field::valuePtr() valuePtr() \endlink.
 
 ### Registering the extension
 Register the extension **before** loading a project, using the \link libscratchcpp::ScratchConfiguration ScratchConfiguration \endlink class:

docs/Extensions.md

@@ -24,5 +24,5 @@ int main(int argc, char **argv) {
 The \link libscratchcpp::Project::run() run() \endlink method runs an event loop which stops after all scripts finish.
 
 For CLI project players, using \link libscratchcpp::Project::run() run() \endlink is enough. If you are developing
-a GUI project player and need to receive input events such as key presses, you'll need to use \link libscratchcpp::Project::runEventLoop() runEventLoop() \endlink
-and run it in another thread (to keep the UI responsive).
+a GUI project player and need to receive input events such as key presses, you'll need to use \link libscratchcpp::IEngine::step() step() \endlink
+for ticks and \link libscratchcpp::Project::start() start() \endlink and \link libscratchcpp::Project::stop() stop() \endlink