fltk/fluid/documentation/src/code.dox

/**

\page codeNodes Code Nodes

Overview of code nodes.


\section function Functions and Methods

![](flFunction.png) Functions

Fluid can generate C functions, C++ functions, and methods in classes.
Functions can contain widgets to build windows and dialogs. *Code* nodes can
be used to add more source code to a function.

### Parents ###
To generate a function, the function node must be created at the top level or
inside a declaration block. If added inside a class node, this node generates
a method inside that class.

### Children ###
Function nodes can contain code nodes and widget trees. The topmost node of a
widget tree must be a window.
If the function node has no children, only a forward declaration will be
created in the header, but no source code will be generated.

\image html flFunctionDialog.png "Function/Method Properties"
\image latex flFunctionDialog.png "Function/Method Properties"

## Declaring a Function ##

A function node at the top level or inside a declaration block generates a C
or C++ function.

The *Name* field  contains the function name and all arguments.
If the *Name* field is left empty, Fluid will generate a typical 'main()' function.
```
// .cxx
int main(int argc, char **argv) {
  /* code generated by children */
  w->show(argc, argv); /* <-- code generated if function has a child widget */
  Fl::run();
}
```

If a function node has a name but no children, a forward declaration is
generated in the header, but the implementation in the source file is omited.
This is used to reference functions in other modules.
```
// .h
void make_window();
```

If the function contains one or more Code nodes, an implementation will also be
generated. The default return type is `void`. Text in the *Return Type* field
overrides the default type.
```
// .cxx
void make_window() {
  /* code generated by children */
}
```

If the function contains a widget, a pointer to the first widget
will be created. The default return type will match the type of the
first widget, and a pointer to the widget will be returned.
```
// .h
Fl_Window* make_window();
```

```
// .cxx
Fl_Window* make_window() {
  Fl_Window* w;
  /* code generated by children:
   * w = new Fl_Window(...)
   */
  return w;
}
```

### Options for Functions ###

Choosing *static* in the pulldown menu will declare the function `static` in the
source file. No prototype will be generated in the header.
```
// .cxx
static Fl_Window* make_window() { ...
```

If the *C* option is checked, the function will be declared as a plain C
function in the header file.
The options *local* and *C* together are not supported.
```
// .h
extern "C" { void my_plain_c_function(); }
```

## Declaring a Method ##

A function node inside a class node generates a C++ method. If a method node has
no children, the declaration is generated in the header, but no implementation
in the source file.
```
// .h
class UserInterface {
public:
  void make_window();
};
```

If the method contains one or more Code nodes, an implementation will also be
generated.

```
// .cxx
void UserInterface::make_window() {
  printf("Hello, World!\n");
}
```

If the method contains at least on widget, a pointer to the topmost widget
will be returned and the return type will be generated accordingly.
```
// .h
class UserInterface {
public:
  Fl_Double_Window* make_window();
};
```

```
// .cxx
Fl_Double_Window* UserInterface::make_window() {
  Fl_Double_Window* w;
  /* code generated by children */
  return w;
}
```

### Options for Methods ###

Class access can be defined with the pulldown menu. It provides a choice of
`private`, `protected`, and `public`.

Fluid recognizes the keyword `static` or `virtual` at the beginning of the
*return type* and will generate the declaration including the keyword, but will
omit it in the implementation. The return type defaults still apply if there
is no text after the keyword.

### Further Options ###

Users can define a comment text in the *comment* field. The first line of the
comment will be shown in the widget browser. The comment text will be generated
in the source file ahead of thefunction.
```
// .cxx
/*
 My multilen comment
 will be here
 */
Fl_Window* make_window() {
```

Fluid recognizes default values in the argument list and geneartes them in the
declaration, but omits them in the implementation.

A short function body can be appended in the *Name* field. With no child, this
creates an inlined function in the header file.

<!-- ----------------------------------------------------------------------- -->

\section code C Source Code

![](flCode.png) Code

...write me.

 \section codeblock Code Block

 \section declaration Declaration

 \section declarationblock Declaration Block

 \section class Classes


 \section widgetclass Widget Class

 \section comment Comments

 \section inlineddata Inlined Data

 */