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EXTENDING DREAMWEAVER CS4

C-level extensibility

Note: The library can be implemented in either C or C++, but the file that contains the MM_Init() function and the

MM_STATE macro must be implemented in C. The C++ compiler garbles function names, which makes it impossible for

Dreamweaver to find the

MM_Init() function.

C-level extensibility and the JavaScript interpreter

The C code in your library must interact with the Dreamweaver JavaScript interpreter at the following different times:

• At startup, to register the library’s functions

• When the function is called, to parse the arguments that JavaScript is passing to C

• Before the function returns, to package the return value

To accomplish these tasks, the interpreter defines several data types and exposes an API. Definitions for the data types

and functions that are listed in this section appear in the mm_jsapi.h file. For your library to work properly, you must

include the mm_jsapi.h file with the following line at the top of each file in your library:

#include "mm_jsapi.h"

Including the mm_jsapi.h file includes, in turn, mm_jsapi_environment.h, which defines the MM_Environment

structure.

Data types

The JavaScript interpreter defines the following data types.

typedef struct JSContext JSContext

A pointer to this opaque data type passes to the C-level function. Some functions in the API accept this pointer as one

of their arguments.

typedef struct JSObject JSObject

A pointer to this opaque data type passes to the C-level function. This data type represents an object, which might be

an array object or some other object type.

typedef struct JSVal JSVal

An opaque data structure that can contain an integer, or a pointer to a floating-point number, string, or object. Some

functions in the API can read the values of function arguments by reading the contents of a JSVal structure, and some

can be used to write the function’s return value by writing a JSVal structure.

typedef enum { JS_FALSE = 0, JS_TRUE = 1 } JSBool

A simple data type that stores a Boolean value.

The C-level API

The C-level extensibility API consists of the following functions:

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Adobe Extending Dreamweaver CS4 Manuale Utente Pagina 355