225 lines
4.4 KiB
HTML
225 lines
4.4 KiB
HTML
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<!DOCTYPE html>
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<html>
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<head>
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<link href="style.css" rel="stylesheet">
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<title>MuJS Examples</title>
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</head>
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<body>
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<header>
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<h1>MuJS Examples</h1>
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</header>
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<nav>
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<a href="introduction.html">Introduction</a>
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<a href="reference.html">Reference</a>
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<a href="examples.html">Examples</a>
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<a href="license.html">License</a>
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<a href="http://git.ghostscript.com/?p=mujs.git;a=summary">Source</a>
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<a href="https://bugs.ghostscript.com/">Bugs</a>
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</nav>
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<article>
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<h2>A stand-alone interpreter</h2>
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<pre>
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#include <stdio.h>
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#include <mujs.h>
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int main(int argc, char **argv)
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{
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char line[256];
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js_State *J = js_newstate(NULL, NULL, JS_STRICT);
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while (fgets(line, sizeof line, stdin))
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js_dostring(J, line);
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js_freestate(J);
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}
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</pre>
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<h2>Hello, world!</h2>
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<pre>
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#include <stdio.h>
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#include <mujs.h>
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static void hello(js_State *J)
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{
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const char *name = js_tostring(J, 1);
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printf("Hello, %s!\n", name);
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js_pushundefined(J);
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}
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int main(int argc, char **argv)
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{
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js_State *J = js_newstate(NULL, NULL, JS_STRICT);
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js_newcfunction(J, hello, "hello", 1);
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js_setglobal(J, "hello");
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js_dostring(J, "hello('world');");
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js_freestate(J);
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}
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</pre>
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<h2>Configuration file</h2>
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<pre>
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js_dofile(J, "config.js")
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js_getglobal(J, "foo");
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foo = js_tonumber(J, -1);
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js_pop(J, 1);
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</pre>
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<h2>Object manipulation</h2>
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<pre>
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// t = { foo: 42, bar: true }
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js_newobject(J);
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{
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js_pushnumber(J, 42);
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js_setproperty(J, -2, "foo");
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js_pushboolean(J, 1);
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js_setproperty(J, -2, "bar");
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}
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js_setglobal(J, "t");
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</pre>
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<h2>Callbacks from C to JS (by name)</h2>
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<pre>
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static int call_callback(js_State *J, const char *arg1, int arg2)
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{
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int result;
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/* Find the function to call. */
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js_getglobal(J, "my_callback");
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/* Push arguments to function. */
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js_pushnull(J); /* the 'this' object to use */
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js_pushstring(J, arg1);
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js_pushnumber(J, arg2);
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/* Call function and check for exceptions. */
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if (js_pcall(J, 2)) {
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fprintf(stderr, "an exception occurred in the javascript callback\n");
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js_pop(J, 1);
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return -1;
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}
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/* Retrieve return value. */
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result = js_tonumber(J, -1);
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js_pop(J, 1);
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return result;
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}
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</pre>
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<h2>Callbacks from C to JS</h2>
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<pre>
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const char *handle = NULL; /* handle to stowed away js function */
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static void set_callback(js_State *J)
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{
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if (handle)
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js_unref(J, handle); /* delete old function */
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js_copy(J, 1);
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handle = js_ref(J); /* stow the js function in the registry */
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}
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static void call_callback(js_State *J, int arg1, int arg2)
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{
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js_getregistry(J, handle); /* retrieve the js function from the registry */
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js_pushnull(J);
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js_pushnumber(J, arg1);
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js_pushnumber(J, arg2);
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js_pcall(J, 2);
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js_pop(J, 1);
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}
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</pre>
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<h2>Complete userdata example</h2>
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<pre>
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#include <stdio.h>
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#include <mujs.h>
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#define TAG "File"
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static void new_File(js_State *J)
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{
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FILE *file;
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if (js_isundefined(J, 1)) {
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file = stdin;
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} else {
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const char *filename = js_tostring(J, 1);
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file = fopen(filename, "r");
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if (!file)
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js_error(J, "cannot open file: '%s'", filename);
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}
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js_currentfunction(J);
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js_getproperty(J, -1, "prototype");
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js_newuserdata(J, TAG, file);
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}
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static void File_prototype_readByte(js_State *J)
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{
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FILE *file = js_touserdata(J, 0, TAG);
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js_pushnumber(J, getc(file));
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}
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static void File_prototype_readLine(js_State *J)
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{
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char line[256], *s;
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FILE *file = js_touserdata(J, 0, TAG);
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s = fgets(line, sizeof line, file);
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if (s)
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js_pushstring(J, line);
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else
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js_pushnull(J);
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}
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static void File_prototype_close(js_State *J)
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{
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FILE *file = js_touserdata(J, 0, TAG);
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fclose(file);
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js_pushundefined(J);
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}
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void initfile(js_State *J)
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{
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js_getglobal(J, "Object");
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js_getproperty(J, -1, "prototype"); // File.prototype.[[Prototype]] = Object.prototype
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js_newuserdata(J, TAG, stdin); // File.prototype.[[Userdata]] = stdin
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{
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js_newcfunction(J, File_prototype_readByte, "File.prototype.readByte", 0);
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js_defproperty(J, -2, "readByte", JS_DONTENUM);
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js_newcfunction(J, File_prototype_readLine, "File.prototype.readLine", 0);
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js_defproperty(J, -2, "readLine", JS_DONTENUM);
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js_newcfunction(J, File_prototype_close, "File.prototype.close", 0);
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js_defproperty(J, -2, "close", JS_DONTENUM);
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}
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js_newcconstructor(J, new_File, new_File, "File", 1);
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js_defglobal(J, "File", JS_DONTENUM);
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}
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</pre>
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</article>
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<footer>
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<a href="http://artifex.com"><img src="artifex-logo.png" align="right"></a>
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Copyright © 2013-2017 Artifex Software Inc.
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</footer>
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</body>
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</html>
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