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