Evgeny Gavrin
133 lines
2.9 KiB
Markdown
133 lines
2.9 KiB
Markdown
---
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layout: page
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title: Development
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permalink: /dev-guide/
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---
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# Embedding
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The JerryScript Engine can be embedded into any application, providing way to run JavaScript in large range of environments - from desktops to low-memory microcontrollers.
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## How to execute simple JavaScript file from your application
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```cpp
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#include <string.h>
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#include "jerry.h"
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int
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main (int argc, char * argv[]) {
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char script [] = "print ('Hello, World!');";
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jerry_init (JERRY_FLAG_EMPTY);
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jerry_parse (script, strlen (script));
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jerry_run ();
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jerry_cleanup ();
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}
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```
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The described application will generate the following output:
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```bash
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Hello, World!
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```
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## Simple JavaScript shell
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```cpp
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#include <assert.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "jerry.h"
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static void
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print_value (const jerry_api_value_t * value_p);
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int
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main (int argc, char * argv[]) {
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jerry_init (JERRY_FLAG_EMPTY);
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char cmd [256];
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while (true) {
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printf ("> ");
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if (fgets (cmd, sizeof (cmd), stdin) == NULL
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|| strcmp (cmd, "quit\n") == 0) {
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break;
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}
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jerry_api_value_t ret_val;
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jerry_completion_code_t status = jerry_api_eval (cmd, strlen (cmd),
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false, false,
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&ret_val);
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if (status == JERRY_COMPLETION_CODE_OK) {
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// 'eval' completed successfully
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print_value (&ret_val);
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jerry_api_release_value (&ret_val);
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} else {
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// evaluated JS code thrown an exception
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// and didn't handle it with try-catch-finally
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printf ("Unhandled JS exception occured\n");
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}
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printf ("\n");
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fflush (stdout);
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}
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jerry_cleanup ();
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return 0;
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}
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static void
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print_value (const jerry_api_value_t * value_p)
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{
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switch (value_p->type)
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{
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case JERRY_API_DATA_TYPE_UNDEFINED:
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printf ("undefined");
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break;
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case JERRY_API_DATA_TYPE_NULL:
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printf ("null");
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break;
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case JERRY_API_DATA_TYPE_BOOLEAN:
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if (value_p->v_bool)
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printf ("true");
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else
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printf ("false");
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break;
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case JERRY_API_DATA_TYPE_FLOAT64:
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printf ("%lf", value_p->v_float64);
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break;
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case JERRY_API_DATA_TYPE_STRING:
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{
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ssize_t neg_req_sz, sz;
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// determining required buffer size
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neg_req_sz = jerry_api_string_to_char_buffer (value_p->v_string,
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NULL,
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0);
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assert (neg_req_sz < 0);
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char * str_buf_p = (char*) malloc (-neg_req_sz);
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sz = jerry_api_string_to_char_buffer (value_p->v_string,
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str_buf_p,
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-neg_req_sz);
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assert (sz == -neg_req_sz);
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printf ("%s", str_buf_p);
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free (str_buf_p);
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break;
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}
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case JERRY_API_DATA_TYPE_OBJECT:
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printf ("[JS object]");
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break;
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}
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printf ("\n");
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}
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```
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