Pros of mjs

• Smaller footprint and lower memory usage
• Simpler codebase, easier to understand and modify
• Better suited for resource-constrained embedded systems

Cons of mjs

• Less feature-rich compared to JerryScript
• Smaller community and fewer resources available
• Limited compatibility with existing JavaScript libraries

Code Comparison

mjs:

void mjs_init(struct mjs *mjs) {
  memset(mjs, 0, sizeof(*mjs));
  mjs->stack.len = 0;
  mjs->stack.size = 8;
  mjs->stack.buf = calloc(1, mjs->stack.size);
}

JerryScript:

jerry_init_t init_flags = JERRY_INIT_EMPTY;
jerry_context_t *context_p = jerry_create_context(init_flags, NULL);
jerry_value_t global_obj_val = jerry_get_global_object();
jerry_release_value(global_obj_val);

Both projects aim to provide JavaScript engines for embedded systems, but mjs focuses on simplicity and minimal resource usage, while JerryScript offers a more comprehensive implementation with broader compatibility. mjs is better suited for extremely resource-constrained environments, while JerryScript provides a more feature-rich experience at the cost of increased complexity and resource requirements.

Pros of MicroPython

• More comprehensive standard library, closer to CPython
• Supports a wider range of microcontrollers and embedded systems
• Active community with frequent updates and contributions

Cons of MicroPython

• Larger memory footprint compared to JerryScript
• Slower execution speed for certain operations
• Less focus on JavaScript compatibility

Code Comparison

MicroPython:

import machine
import time

led = machine.Pin(2, machine.Pin.OUT)
while True:
    led.toggle()
    time.sleep(1)

JerryScript:

var led = Pin(2, Pin.OUT);
setInterval(function() {
  led.toggle();
}, 1000);

Both examples demonstrate LED blinking, but MicroPython uses Python syntax and built-in modules, while JerryScript uses JavaScript with a hypothetical Pin API. MicroPython's approach is more familiar to Python developers, while JerryScript caters to those preferring JavaScript for embedded development.

JerryScript focuses on providing a lightweight JavaScript engine for resource-constrained devices, while MicroPython aims to bring a more complete Python implementation to microcontrollers. The choice between them depends on factors such as target hardware, preferred language, and specific project requirements.

Pros of Espruino

• Designed specifically for microcontrollers, offering better optimization for low-resource environments
• Includes a Web IDE for easy development and flashing of devices
• Provides a comprehensive set of built-in modules for hardware interaction

Cons of Espruino

• Less flexible for general-purpose JavaScript applications
• Smaller community and ecosystem compared to JerryScript
• More focused on specific hardware platforms, potentially limiting portability

Code Comparison

Espruino:

var led = LED1;
setInterval(function() {
  led.toggle();
}, 500);

JerryScript:

var pin = 13;
setInterval(function() {
  digitalWrite(pin, !digitalRead(pin));
}, 500);

Both examples demonstrate LED blinking, but Espruino's API is more abstracted and tailored for its specific hardware, while JerryScript uses a more generic approach that might require additional setup or libraries depending on the platform.

Espruino is optimized for quick prototyping and ease of use on supported microcontrollers, whereas JerryScript offers more flexibility and can be integrated into a wider range of projects and platforms. The choice between them depends on the specific requirements of your project and the target hardware.

Pros of ChezScheme

• Highly optimized Scheme implementation with a focus on performance
• Supports both interpreted and compiled execution modes
• Extensive standard library and documentation

Cons of ChezScheme

• Larger footprint and resource requirements compared to JerryScript
• Less suitable for embedded or resource-constrained environments
• Steeper learning curve for developers new to Scheme

Code Comparison

ChezScheme:

(define (factorial n)
  (if (= n 0)
      1
      (* n (factorial (- n 1)))))

JerryScript:

function factorial(n) {
  return n === 0 ? 1 : n * factorial(n - 1);
}

Summary

ChezScheme is a powerful Scheme implementation designed for performance and flexibility, while JerryScript is a lightweight JavaScript engine for resource-constrained devices. ChezScheme offers more advanced features and a comprehensive standard library, making it suitable for complex applications. JerryScript, on the other hand, excels in embedded systems and IoT devices due to its small footprint and low memory requirements.

The code comparison demonstrates the syntactical differences between Scheme and JavaScript, with ChezScheme using a more functional style and JerryScript following JavaScript conventions. Both implementations achieve the same result, but ChezScheme's syntax may be less familiar to developers accustomed to C-style languages.