Nested ternary examples in JavaScript, Python, PHP

!ternary-example.md

ternary-example

Example of nested ternary not acting the same in JavaScript and PHP.

Furthermore, PHP 8.0 now throws a fatal error when nested ternaries are used without parentheses.

Conclusion: just don't use nested ternaries.

Usage

# Run the JavaScript example
./ternary.js

# Run the Python example
./ternary.py

# Run the PHP examples using Docker
docker-compose up --build

Expected output

JavaScript
two

Python
two

ternary-php7-1  | PHP 7.4.33
ternary-php7-1  | three
ternary-php7-1 exited with code 0

ternary-php8-1  |
ternary-php8-1  | Fatal error: Unparenthesized `a ? b : c ? d : e` is not supported. Use either `(a ? b : c) ? d : e` or `a ? b : (c ? d : e)` in /usr/src/myapp/ternary.php on line 9
ternary-php8-1 exited with code 255

docker-compose.yml

version: '3.8'

services:
  ternary-php7:
    build:
      context: .
      dockerfile: Dockerfile.php7
    volumes:
      - ./ternary.php:/usr/src/myapp/ternary.php

  ternary-php8:
    build:
      context: .
      dockerfile: Dockerfile.php8
    volumes:
      - ./ternary.php:/usr/src/myapp/ternary.php

Dockerfile.php7

FROM php:7.4-cli
COPY ternary.php /usr/src/myapp/ternary.php
WORKDIR /usr/src/myapp
CMD [ "php", "./ternary.php" ]

Dockerfile.php8

FROM php:8.3-cli
COPY ternary.php /usr/src/myapp/ternary.php
WORKDIR /usr/src/myapp
CMD [ "php", "./ternary.php" ]

ternary.js

#!/usr/bin/env node

console.log('JavaScript')

const a = 2;

console.log(
	  a === 1 ? 'one'
	: a === 2 ? 'two'
	: a === 3 ? 'three'
	          : 'other'
)

ternary.php

#!/usr/bin/env php
<?php

echo "PHP " . PHP_VERSION . "\n";

$a = 2;

print(
	  $a === 1 ? 'one'
	: $a === 2 ? 'two'
	: $a === 3 ? 'three'
	           : 'other'
);

ternary.py

#!/usr/bin/env python3

print('Python')

a = 2

print(
    'one' if a == 1
    else 'two' if a == 2
    else 'three' if a == 3
    else 'other'
)