What is the difference between PHP functions and Erlang functions?

Key differences between PHP functions and Erlang functions: Syntax: PHP uses C-style syntax with parameters enclosed in parentheses, while Erlang uses suffix notation with parameters following the function name. Return value: PHP functions return a value explicitly, while Erlang functions return the value of the last expression. Parameter passing: PHP can pass parameters by value or reference, while Erlang always passes by reference. Variadics: PHP supports variadic arguments, while Erlang does not.

The difference between PHP functions and Erlang functions

In PHP and Erlang, two different programming languages, the concept of functions There are some key differences. Understanding these differences is crucial for converting from one language to another and for programming effectively in these languages.

Syntax

PHP functions follow traditional C-style syntax, with the parameter list enclosed in parentheses:

function myFunction($param1, $param2) {
  // 函数体
}

Erlang functions, on the other hand, are represented using suffixes method, where the parameters follow the function name and are separated by periods:

myFunction(Param1, Param2) ->
  % 函数体

Return value

For a PHP function to explicitly return a value, use return Keywords:

function myFunction() {
  return "Hello world!";
}

In Erlang, functions have no explicit return value. Instead, the value of the last evaluated expression is returned as the result of the function, similar to pattern matching:

myFunction() ->
  case 1 =:= 1 of
    true -> "Hello world!";
    false -> "Error"
  end.

Parameter passing

PHP functions pass parameters by value or reference. By default, parameters are passed by value. To pass by reference, use the & symbol before the parameter type:

function myFunction(&$param) {
  // 对 $param 的修改将反映在调用方
}

In Erlang, functions always pass parameters by reference. This is because Erlang uses a procedural programming paradigm where variables point to values ​​in memory.

Variable parameters

PHP allows functions to define a variable number of parameters, using the ... notation:

function myFunction(...$params) {
  // $params 是一个数组，包含了所有参数
}

Erlang does not support variadic arguments.

Practical Case

Consider the following example of a PHP and Erlang function for calculating the sum of two numbers:

PHP

function sum($num1, $num2) {
  return $num1 + $num2;
}

Erlang

sum(Num1, Num2) ->
  Num1 + Num2.

When calling these functions, the PHP function will return a value, while the Erlang function will have no explicit return value. The following are examples of calling these two functions:

PHP

$result = sum(10, 20);
echo $result; // 输出：30

Erlang

X = sum(10, 20),
io:fwrite("Result: ~p\n", [X]). % 输出：Result: 30

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