Conversion of AST of an arithmetic expression into a string representation of code

Given: an arithmetic expression represented as an AST (Abstract Syntax Tree) in prefix notation.

The AST can be either a floating-point number or an array where the first element is always a string representing an arithmetic operation, and the subsequent elements are its arguments (also in the form of AST):

AST = float | ['operation', operand1, operand2, ..., operandN], where operand1, operand2, ... are ASTs.

Supported operations:

• unary minus (-)
• unary plus (+)
• addition (+)
• subtraction (-)
• multiplication (*)
• division (/).

It can be assumed that the input data is always correct.

You need to implement the function astToCode that takes an AST and returns a string with the equivalent code.

function astToCode(array|float $node): string
{
    // implementation of transformation
}

function test(array|float $node, string $expected): void
{
    $actual = astToCode($node);
    echo $actual === $expected ? 'OK' : "FAIL ";
    echo ": $expected" . PHP_EOL;
}

test(5, '5');
test([['+', 1, 2], '-', 3]], '-(+1 2)');
test(['+', -1], '+(-1)');
test([['*', 1, 2], '*', [ '-', 3, 1]], '(1 * 2) * (3 - 1)');
test([[['*', 2, 5], '*', 7], '/', ['-', 8, ['+', 5, 6]]]], '2 * 5 * 7 / (8 - (5 + 6))');
test([['+', 1, 2], '-', ['-', 3, 4], '-', ['+', 5, 6]],], '1 + 2 - (3 - 4) - (5 + 6)');