PHP code example of nathanjel / sel-lang

    
        
<?php
require_once('vendor/autoload.php');

/* Start to develop here. Best regards https://php-download.com/ */

    

nathanjel / sel-lang example snippets

$rule = Sel::compile('IF(QTY * PRICE > LIMIT, "over budget", "ok")');
foreach ([['QTY' => '3', 'PRICE' => '19.99'], ['QTY' => '1', 'PRICE' => '5.00']] as $row) {
    $ctx = Value::fromNative($row + ['LIMIT' => '50.00']);
    printf("   QTY=%s PRICE=%s => %s\n", $row['QTY'], $row['PRICE'], $rule->run($ctx)->asText());
}

final class RuleSet
{
    private array $rules = [];

    public function __construct(array $sources)      // field => SEL source
    {
        foreach ($sources as $field => $source) {
            $this->rules[$field] = Sel::compile($source);
        }
    }

    public function validate(array $payload): array
    {
        $messages = [];
        foreach ($this->rules as $field => $program) {
            $context = Value::fromNative($payload);
            try {
                $result = $program->run($context)->asText();
            } catch (SelError $e) {
                $result = self::present($field, $e);
            }
            if ($result !== '') {
                $messages[$field] = $result;
            }
        }
        return $messages;
    }

    private static function present(string $field, SelError $e): string
    {
        if ($e->code === 'E_ABORT') {
            return $e->getMessage();
        }
        error_log("SEL rule for {$field} failed: {$e}");
        return 'could not be validated';
    }

$ node js/bin/sel.mjs -e '2.50 + 2.50'
5.00
$ php php/bin/sel -e 'JOIN(MAP((1,2,3), _ * _), ",")'
1,4,9
$ php php/bin/sel --deps -e 'T = QTY * PRICE; T > LIMIT'
LIMIT
PRICE
QTY
$ node js/bin/sel.mjs          # REPL, keeps its context between lines
sel> A = (1, 2, 3)
-{"1"=t"1", "2"=t"2", "3"=t"3"}
sel> SUM(A, _)
6

sel
A[1] = (A = 2); A       => t"2"{"1"=t"2"}

sel
A[COUNT(A)] = 1; A          => -{"0"=t"1"}
A = 1; A += (A = 5); A      => 6

sel
2.50 + 2.50                       => 5.00
0.10 + 0.20 == 0.30               => TRUE
1 / 3                             => 0.3333333333
"5.00" == "5"                     => TRUE
"5.00" $== "5"                    => FALSE
A = 3; "value {A} here"           => value 3 here
JOIN(("a", "b", "c"), "-")        => a-b-c
A = (1, 2); A = (A, 3); COUNT(A)  => 3
A[1] = 3; A == 3                  => TRUE
ALL((1, 2, 3), _ > 0)             => TRUE
JOIN(MAP((1, 2), _ * 2), ",")     => 2,4
SUM((1.5, 2.5), _)                => 4.0
S = 85; COND(S >= 90, "A", S >= 80, "B", "F")  => B
LEN("Zażółć") & "/" & BLEN("Zażółć")           => 6/10
RMATCH('^\d{2}-\d{3}$', "31-874")              => TRUE
IF(1, "a", "b")                   => !E_NOT_BOOL
" 2" + 1                          => !E_NOT_NUM
1 < 2 < 3                         => !E_SYNTAX
NULL ?? "default"                 => default
"   " ??? "fallback"              => fallback
IS_NULL(NULL)                     => TRUE
IS_BLANK("   ")                   => TRUE