${} string interpolation migration script

README.md

Copy the migrator.php file to the root of your project and run the following command:

for file in **/*.php; do php ./migrator.php "$file"; done

BACK UP YOUR REPOSITORY BEFORE RUNNING THIS SCRIPT!

migrator.php

<?php

if ($argc !== 2) {
    fwrite(STDERR, "Missing input script\n");
    die(1);
}

$fileName = $argv[1];
$fileContent = file_get_contents($fileName);
$phpBinary = PHP_BINARY;

exec("$phpBinary -l $fileName", $output, $status);
if ($status !== 0) {
    die($status);
}

$tokens = \PhpToken::tokenize($fileContent);

$nestingStack = [];

foreach ($tokens as $i => $token) {
    $nextToken = $tokens[$i + 1] ?? null;

    if ($token->id === T_DOLLAR_OPEN_CURLY_BRACES) {
        if ($nextToken?->id === T_STRING_VARNAME) {
            // Option 3
            $tokens[$i] = new \PhpToken(T_CURLY_OPEN, '{');
            $tokens[$i + 1] = new \PhpToken(T_VARIABLE, "\$$nextToken->text");
        } else {
            // Option 4
            $token->text = '{${';
            $nestingStack[] = 0;
        }
    }

    if ($token->text === '{' && !empty($nestingStack)) {
        ++$nestingStack[array_key_last($nestingStack)];
    }

    if ($token->text === '}' && !empty($nestingStack)) {
        $nesting = $nestingStack[array_key_last($nestingStack)];
        if ($nesting === 0) {
            $token->text = '}}';
            array_pop($nestingStack);
        } else {
            --$nestingStack[array_key_last($nestingStack)];
        }
    }
}

$result = join('', array_map(fn ($t) => $t->text, $tokens));
file_put_contents($fileName, $result);

test.php

<?php

// Simple
"$foo";
"{$foo}";
"${foo}";

// DIM
"$foo[bar]";
"{$foo['bar']}";
"${foo['bar']}";

// Property
"$foo->bar";
"{$foo->bar}";

// Method
"{$foo->bar()}";

// Closure
"{$foo()}";

// Chain
"{$foo['bar']->baz()()}";

// Variable variables
"${$bar}";
"${(foo)}";
"${foo->bar}";

// Nested
"${foo["${bar}"]}";
"${foo["${bar['baz']}"]}";
"${foo->{$baz}}";
"${foo->{${'a'}}}";
"${foo->{"${'a'}"}}";