Revisit trailing commas in function arguments View as Markdown

Introduction

Arrays in PHP have long since supported trailing commas.

Trailing array commas

$foo = [
    'foo',
    'bar',
];

This makes for clean diffs and easy appending of new values in user-land.

Unfortunately, the argument list for function/method declarations and calls do not share the same luxury.

Declarations raise a parse error

// Parse error
function myFunc(
    $foo,
    $bar,
    ) {
  /* ... */
}

Calls raise a parse error

// Parse error
myFunc(
    $foo,
    $bar,
    );

Proposal

This RFC proposes allowing function/method declarations and calls to allow for trailing commas in order to:

1. Offer a consistent API and match the existing array functionality.
2. Make it easy to append new arguments in user-land.
3. Have cleaner diffs (so only one line shows up as being modified when appending arguments instead of two).
4. Match what HHVM did a while ago.

Backward Incompatible Changes

This change would have no breaking changes.

Proposed PHP Version

PHP 7.1

Proposed Voting Choices

Project requires a 2/3 majority.

Patches and Tests

The original patch by Sara Golemon.