CEF Writer

A small PHP library that streams valid Condorcet Election Format (CEF) documents to a file or string with a friendly object API.

• Streaming: every add*() call writes one line immediately — nothing is buffered, nothing can be edited afterwards.
• Format-safe: the spec's syntactic rules (reserved characters, blank-ballot sentinel, single-line constraints, parameter-before-vote ordering) are enforced. Invalid input throws.
• Semantics-free on purpose: this library checks format, never election logic (it will, for example, happily let a vote reference a candidate that is not in #/Candidates:).
• Works with \SplFileObject, \SplFileInfo, a filesystem path, or a string passed by reference.

Full API reference — generated from the source with PhpReference.

Requirements

• PHP 8.5 or later
• ext-mbstring (used for UTF-8 validation; bundled with PHP)

Installation

composer require condorcet-vote/cef-writer

Quick start

use CondorcetVote\CefWriter\Cef;
use CondorcetVote\CefWriter\CommentLine;
use CondorcetVote\CefWriter\VoteLine;
use CondorcetVote\CefWriter\Parameter\CandidatesParameter;
use CondorcetVote\CefWriter\Parameter\ImplicitRankingParameter;
use CondorcetVote\CefWriter\Parameter\WeightAllowedParameter;

$cef = new Cef(file: '/tmp/election.cvotes');

$cef->addComment(new CommentLine('My beautiful election'));
$cef->addParameter(new CandidatesParameter(['Alice', 'Bob', 'Charlie']));
$cef->addParameter(new ImplicitRankingParameter(true));
$cef->addParameter(new WeightAllowedParameter(true));

$cef->addVote(new VoteLine(
    ranking: [['Alice'], ['Bob'], ['Charlie']],
    quantifier: 42,
));
$cef->addVote(new VoteLine(
    ranking: [['Charlie'], ['Alice', 'Bob']],
    weight: 7,
    quantifier: 8,
));
$cef->addVote(new VoteLine(ranking: [])); // blank ballot (/EMPTY_RANKING/)

produces:

# My beautiful election
#/Candidates: Alice ; Bob ; Charlie
#/Implicit Ranking: true
#/Weight Allowed: true

Alice > Bob > Charlie * 42
Charlie > Alice = Bob ^7 * 8
/EMPTY_RANKING/

Output targets

The Cef constructor accepts exactly one of the following:

Argument	Type	Behaviour
file: $path	string	Opened with mode wb (created/truncated).
file: $info	\SplFileInfo	Opened with mode wb.
file: $object	\SplFileObject (must already be open)	Used as-is.
string: $buf	string passed by reference	Each line is appended to the caller's variable.

$buffer = '';
$cef = new Cef(string: $buffer);
$cef->addParameter(new CandidatesParameter(['A', 'B']));
echo $buffer; // "#/Candidates: A ; B\n"

autoFormat

$cef->autoFormat is a public bool (default true):

• true — writes the readable flavor of the spec: spaces around >, =, ;, ,, ||, ^, *; one blank line is inserted automatically between the parameter block and the first vote.
• false — writes the compact form with no optional whitespace and no auto blank line.

$cef->autoFormat = false;
$cef->addParameter(new CandidatesParameter(['A', 'B']));
$cef->addVote(new VoteLine([['A'], ['B']]));
// "#/Candidates:A;B\nA>B\n"

Building blocks

Parameters

Each standard parameter has its own typed object. Custom parameters are supported via CustomParameter. The StandardParameter enum lists the exact spec names.

Class	CEF name	Constructor
CandidatesParameter	Candidates	array<int, string>
NumberOfSeatsParameter	Number of Seats	int >= 1
ImplicitRankingParameter	Implicit Ranking	bool
VotingMethodsParameter	Voting Methods	array<int, string>
WeightAllowedParameter	Weight Allowed	bool
CustomParameter	(free-form)	string $name, string $value

Parameters can only be added before the first vote — any later call throws CefFormatException.

Vote lines

The typed way — build a VoteLine and pass it to Cef::addVote():

new VoteLine(
    ranking:       [['Alice'], ['Bob', 'Charlie']], // [] => /EMPTY_RANKING/
    tags:          ['voter@example.com'],
    weight:        7,
    quantifier:    3,
    inlineComment: 'late ballot',
);

Each rank is itself a list of tied candidates. An empty top-level ranking emits the /EMPTY_RANKING/ blank-ballot sentinel.

From a raw string — VoteLine::fromString()

Parse a full CEF vote-line string into a VoteLine instance. Every component is optional except the ranking; both the relaxed (A > B ^7 * 2) and the compact (A>B^7*2) spacing flavors are accepted, plus the /EMPTY_RANKING/ sentinel.

$cef->addVote(VoteLine::fromString('voter@example.com || Alice > Bob ^7 * 3 # late ballot'));

The string is parsed, every component is validated against the same rules as the constructor, and a VoteLine is returned. Throws CefFormatException on any malformed component.

Pre-validated raw lines — Cef::addRawVoteLine()

When you already have ballots as text and want the fastest write path, addRawVoteLine() skips the VoteLine allocation while still enforcing the full CEF format:

$cef->addRawVoteLine('Alice > Bob = Charlie ^7 * 8');

It strips one trailing line terminator (\r\n, \n, \r), trims, rejects empty / multi-line / leading-# inputs, then runs VoteLine::assertValidString() for the same deep validation as fromString(). The autoFormat flag is not applied — what you pass is what gets written. About 1.8× faster than addVote(VoteLine::fromString()) in practice.

Validation-only — VoteLine::assertValidString()

If you want to validate a vote-line string without allocating a VoteLine (e.g. to pre-flight user input before queueing it elsewhere), call the static assertValidString() — same pipeline as fromString(), no object returned, throws CefFormatException on any violation.

Comments and blank lines

$cef->addComment(new CommentLine('section divider'));
$cef->addCommentLine('shortcut — builds the CommentLine for you');
$cef->addEmptyLine();

Inline comments attached to vote lines live on VoteLine::$inlineComment. The CEF spec forbids inline comments on parameter lines, so the parameter classes intentionally do not expose one.

Errors

Two top-level hierarchies, each for a different layer.

Format & input violations — CefFormatException

Base class for every specification or input violation. Catch this one to handle any format-related failure uniformly; catch a specific subclass below to branch on a kind of violation. Each message names the offending field and the rule that was broken.

Subclass	Thrown for
InvalidUtf8Exception	Byte sequence that does not decode as valid UTF-8.
ReservedCharacterException	One of the spec-reserved characters (> = ; , # / * ^), a : in a custom parameter name, || inside a tag, or a leading # on a raw vote line.
InvalidValueException	Empty required string, embedded line break, null byte, non-positive weight / quantifier, empty #/Candidates: or #/Voting Methods: list, or empty rank inside a ranking.
DuplicateCandidateException	Same candidate label appearing twice in #/Candidates: or anywhere inside a ranking (including across tied groups).
InvalidWriterStateException	Cef constructed with neither a file nor a string target (or with both); parameter added after the first vote; vote-line string parsed without a ranking.

All subclasses extend CefFormatException, which itself extends \RuntimeException.

I/O failures — CefWriteException

Thrown when writing to the underlying target (file or string buffer) fails — typically a closed handle, a read-only file, or a full disk. Distinct from CefFormatException because the cause is I/O, not your input. Extends \RuntimeException.

Development

composer install
vendor/bin/pest                                # run tests
vendor/bin/phpstan analyse                     # static analysis
vendor/bin/php-cs-fixer fix                    # apply lint
vendor/bin/php-cs-fixer fix --dry-run --diff   # check lint without writing

CI (.github/workflows/ci.yml) runs the test suite on Linux / Windows / macOS, plus a dedicated job with JIT function mode enabled, plus PHPStan and PHP CS Fixer.

License

MIT — see LICENSE.