Linting

Linting reports structural, link, accessibility, code, and style problems without changing the document.

Run the recommended rules

<?php
use Alto\Markdown\Lint\LintConfig;
use Alto\Markdown\Markdown;

$document = Markdown::github()->fromString(
    "# Guide\n\nVisit https://example.com",
);
$report = $document->lint(LintConfig::recommended());

foreach ($report as $problem) {
    echo $problem->ruleId.': '.$problem->message."\n";
}

LintReport is iterable and countable. isClean() means no problem was reported; hasErrors() means at least one problem has error severity. Each problem carries its rule ID, severity, message, original byte range, and an optional safe fix.

Derive a policy

LintConfig is immutable:

<?php
use Alto\Markdown\Lint\LintConfig;
use Alto\Markdown\Lint\LintSeverity;

$config = LintConfig::recommended()
    ->withoutRule('no-bare-urls')
    ->withRule('require-code-block-language')
    ->withSeverity('require-code-block-language', LintSeverity::Warning);

Rules with options accept their dedicated LintRuleOptions type. Unknown rules and invalid option types fail before traversal.

The built-in set covers title and heading structure, dead anchors and references, image alternatives, empty and bare links, code fence language and closure, GFM table columns, trailing spaces, and final newlines.

Continue with Fixing to apply attached safe fixes. Use Formatting for syntax style rather than diagnostics.