Parameter.php

<?php

declare(strict_types=1);

/*
 * Parameter includes parsing functions to extract parameters, values, and metadata
 * from templates.
 */

require_once 'user_messages.php';  // @codeCoverageIgnore
require_once 'constants.php';      // @codeCoverageIgnore

final class Parameter {
  public string $pre = '';
  public string $param = '';
  public string $eq = '';
  public string $val = '';
  public string $post = '';

/*
 * Breaks a citation template down to component parts.
 * Expects that any instances of "|" in $text will have been replaced with
 * PIPE_PLACEHOLDER (usually '%%CITATION_BOT_PIPE_PLACEHOLDER%%') before this is called.
 */
  public function parse_text(string $text): void {
    $text = str_replace(PIPE_PLACEHOLDER, '|', $text);
    $split = explode('=', $text, 2);
    // Split the text before the '=' into constituent parts:
    // $pre_eq[1]: any whitespace before the parameter name (including newlines)
    // $pre_eq[2]: the parameter name itself (which can span multiple lines)
    // $pre_eq[3]: any whitespace after the parameter name (including newlines)
    preg_match('~^(\s*?)(\S[\s\S]*?)(\s*+)$~u', $split[0], $pre_eq);
    if (count($split) === 2) {
      // Split the text after the '=' into constituent parts:
      // $post_eq[1]: any whitespace before the parameter value (including newlines)
      // $post_eq[2]: the parameter value itself (which can span multiple lines)
      // $post_eq[3]: any whitespace after the parameter value (including newlines)
      preg_match('~^([ \n\r\t\p{Zs}]*)([\s\S]*?)(\s*+)$~u', $split[1], $post_eq);
      if (count($pre_eq) === 0) {
        $this->eq    = $split[0] . '=' . $post_eq[1];
      } else {
        $this->pre   = $pre_eq[1];
        $this->param = $pre_eq[2];
        $this->eq    = $pre_eq[3] . '=' . $post_eq[1];
      }
      $this->post  = $post_eq[3];
      $this->val   = $post_eq[2];
    } elseif ($pre_eq) {
      $this->pre  = $pre_eq[1];
      $this->val  = $pre_eq[2];
      $this->post = $pre_eq[3];
    } else {
      $this->val  = $text;
    }
    // Comments before parameter names
    while (preg_match('~^# # # CITATION_BOT_PLACEHOLDER_COMMENT \d+ # # #(?:\s*)~isu', $this->param, $match)) {
      $this->pre .= $match[0];
      $this->param = str_replace($match[0], '', $this->param);
    }
    // Comments after parameter names
    while (preg_match('~(?:\s*)# # # CITATION_BOT_PLACEHOLDER_COMMENT \d+ # # #$~isu', $this->param, $match)) {
      $this->eq = $match[0] . $this->eq;
      $this->param = str_replace($match[0], '', $this->param);
    }
    // Clean up line feeds
    if ($this->val === '' && $this->post === '') {
      if (preg_match('~^([^=]*=[^\n\r]*)([\n\r][\s\S]*)$~u', $this->eq, $match)) {
        $this->eq = $match[1];
        $this->post = $match[2];
      }
    }

  }

/*
 * Returns a string with, for example, 'param1 = value1 | param2 = value2, etc.'
 */
  public function parsed_text(): string {
    if ($this->param && empty($this->eq)) {              // code used to do this
      report_error('Missing equals in parameter');       // @codeCoverageIgnore
    }
    return $this->pre . $this->param . $this->eq . $this->val . $this->post;
  }
}