What is the advantage of using heredoc in PHP? [closed]

What is the advantage of using heredoc in PHP, and can you show an example?

Answer

The heredoc syntax is much cleaner to me and it is really useful for multi-line strings and avoiding quoting issues. Back in the day I used to use them to construct SQL queries:

$sql = <<<SQL
select *
  from $tablename
 where id in [$order_ids_list]
   and product_name = "widgets"
SQL;

To me this has a lower probability of introducing a syntax error than using quotes:

$sql = "
select *
  from $tablename
 where id in [$order_ids_list]
   and product_name = "widgets"
";

Another point is to avoid escaping double quotes in your string:

$x = "The point of the "argument" was to illustrate the use of here documents";

The problem with the above is the syntax error (the missing escaped quote) I just introduced as opposed to here document syntax:

$x = <<<EOF
The point of the "argument" was to illustrate the use of here documents
EOF;

It is a bit of style, but I use the following as rules for single, double and here documents for defining strings:

• Single quotes are used when the string is a constant like 'no variables here'
• Double quotes when I can put the string on a single line and require variable interpolation or an embedded single quote "Today is ${user}'s birthday"
• Here documents for multi-line strings that require formatting and variable interpolation.