PHP heredoc syntax

Question

I was wondering whether:

$foo = <<< EOT
Hello, World!
EOT;

is just as valid as

$foo = <<<EOT
Hello, World!
EOT;

and in particular whether this is true in all versions of PHP (or just the latest ones).

I wonder because I want to know whether a space between the <<< and first EOT identifier is syntactically valid. For instance, my PHP interpreter 5.3.10 runs this correctly but my vim text editor does not syntax-highlight the heredoc in the same way if there is a space between <<< and EOT (the EOT identifier is colored white instead of purple).

So what is the deal here? Are both legal in all versions of PHP or not?

I would always trust the compiler/interpretor before i trust a syntax higlighting parser. If it works it works. — Mihai Stancu
– Mihai Stancu, Commented Jul 13, 2012 at 9:27
if it works, the only thing he knows is that it works with that version. — Karoly Horvath
– Karoly Horvath, Commented Jul 13, 2012 at 9:28
Whether it works with one version or all versions, you can't rely on it working in the future unless PHP specifically allows it. EDIT - which apparently it does... according to answers below. — Pete
– Pete, Commented Jul 13, 2012 at 9:31
Welcome to Stack Overflow! Please learn how to accept answers ... if you have no idea what I'm talking about click here — Manse
– Manse, Commented Jul 13, 2012 at 9:31

Sjoerd · Accepted Answer · 2012-07-13 09:40:59Z

5

Tabs and spaces are allowed, and apparently so are quotes:

<ST_IN_SCRIPTING>b?"<<<"{TABS_AND_SPACES}({LABEL}|([']{LABEL}['])|(["]{LABEL}["])){NEWLINE} {

Source

Edit:

tabs and spaces are allowed from at least 2001
quotes were added in 2008

edited Jul 13, 2012 at 9:40

answered Jul 13, 2012 at 9:29

Sjoerd

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1 Comment

Destralak Over a year ago

Even though this is how the code looks right now, the manual states you should only use alphanumeric chars and underscores, so this code could change in future PHP versions.

Jon · Accepted Answer · 2012-07-13 09:31:01Z

3

The manual says (emphasis mine) that

A third way to delimit strings is the heredoc syntax: <<<. After this operator, an identifier is provided, then a newline.

To me this means that the space is optional (and will always be optional), since in the language as a whole identifiers can be separated from neighboring tokens by any amount of whitespace -- including none.

answered Jul 13, 2012 at 9:31

Jon

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Comments

Destralak · Accepted Answer · 2012-07-13 09:29:34Z

0

No, you should not provide a space between the <<< and the identifier. As specified in the PHP documentation:

(...) the identifier must follow the same naming rules as any other label in PHP: it must contain only alphanumeric characters and underscores, and must start with a non-digit character or underscore.

Source: http://www.php.net/manual/en/language.types.string.php#language.types.string.syntax.heredoc

answered Jul 13, 2012 at 9:29

Destralak

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2 Comments

Destralak Over a year ago

The space is invalid, because the identifier should be there right after the >>>; as quoted: After this operator, an identifier is provided, then a newline

Jon Over a year ago

That's exactly what it looks like to the parser even if you include a hundred spaces in between.

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