Editing PHP Skills Tests (section)

=== Is `print()` a function? ===

`print()` is a language construct. <ref>[http://php.net/manual/en/function.print.php print()], PHP documentation</ref>

<syntaxhighlight lang="php">
echo ((function_exists("print"))?("y"):("n")); /* <<< output is "n" */
echo ((function_exists("printf"))?("y"):("n")); /* <<< output is "y" */
echo ((function_exists("echo"))?("y"):("n")); /* <<< output is "n" */
</syntaxhighlight>

* Both `echo` and `print` are constructs, not functions. This makes parentheses deceiving. 
* Both `echo` and `print` will output everything that follows to the right.
* `echo` does not return a value.
* `print` ''always'' returns `1`, never the value to the right of it.
* Also, the string concatenation operator (`.`) has high precedence in PHP. But that's a red herring in the following example.

<syntaxhighlight lang="php">
echo '1'.print(2)+3; // result: 511
/**
 * `echo` in this example prints everything that comes after it. It's necessary to evaluate everything to the right of 'echo' first.
 * `print` also outputs everything to the right, regardless of parentheses.
 * (1) Add (2) + 3 results in the value 5
 * (2) print 5 outputs 5 to stdout, and returns the value `1`.
 * (3) Concatenate '1' with the return value of 'print' results in "11"
 * (4) 'echo' the output after what's already been sent to stdout, so "11" follows the "5".
 */
</syntaxhighlight>