Echoing of all variables is nearly foolproof - I can't quite get the meaning of "echoing of all variables"

Question

Parameters send information to a function, and then the function executes the code. Functions can use anywhere from zero parameters to a whole list of them. In Example 5-1, you’ll use the echo function to display some text. echo displays text that you send to it as a parameter. Most functions require you to place their parameters inside of parentheses, but echo is an exception to this rule. Echoing of all variables is nearly foolproof!

(From Learning PHP & MySQL by Michele E. Davis, Jon A. Phillips, p. 86)

I don't understand what it really says. Maybe it's better to say echoing variables is nearly foolproof!?

Answer 1

Programming languages usually have a method for causing a string or variable to be output as text.

• echo
• print
• puts
• ...

Often these are used in the same manner as any function in the language's standard library, but are often implemented as a language construct rather than an actual function.

The author is pointing out that in PHP, although you can use parenthesis around the input to "echo" you don't need to! I agree that the way the author wrote this is not very clear. He say's that the echoing (printing a variable to the output) is nearly foolproof because if you forget the parens it will still output.

echo $my_var;

is just as correct as

echo($my_var);