PHP and MySQL Web Development 4th Ed-tqw-_darksiderg

Writing Maintainable Code
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Variable names should describe the data they contain. If you are storing somebody’s surname,
call it $surname.You need to find a balance between length and readability. For
example, storing the name in $n makes it easy to type, but the code is difficult to understand.
Storing the name in $surname_of_the_current_user is more informative, but it’s
a lot to type (and therefore easier to make a typing error) and doesn’t really add that
much value.
You need to make a decision on capitalization.Variable names are case sensitive in
PHP, as we’ve mentioned previously.You need to decide whether your variable names will
be all lowercase, all uppercase, or a mix—for example, capitalizing the first letters of
words.We tend to use all lowercase because this scheme is the easiest to remember for us.
Distinguishing between variables and constants with case is also a good idea. A common
scheme is to use all lowercase for variables (for example, $result) and all uppercase
for constants (for example, PI).
One bad practice some programmers use is to have two variables with the same name
but different capitalization just because they can, such as $name and $Name.We hope it is
obvious why this practice is a terrible idea.
It is also best to avoid amusing capitalization schemes such as $WaReZ because no one
will be able to remember how it works.
You should also think about what scheme to use for multiword variable names. For
example, we’ve seen all the following schemes:
$username
$user_name
$userName
It doesn’t matter which you opt for, but you should try to be consistent about usage.You
might also want to set a sensible maximum limit of two to three words in a variable
name.
Function names have many of the same considerations, with a couple of extras.
Function names should generally be verb oriented. Consider built-in PHP functions
such as addslashes() or mysqli_connect(), which describe what they are going to do
to or with the parameters they are passed.This naming scheme greatly enhances code
readability. Notice that these two functions have a different naming scheme for dealing
with multiword function names. PHP’s functions are inconsistent in this regard, partly as
a result of having been written by a large group of people, but mostly because many
function names have been adopted unchanged from various different languages and
APIs.
Also remember that function names are not case sensitive in PHP.You should probably
stick to a particular format anyway, just to avoid confusion.
You might want to consider using the module-naming scheme used in many PHP
modules—that is, prefixing the name of functions with the module name. For example,
all the improved MySQL functions begin with mysqli_, and all the IMAP functions
begin with imap_. If, for example, you have a shopping cart module in your code, you
could prefix the function in that module with cart_.