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Control Structures

Control Structures

In this lesson we will look at the styling rules for control structures.

The general style rules for control structures are as follows:

  • There MUST be one space after the control structure keyword

  • There MUST NOT be a space after the opening parenthesis

  • There MUST NOT be a space before the closing parenthesis

  • There MUST be one space between the closing parenthesis and the opening brace

  • The structure body MUST be indented once

  • The closing brace MUST be on the next line after the body

The body of each structure MUST be enclosed by braces. This standardizes how the structures look, and reduces the likelihood of introducing errors as new lines get added to the body.

if, elseif, else

An if structure looks like the following.

Note the placement of parentheses, spaces, and braces; and that else and elseif are on the same line as the closing brace from the earlier body.

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<?php
if ($expr1) {
    // if body
} elseif ($expr2) {
    // elseif body
} else {
    // else body;
}

The keyword elseif SHOULD be used instead of else if so that all control keywords look like single words.

switch, case

A switch structure looks like the following.

Note the placement of parentheses, spaces, and braces.

The case statement MUST be indented once from switch, and the break keyword (or other terminating keyword) MUST be indented at the same level as the case body.

There MUST be a comment such as // no break when fall-through is intentional in a non-empty case body.

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<?php
switch ($expr) {
    case 0:
        echo 'First case, with a break';
        break;
    case 1:
        echo 'Second case, which falls through';
        // no break
    case 2:
    case 3:
    case 4:
        echo 'Third case, return instead of break';
        return;
    default:
        echo 'Default case';
        break;
}

while, do while

A while statement looks like the following.

Note the placement of parentheses, spaces, and braces.

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<?php
while ($expr) {
    // structure body
}

Similarly, a do while statement looks like the following.

Note the placement of parentheses, spaces, and braces.

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<?php
do {
    // structure body;
} while ($expr);

for

A for statement looks like the following. Note the placement of parentheses, spaces, and braces.

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<?php
for ($i = 0; $i < 10; $i++) {
    // for body
}

foreach

A foreach statement looks like the following.

Note the placement of parentheses, spaces, and braces.

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<?php
foreach ($iterable as $key => $value) {
    // foreach body
}

try, catch

A try catch block looks like the following. Note the placement of parentheses, spaces, and braces.

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<?php
try {
    // try body
} catch (FirstExceptionType $e) {
    // catch body
} catch (OtherExceptionType $e) {
    // catch body
}