Statements (GNU Radius Reference Manual)

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10.2.8.8 Rewrite Statements

The Rewrite statements are: expressions, conditionals, loops, and return statements. A simple statement is terminated by a semicolon. A compound statement is one or more statements enclosed in curly brackets.

Conditionals

A conditional statement is:

if (expr)
 a
else
 b

Here, expr is any expression, a and b are statements (simple or compound). The expression expr is evaluated and its result is coerced to boolean value. If the resulting value is ‘true’, then the statement a is executed, otherwise, the statement b is executed. The else part is optional. Conditional expressions can be chained:

if (e1)
 a;
else if (e2)
 b;
else if (e3)
 c;
else
 d;

This is equivalent to

if (e1)
 a;
else {
 if (e2)
 b;
 else {
 if (e3)
 c;
 else
 d;
 }
}

Loops

Two kinds of loops are provided: while, and do-while loops.

A while loop is:

while (expr) stmt

A do-while loop is:

do stmt while (expr)

Both loops run stmt (which is usually a compound statement) for as long as expr evaluates to ‘true’. The main difference is that a while loop is executed 0 or more times, while a do-while loop is executed 1 or more times.

The following statements can appear within a stmt in a loop:

break ¶: Break from the loop immediately. Control flow resumes at the first statement after the loop.
continue ¶: Branch to expr immediately.

The `return` statement

return expr

The return statement stops execution of the current function and returns to the caller. Its argument is evaluated and the resulting value becomes the function return value.