In SIL, the for statement

provides two

primary iteration methods:

• standard

• form: simply for

• foreach form

The

standard form

Syntax

for(<init>; <condition>; <increment>){
   Instruction1;
   ...
   InstructionN;
}

Example

// Prints numbers from 0 to 9
for (

Example Description

This example demonstrates a basic iteration:

• Initializes a counter i to 0

• Continues looping while i is less than 10

• Increments i by 1 in each iteration

• Prints each number from 0 to 9 (total 10 numbers)

The foreach form

Syntax

for(

in #{array}){
   Instruction1;
   ...
   InstructionN;
}

Example

Code Block
for(string user in watchers){ print(user); }

Example description

This foreach loop iterates through a collection of watchers of a specific issue and prints the list of the watchers:

• Automatically iterates through each element in the watchers array

• Assigns each element to the user variable in each iteration

• Prints the name of each watcher

While Statement 

The while statement

provides support for

conditional repetative execution of a code block. It evaluates the condition first

:

• If the condition is true, the instructions in the body (the loop) is executed.

• If the condition is false from the start, the loop body is never executed.

Syntax

while(condition) {
    Instruction1;
    ...                // Instructions when condition is true
    InstructionN;
}

Example

number i = 1;
while(i <= 3) {
    multisel = arrayAddElement(multisel,"value" + i);
    i = i + 1;
}

Example Description

This while loop in this example demonstrates how to build a collection incrementally:

• Starts with i as 1

• Continues looping while i is less than or equal to 3

• In each iteration, adds a new element to multisel array

• Element is created by concatenating "value" with the current value of i

• After completion, multisel will contain ["value1", "value2", "value"]

Do-While Statement

The do-while statement is similar to the while statement

except that it guarantees at least one execution of its code block before evaluating the termination condition. Even if the condition is false, the instructions will still be evaluated once.

Syntax

The general syntax:

do {
    Instruction1;
    ...
    InstructionN;
} while(condition);

Example

number i = 1;
string [] people;
do {
    people += watchers[i];
    i = i + 1;
} while(i < 5);

Example description

This example do-while loop populates a people array, ensuring at least one processing of the loop body:

• Starts with i as 1

• Adds watchers to the people array from index 1

• Increments i after each iteration

• Continues until i is no longer less than 5

Switch Statement

The switch statement

provides a structured mechanism for conditional execution based on the value of a specific variable.

• It accepts both number and string variables.

• Evaluates the input variable against multiple predefined case values.

• Executes the first matching case's code block.

• Continues executing subsequent cases unless a break statement is used.

• Can support specific handling for unmatched cases through the default branch.

Syntax

Example 1: Switch with numbers (with break statements and default branch)

switch (priority) {    // priority is a number variable
    case 1:
        // Executes only when priority equals 1
        escalateImmediately();
        break;         // Prevents fallthrough to case 2
    case 2:
        // Executes only when priority equals 2
        scheduleReview();
        break;         // Prevents fallthrough to case 3
    case 3:
        // Executes only when priority equals 3
        addToBacklog();
        break;         // Prevents fallthrough to default
    default:
        // Executes when priority doesn't match 1, 2, or 3
        logInvalidPriority();
}

Example 2: Switch with string matching

switch (

// Handles any status value not matching above cases
        logUnknownStatus();
}

Examples description:

In both examples, cases are evaluated from top to bottom. Only equal values trigger case execution.

• The break statement terminates the switch block's execution after a case is handled, preventing unintended fallthrough to subsequent cases. The second example demonstrates an intentional fallthrough. For additional information about the break statement, refer to the Break Statement section.

• The default branch functions as an essential catch-all mechanism within the switch statement. It executes when the input value doesn't match any of the defined case values, providing a way to handle unexpected or unspecified inputs. While optional, including a default branch is considered best practice as it ensures comprehensive handling of all possible input values and helps prevent undefined behavior.

Break Statement

The break statement

serves two distinct control flow purposes:

• Loop termination: When used within loops (for, while

• , do-while), the break statement provides immediate termination of the entire loop execution, transferring control to the first statement following the loop block. This enables early exit from loops based on specific conditions.

• Switch exit: Within switch statements, break terminates the switch block execution, preventing fallthrough to subsequent cases and transferring control to the code following the switch structure.

Example

// Prints numbers 0-4, then exits loop early
for (number i = 0; i < 10; i = i + 1) {
   if (i >= 5) {
    

  break;  // Terminates loop when i reaches 5
   }
   print(i);  // Only prints 0,1,2,3,4
}
// Execution continues here after break

Continue Statement

The 

continue statement is used inside a loop (for, while)

. It provides a mechanism to skip the remaining code within the current loop iteration, immediately jumping to the loop’s next iteration.

Example

number i = 1;
while (i <= 10) {
  

            // Prints: 1,2,4,5,7,8,10
    i = i + 1;
}

Best practices for using statements in SIL

Following some simple best practices can prevent common pitfalls and ensure your code is maintainable, reliable, and efficient.

General

• Keep statement blocks concise and focused.

• Avoid mixing too many different control structures.

• Use meaningful variable names that indicate purpose.

• Add comments for complex logic or business rules.

• Test thoroughly.

• Include appropriate error-handling mechanisms. For example, validate inputs before processing, log or report errors.

• Keep your code well organized by grouping related control structures.

• Maintain consistent indentation and formatting

• Document complex control flow patterns.

If-Else Statements

• Keep conditions simple and readable.

• For multiple conditions, consider using switch statements instead.

• Avoid deeply nested if statements (maximum 3-4 levels).

• Consider extracting complex conditions into separate boolean functions.

Switch Statements

• Always include a default case for error handling.

• Use break statements consistently to prevent unintended fallthrough.

• Document intentional fallthrough cases with comments.

• Consider switch instead of if-else when comparing a single variable against multiple values.

For Loops

• When the iteration count is known, use the standard form for loops.

• When processing arrays, preferably use for each loops.

• Initialize variables properly before the loop.

• Avoid modifying loop variables inside the loop body.

While Loops

• Ensure loop conditions can eventually become false.

• Initialize all variables before the loop.

• Use while when iteration count is unknown.

• Include safeguards against infinite loops.

Do-While Loops

• Use when code must execute at least once. Best suited for validation scenarios.

• Keep the loop body focused on a single task.

• Ensure the condition can be met within the loop body.

Break Statements

• Use to exit loops early when a condition is met.

• Avoid using multiple breaks in a single loop.

• Document the exit condition clearly.

• Consider extracting complex logic into separate functions.

Continue Statement

• Use to skip iterations based on specific conditions.

• Place continue statements early in the loop body.

• Avoid multiple continue statements in a single loop.

• Ensure all necessary variables are updated before continue.

See also

• Syntax and types

• Operators

• Variable Resolution