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15.25.10 Conditional Execution

Constructs for loop clauses to operate under a specified condition.

• ‘if’
• ‘when’
• ‘unless’
• ‘else’
• ‘and’
• ‘end’
• ‘it’

True Conditions

• If the specified condition is ‘true’, the succeeding loop clause is executed.

Not True Conditions

• If the specified condition is ‘not true’, the succeeding clause is skipped, and program control moves to the clause that follows the loop keyword else.
• If the specified condition is ‘not true’ and no ‘else’ clause is specified, the entire conditional construct is skipped.

Compound Clauses

• Several clauses can be connected into one compound clause with the loop keyword ‘and’.

End of Conditions

• The end of the conditional clause can be marked with the keyword ‘end’.

• if - when - unless