Try Conditional Execution Flow and Nesting

TRY BLOCK : ... :catch /{pattern}/ : ... : ... CATCH CLAUSE : ... :catch /{pattern}/ : ... : ... CATCH CLAUSE : ... :finally : ... : ... FINALLY CLAUSE : ... :endtry The try conditional allows to watch code for exceptions and to take the appropriate actions. Exceptions from the try block may be caught. Exceptions from the try block and also the catch clauses may cause cleanup actions. When no exception is thrown during execution of the try block, the control is transferred to the finally clause, if present. After its execution, the script continues with the line following the ":endtry". When an exception occurs during execution of the try block, the remaining lines in the try block are skipped. The exception is matched against the patterns specified as arguments to the ":catch" commands. The catch clause after the first matching ":catch" is taken, other catch clauses are not executed. The catch clause ends when the next ":catch", ":finally", or ":endtry" command is reached - whatever is first. Then, the finally clause (if present) is executed. When the ":endtry" is reached, the script execution continues in the following line as usual. When an exception that does not match any of the patterns specified by the ":catch" commands is thrown in the try block, the exception is not caught by that try conditional and none of the catch clauses is executed. Only the finally clause, if present, is taken. The exception pends during execution of the finally clause. It is resumed at the ":endtry", so that commands after the ":endtry" are not executed and the exception might be caught elsewhere, see |try-nesting|. When during execution of a catch clause another exception is thrown, the remaining lines in that catch clause are not executed. The new exception is not matched against the patterns in any of the ":catch" commands of the same try conditional and none of its catch clauses is taken. If there is, however, a finally clause, it is executed, and the exception pends during its execution. The commands following the ":endtry" are not executed. The new exception might, however, be caught elsewhere, see |try-nesting|. When during execution of the finally clause (if present) an exception is thrown, the remaining lines in the finally clause are skipped. If the finally clause has been taken because of an exception from the try block or one of the catch clauses, the original (pending) exception is discarded. The commands following the ":endtry" are not executed, and the exception from the finally clause is propagated and can be caught elsewhere, see |try-nesting|. The finally clause is also executed, when a ":break" or ":continue" for a ":while" loop enclosing the complete try conditional is executed from the try block or a catch clause. Or when a ":return" or ":finish" is executed from the try block or a catch clause of a try conditional in a function or sourced script, respectively. The ":break", ":continue", ":return", or ":finish" pends during execution of the finally clause and is resumed when the ":endtry" is reached. It is, however, discarded when an exception is thrown from the finally clause. When a ":break" or ":continue" for a ":while" loop enclosing the complete try conditional or when a ":return" or ":finish" is encountered in the finally clause, the rest of the finally clause is skipped, and the ":break", ":continue", ":return" or ":finish" is executed as usual. If the finally clause has been taken because of an exception or an earlier ":break", ":continue", ":return", or ":finish" from the try block or a catch clause, this pending exception or command is discarded. For examples see |throw-catch| and |try-finally|. NESTING OF TRY CONDITIONALS *try-nesting* Try conditionals can be nested arbitrarily. That is, a complete try conditional can be put into the try block, a catch clause, or the finally clause of another

This section details the execution flow of `try` conditionals in Vim script, including the behavior of `try` blocks, `catch` clauses, and the `finally` clause under various circumstances such as exceptions being thrown or not thrown. It explains how exceptions are matched against catch patterns, what happens when exceptions occur within catch or finally clauses, and how commands like `:break`, `:continue`, `:return`, and `:finish` interact with the `finally` clause. Finally, it introduces the concept of nesting `try` conditionals, allowing them to be placed within `try` blocks, `catch` clauses, or `finally` clauses.