command: ")
: try
: if command == ""
: continue
: elseif command == "END"
: break
: elseif command == "TASK1"
: call TASK1()
: elseif command == "TASK2"
: call TASK2()
: else
: echo "\nIllegal command:" command
: continue
: endif
: catch /^Vim:Interrupt$/
: echo "\nCommand interrupted"
: " Caught the interrupt. Continue with next prompt.
: endtry
:endwhile
You can interrupt a task here by pressing CTRL-C; the script then asks for
a new command. If you press CTRL-C at the prompt, the script is terminated.
For testing what happens when CTRL-C would be pressed on a specific line in
your script, use the debug mode and execute the |>quit| or |>interrupt|
command on that line. See |debug-scripts|.
CATCHING ALL *catch-all*
The commands >
:catch /.*/
:catch //
:catch
catch everything, error exceptions, interrupt exceptions and exceptions
explicitly thrown by the |:throw| command. This is useful at the top level of
a script in order to catch unexpected things.
Example: >
:try
:
: " do the hard work here
:
:catch /MyException/
:
: " handle known problem
:
:catch /^Vim:Interrupt$/
: echo "Script interrupted"
:catch /.*/
: echo "Internal error (" .. v:exception .. ")"
: echo " - occurred at " .. v:throwpoint
:endtry
:" end of script
Note: Catching all might catch more things than you want. Thus, you are
strongly encouraged to catch only for problems that you can really handle by
specifying a pattern argument to the ":catch".
Example: Catching all could make it nearly impossible to interrupt a script
by pressing CTRL-C: >
:while 1
: try
: sleep 1
: catch
: endtry
:endwhile
EXCEPTIONS AND AUTOCOMMANDS *except-autocmd*
Exceptions may be used during execution of autocommands. Example: >
:autocmd User x try
:autocmd User x throw "Oops!"
:autocmd User x catch
:autocmd User x echo v:exception
:autocmd User x endtry
:autocmd User x throw "Arrgh!"
:autocmd User x echo "Should not be displayed"
:
:try
: doautocmd User x
:catch
: echo v:exception
:endtry
This displays "Oops!" and "Arrgh!".
*except-autocmd-Pre*
For some commands, autocommands get executed before the main action of the
command takes place. If an exception is thrown and not caught in the sequence
of autocommands, the sequence and the command that caused its execution are
abandoned and the exception is propagated to the caller of the command.
Example: >
:autocmd BufWritePre * throw "FAIL"
:autocmd BufWritePre * echo "Should not be displayed"
:
:try
: write
:catch
: echo "Caught:" v:exception "from" v:throwpoint
:endtry
Here, the ":write" command does not write the file currently being edited (as
you can see by checking 'modified'), since the exception from the BufWritePre
autocommand abandons the ":write". The exception is then caught and the
script displays: >
Caught: FAIL from BufWrite Auto commands for "*"
<
*except-autocmd-Post*
For some commands, autocommands get executed after the main action of the
command has taken place. If this main action fails and the command is inside
an active try conditional, the autocommands are skipped and an error exception
is thrown that can be caught by the caller of the command.
Example: >
:autocmd BufWritePost * echo "File successfully written!"
:
:try
: write /i/m/p/o/s/s/i/b/l/e
:catch
: echo v:exception
:endtry
This just displays: >
Vim(write):E212: Can't open file for writing (/i/m/p/o/s/s/i/b/l/e)
If you really need to execute the autocommands even when the main action
fails, trigger the event from the catch clause.
Example: >
:autocmd BufWritePre * set noreadonly
:autocmd BufWritePost * set readonly
:
:try
: write /i/m/p/o/s/s/i/b/l/e
:catch
: doautocmd BufWritePost /i/m/p/o/s/s/i/b/l/e
:endtry
<
You can also use ":silent!": >
:let x = "ok"
:let v:errmsg = ""
:autocmd BufWritePost * if v:errmsg != ""
:autocmd