ConvertBot: causes a macro to terminate with an error

2020-04-27T22:04:41Z

causes a macro to terminate with an error

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causes a macro to terminate with an error
<pre>
<text> - message to print to screen when the error occurs

The ERROR command is the macro equivalent of the M.error() function that
a primitive would use. Its primary function is to signal an error to the
calling macro. The command simply throws a MidasException with the given
message. If the macro has PROCESSEXCEPTION procedure, it can handle the
exceptions on a case by case basis. If not, a message is generated, and
the macro continues to execute.

Examples:
This example shows how a calling macro can use the TRAP command to trap an
error generated by ERROR. In this case, MYMACRO wants to call FIXIT if the
macro DANGEROUS has an error:

-- MYMACRO.M --
mymacro a:file
TRAP error handler
say "Going to call %DANGEROUS."
%dangerous file
TRAP error off
say "%DANGEROUS executed OK."
STOP
endmacro

procedure handler m:msg
say "%DANGEROUS had the problem ^msg.data"
return

procedure processException m:msg
say "The file had better have some data elements in it."
return
-- END MYMACRO.M --

Switches:
None

See Also: PAUSE, TRAP

</pre>

[[Category:NXM_Explain]]

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ConvertBot: causes a macro to terminate with an error