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fail()


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 Function  [other Function type actions]

 Item  [operators of similar scope]

 Stream parsing  [other Stream parsing operators]

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 As at baseline


fail

The fail operator makes an explicit declaration of a failure, and if invoked only ever returns false.

Often, in stream processing a failure occurs implicitly, for example because the end of the processed string is reached without finding the desired data. However, sometimes, there is a definite need to signal failure; for example, because the parsed data are invalid.

For example:

	$MyString.try{
	   $MyString.skipTo(':').captureWord("TheWord");
	   if($TheWord.contains("None")) {
	      fail();
	   }
	}

The above skips through $MyString to the first colon and then captures the next discrete word after the colon into $TheWord. The action fails if: