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Error.if_not_error

if_not_errorpassthru

Documentation​

Returns the provided passthru value, unless self is an error.

The primary application of this function is to introduce a dataflow dependency between two otherwise unrelated operations. Very useful if one of the operations is performing a side-effect.

Aside from ensuring that any dataflow errors are propagated, the result will also inherit any warnings attached to any of the two inputs.

Arguments​

  • passthru: The value to return if self is not an error.

Returns​

passthru if self is not an error; otherwise, returns the error.

Returns​

passthru if self is not an error; otherwise, returns the error.

Examples​

Writing to a file and returning the file object if all went well, or an​

error if it failed.

      file.write "foo" . if_not_error file