recover {methods}R Documentation

Browsing on an Error

Description

This function allows the user to browse directly on any of the currently active function calls, and is suitable as an error option. The expression options(error=recover) will make this the error option.

Usage

recover()

Details

When called, recover prints the list of current calls, and prompts the user to select one of them. The standard R browser is then invoked from the corresponding environment; the user can type ordinary S language expressions to be evaluated in that environment.

When finished browsing in this call, type c to return to recover from the browser. Type another frame number to browse some more, or type 0 to exit recover.

WARNING: Do not use the special Q command to go directly from the browser to the prompt level of the evaluator. This currently interacts with recover to effectively turn off the error option for the next error (on subsequent errors, recover will be called normally)

Value

Nothing useful is returned. However, you can invoke recover directly from a function, rather than through the error option shown the usage section. In this case, execution continues after you type 0 to exit recover.

Compatibility Note

The R recover function can be used in the same way as the S-Plus function of the same name; therefore, the error option shown is a compatible way to specify the error action. However, the actual functions are essentially unrelated and interact quite differently with the user.

References

Programming with Data, (John M. Chambers, Springer, 1998). See the compatibility note above, however.

See Also

See dump.frames and debugger for the more traditional approach to error recovery.


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