withOption: Alternative option mechanism
In operators: Additional Binary Operators

Description Usage Arguments Details Value Author(s) See Also Examples

options is a slight rework on options that gives a S3 class options to the result. This allows the definition of a with method for the options. This is useful to execute a block of code with a set of options.

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## S3 method for class 'options'
with(data, expr, ...)
options(...)

`...`	Options to use. See `options` for details.
`data`	Options to use. This is typically a call to the `options` function
`expr`	Code to execute.

The result of the expression that is evaulated is modified in order to keep the option context it is associated with. The class of the object created by the expression is expanded to include the withOptions class and the withOptions attribute that keeps the context in which the object has been created.

This mechanism has been implemented specially for the automatic printing of objects that happens outside the call to the with.options function and not reflect the options requested by the user when the object is printed.

For the function with.options, the result of the expression given in expr is returned. See details below.

Romain Francois <francoisromain@free.fr>

The original options function in the base package.

	
	# part of ?glm
	counts <- c(18,17,15,20,10,20,25,13,12)
  outcome <- gl(3,1,9)
  treatment <- gl(3,3)
  print(d.AD <- data.frame(treatment, outcome, counts))
  glm.D93 <- glm(counts ~ outcome + treatment, family=poisson())
	
	summary( glm.D93 )
	
	with( options(show.signif.stars = FALSE,show.coef.Pvalues=FALSE), 
		summary( glm.D93) )
	
	a <- try( 
	  with( options( warn = 2) , warning( "more than a warning" ) ), 
		silent = TRUE )
  class( a )