6 Evaluation modes

Package wyz.code.offensiveProgramming comes with several evaluation modes. Evaluation modes allow you to set up a particular execution context according to our needs. This allows to run R function under the given evaluation context, and to get back an evaluation mode compliance analysis result.

You may retrieve evaluation modes by using function defineEvaluationModes that returns the 3 following modes

print(defineEvaluationModes())
#> [1] "standard_R_evaluation"     "enhanced_R_evaluation"    
#> [3] "type_checking_enforcement"

6.1 Understanding evaluation modes

The first mode, standard_R_evaluation, is to ease comparisons with standard R evaluation. It does not make any sense to use only this mode when using wyz.code.offensiveProgramming.

The second mode, enhanced_R_evaluation, goes further than standard R evaluation, as it implies a function return type verification. This mode will check your function returns values in accordance with the declared returned type. This mode let you add to R a way to declared expected return type for a function.

The third mode, type_checking_enforcement, goes still further than the second mode, as it implies a function parameter types verification. This mode will check that each parameter provided to the function will match its semantic name defined type. This mode mimics a compiler output for R but it still interpreted language.

6.2 Instantiating evaluation mode

To handle evaluation mode, use function EvaluationMode. A typical way to do so is

em <- EvaluationMode(defineEvaluationModes()[3])

# convenient definitions, I will reuse in the coming book chapters to simplify writing
emo <- list(
  standard = EvaluationMode(defineEvaluationModes()[1]),
  enhanced = EvaluationMode(defineEvaluationModes()[2]),
  type     = EvaluationMode(defineEvaluationModes()[3])
)