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How boomer works

This vignette summarizes how the internals of boomer work.

Overview

An important principle of {boomer} is that we don’t modify the body of the function we rig.

rigged_file_ext <- boomer::rig(tools::file_ext)
tools::file_ext
#> function (x) 
#> {
#>     pos <- regexpr("\\.([[:alnum:]]+)$", x)
#>     ifelse(pos > -1L, substring(x, pos + 1L), "")
#> }
#> <bytecode: 0x11e0aac90>
#> <environment: namespace:tools>
rigged_file_ext
#> function (x) 
#> {
#>     pos <- regexpr("\\.([[:alnum:]]+)$", x)
#>     ifelse(pos > -1L, substring(x, pos + 1L), "")
#> }
#> <environment: 0x11e18f6e0>

Instead we copy the original function but give it a new environment. This new environment is a child of the original environment, and is populated with shims of the functions called by the original function. We call this environment the mask.

# the original environment
environment(tools::file_ext)
#> <environment: namespace:tools>

# our new environment
env <- environment(rigged_file_ext)
env
#> <environment: 0x11e18f6e0>

# its parent
parent.env(env)
#> <environment: namespace:tools>

# its content
ls(env)
#>  [1] "("         "+"         "-"         "::"        ":::"       "<-"       
#>  [7] "="         ">"         "ifelse"    "regexpr"   "substring" "{"

rig_impl() does this job and is the main function of the package. It calls wrap(), the other important function, whose mission is to build verbose shims of functions used in the rigged function. Both are detailed thereafter.

Individual functions

boom() and rig()

boom() is a wrapper around rig_impl() , it rigs the calling function and runs the call, it also has some hacky code so we can pipe to boom() with {magrittr} (The hack is not needed for the base pipe)

rig_impl()

Here’s the diagram of dependencies of rig_impl()

flow::flow_view_deps(boomer:::rig_impl, show_imports = "packages")

rig_impl() :

wrap()

wrap() builds verbose wrapper functions.

Its main aim is to print information directly related to the wrapped function (e.g. argument values and execution time).

However it does a couple more things:

rig_in_namespace()

rig_in_namespace() calls rig_impl() on its inputs but unlike rig() we want the rigged functions to be bound in the namespace instead of the original functions.

To do this we unlock the namespace and assigned rigged functions there.

Since rig_in_namespace() accepts several functions as arguments, and that they might call each other, we also make sure we include wrapped versions of our rigged functions in all the masks.

These binaries (installable software) and packages are in development.
They may not be fully stable and should be used with caution. We make no claims about them.
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