These functions analyze the meta-information about code blocks and determine when a variable is no longer needed and can add code to the relevant code block to remove the variable.
findWhenUnneeded(var, frags, info = lapply(frags, getInputs), simplify,
index = TRUE, end = NA, redefined = FALSE)
addRemoveIntermediates(doc, frags = readScript(doc),
info = getInputs(frags),
vars = getVariables(info))the name of the variable(s) whose final
the location of the script, given as a file name or a connection
an object of class Script which is a list containing
the code blocks in the script. This is typically obtained via a call to
readScript.
an object of class
ScriptInfo which is a list of ScriptNodeInfo objects.
ignored
a logical value indicating whether
findWhenUnneeded should return the indices of the code
blocks/fragments or the code fragments themselves.
the names of all the variables of interest
the value to use if the variable is used in the last code block, i.e. the end of the script.
a logical value which controls whether we return the earliest code block in which the variable is redefined rather than when the variable is no longer used. Redefinition is a kind of "no longer being used" but for the value, not the variable.
A vector of indices indicating the last expression in which each of the specified variables is an input.
# NOT RUN {
f = system.file("samples", "cleanVars.R", package = "CodeDepends")
sc = readScript(f)
findWhenUnneeded("x", sc)
findWhenUnneeded(c("x", "y"), sc)
# z is never used
findWhenUnneeded("z", sc)
findWhenUnneeded("z", sc, end = 1L)
code = addRemoveIntermediates(f)
# Note that rm(x), rm(y) and rm(d) are added.
code[c(4, 5, 6)]
# }