sourceVariable: Evaluate code in document in order to define the specified variables

Description

This function allows the caller to evaluate the code within the document (or list of code chunks directly) in order to define one or more variables and then terminate. This is similar to runUpToSection but is oriented towards variables rather than particular code blocks.

Usage

sourceVariable(vars, doc, frags = readScript(doc), eval = TRUE, env = globalenv(), 
                nestedEnvironments = FALSE, verbose = TRUE,
                 checkLibraries = eval, force = FALSE, first = FALSE,
                  info = lapply(frags, getInputs))

Value

If eval is TRUE, a list of the results of evaluating the code blocks. Alternatively, if eval is FALSE, this returns the expressions constituting the code blocks. In this case, the function is the same as getVariableDepends

Arguments

vars: the names of the variables which are of interest. This need not include intermediate variables, but instead is the vector of names of the variables that the caller wants defined ultimately.
doc: the document containing the code blocks
frags: the code fragments
eval: whether to evaluate the necessary code blocks or just return them.
env: the environment in which to evaluate the code blocks.
nestedEnvironments: a logical value indicating whether to evaluate each of the different code blocks within their own environment that is chained to the previous one.
verbose: a logical value indicating whether to print the expression being evaluated before it is actually evaluated.
checkLibraries: a logical value that controls whether we check for functions that are not currently available and if there are any whether we add calls to load libraries in getVariableDepends.
force: a logical value that controls whether we evaluate the expressions if they variables appear to exist.
first: a logical value. This is intended to allow running up to the first instance of the variable, not all of them.
info: the information about each expression. This is computed automatically, but the caller can specify it to avoid redundant computations.

Author

Duncan Temple Lang

Examples

Run this code

 f = system.file("samples", "dual.R", package = "CodeDepends")
 e = readScript(f)
 getVariableDepends("k", frags = e)
 sourceVariable("k", frags = e, verbose = TRUE)