getFunctionDefs: Get function definitions in R code files, functions,...

In duncantl/CodeAnalysis: Tools for Static Analysis of R code

Get function definitions in R code files, functions, environments, namespaces and packages.

Description

These functions use static analysis (rather than source'ing and evaluating the code) to find function definitions in the specified R code. The code can be an individual R code file, a directory, an environment, a list (of functions), or an individual function, an expression, a call (language) object.

These skip/ignore code within if(FALSE) clauses.

getFunctionDefs can optionally recursively process the body of the functions to find function definitions contained there. findFunctionDefs finds only top-level functions.

getFunctionDefs reads the code sequentially as if evaluating it and replaces/reassigns functions assigned to the same variable name. In contrast, findFunctionDefs collects all function definitions, including those assigned to the same variable name.

findFunctionDefs knows about functions that return functions, e.g., Vectorize, and can be told about others. It will then include top-level assignments in the results when they are created by calls to such functions. getFunctionDefs does not currently do this.

At some point in the future, we may merge the functionality of findFunctionDefs into getFunctionDefs.

getPkgFunctions is shorter than getFunctionDefs(getNamespace(pkgName)) and/but does currenty load the package.

Usage

getFunctionDefs(x, ...)
getPkgFunctions(pkg)

Arguments

x	a character vector of file or directory names or a language object from parsing R code
pkg	the name of the installed package as a character vector of length 1.
...	additional arguments for methods. Additional arguments include recursive that controls whether the bodies of top-level functions are searched for function definitions, both anonymous and assigned functions.

Value

A list of top-level functions defined in the given code.

Author(s)

Duncan Temple Lang

Examples

  # A package namespace/environment
  fns = getFunctionDefs(getNamespace("base"))
  fns = getFunctionDefs(.BaseNamespaceEnv)

  # A file
  f = system.file("sampleCode/sampleFuns.R", package = "CodeAnalysis")
  
  f1 = getFunctionDefs(f)
  # Find nested functions
  f2 = getFunctionDefs(f, recursive = TRUE)
  f2[[3]]
  attributes(f2)

  # An environment
  e = new.env()
  source(f, e)
  f3 = getFunctionDefs(e)

  # a function so find nested functions
  nested = getFunctionDefs(tools:::.check_packages)
  length(nested)

  # An expression - same as from reading the file directly
  # but if we start from an expression ....
  ex = parse(f)
  f4 = getFunctionDefs(ex)
  f5 = getFunctionDefs(ex, recursive = TRUE)

  # A call
  getFunctionDefs(quote(x <- function(x, y) x + y))
  getFunctionDefs(quote(function(x, y) x + y))

  # A call that creates a function, but is not an actual function until evaluated.
  getFunctionDefs(quote(function(x)  function(mu, sd) prod(dnorm(x, mu, sd))))
  getFunctionDefs(quote(function(x)  function(mu, sd) prod(dnorm(x, mu, sd))), recursive = TRUE)

  ifCall = quote(if(x< 2) function(mu, sd) prod(dnorm(x, mu, sd)))
  getFunctionDefs(ifCall)

  whileCall = quote(while( x < 2) {
                     optim(c(0, 1), function(mu, sd) prod(dnorm(x, mu, sd)))
                    })
  getFunctionDefs(whileCall)


  #XXX better example
  forCall = quote(for(i in x) {
                      f = function(a) a + i
                      f(10)
                    })
  getFunctionDefs(forCall)

duncantl/CodeAnalysis documentation built on Feb. 21, 2024, 10:49 p.m.