environment variables - Resuming stopped evaluation in R with correct search path -

i have function within loaded library stops evaluation on arguments using substitute function. function calls within same library, calls function library, , forth, until several calls later when want evaluated initial argument in original environment in provided. problem have search path functions in loaded libraries includes namespace::base before global environment. example, let's foo , bar both functions in library lib. such, environment in defined namespace::lib. consider following:

> require(lib) > foo function (x)  {     x <- substitute(x)     bar(x) } <environment: namespace:lib> > bar function (x)  {      eval(x) } <environment: namespace:lib> > length = 2 > foo(length) function (x)  .primitive("length") 

because bar function within loaded library, searches namespace::base first , finds above. however, if bar defined user in interactive session, have returned 2. looking way cause these functions behave if never halted evaluation, in case 2 returned regardless of environment in functions defined.

i can't use mget evaluate length starting @ .globalenv because following not work:

> baz = function() + { + length <- 3 + foo(length) + } > baz() function (x)  .primitive("length") 

i instead add argument involved functions tracks how many frames ago evaluation halted. however, pretty messy , not ideal.

i call sys.function inside last function, bar, , trace way through previous calls , evaluate argument in environment above function halted evaluation. example, if call sys.function(1) within body of bar after calling foo(length) following:

function (x)  {     eval(x) } 

this indeed identical foo. can use eval sys.frames. seems more general less perfect. have know functions stop evaluation.

does have more general solution?

does adding default enviroment these function problem?

lib<-new.env() assign("foo", function(x, env=parent.frame()) {     x<-substitute(x);      bar(x, env) }, envir=lib) assign("bar", function(x, env=parent.frame()) {     eval(x, env) }, envir=lib) attach(lib)  length = 2 foo(length) # [1] 2  baz <- function() {   length <- 3   foo(length) } baz() # [1] 3  bar(expression(baz())) # [1] 3 

if not, perhaps make clearer, reproducible example function calls , expected output. otherwise it's unclear having trouble.