Jeff,
On Oct 1, 2009, at 12:37 , Jeff Horner wrote:
Jeff Horner wrote:
Martin Becker wrote:
Dear developers,
is it possible to create environments in C code of packages?
Simply using
SEXP env;
PROTECT (env = allocSExp(ENVSXP));
and assigning the enclosing environment with SET_ENCLOS seems to
be insufficient.
Best wishes,
Here's a function I use in rapache to create one:
static SEXP NewEnv(SEXP enclos){
SEXP env;
PROTECT(env = allocSExp(ENVSXP));
SET_FRAME(env, R_NilValue);
SET_ENCLOS(env, (enclos)? enclos: R_GlobalEnv);
SET_HASHTAB(env, R_NilValue);
SET_ATTRIB(env, R_NilValue);
UNPROTECT(1);
return env;
}
eek ... that some dangerous bit of code ;). I think Rf_NewEnviroment
is safer even if it's not the headers :P.
Oops! I forgot the definition of my simple function NewInteger:
static SEXP NewInteger(int i){
SEXP val;
PROTECT(val = NEW_INTEGER(1));
INTEGER_DATA(val)[0] = i;
UNPROTECT(1);
return val;
}
I suspect you like reinventing the wheel ;). Your NewInteger is part
of the R API and is called ScalarInteger(). When you need something,
chances are that R has it already, so it's worth greping through the
headers (and sometimes even through the main sources).
Cheers,
Simon
and an example that creates a new environment and then assigns a
variable named OK an integer vector length 1 with value 0:
SEXP env = NewEnv(R_GlobalEnv);
defineVar(install("OK"),NewInteger(0),env);
Best
Jeff
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