R devel - Aug 2008 - Parsing code with newlines

Dear List,

When I try to parse code containing newline characters with R_ParseVector, I
get a compilation error. How can I compile code that includes comments and
newlines?

I am using the following:

void* my_compile(char *code)
{
    SEXP cmdSexp, cmdExpr = R_NilValue;
    ParseStatus status;

    PROTECT (cmdSexp = allocVector (STRSXP, 1));
    SET_STRING_ELT (cmdSexp, 0, mkChar (code));
    PROTECT (cmdExpr = R_ParseVector (cmdSexp,-1,&status,
        R_NilValue));
    UNPROTECT_PTR (cmdSexp);

    if (status != PARSE_OK) {
        return (void*)0;
    } else {
        return (void*)cmdExpr;
    }
}

Regards,
Peter

	[[alternative HTML version deleted]]

On 04/08/2008 8:50 AM, Peter Jaeger wrote:
> Dear List,
> 
> When I try to parse code containing newline characters with R_ParseVector,
I
> get a compilation error. How can I compile code that includes comments and
> newlines?
> 
> I am using the following:
> 
> void* my_compile(char *code)
> {
>     SEXP cmdSexp, cmdExpr = R_NilValue;
>     ParseStatus status;
> 
>     PROTECT (cmdSexp = allocVector (STRSXP, 1));
>     SET_STRING_ELT (cmdSexp, 0, mkChar (code));
>     PROTECT (cmdExpr = R_ParseVector (cmdSexp,-1,&status,
>         R_NilValue));
>     UNPROTECT_PTR (cmdSexp);
> 
>     if (status != PARSE_OK) {
>         return (void*)0;
>     } else {
>         return (void*)cmdExpr;
>     }
> }
You need to put together a reproducible example if you want help. 
parse() uses R_ParseVector, and it handles newlines fine.

Duncan Murdoch

This adds nothing to your previous post: please don't be annoying and post 
almost identical messages.

I strongly suspect you mean 'parse error' and 'how can I parse R
code',
but we don't know what the example was and what the error message was. 
Nor do we know what you are doing with this fragement of C code (and 
returnng an unprotected SEXP via a (void *) cast is a recipe for tears).

parse(text=) uses R_ParseVector, and that works for 'code that includes 
comments and newlines', so please check out the internal code used (in 
src/main/gram.c).

If you study the posting guide you should be able to formulate a posting 
that people can actually help you with.

On Mon, 4 Aug 2008, Peter Jaeger wrote:
> Dear List,
>
> When I try to parse code containing newline characters with R_ParseVector,
I
> get a compilation error. How can I compile code that includes comments and
> newlines?
>
> I am using the following:
>
> void* my_compile(char *code)
> {
>    SEXP cmdSexp, cmdExpr = R_NilValue;
>    ParseStatus status;
>
>    PROTECT (cmdSexp = allocVector (STRSXP, 1));
>    SET_STRING_ELT (cmdSexp, 0, mkChar (code));
>    PROTECT (cmdExpr = R_ParseVector (cmdSexp,-1,&status,
>        R_NilValue));
>    UNPROTECT_PTR (cmdSexp);
>
>    if (status != PARSE_OK) {
>        return (void*)0;
>    } else {
>        return (void*)cmdExpr;
>    }
> }
>
> Regards,
> Peter
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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