The R Project SVN R

/*
 *  R : A Computer Langage for Statistical Data Analysis
 *  Copyright (C) 1995, 1996  Robert Gentleman and Ross Ihaka
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "Defn.h"
#include "Fileio.h"
#include "IOStuff.h"
#include "Parse.h"

extern IoBuffer R_ConsoleIob;
extern int errno;

static int ValidFileSpec(SEXP f)
{
    if(isString(f) && length(f) > 0 && CHAR(STRING(f)[0])[0])
        return 1;
    return 0;
}

    /*  do_parse - the user interface input/output to files.  */
    /*  See parse, below, for the internal function.  The     */
    /*  arguments are "file", "number", "text", "prompt".     */
    /*  If there is text then that is read and the other      */
    /*  arguments are ignored.                                */

SEXP do_parse(SEXP call, SEXP op, SEXP args, SEXP env)
{
    SEXP file, text, prompt, s;
    FILE *fp;
    int num, pstacktop, status;

    checkArity(op, args);

    pstacktop = R_PPStackTop;
    R_ParseError = 0;
    R_ParseCnt = 0;

    PROTECT(file = coerceVector(CAR(args), STRSXP)); args = CDR(args);
    num = asInteger(CAR(args)); args = CDR(args);
    PROTECT(text = coerceVector(CAR(args), STRSXP)); args = CDR(args);
    prompt = CAR(args);
    if(prompt == R_NilValue) PROTECT(prompt);
    else PROTECT(prompt = coerceVector(prompt, STRSXP));
    args = CDR(args);

    if (length(text) > 0) {
        if(num == NA_INTEGER) num = -1;
        s = R_ParseVector(text, num, &status);
        if(status != PARSE_OK)
            errorcall(call, "parse error\n");
        UNPROTECT(3);
        return s;
    }
    else if(ValidFileSpec(file)) {
        if(num == NA_INTEGER) num = -1;
        fp = R_fopen(R_ExpandFileName(CHAR(STRING(file)[0])), "r");
        if (!fp) errorcall(call, "unable to open file for parsing\n");
        s = R_ParseFile(fp, num, &status);
        fclose(fp);
        if(status != PARSE_OK)
            errorcall(call, "syntax error on line %d\n",
                R_ParseError);
        UNPROTECT(3);
        return s;
    }
    else {
        if(num == NA_INTEGER) num = 1;
        s = R_ParseBuffer(&R_ConsoleIob, num, &status, prompt);
        if(status != PARSE_OK)
            errorcall(call, "parse error\n");
        UNPROTECT(3);
        return s;
    }
}