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;
    }
}