The R Project SVN R

/*
 *  R : A Computer Language for Statistical Data Analysis
 *  Copyright (C) 1995, 1996  Robert Gentleman and Ross Ihaka
 *  Copyright (C) 1998-2015   The R Core Team.
 *
 *  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, a copy is available at
 *  https://www.R-project.org/Licenses/
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "Defn.h"
#include <Internal.h>
#include "Print.h"
#include <Rinternals.h>

/* The global var. R_Expressions is in Defn.h */
#define R_MIN_EXPRESSIONS_OPT   25
#define R_MAX_EXPRESSIONS_OPT   500000

/* Interface to the (polymorphous!)  options(...)  command.
 *
 * We have two kind of options:
 *   1) those used exclusively from R code,
 *  typically initialized in Rprofile.

 *  Their names need not appear here, but may, when we want
 *  to make sure that they are assigned `valid' values only.
 *
 *   2) Those used (and sometimes set) from C code;
 *  Either accessing and/or setting a global C variable,
 *  or just accessed by e.g.  GetOption1(install("pager"))
 *
 * A (complete?!) list of these (2):
 *
 *  "prompt"
 *  "continue"
 *  "expressions"
 *  "width"
 *  "digits"
 *  "echo"
 *  "verbose"
 *  "keep.source"
 *  "keep.source.pkgs"
 *  "browserNLdisabled"

 *  "de.cellwidth"      ../unix/X11/ & ../gnuwin32/dataentry.c
 *  "device"
 *  "pager"
 *  "paper.size"        ./devPS.c

 *  "timeout"       ./connections.c

 *  "check.bounds"
 *  "error"
 *  "error.messages"
 *  "show.error.messages"
 *  "warn"
 *  "warning.length"
 *  "warning.expression"
 *  "nwarnings"

 *
 * S additionally/instead has (and one might think about some)
 * "free",  "keep"
 * "length",    "memory"
 * "object.size"
 * "reference", "show"
 * "scrap"
 */


static SEXP Options(void)
{
    static SEXP sOptions = NULL;
    if(!sOptions) sOptions = install(".Options");
    return sOptions;
}

static SEXP FindTaggedItem(SEXP lst, SEXP tag)
{
    for ( ; lst != R_NilValue ; lst = CDR(lst)) {
    if (TAG(lst) == tag)
        return lst;
    }
    return R_NilValue;
}

static SEXP makeErrorCall(SEXP fun)
{
  SEXP call;
  PROTECT(call = allocList(1));
  SET_TYPEOF(call, LANGSXP);
  SETCAR(call, fun);
  UNPROTECT(1);
  return call;
}

SEXP GetOption(SEXP tag, SEXP rho)
{
    return GetOption1(tag);
}


SEXP GetOption1(SEXP tag)
{
    SEXP opt = SYMVALUE(Options());
    if (!isList(opt)) error(_("corrupted options list"));
    opt = FindTaggedItem(opt, tag);
    return CAR(opt);
}

int GetOptionWidth(void)
{
    int w;
    w = asInteger(GetOption1(install("width")));
    if (w < R_MIN_WIDTH_OPT || w > R_MAX_WIDTH_OPT) {
    warning(_("invalid printing width, used 80"));
    return 80;
    }
    return w;
}

int GetOptionDigits(void)
{
    int d;
    d = asInteger(GetOption1(install("digits")));
    if (d < R_MIN_DIGITS_OPT || d > R_MAX_DIGITS_OPT) {
    warning(_("invalid printing digits, used 7"));
    return 7;
    }
    return d;
}

attribute_hidden
int GetOptionCutoff(void)
{
    int w;
    w = asInteger(GetOption1(install("deparse.cutoff")));
    if (w == NA_INTEGER || w <= 0) {
    warning(_("invalid 'deparse.cutoff', used 60"));
    w = 60;
    }
    return w;
}

attribute_hidden
Rboolean Rf_GetOptionDeviceAsk(void)
{
    int ask;
    ask = asLogical(GetOption1(install("device.ask.default")));
    if(ask == NA_LOGICAL) {
    warning(_("invalid value for \"device.ask.default\", using FALSE"));
    return FALSE;
    }
    return ask != 0;
}


/* Change the value of an option or add a new option or, */
/* if called with value R_NilValue, remove that option. */

static SEXP SetOption(SEXP tag, SEXP value)
{
    SEXP opt, old, t;
    PROTECT(value);
    t = opt = SYMVALUE(Options());
    if (!isList(opt))
    error(_("corrupted options list"));
    opt = FindTaggedItem(opt, tag);

    /* The option is being removed. */
    if (value == R_NilValue) {
    for ( ; t != R_NilValue ; t = CDR(t))
        if (TAG(CDR(t)) == tag) {
        old = CAR(CDR(t));
        SETCDR(t, CDDR(t));
        UNPROTECT(1); /* value */
        return old;
        }
    UNPROTECT(1); /* value */
    return R_NilValue;
    }
    /* If the option is new, a new slot */
    /* is added to the end of .Options */
    if (opt == R_NilValue) {
    while (CDR(t) != R_NilValue)
        t = CDR(t);
    SETCDR(t, allocList(1));
    opt = CDR(t);
    SET_TAG(opt, tag);
    }
    old = CAR(opt);
    SETCAR(opt, value);
    UNPROTECT(1); /* value */
    return old;
}

/* Set the width of lines for printing i.e. like options(width=...) */
/* Returns the previous value for the options. */

int attribute_hidden R_SetOptionWidth(int w)
{
    SEXP t, v;
    if (w < R_MIN_WIDTH_OPT) w = R_MIN_WIDTH_OPT;
    if (w > R_MAX_WIDTH_OPT) w = R_MAX_WIDTH_OPT;
    PROTECT(t = install("width"));
    PROTECT(v = ScalarInteger(w));
    v = SetOption(t, v);
    UNPROTECT(2);
    return INTEGER(v)[0];
}

int attribute_hidden R_SetOptionWarn(int w)
{
    SEXP t, v;

    t = install("warn");
    PROTECT(v = ScalarInteger(w));
    v = SetOption(t, v);
    UNPROTECT(1);
    return INTEGER(v)[0];
}

/* Note that options are stored as a dotted pair list */
/* This is barely historical, but is also useful. */

void attribute_hidden InitOptions(void)
{
    SEXP val, v;
    char *p;

#ifdef HAVE_RL_COMPLETION_MATCHES
    PROTECT(v = val = allocList(17));
#else
    PROTECT(v = val = allocList(16));
#endif

    SET_TAG(v, install("prompt"));
    SETCAR(v, mkString("> "));
    v = CDR(v);

    SET_TAG(v, install("continue"));
    SETCAR(v, mkString("+ "));
    v = CDR(v);

    SET_TAG(v, install("expressions"));
    SETCAR(v, ScalarInteger(R_Expressions));
    v = CDR(v);

    SET_TAG(v, install("width"));
    SETCAR(v, ScalarInteger(80));
    v = CDR(v);

    SET_TAG(v, install("deparse.cutoff"));
    SETCAR(v, ScalarInteger(60));
    v = CDR(v);

    SET_TAG(v, install("digits"));
    SETCAR(v, ScalarInteger(7));
    v = CDR(v);

    SET_TAG(v, install("echo"));
    SETCAR(v, ScalarLogical(!R_Slave));
    v = CDR(v);

    SET_TAG(v, install("verbose"));
    SETCAR(v, ScalarLogical(R_Verbose));
    v = CDR(v);

    SET_TAG(v, install("check.bounds"));
    SETCAR(v, ScalarLogical(0));    /* no checking */
    v = CDR(v);

    p = getenv("R_KEEP_PKG_SOURCE");
    R_KeepSource = (p && (strcmp(p, "yes") == 0)) ? 1 : 0;

    SET_TAG(v, install("keep.source")); /* overridden in common.R */
    SETCAR(v, ScalarLogical(R_KeepSource));
    v = CDR(v);

    SET_TAG(v, install("keep.source.pkgs"));
    SETCAR(v, ScalarLogical(R_KeepSource));
    v = CDR(v);

    SET_TAG(v, install("warning.length"));
    SETCAR(v, ScalarInteger(1000));
    v = CDR(v);

    SET_TAG(v, install("nwarnings"));
    SETCAR(v, ScalarInteger(50));
    v = CDR(v);

    SET_TAG(v, install("OutDec"));
    SETCAR(v, mkString("."));
    v = CDR(v);

    SET_TAG(v, install("browserNLdisabled"));
    SETCAR(v, ScalarLogical(FALSE));
    v = CDR(v);

    p = getenv("R_C_BOUNDS_CHECK");
    R_CBoundsCheck = (p && (strcmp(p, "yes") == 0)) ? 1 : 0;

    SET_TAG(v, install("CBoundsCheck"));
    SETCAR(v, ScalarLogical(R_CBoundsCheck));
    v = CDR(v);

#ifdef HAVE_RL_COMPLETION_MATCHES
    /* value from Rf_initialize_R */
    SET_TAG(v, install("rl_word_breaks"));
    SETCAR(v, mkString(" \t\n\"\\'`><=%;,|&{()}"));
    set_rl_word_breaks(" \t\n\"\\'`><=%;,|&{()}");
#endif

    SET_SYMVALUE(install(".Options"), val);
    UNPROTECT(1);
}


SEXP attribute_hidden do_getOption(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    checkArity(op, args);
    SEXP x = CAR(args);
    if (!isString(x) || LENGTH(x) != 1)
    error(_("'%s' must be a character string"), "x");
    return duplicate(GetOption1(install(CHAR(STRING_ELT(x, 0)))));
}


/* This needs to manage R_Visible */
SEXP attribute_hidden do_options(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    SEXP names, value, options;

    /* Locate the options values in the symbol table.
       This will need to change if options are to live in the session
       frame.
       */

    options = SYMVALUE(Options());

    /* This code is not re-entrant and people have used it in
       finalizers.

       If a re-entrancy lock needs to be added, note that it
       would apply to R_SetOption* too.
    */

    checkArity(op, args);
    if (args == R_NilValue) {
    /* This is the zero argument case.
       We alloc up a vector list and write the system values into it.
    */
    int n = length(options);
    PROTECT(value = allocVector(VECSXP, n));
    PROTECT(names = allocVector(STRSXP, n));
    for (int i = 0; i < n; i++) {
        SET_STRING_ELT(names, i, PRINTNAME(TAG(options)));
        SET_VECTOR_ELT(value, i, duplicate(CAR(options)));
        options = CDR(options);
    }
    SEXP sind = PROTECT(allocVector(INTSXP, n));
    int *indx = INTEGER(sind);
    for (int i = 0; i < n; i++) indx[i] = i;
    orderVector1(indx, n, names, TRUE, FALSE, R_NilValue);
    SEXP value2 = PROTECT(allocVector(VECSXP, n));
    SEXP names2 = PROTECT(allocVector(STRSXP, n));
    for(int i = 0; i < n; i++) {
        SET_STRING_ELT(names2, i, STRING_ELT(names, indx[i]));
        SET_VECTOR_ELT(value2, i, VECTOR_ELT(value, indx[i]));
    }
    setAttrib(value2, R_NamesSymbol, names2);
    UNPROTECT(5);
    R_Visible = TRUE;
    return value2;
    }

    /* The arguments to "options" can either be a sequence of
       name = value form, or can be a single list.
       This means that we must code so that both forms will work.
       [ Vomits quietly onto shoes ... ]
       */

    int n = length(args);
    if (n == 1 && (isPairList(CAR(args)) || isVectorList(CAR(args)))
    && TAG(args) == R_NilValue ) {
    args = CAR(args);
    n = length(args);
    }
    PROTECT(value = allocVector(VECSXP, n));
    PROTECT(names = allocVector(STRSXP, n));

    SEXP argnames = R_NilValue;
    switch (TYPEOF(args)) {
    case NILSXP:
    case LISTSXP:
    break;
    case VECSXP:
    if(n > 0) {
        argnames = getAttrib(args, R_NamesSymbol);
        if(LENGTH(argnames) != n)
        error(_("list argument has no valid names"));
    }
    break;
    default:
    UNIMPLEMENTED_TYPE("options", args);
    }

    R_Visible = FALSE;
    for (int i = 0 ; i < n ; i++) { /* i-th argument */
    SEXP argi = R_NilValue, namei = R_NilValue;
    switch (TYPEOF(args)) {
    case LISTSXP:
        argi = CAR(args);
        namei = EnsureString(TAG(args)); /* gives "" for no tag */
        args = CDR(args);
        break;
    case VECSXP:
        argi = VECTOR_ELT(args, i);
        namei = STRING_ELT(argnames, i);
        break;
    default: /* already checked, but be safe here */
        UNIMPLEMENTED_TYPE("options", args);
    }

    if (*CHAR(namei)) { /* name = value  ---> assignment */
        SEXP tag = installTrChar(namei);
        if (streql(CHAR(namei), "width")) {
        int k = asInteger(argi);
        if (k < R_MIN_WIDTH_OPT || k > R_MAX_WIDTH_OPT)
            error(_("invalid 'width' parameter, allowed %d...%d"),
              R_MIN_WIDTH_OPT, R_MAX_WIDTH_OPT);
        SET_VECTOR_ELT(value, i, SetOption(tag, ScalarInteger(k)));
        }
        else if (streql(CHAR(namei), "deparse.cutoff")) {
        int k = asInteger(argi);
        SET_VECTOR_ELT(value, i, SetOption(tag, ScalarInteger(k)));
        }
        else if (streql(CHAR(namei), "digits")) {
        int k = asInteger(argi);
        if (k < R_MIN_DIGITS_OPT || k > R_MAX_DIGITS_OPT)
            error(_("invalid 'digits' parameter, allowed %d...%d"),
              R_MIN_DIGITS_OPT, R_MAX_DIGITS_OPT);
        SET_VECTOR_ELT(value, i, SetOption(tag, ScalarInteger(k)));
        }
        else if (streql(CHAR(namei), "expressions")) {
        int k = asInteger(argi);
        if (k < R_MIN_EXPRESSIONS_OPT || k > R_MAX_EXPRESSIONS_OPT)
            error(_("'expressions' parameter invalid, allowed %d...%d"),
              R_MIN_EXPRESSIONS_OPT, R_MAX_EXPRESSIONS_OPT);
        R_Expressions = R_Expressions_keep = k;
        SET_VECTOR_ELT(value, i, SetOption(tag, ScalarInteger(k)));
        }
        else if (streql(CHAR(namei), "keep.source")) {
        if (TYPEOF(argi) != LGLSXP || LENGTH(argi) != 1)
            error(_("invalid value for '%s'"), CHAR(namei));
        int k = asLogical(argi);
        R_KeepSource = k;
        SET_VECTOR_ELT(value, i, SetOption(tag, ScalarLogical(k)));
        }
        else if (streql(CHAR(namei), "editor") && isString(argi)) {
        SEXP s =  asChar(argi);
        if (s == NA_STRING || LENGTH(s) == 0)
            error(_("invalid value for '%s'"), CHAR(namei));
        SET_VECTOR_ELT(value, i, SetOption(tag, ScalarString(s)));
        }
        else if (streql(CHAR(namei), "continue")) {
        SEXP s =  asChar(argi);
        if (s == NA_STRING || LENGTH(s) == 0)
            error(_("invalid value for '%s'"), CHAR(namei));
        /* We want to make sure these are in the native encoding */
        SET_VECTOR_ELT(value, i,
                   SetOption(tag, mkString(translateChar(s))));
        }
        else if (streql(CHAR(namei), "prompt")) {
        SEXP s =  asChar(argi);
        if (s == NA_STRING || LENGTH(s) == 0)
            error(_("invalid value for '%s'"), CHAR(namei));
        /* We want to make sure these are in the native encoding */
        SET_VECTOR_ELT(value, i,
                   SetOption(tag, mkString(translateChar(s))));
        }
        else if (streql(CHAR(namei), "contrasts")) {
        if (TYPEOF(argi) != STRSXP || LENGTH(argi) != 2)
            error(_("invalid value for '%s'"), CHAR(namei));
        SET_VECTOR_ELT(value, i, SetOption(tag, argi));
        }
        else if (streql(CHAR(namei), "check.bounds")) {
        if (TYPEOF(argi) != LGLSXP || LENGTH(argi) != 1)
            error(_("invalid value for '%s'"), CHAR(namei));
        int k = asLogical(argi);
        /* R_CheckBounds = k; */
        SET_VECTOR_ELT(value, i, SetOption(tag, ScalarLogical(k)));
        }
        else if (streql(CHAR(namei), "warn")) {
        if (!isNumeric(argi) || LENGTH(argi) != 1)
            error(_("invalid value for '%s'"), CHAR(namei));
        SET_VECTOR_ELT(value, i, SetOption(tag, argi));
        }
        else if (streql(CHAR(namei), "warning.length")) {
        int k = asInteger(argi);
        if (k < 100 || k > 8170)
            error(_("invalid value for '%s'"), CHAR(namei));
        R_WarnLength = k;
        SET_VECTOR_ELT(value, i, SetOption(tag, argi));
        }
        else if ( streql(CHAR(namei), "warning.expression") )  {
        if( !isLanguage(argi) &&  ! isExpression(argi) )
            error(_("invalid value for '%s'"), CHAR(namei));
        SET_VECTOR_ELT(value, i, SetOption(tag, argi));
        }
        else if (streql(CHAR(namei), "max.print")) {
        int k = asInteger(argi);
        if (k < 1) error(_("invalid value for '%s'"), CHAR(namei));
        SET_VECTOR_ELT(value, i, SetOption(tag, ScalarInteger(k)));
        }
        else if (streql(CHAR(namei), "nwarnings")) {
        int k = asInteger(argi);
        if (k < 1) error(_("invalid value for '%s'"), CHAR(namei));
        R_nwarnings = k;
        R_CollectWarnings = 0; /* force a reset */
        SET_VECTOR_ELT(value, i, SetOption(tag, ScalarInteger(k)));
        }
        else if ( streql(CHAR(namei), "error") ) {
        if(isFunction(argi))
          argi = makeErrorCall(argi);
        else if( !isLanguage(argi) &&  !isExpression(argi) )
            error(_("invalid value for '%s'"), CHAR(namei));
        SET_VECTOR_ELT(value, i, SetOption(tag, argi));
        }
/* handle this here to avoid GetOption during error handling */
        else if ( streql(CHAR(namei), "show.error.messages") ) {
        if( !isLogical(argi) && LENGTH(argi) != 1 )
            error(_("invalid value for '%s'"), CHAR(namei));
        SET_VECTOR_ELT(value, i, SetOption(tag, argi));
        R_ShowErrorMessages = LOGICAL(argi)[0];
        }
        else if (streql(CHAR(namei), "echo")) {
        if (TYPEOF(argi) != LGLSXP || LENGTH(argi) != 1)
            error(_("invalid value for '%s'"), CHAR(namei));
        int k = asLogical(argi);
        /* Should be quicker than checking options(echo)
           every time R prompts for input:
           */
        R_Slave = !k;
        SET_VECTOR_ELT(value, i, SetOption(tag, ScalarLogical(k)));
        }
        else if (streql(CHAR(namei), "OutDec")) {
        if (TYPEOF(argi) != STRSXP || LENGTH(argi) != 1)
            error(_("invalid value for '%s'"), CHAR(namei));
        static char sdec[11];
        if(R_nchar(STRING_ELT(argi, 0), Chars,
               /* allowNA = */ FALSE, /* keepNA = */ FALSE,
               "OutDec") != 1) // will become an error
            warning(_("'OutDec' must be a string of one character"));
        strncpy(sdec, CHAR(STRING_ELT(argi, 0)), 10);
        sdec[10] = '\0';
        OutDec = sdec;
        SET_VECTOR_ELT(value, i, SetOption(tag, duplicate(argi)));
        }
        else if (streql(CHAR(namei), "max.contour.segments")) {
        int k = asInteger(argi);
        if (k < 0) // also many times above: rely on  NA_INTEGER  <  <finite_int>
            error(_("invalid value for '%s'"), CHAR(namei));
        max_contour_segments = k;
        SET_VECTOR_ELT(value, i, SetOption(tag, ScalarInteger(k)));
        }
        else if (streql(CHAR(namei), "rl_word_breaks")) {
        if (TYPEOF(argi) != STRSXP || LENGTH(argi) != 1)
            error(_("invalid value for '%s'"), CHAR(namei));
#ifdef HAVE_RL_COMPLETION_MATCHES
        set_rl_word_breaks(CHAR(STRING_ELT(argi, 0)));
#endif
        SET_VECTOR_ELT(value, i, SetOption(tag, duplicate(argi)));
        }
        else if (streql(CHAR(namei), "warnPartialMatchDollar")) {
        if (TYPEOF(argi) != LGLSXP || LENGTH(argi) != 1)
            error(_("invalid value for '%s'"), CHAR(namei));
        int k = asLogical(argi);
        R_warn_partial_match_dollar = k;
        SET_VECTOR_ELT(value, i, SetOption(tag, ScalarLogical(k)));
        }
        else if (streql(CHAR(namei), "warnPartialMatchArgs")) {
        if (TYPEOF(argi) != LGLSXP || LENGTH(argi) != 1)
            error(_("invalid value for '%s'"), CHAR(namei));
        int k = asLogical(argi);
        R_warn_partial_match_args = k;
        SET_VECTOR_ELT(value, i, SetOption(tag, ScalarLogical(k)));
        }
        else if (streql(CHAR(namei), "warnPartialMatchAttr")) {
        if (TYPEOF(argi) != LGLSXP || LENGTH(argi) != 1)
            error(_("invalid value for '%s'"), CHAR(namei));
        int k = asLogical(argi);
        R_warn_partial_match_attr = k;
        SET_VECTOR_ELT(value, i, SetOption(tag, ScalarLogical(k)));
        }
        else if (streql(CHAR(namei), "showWarnCalls")) {
        if (TYPEOF(argi) != LGLSXP || LENGTH(argi) != 1)
            error(_("invalid value for '%s'"), CHAR(namei));
        int k = asLogical(argi);
        R_ShowWarnCalls = k;
        SET_VECTOR_ELT(value, i, SetOption(tag, ScalarLogical(k)));
        }
        else if (streql(CHAR(namei), "showErrorCalls")) {
        if (TYPEOF(argi) != LGLSXP || LENGTH(argi) != 1)
            error(_("invalid value for '%s'"), CHAR(namei));
        int k = asLogical(argi);
        R_ShowErrorCalls = k;
        SET_VECTOR_ELT(value, i, SetOption(tag, ScalarLogical(k)));
        }
        else if (streql(CHAR(namei), "showNCalls")) {
        int k = asInteger(argi);
        if (k < 30 || k > 500 || k == NA_INTEGER || LENGTH(argi) != 1)
            error(_("invalid value for '%s'"), CHAR(namei));
        R_NShowCalls = k;
        SET_VECTOR_ELT(value, i, SetOption(tag, ScalarInteger(k)));
        }
        else if (streql(CHAR(namei), "par.ask.default")) {
        error(_("\"par.ask.default\" has been replaced by \"device.ask.default\""));
        }
        else if (streql(CHAR(namei), "browserNLdisabled")) {
        if (TYPEOF(argi) != LGLSXP || LENGTH(argi) != 1)
            error(_("invalid value for '%s'"), CHAR(namei));
        int k = asLogical(argi);
        if (k == NA_LOGICAL)
            error(_("invalid value for '%s'"), CHAR(namei));
        R_DisableNLinBrowser = k;
        SET_VECTOR_ELT(value, i, SetOption(tag, ScalarLogical(k)));
        }
        else if (streql(CHAR(namei), "CBoundsCheck")) {
        if (TYPEOF(argi) != LGLSXP || LENGTH(argi) != 1)
            error(_("invalid value for '%s'"), CHAR(namei));
        int k = asLogical(argi);
        R_CBoundsCheck = k;
        SET_VECTOR_ELT(value, i, SetOption(tag, ScalarLogical(k)));
        }
        else {
        SET_VECTOR_ELT(value, i, SetOption(tag, duplicate(argi)));
        }
        SET_STRING_ELT(names, i, namei);
    }
    else { /* querying arg */
        const char *tag;
        if (!isString(argi) || LENGTH(argi) <= 0)
        error(_("invalid argument"));
        tag = CHAR(STRING_ELT(argi, 0));
        if (streql(tag, "par.ask.default")) {
        error(_("\"par.ask.default\" has been replaced by \"device.ask.default\""));
        }

        SET_VECTOR_ELT(value, i, duplicate(CAR(FindTaggedItem(options, install(tag)))));
        SET_STRING_ELT(names, i, STRING_ELT(argi, 0));
        R_Visible = TRUE;
    }
    } /* for() */
    setAttrib(value, R_NamesSymbol, names);
    UNPROTECT(2);
    return value;
}