The R Project SVN R

/*
 *  R : A Computer Language for Statistical Data Analysis
 *  Copyright (C) 1995-2007  Robert Gentleman, Ross Ihaka and the
 *               R Development 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
 *  http://www.r-project.org/Licenses/
 */

/* <UTF8> char here is either ASCII or handled as a whole */

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

#include <Defn.h> /*-- Maybe modularize into own Coerce.h ..*/
#include <Rmath.h>
#include <Print.h>


/* This section of code handles type conversion for elements */
/* of data vectors.  Type coercion throughout R should use these */
/* routines to ensure consistency. */

/* Coercion warnings will be OR'ed : */
#define WARN_NA    1
#define WARN_INACC 2
#define WARN_IMAG  4
#define WARN_RAW  8

/* The following two macros copy or clear the attributes.  They also
   ensure that the object bit is properly set.  They avoid calling the
   assignment functions when possible, since the write barrier (and
   possibly cache behavior on some architectures) makes assigning more
   costly than dereferencing. */
#define DUPLICATE_ATTRIB(to, from) do {\
  SEXP __from__ = (from); \
  if (ATTRIB(__from__) != R_NilValue) { \
    SEXP __to__ = (to); \
    (DUPLICATE_ATTRIB)(__to__, __from__);   \
  } \
} while (0)

#define CLEAR_ATTRIB(x) do {\
  SEXP __x__ = (x); \
  if (ATTRIB(__x__) != R_NilValue) { \
    SET_ATTRIB(__x__, R_NilValue); \
    if (OBJECT(__x__)) SET_OBJECT(__x__, 0); \
    if (IS_S4_OBJECT(__x__)) UNSET_S4_OBJECT(__x__); \
  } \
} while (0)

void attribute_hidden CoercionWarning(int warn)
{
/* FIXME: Use
   =====
   WarningMessage(R_NilValue, WARNING_....);
*/
    if (warn & WARN_NA)
    warning(_("NAs introduced by coercion"));
    if (warn & WARN_INACC)
    warning(_("inaccurate integer conversion in coercion"));
    if (warn & WARN_IMAG)
    warning(_("imaginary parts discarded in coercion"));
    if (warn & WARN_RAW)
    warning(_("out-of-range values treated as 0 in coercion to raw"));
}

/* allows integers including hex representations */
static double R_strtol(const char *nptr, char **endptr)
{
    double ret = 0, sign = +1;
    const char *p = nptr;

    if(strlen(p) >= 2 && p[0] == '0' && (p[1] == 'x' || p[1] == 'X')) {
    /* a hex number */
    p +=2;
    for(; p; p++) {
        if('0' <= *p && *p <= '9') ret = 16*ret + (*p -'0');
        else if('a' <= *p && *p <= 'f') ret = 16*ret + (*p -'a' + 10);
        else if('A' <= *p && *p <= 'F') ret = 16*ret + (*p -'A' + 10);
        else goto done;
    }
    }

    for(p = nptr; p; p++) {
    if(*p == '+') continue;
    if(*p == '-') { sign = -1; continue;}
    if('0' <= *p && *p <= '9') ret = 10*ret + (*p -'0');
    else goto done;
    }

done:
    if(endptr) *endptr = (char *)p;
    return sign*ret;
}

/* used in X11 module */
double R_strtod(const char *c, char **end)
{
    double x;

    if (strncmp(c, "NA", 2) == 0){
    x = NA_REAL; *end = (char *)c + 2; /* coercion for -Wall */
    }
    else if (strncmp(c, "NaN", 3) == 0) {
    x = R_NaN; *end = (char *)c + 3;
    }
    else if (strncmp(c, "Inf", 3) == 0) {
    x = R_PosInf; *end = (char *)c + 3;
    }
    else if (strncmp(c, "-Inf", 4) == 0) {
    x = R_NegInf; *end = (char *)c + 4;
    }
    else if (!strncmp(c, "0x", 2) || !strncmp(c, "0x", 2)) {
    x = R_strtol(c, end);
    } else
        x = strtod(c, end);
    return x;
}

int attribute_hidden
LogicalFromInteger(int x, int *warn)
{
    return (x == NA_INTEGER) ?
    NA_LOGICAL : (x != 0);
}

int attribute_hidden
LogicalFromReal(double x, int *warn)
{
    return ISNAN(x) ?
    NA_LOGICAL : (x != 0);
}

int attribute_hidden
LogicalFromComplex(Rcomplex x, int *warn)
{
    return (ISNAN(x.r) || ISNAN(x.i)) ?
    NA_LOGICAL : (x.r != 0 || x.i != 0);
}

int attribute_hidden
LogicalFromString(SEXP x, int *warn)
{
    if (x != R_NaString) {
    if (StringTrue(CHAR(x))) return 1;
    if (StringFalse(CHAR(x))) return 0;
    }
    return NA_LOGICAL;
}

int attribute_hidden
IntegerFromLogical(int x, int *warn)
{
    return (x == NA_LOGICAL) ?
    NA_INTEGER : x;
}

int attribute_hidden
IntegerFromReal(double x, int *warn)
{
    if (ISNAN(x))
    return NA_INTEGER;
    else if (x > INT_MAX || x <= INT_MIN ) {
    *warn |= WARN_NA;
    return NA_INTEGER;
    }
    return x;
}

int attribute_hidden
IntegerFromComplex(Rcomplex x, int *warn)
{
    if (ISNAN(x.r) || ISNAN(x.i))
    return NA_INTEGER;
    else if (x.r > INT_MAX || x.r <= INT_MIN ) {
    *warn |= WARN_NA;
    return NA_INTEGER;;
    }
    if (x.i != 0)
    *warn |= WARN_IMAG;
    return x.r;
}


int attribute_hidden
IntegerFromString(SEXP x, int *warn)
{
    double xdouble;
    char *endp;
    if (x != R_NaString && !isBlankString(CHAR(x))) { /* ASCII */
    xdouble = R_strtod(CHAR(x), &endp); /* ASCII */
    if (isBlankString(endp)) {
        if (xdouble > INT_MAX) {
        *warn |= WARN_INACC;
        return INT_MAX;
        }
        else if(xdouble < INT_MIN+1) {
        *warn |= WARN_INACC;
        return INT_MIN;
        }
        else
        return xdouble;
    }
    else *warn |= WARN_NA;
    }
    return NA_INTEGER;
}

double attribute_hidden
RealFromLogical(int x, int *warn)
{
    return (x == NA_LOGICAL) ?
    NA_REAL : x;
}

double attribute_hidden
RealFromInteger(int x, int *warn)
{
    if (x == NA_INTEGER)
    return NA_REAL;
    else
    return x;
}

double attribute_hidden
RealFromComplex(Rcomplex x, int *warn)
{
    if (ISNAN(x.r) || ISNAN(x.i))
    return NA_REAL;
    if (x.i != 0)
    *warn |= WARN_IMAG;
    return x.r;
}

double attribute_hidden
RealFromString(SEXP x, int *warn)
{
    double xdouble;
    char *endp;
    if (x != R_NaString && !isBlankString(CHAR(x))) { /* ASCII */
    xdouble = R_strtod(CHAR(x), &endp); /* ASCII */
    if (isBlankString(endp))
        return xdouble;
    else
        *warn |= WARN_NA;
    }
    return NA_REAL;
}

Rcomplex attribute_hidden
ComplexFromLogical(int x, int *warn)
{
    Rcomplex z;
    if (x == NA_LOGICAL) {
    z.r = NA_REAL;
    z.i = NA_REAL;
    }
    else {
    z.r = x;
    z.i = 0;
    }
    return z;
}

Rcomplex attribute_hidden
ComplexFromInteger(int x, int *warn)
{
    Rcomplex z;
    if (x == NA_INTEGER) {
    z.r = NA_REAL;
    z.i = NA_REAL;
    }
    else {
    z.r = x;
    z.i = 0;
    }
    return z;
}

Rcomplex attribute_hidden
ComplexFromReal(double x, int *warn)
{
    Rcomplex z;
    if (ISNAN(x)) {
    z.r = NA_REAL;
    z.i = NA_REAL;
    }
    else {
    z.r = x;
    z.i = 0;
    }
    return z;
}

Rcomplex attribute_hidden
ComplexFromString(SEXP x, int *warn)
{
    double xr, xi;
    Rcomplex z;
    const char *xx = CHAR(x); /* ASCII */
    char *endp;

    z.r = z.i = NA_REAL;
    if (x != R_NaString && !isBlankString(xx)) {
    xr = R_strtod(xx, &endp);
    if (isBlankString(endp)) {
        z.r = xr;
        z.i = 0.0;
    }
    else if (*endp == '+' || *endp == '-') {
        xi = R_strtod(endp, &endp);
        if (*endp++ == 'i' && isBlankString(endp)) {
        z.r = xr;
        z.i = xi;
        }
        else *warn |= WARN_NA;
    }
    else *warn |= WARN_NA;
    }
    return z;
}

SEXP attribute_hidden StringFromLogical(int x, int *warn)
{
    int w;
    formatLogical(&x, 1, &w);
    if (x == NA_LOGICAL) return NA_STRING;
    else return mkChar(EncodeLogical(x, w));
}

SEXP attribute_hidden StringFromInteger(int x, int *warn)
{
    int w;
    formatInteger(&x, 1, &w);
    if (x == NA_INTEGER) return NA_STRING;
    else return mkChar(EncodeInteger(x, w));
}

SEXP attribute_hidden StringFromReal(double x, int *warn)
{
    int w, d, e;
    formatReal(&x, 1, &w, &d, &e, 0);
    if (ISNA(x)) return NA_STRING;
    else return mkChar(EncodeReal(x, w, d, e, OutDec));
}

SEXP attribute_hidden StringFromComplex(Rcomplex x, int *warn)
{
    int wr, dr, er, wi, di, ei;
    formatComplex(&x, 1, &wr, &dr, &er, &wi, &di, &ei, 0);
    if (ISNA(x.r) || ISNA(x.i)) return NA_STRING;
    else
    return mkChar(EncodeComplex(x, wr, dr, er, wi, di, ei, OutDec));
}

static SEXP StringFromRaw(Rbyte x, int *warn)
{
    char buf[3];
    sprintf(buf, "%02x", x);
    return mkChar(buf);
}

/* Conversion between the two list types (LISTSXP and VECSXP). */

SEXP PairToVectorList(SEXP x)
{
    SEXP xptr, xnew, xnames;
    int i, len = 0, named = 0;
    for (xptr = x ; xptr != R_NilValue ; xptr = CDR(xptr)) {
    named = named | (TAG(xptr) != R_NilValue);
    len++;
    }
    PROTECT(x);
    PROTECT(xnew = allocVector(VECSXP, len));
    for (i = 0, xptr = x; i < len; i++, xptr = CDR(xptr))
    SET_VECTOR_ELT(xnew, i, CAR(xptr));
    if (named) {
    PROTECT(xnames = allocVector(STRSXP, len));
    xptr = x;
    for (i = 0, xptr = x; i < len; i++, xptr = CDR(xptr)) {
        if(TAG(xptr) == R_NilValue)
        SET_STRING_ELT(xnames, i, R_BlankString);
        else
        SET_STRING_ELT(xnames, i, PRINTNAME(TAG(xptr)));
    }
    setAttrib(xnew, R_NamesSymbol, xnames);
    UNPROTECT(1);
    }
    copyMostAttrib(x, xnew);
    UNPROTECT(2);
    return xnew;
}

SEXP VectorToPairList(SEXP x)
{
    SEXP xptr, xnew, xnames;
    int i, len, named;
    len = length(x);
    PROTECT(x);
    PROTECT(xnew = allocList(len));
    PROTECT(xnames = getAttrib(x, R_NamesSymbol));
    named = (xnames != R_NilValue);
    xptr = xnew;
    for (i = 0; i < len; i++) {
    SETCAR(xptr, VECTOR_ELT(x, i));
    if (named && CHAR(STRING_ELT(xnames, i))[0] != '\0') /* ASCII */
        SET_TAG(xptr, install(translateChar(STRING_ELT(xnames, i))));
    xptr = CDR(xptr);
    }
    if (len>0)       /* can't set attributes on NULL */
    copyMostAttrib(x, xnew);
    UNPROTECT(3);
    return xnew;
}

static SEXP coerceToSymbol(SEXP v)
{
    SEXP ans = R_NilValue;
    int warn = 0;
    if (length(v) <= 0)
    error(_("invalid data of mode \"%s\" (too short)"),
          type2char(TYPEOF(v)));
    PROTECT(v);
    switch(TYPEOF(v)) {
    case LGLSXP:
    ans = StringFromLogical(LOGICAL(v)[0], &warn);
    break;
    case INTSXP:
    ans = StringFromInteger(INTEGER(v)[0], &warn);
    break;
    case REALSXP:
    ans = StringFromReal(REAL(v)[0], &warn);
    break;
    case CPLXSXP:
    ans = StringFromComplex(COMPLEX(v)[0], &warn);
    break;
    case STRSXP:
    ans = STRING_ELT(v, 0);
    break;
    case RAWSXP:
    ans = StringFromRaw(RAW(v)[0], &warn);
    break;
    default:
    UNIMPLEMENTED_TYPE("coerceToSymbol", v);
    }
    if (warn) CoercionWarning(warn);/*2000/10/23*/
    ans = install(CHAR(ans));
    UNPROTECT(1);
    return ans;
}

static SEXP coerceToLogical(SEXP v)
{
    SEXP ans;
    int i, n, warn = 0;
    PROTECT(ans = allocVector(LGLSXP, n = length(v)));
#ifdef R_MEMORY_PROFILING
    if (TRACE(v)){
       memtrace_report(v,ans);
       SET_TRACE(ans,1);
    }
#endif
    DUPLICATE_ATTRIB(ans, v);
    switch (TYPEOF(v)) {
    case INTSXP:
    for (i = 0; i < n; i++)
        LOGICAL(ans)[i] = LogicalFromInteger(INTEGER(v)[i], &warn);
    break;
    case REALSXP:
    for (i = 0; i < n; i++)
        LOGICAL(ans)[i] = LogicalFromReal(REAL(v)[i], &warn);
        break;
    case CPLXSXP:
    for (i = 0; i < n; i++)
        LOGICAL(ans)[i] = LogicalFromComplex(COMPLEX(v)[i], &warn);
    break;
    case STRSXP:
    for (i = 0; i < n; i++)
        LOGICAL(ans)[i] = LogicalFromString(STRING_ELT(v, i), &warn);
    break;
    case RAWSXP:
    for (i = 0; i < n; i++)
        LOGICAL(ans)[i] = LogicalFromInteger((int)RAW(v)[i], &warn);
    break;
    default:
    UNIMPLEMENTED_TYPE("coerceToLogical", v);
    }
    if (warn) CoercionWarning(warn);
    UNPROTECT(1);
    return ans;
}

static SEXP coerceToInteger(SEXP v)
{
    SEXP ans;
    int i, n, warn = 0;
    PROTECT(ans = allocVector(INTSXP, n = LENGTH(v)));
#ifdef R_MEMORY_PROFILING
    if (TRACE(v)){
       memtrace_report(v,ans);
       SET_TRACE(ans,1);
    }
#endif
    DUPLICATE_ATTRIB(ans, v);
    switch (TYPEOF(v)) {
    case LGLSXP:
    for (i = 0; i < n; i++)
        INTEGER(ans)[i] = IntegerFromLogical(LOGICAL(v)[i], &warn);
        break;
    case REALSXP:
    for (i = 0; i < n; i++)
        INTEGER(ans)[i] = IntegerFromReal(REAL(v)[i], &warn);
    break;
    case CPLXSXP:
    for (i = 0; i < n; i++)
        INTEGER(ans)[i] = IntegerFromComplex(COMPLEX(v)[i], &warn);
    break;
    case STRSXP:
    for (i = 0; i < n; i++)
        INTEGER(ans)[i] = IntegerFromString(STRING_ELT(v, i), &warn);
    break;
    case RAWSXP:
    for (i = 0; i < n; i++)
        INTEGER(ans)[i] = (int)RAW(v)[i];
        break;
    default:
    UNIMPLEMENTED_TYPE("coerceToInteger", v);
    }
    if (warn) CoercionWarning(warn);
    UNPROTECT(1);
    return ans;
}

static SEXP coerceToReal(SEXP v)
{
    SEXP ans;
    int i, n, warn = 0;
    PROTECT(ans = allocVector(REALSXP, n = LENGTH(v)));
#ifdef R_MEMORY_PROFILING
    if (TRACE(v)){
       memtrace_report(v,ans);
       SET_TRACE(ans,1);
    }
#endif
    DUPLICATE_ATTRIB(ans, v);
    switch (TYPEOF(v)) {
    case LGLSXP:
    for (i = 0; i < n; i++)
        REAL(ans)[i] = RealFromLogical(LOGICAL(v)[i], &warn);
    break;
    case INTSXP:
    for (i = 0; i < n; i++)
        REAL(ans)[i] = RealFromInteger(INTEGER(v)[i], &warn);
    break;
    case CPLXSXP:
    for (i = 0; i < n; i++)
        REAL(ans)[i] = RealFromComplex(COMPLEX(v)[i], &warn);
    break;
    case STRSXP:
    for (i = 0; i < n; i++)
        REAL(ans)[i] = RealFromString(STRING_ELT(v, i), &warn);
    break;
    case RAWSXP:
    for (i = 0; i < n; i++)
        REAL(ans)[i] = RealFromInteger((int)RAW(v)[i], &warn);
    break;
    default:
    UNIMPLEMENTED_TYPE("coerceToReal", v);
    }
    if (warn) CoercionWarning(warn);
    UNPROTECT(1);
    return ans;
}

static SEXP coerceToComplex(SEXP v)
{
    SEXP ans;
    int i, n, warn = 0;
    PROTECT(ans = allocVector(CPLXSXP, n = LENGTH(v)));
#ifdef R_MEMORY_PROFILING
    if (TRACE(v)){
       memtrace_report(v,ans);
       SET_TRACE(ans,1);
    }
#endif
    DUPLICATE_ATTRIB(ans, v);
    switch (TYPEOF(v)) {
    case LGLSXP:
    for (i = 0; i < n; i++)
        COMPLEX(ans)[i] = ComplexFromLogical(LOGICAL(v)[i], &warn);
    break;
    case INTSXP:
    for (i = 0; i < n; i++)
        COMPLEX(ans)[i] = ComplexFromInteger(INTEGER(v)[i], &warn);
    break;
    case REALSXP:
    for (i = 0; i < n; i++)
        COMPLEX(ans)[i] = ComplexFromReal(REAL(v)[i], &warn);
    break;
    case STRSXP:
    for (i = 0; i < n; i++)
        COMPLEX(ans)[i] = ComplexFromString(STRING_ELT(v, i), &warn);
    break;
    case RAWSXP:
    for (i = 0; i < n; i++)
        COMPLEX(ans)[i] = ComplexFromInteger((int)RAW(v)[i], &warn);
    break;
    default:
    UNIMPLEMENTED_TYPE("coerceToComplex", v);
    }
    if (warn) CoercionWarning(warn);
    UNPROTECT(1);
    return ans;
}

static SEXP coerceToRaw(SEXP v)
{
    SEXP ans;
    int i, n, warn = 0, tmp;

    PROTECT(ans = allocVector(RAWSXP, n = LENGTH(v)));
#ifdef R_MEMORY_PROFILING
    if (TRACE(v)){
       memtrace_report(v,ans);
       SET_TRACE(ans,1);
    }
#endif
    DUPLICATE_ATTRIB(ans, v);
    switch (TYPEOF(v)) {
    case LGLSXP:
    for (i = 0; i < n; i++) {
        tmp = IntegerFromLogical(LOGICAL(v)[i], &warn);
        if(tmp == NA_INTEGER) {
        tmp = 0;
        warn |= WARN_RAW;
        }
        RAW(ans)[i] = (Rbyte) tmp;
    }
    break;
    case INTSXP:
    for (i = 0; i < n; i++) {
        tmp = INTEGER(v)[i];
        if(tmp == NA_INTEGER || tmp < 0 || tmp > 255) {
        tmp = 0;
        warn |= WARN_RAW;
        }
        RAW(ans)[i] = (Rbyte) tmp;
    }
    break;
    case REALSXP:
    for (i = 0; i < n; i++) {
        tmp = IntegerFromReal(REAL(v)[i], &warn);
        if(tmp == NA_INTEGER || tmp < 0 || tmp > 255) {
        tmp = 0;
        warn |= WARN_RAW;
        }
        RAW(ans)[i] = (Rbyte) tmp;
    }
    break;
    case CPLXSXP:
    for (i = 0; i < n; i++) {
        tmp = IntegerFromComplex(COMPLEX(v)[i], &warn);
        if(tmp == NA_INTEGER || tmp < 0 || tmp > 255) {
        tmp = 0;
        warn |= WARN_RAW;
        }
        RAW(ans)[i] = (Rbyte) tmp;
    }
    break;
    case STRSXP:
    for (i = 0; i < n; i++) {
        tmp = IntegerFromString(STRING_ELT(v, i), &warn);
        if(tmp == NA_INTEGER || tmp < 0 || tmp > 255) {
        tmp = 0;
        warn |= WARN_RAW;
        }
        RAW(ans)[i] = (Rbyte) tmp;
    }
    break;
    default:
    UNIMPLEMENTED_TYPE("coerceToRaw", v);
    }
    if (warn) CoercionWarning(warn);
    UNPROTECT(1);
    return ans;
}

static SEXP coerceToString(SEXP v)
{
    SEXP ans;
    int i, n, savedigits, warn = 0;
    PROTECT(ans = allocVector(STRSXP, n = LENGTH(v)));
#ifdef R_MEMORY_PROFILING
    if (TRACE(v)){
       memtrace_report(v,ans);
       SET_TRACE(ans,1);
    }
#endif
    DUPLICATE_ATTRIB(ans, v);
    switch (TYPEOF(v)) {
    case LGLSXP:
    for (i = 0; i < n; i++)
        SET_STRING_ELT(ans, i, StringFromLogical(LOGICAL(v)[i], &warn));
    break;
    case INTSXP:
    for (i = 0; i < n; i++)
        SET_STRING_ELT(ans, i, StringFromInteger(INTEGER(v)[i], &warn));
    break;
    case REALSXP:
    PrintDefaults(R_NilValue);
    savedigits = R_print.digits; R_print.digits = DBL_DIG;/* MAX precision */
    for (i = 0; i < n; i++)
        SET_STRING_ELT(ans, i, StringFromReal(REAL(v)[i], &warn));
    R_print.digits = savedigits;
    break;
    case CPLXSXP:
    PrintDefaults(R_NilValue);
    savedigits = R_print.digits; R_print.digits = DBL_DIG;/* MAX precision */
    for (i = 0; i < n; i++)
        SET_STRING_ELT(ans, i, StringFromComplex(COMPLEX(v)[i], &warn));
    R_print.digits = savedigits;
    break;
    case RAWSXP:
    for (i = 0; i < n; i++)
        SET_STRING_ELT(ans, i, StringFromRaw(RAW(v)[i], &warn));
    break;
    default:
    UNIMPLEMENTED_TYPE("coerceToString", v);
    }
    if (warn) CoercionWarning(warn);/*2000/10/23*/
    UNPROTECT(1);
    return (ans);
}

static SEXP coerceToExpression(SEXP v)
{
    SEXP ans;
    int i, n;
    if (isVectorAtomic(v)) {
    n = LENGTH(v);
    PROTECT(ans = allocVector(EXPRSXP, n));
#ifdef R_MEMORY_PROFILING
    if (TRACE(v)){
       memtrace_report(v,ans);
       SET_TRACE(ans,1);
    }
#endif
    switch (TYPEOF(v)) {
    case LGLSXP:
        for (i = 0; i < n; i++)
        SET_VECTOR_ELT(ans, i, ScalarLogical(LOGICAL(v)[i]));
        break;
    case INTSXP:
        for (i = 0; i < n; i++)
        SET_VECTOR_ELT(ans, i, ScalarInteger(INTEGER(v)[i]));
        break;
    case REALSXP:
        for (i = 0; i < n; i++)
        SET_VECTOR_ELT(ans, i, ScalarReal(REAL(v)[i]));
        break;
    case CPLXSXP:
        for (i = 0; i < n; i++)
        SET_VECTOR_ELT(ans, i, ScalarComplex(COMPLEX(v)[i]));
        break;
    case STRSXP:
        for (i = 0; i < n; i++)
        SET_VECTOR_ELT(ans, i, ScalarString(STRING_ELT(v, i)));
        break;
    case RAWSXP:
        for (i = 0; i < n; i++)
        SET_VECTOR_ELT(ans, i, ScalarRaw(RAW(v)[i]));
        break;
    default:
        UNIMPLEMENTED_TYPE("coerceToExpression", v);
    }
    }
    else {/* not used either */
    PROTECT(ans = allocVector(EXPRSXP, 1));
    SET_VECTOR_ELT(ans, 0, duplicate(v));
    }
    UNPROTECT(1);
    return ans;
}

static SEXP coerceToVectorList(SEXP v)
{
    SEXP ans, tmp;
    int i, n;
    n = length(v);
    PROTECT(ans = allocVector(VECSXP, n));
#ifdef R_MEMORY_PROFILING
    if (TRACE(v)){
       memtrace_report(v,ans);
       SET_TRACE(ans,1);
    }
#endif
    switch (TYPEOF(v)) {
    case LGLSXP:
    for (i = 0; i < n; i++)
        SET_VECTOR_ELT(ans, i, ScalarLogical(LOGICAL(v)[i]));
    break;
    case INTSXP:
    for (i = 0; i < n; i++)
        SET_VECTOR_ELT(ans, i, ScalarInteger(INTEGER(v)[i]));
    break;
    case REALSXP:
    for (i = 0; i < n; i++)
        SET_VECTOR_ELT(ans, i, ScalarReal(REAL(v)[i]));
    break;
    case CPLXSXP:
    for (i = 0; i < n; i++)
        SET_VECTOR_ELT(ans, i, ScalarComplex(COMPLEX(v)[i]));
    break;
    case STRSXP:
    for (i = 0; i < n; i++)
        SET_VECTOR_ELT(ans, i, ScalarString(STRING_ELT(v, i)));
    break;
    case RAWSXP:
    for (i = 0; i < n; i++)
        SET_VECTOR_ELT(ans, i, ScalarRaw(RAW(v)[i]));
    break;
    case LISTSXP:
    case LANGSXP:
    tmp = v;
    for (i = 0; i < n; i++) {
        SET_VECTOR_ELT(ans, i, CAR(tmp));
        tmp = CDR(tmp);
    }
    break;
    default:
    UNIMPLEMENTED_TYPE("coerceToVectorList", v);
    }
    tmp = getAttrib(v, R_NamesSymbol);
    if (tmp != R_NilValue)
    setAttrib(ans, R_NamesSymbol, tmp);
    UNPROTECT(1);
    return (ans);
}

static SEXP coerceToPairList(SEXP v)
{
    SEXP ans, ansp;
    int i, n;
    n = LENGTH(v);
    PROTECT(ansp = ans = allocList(n));
    for (i = 0; i < n; i++) {
    switch (TYPEOF(v)) {
    case LGLSXP:
        SETCAR(ansp, allocVector(LGLSXP, 1));
        INTEGER(CAR(ansp))[0] = INTEGER(v)[i];
        break;
    case INTSXP:
        SETCAR(ansp, allocVector(INTSXP, 1));
        INTEGER(CAR(ansp))[0] = INTEGER(v)[i];
        break;
    case REALSXP:
        SETCAR(ansp, allocVector(REALSXP, 1));
        REAL(CAR(ansp))[0] = REAL(v)[i];
        break;
    case CPLXSXP:
        SETCAR(ansp, allocVector(CPLXSXP, 1));
        COMPLEX(CAR(ansp))[0] = COMPLEX(v)[i];
        break;
    case STRSXP:
        SETCAR(ansp, ScalarString(STRING_ELT(v, i)));
        break;
    case RAWSXP:
        SETCAR(ansp, allocVector(RAWSXP, 1));
        RAW(CAR(ansp))[0] = RAW(v)[i];
        break;
    case VECSXP:
        SETCAR(ansp, VECTOR_ELT(v, i));
        break;
    case EXPRSXP:
        SETCAR(ansp, VECTOR_ELT(v, i));
        break;
    default:
        UNIMPLEMENTED_TYPE("coerceToPairList", v);
    }
    ansp = CDR(ansp);
    }
    ansp = getAttrib(v, R_NamesSymbol);
    if (ansp != R_NilValue)
    setAttrib(ans, R_NamesSymbol, ansp);
    UNPROTECT(1);
    return (ans);
}

/* Coerce a pairlist to the given type */
static SEXP coercePairList(SEXP v, SEXPTYPE type)
{
    int i, n=0;
    SEXP rval= R_NilValue, vp, names;

    /* Hmm, this is also called to LANGSXP, and coerceVector already
       did the check of TYPEOF(v) == type */
    if(type == LISTSXP) return v;/* IS pairlist */

    names = v;
    if (type == EXPRSXP) {
    PROTECT(rval = allocVector(type, 1));
    SET_VECTOR_ELT(rval, 0, v);
    UNPROTECT(1);
    return rval;
    }
    else if (type == STRSXP) {
    n = length(v);
    PROTECT(rval = allocVector(type, n));
    for (vp = v, i = 0; vp != R_NilValue; vp = CDR(vp), i++) {
        if (isString(CAR(vp)) && length(CAR(vp)) == 1)
        SET_STRING_ELT(rval, i, STRING_ELT(CAR(vp), 0));
        else
        SET_STRING_ELT(rval, i, STRING_ELT(deparse1line(CAR(vp), 0), 0));
    }
    }
    else if (type == VECSXP) {
    rval = PairToVectorList(v);
    return rval;
    }
    else if (isVectorizable(v)) {
    n = length(v);
    PROTECT(rval = allocVector(type, n));
    switch (type) {
    case LGLSXP:
        for (i = 0, vp = v; i < n; i++, vp = CDR(vp))
        LOGICAL(rval)[i] = asLogical(CAR(vp));
        break;
    case INTSXP:
        for (i = 0, vp = v; i < n; i++, vp = CDR(vp))
        INTEGER(rval)[i] = asInteger(CAR(vp));
        break;
    case REALSXP:
        for (i = 0, vp = v; i < n; i++, vp = CDR(vp))
        REAL(rval)[i] = asReal(CAR(vp));
        break;
    case CPLXSXP:
        for (i = 0, vp = v; i < n; i++, vp = CDR(vp))
        COMPLEX(rval)[i] = asComplex(CAR(vp));
        break;
    case RAWSXP:
        for (i = 0, vp = v; i < n; i++, vp = CDR(vp))
        RAW(rval)[i] = (Rbyte) asInteger(CAR(vp));
        break;
    default:
        UNIMPLEMENTED_TYPE("coercePairList", v);
    }
    }
    else
    error(_("'pairlist' object cannot be coerced to '%s'"),
          type2char(type));

    /* If any tags are non-null then we */
    /* need to add a names attribute. */
    for (vp = v, i = 0; vp != R_NilValue; vp = CDR(vp))
    if (TAG(vp) != R_NilValue)
        i = 1;

    if (i) {
    i = 0;
    names = allocVector(STRSXP, n);
    for (vp = v; vp != R_NilValue; vp = CDR(vp), i++)
        if (TAG(vp) != R_NilValue)
        SET_STRING_ELT(names, i, PRINTNAME(TAG(vp)));
    setAttrib(rval, R_NamesSymbol, names);
    }
    UNPROTECT(1);
    return rval;
}

/* Coerce a vector list to the given type */
static SEXP coerceVectorList(SEXP v, SEXPTYPE type)
{
    int i, n, warn = 0, tmp;
    SEXP rval, names;

    names = v;
    rval = R_NilValue;  /* -Wall */

    /* expression -> list, new in R 2.4.0 */
    if (type == VECSXP && TYPEOF(v) == EXPRSXP) {
    /* This is sneaky but saves us rewriting a lot of the duplicate code */
    rval = NAMED(v) ? duplicate(v) : v;
    SET_TYPEOF(rval, VECSXP);
    return rval;
    }

    if (type == EXPRSXP && TYPEOF(v) == VECSXP) {
    rval = NAMED(v) ? duplicate(v) : v;
    SET_TYPEOF(rval, EXPRSXP);
    return rval;
    }

    if (type == STRSXP) {
    n = length(v);
    PROTECT(rval = allocVector(type, n));
#ifdef R_MEMORY_PROFILING
    if (TRACE(v)){
       memtrace_report(v, rval);
       SET_TRACE(rval,1);
    }
#endif
    for (i = 0; i < n;  i++) {
        if (isString(VECTOR_ELT(v, i)) && length(VECTOR_ELT(v, i)) == 1)
        SET_STRING_ELT(rval, i, STRING_ELT(VECTOR_ELT(v, i), 0));
#if 0
        /* this will make as.character(list(s)) not backquote
         * non-syntactic name s. It is not entirely clear that
         * that is really desirable though....
         */
        else if (isSymbol(VECTOR_ELT(v, i)))
            SET_STRING_ELT(rval, i, PRINTNAME(VECTOR_ELT(v, i)));
#endif
        else
        SET_STRING_ELT(rval, i,
                   STRING_ELT(deparse1line(VECTOR_ELT(v, i), 0), 0));
    }
    }
    else if (type == LISTSXP) {
    rval = VectorToPairList(v);
    return rval;
    }
    else if (isVectorizable(v)) {
    n = length(v);
    PROTECT(rval = allocVector(type, n));
    switch (type) {
    case LGLSXP:
        for (i = 0; i < n; i++)
        LOGICAL(rval)[i] = asLogical(VECTOR_ELT(v, i));
        break;
    case INTSXP:
        for (i = 0; i < n; i++)
        INTEGER(rval)[i] = asInteger(VECTOR_ELT(v, i));
        break;
    case REALSXP:
        for (i = 0; i < n; i++)
        REAL(rval)[i] = asReal(VECTOR_ELT(v, i));
        break;
    case CPLXSXP:
        for (i = 0; i < n; i++)
        COMPLEX(rval)[i] = asComplex(VECTOR_ELT(v, i));
        break;
    case RAWSXP:
        for (i = 0; i < n; i++) {
        tmp = asInteger(VECTOR_ELT(v, i));
        if (tmp < 0 || tmp > 255) { /* includes NA_INTEGER */
            tmp = 0;
            warn |= WARN_RAW;
        }
        RAW(rval)[i] = (Rbyte) tmp;
        }
        break;
    default:
        UNIMPLEMENTED_TYPE("coerceVectorList", v);
    }
    }
    else
    error(_("(list) object cannot be coerced to '%s'"), type2char(type));

    if (warn) CoercionWarning(warn);
    names = getAttrib(v, R_NamesSymbol);
    if (names != R_NilValue)
    setAttrib(rval, R_NamesSymbol, names);
    UNPROTECT(1);
    return rval;
}

static SEXP coerceSymbol(SEXP v, SEXPTYPE type)
{
    SEXP rval = R_NilValue;
    if (type == EXPRSXP) {
    PROTECT(rval = allocVector(type, 1));
    SET_VECTOR_ELT(rval, 0, v);
    UNPROTECT(1);
    }
    return rval;
}

SEXP coerceVector(SEXP v, SEXPTYPE type)
{
    SEXP op, vp, ans = R_NilValue;  /* -Wall */
    int i,n;

    if (TYPEOF(v) == type)
    return v;

    switch (TYPEOF(v)) {
#ifdef NOTYET
    case NILSXP:
    ans = coerceNull(v, type);
    break;
#endif
    case SYMSXP:
    ans = coerceSymbol(v, type);
    break;
    case NILSXP:
    case LISTSXP:
    ans = coercePairList(v, type);
    break;
    case LANGSXP:
    if (type != STRSXP) {
        ans = coercePairList(v, type);
        break;
    }

    /* This is mostly copied from coercePairList, but we need to
     * special-case the first element so as not to get operators
     * put in backticks. */
    n = length(v);
    PROTECT(ans = allocVector(type, n));
    if (n == 0) break; /* Can this actually happen? */
    i = 0;
    op = CAR(v);
    /* The case of practical relevance is "lhs ~ rhs", which
     * people tend to split using as.character(), modify, and
     * paste() back together. However, we might as well
     * special-case all symbolic operators here. */
    if (TYPEOF(op) == SYMSXP) {
        SET_STRING_ELT(ans, i, PRINTNAME(op));
        i++;
        v = CDR(v);
    }

    /* The distinction between strings and other elements was
     * here "always", but is really dubious since it makes x <- a
     * and x <- "a" come out identical. Won't fix just now. */
    for (vp = v;  vp != R_NilValue; vp = CDR(vp), i++) {
        if (isString(CAR(vp)) && length(CAR(vp)) == 1)
        SET_STRING_ELT(ans, i, STRING_ELT(CAR(vp), 0));
        else
        SET_STRING_ELT(ans, i, STRING_ELT(deparse1line(CAR(vp), 0), 0));
    }
    UNPROTECT(1);
    break;
    case VECSXP:
    case EXPRSXP:
    ans = coerceVectorList(v, type);
    break;
    case ENVSXP:
    error(_("environments cannot be coerced to other types"));
    break;
    case LGLSXP:
    case INTSXP:
    case REALSXP:
    case CPLXSXP:
    case STRSXP:
    case RAWSXP:

#define COERCE_ERROR                        \
    error(_("cannot coerce type %s to %s vector"),      \
          type2char(TYPEOF(v)), type2char(type))

    switch (type) {
    case SYMSXP:
        ans = coerceToSymbol(v);        break;
    case LGLSXP:
        ans = coerceToLogical(v);       break;
    case INTSXP:
        ans = coerceToInteger(v);       break;
    case REALSXP:
        ans = coerceToReal(v);      break;
    case CPLXSXP:
        ans = coerceToComplex(v);       break;
    case RAWSXP:
        ans = coerceToRaw(v);       break;
    case STRSXP:
        ans = coerceToString(v);        break;
    case EXPRSXP:
        ans = coerceToExpression(v);    break;
    case VECSXP:
        ans = coerceToVectorList(v);    break;
    case LISTSXP:
        ans = coerceToPairList(v);      break;
    default:
        COERCE_ERROR;
    }
    break;
    default:
    COERCE_ERROR;
    }
    return ans;
}
#undef COERCE_ERROR


SEXP CreateTag(SEXP x)
{
    if (isNull(x) || isSymbol(x))
    return x;
    if (isString(x)
    && length(x) >= 1
    && length(STRING_ELT(x, 0)) >= 1)
    x = install(translateChar(STRING_ELT(x, 0)));
    else
    x = install(CHAR(STRING_ELT(deparse1(x, 1, SIMPLEDEPARSE), 0)));
    return x;
}

static SEXP asFunction(SEXP x)
{
    SEXP f, pf;
    int n;
    if (isFunction(x)) return x;
    PROTECT(f = allocSExp(CLOSXP));
    SET_CLOENV(f, R_GlobalEnv);
    if (NAMED(x)) PROTECT(x = duplicate(x));
    else PROTECT(x);

    if (isNull(x) || !isList(x)) {
    SET_FORMALS(f, R_NilValue);
    SET_BODY(f, x);
    }
    else {
    n = length(x);
    pf = allocList(n - 1);
    SET_FORMALS(f, pf);
    while(--n) {
        if (TAG(x) == R_NilValue) {
        SET_TAG(pf, CreateTag(CAR(x)));
        SETCAR(pf, R_MissingArg);
        }
        else {
        SETCAR(pf, CAR(x));
        SET_TAG(pf, TAG(x));
        }
        pf = CDR(pf);
        x = CDR(x);
    }
    SET_BODY(f, CAR(x));
    }
    UNPROTECT(2);
    return f;
}

static SEXP ascommon(SEXP call, SEXP u, SEXPTYPE type)
{
    /* -> as.vector(..) or as.XXX(.) : coerce 'u' to 'type' : */
    SEXP v;
    if (type == CLOSXP) {
    return asFunction(u);
    }
    else if (isVector(u) || isList(u) || isLanguage(u)
         || (isSymbol(u) && type == EXPRSXP)) {
    /* this duplication appears not to be needed in all cases,
       but beware that other code relies on it */
    v = NAMED(u) ? duplicate(u) : u;
    if (type != ANYSXP) {
        PROTECT(v);
        v = coerceVector(v, type);
        UNPROTECT(1);
    }
    /* drop attributes() and class() in some cases: */
    if ((type == LISTSXP
         /* already loses 'names' where it shouldn't:
        || type == VECSXP) */
        ) &&
        !(TYPEOF(u) == LANGSXP || TYPEOF(u) == LISTSXP ||
          TYPEOF(u) == EXPRSXP || TYPEOF(u) == VECSXP)) {
        CLEAR_ATTRIB(v);
    }
    return v;
    }
    else if (isSymbol(u) && type == STRSXP)
    return ScalarString(PRINTNAME(u));
    else if (isSymbol(u) && type == SYMSXP)
    return u;
    else if (isSymbol(u) && type == VECSXP) {
    v = allocVector(VECSXP, 1);
    SET_VECTOR_ELT(v, 0, u);
    return v;
    }
    else errorcall(call, _("cannot coerce to vector"));
    return u;/* -Wall */
}

/* A historical anomaly: as.character is primitive, the other ops are not */
SEXP attribute_hidden do_ascharacter(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    SEXP ans, x;

    int type = STRSXP, op0 = PRIMVAL(op);
    char *name = NULL /* -Wall */;
    
    switch(op0) {
    case 0: 
        name = "as.character"; break;
    case 1: 
        name = "as.integer"; type = INTSXP; break;
    case 2: 
        name = "as.double"; type = REALSXP; break;
    case 3: 
        name = "as.complex"; type = CPLXSXP; break;
    case 4: 
        name = "as.logical"; type = LGLSXP; break;
    case 5: 
        name = "as.raw"; type = RAWSXP; break;
    }
    if (DispatchOrEval(call, op, name, args, rho, &ans, 0, 1))
    return(ans);

    /* Method dispatch has failed, we now just */
    /* run the generic internal code */

    checkArity(op, args);
    x = CAR(args);
    if(TYPEOF(x) == type && ATTRIB(x) == R_NilValue) return x;
    ans = ascommon(call, CAR(args), type);
    CLEAR_ATTRIB(ans);
    return ans;
}


SEXP attribute_hidden do_asvector(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    SEXP x, ans;
    int type;

    if (DispatchOrEval(call, op, "as.vector", args, rho, &ans, 0, 1))
    return(ans);

    /* Method dispatch has failed, we now just */
    /* run the generic internal code */

    checkArity(op, args);
    x = CAR(args);

    if (!isString(CADR(args)) || LENGTH(CADR(args)) < 1)
    errorcall_return(call, R_MSG_mode);
    if (!strcmp("function", (CHAR(STRING_ELT(CADR(args), 0))))) /* ASCII */
    type = CLOSXP;
    else
    type = str2type(CHAR(STRING_ELT(CADR(args), 0))); /* ASCII */

    if(TYPEOF(x) == type) {
    switch(type) {
    case LGLSXP:
    case INTSXP:
    case REALSXP:
    case CPLXSXP:
    case STRSXP:
    case RAWSXP:
        if(ATTRIB(x) != R_NilValue) break;
    case EXPRSXP:
    case VECSXP:
        return x;
    default:
        ;
    }
    }

    switch(type) {/* only those are valid : */
    case SYMSXP:
    case LGLSXP:
    case INTSXP:
    case REALSXP:
    case CPLXSXP:
    case STRSXP:
    case EXPRSXP:
    case VECSXP: /* list */
    case LISTSXP:/* pairlist */
    case CLOSXP: /* non-primitive function */
    case RAWSXP:
    case ANYSXP: /* any */
    break;
    default:
    errorcall_return(call, R_MSG_mode);
    }
    ans = ascommon(call, x, type);
    switch(TYPEOF(ans)) {/* keep attributes for these:*/
    case NILSXP:
    case VECSXP:
    case EXPRSXP:
    case LISTSXP:
    case LANGSXP:
    break;
    default:
    CLEAR_ATTRIB(ans);
    break;
    }
    return ans;
}


SEXP attribute_hidden do_asfunction(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    SEXP arglist, envir, names, pargs, body;
    int i, n;

    checkArity(op, args);

    /* Check the arguments; we need a list and environment. */

    arglist = CAR(args);
    if (!isNewList(arglist))
    errorcall(call, _("list argument expected"));

    envir = CADR(args);
    if (isNull(envir)) {
    error(_("use of NULL environment is defunct"));
    envir = R_BaseEnv;
    } else
    if (!isEnvironment(envir))
    errorcall(call, _("invalid environment"));

    n = length(arglist);
    if (n < 1)
    errorcall(call, _("argument must have length at least 1"));
    names = getAttrib(arglist, R_NamesSymbol);
    PROTECT(pargs = args = allocList(n - 1));
    for (i = 0; i < n - 1; i++) {
    SETCAR(pargs, VECTOR_ELT(arglist, i));
    if (names != R_NilValue && *CHAR(STRING_ELT(names, i)) != '\0') /* ASCII */
        SET_TAG(pargs, install(translateChar(STRING_ELT(names, i))));
    else
        SET_TAG(pargs, R_NilValue);
    pargs = CDR(pargs);
    }
    CheckFormals(args);
    PROTECT(body = VECTOR_ELT(arglist, n-1));
    /* the main (only?) thing to rule out is body being
       a function already. If we test here then
       mkCLOSXP can continue to overreact when its
       test fails (PR#1880, 7535, 7702) */
    if(isList(body) || isLanguage(body) || isSymbol(body)
       || isExpression(body) || isVector(body)
#ifdef BYTECODE
       || isByteCode(body)
#endif
       )
        args =  mkCLOSXP(args, body, envir);
    else
        errorcall(call, _("invalid body for function"));
    UNPROTECT(2);
    return args;
}


SEXP attribute_hidden do_ascall(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    SEXP ap, ans, names;
    int i, n;
    checkArity(op, args);
    args = CAR(args);
    switch (TYPEOF(args)) {
    case LANGSXP:
    ans = args;
    break;
    case VECSXP:
    case EXPRSXP:
    if(0 == (n = length(args)))
        errorcall(call, _("invalid length 0 argument"));
    names = getAttrib(args, R_NamesSymbol);
    PROTECT(ap = ans = allocList(n));
    for (i = 0; i < n; i++) {
        SETCAR(ap, VECTOR_ELT(args, i));
        if (names != R_NilValue && !StringBlank(STRING_ELT(names, i)))
        SET_TAG(ap, install(translateChar(STRING_ELT(names, i))));
        ap = CDR(ap);
    }
    UNPROTECT(1);
    break;
    case LISTSXP:
    ans = duplicate(args);
    break;
    default:
    errorcall(call, _("invalid argument list"));
    ans = R_NilValue;
    }
    SET_TYPEOF(ans, LANGSXP);
    SET_TAG(ans, R_NilValue);
    return ans;
}


/* int, not Rboolean, for NA_LOGICAL : */
int asLogical(SEXP x)
{
    int warn = 0;

    if (isVectorAtomic(x)) {
    if (LENGTH(x) < 1)
        return NA_LOGICAL;
    switch (TYPEOF(x)) {
    case LGLSXP:
        return LOGICAL(x)[0];
    case INTSXP:
        return Rf_LogicalFromInteger(INTEGER(x)[0], &warn);
    case REALSXP:
        return Rf_LogicalFromReal(REAL(x)[0], &warn);
    case CPLXSXP:
        return Rf_LogicalFromComplex(COMPLEX(x)[0], &warn);
    case STRSXP:
        return Rf_LogicalFromString(STRING_ELT(x, 0), &warn);
    default:
        UNIMPLEMENTED_TYPE("asLogical", x);
    }
    } else if(TYPEOF(x) == CHARSXP) {
        return Rf_LogicalFromString(x, &warn);
    }
    return NA_LOGICAL;
}

int asInteger(SEXP x)
{
    int warn = 0, res;

    if (isVectorAtomic(x) && LENGTH(x) >= 1) {
    switch (TYPEOF(x)) {
    case LGLSXP:
        return Rf_IntegerFromLogical(LOGICAL(x)[0], &warn);
    case INTSXP:
        return INTEGER(x)[0];
    case REALSXP:
        res = Rf_IntegerFromReal(REAL(x)[0], &warn);
        Rf_CoercionWarning(warn);
        return res;
    case CPLXSXP:
        res = Rf_IntegerFromComplex(COMPLEX(x)[0], &warn);
        Rf_CoercionWarning(warn);
        return res;
    case STRSXP:
        res = Rf_IntegerFromString(STRING_ELT(x, 0), &warn);
        Rf_CoercionWarning(warn);
        return res;
    default:
        UNIMPLEMENTED_TYPE("asInteger", x);
    }
    } else if(TYPEOF(x) == CHARSXP) {
    res = Rf_IntegerFromString(x, &warn);
    Rf_CoercionWarning(warn);
    return res;
    }
    return NA_INTEGER;
}

double asReal(SEXP x)
{
    int warn = 0;
    double res;

    if (isVectorAtomic(x) && LENGTH(x) >= 1) {
    switch (TYPEOF(x)) {
    case LGLSXP:
        res = Rf_RealFromLogical(LOGICAL(x)[0], &warn);
        Rf_CoercionWarning(warn);
        return res;
    case INTSXP:
        res = Rf_RealFromInteger(INTEGER(x)[0], &warn);
        Rf_CoercionWarning(warn);
        return res;
    case REALSXP:
        return REAL(x)[0];
    case CPLXSXP:
        res = Rf_RealFromComplex(COMPLEX(x)[0], &warn);
        Rf_CoercionWarning(warn);
        return res;
    case STRSXP:
        res = Rf_RealFromString(STRING_ELT(x, 0), &warn);
        Rf_CoercionWarning(warn);
        return res;
    default:
        UNIMPLEMENTED_TYPE("asReal", x);
    }
    } else if(TYPEOF(x) == CHARSXP) {
    res = Rf_RealFromString(x, &warn);
    Rf_CoercionWarning(warn);
    return res;
    }
    return NA_REAL;
}

Rcomplex asComplex(SEXP x)
{
    int warn = 0;
    Rcomplex z;

    z.r = NA_REAL;
    z.i = NA_REAL;
    if (isVectorAtomic(x) && LENGTH(x) >= 1) {
    switch (TYPEOF(x)) {
    case LGLSXP:
        return Rf_ComplexFromLogical(LOGICAL(x)[0], &warn);
    case INTSXP:
        return Rf_ComplexFromInteger(INTEGER(x)[0], &warn);
    case REALSXP:
        return Rf_ComplexFromReal(REAL(x)[0], &warn);
    case CPLXSXP:
        return COMPLEX(x)[0];
    case STRSXP:
        return Rf_ComplexFromString(STRING_ELT(x, 0), &warn);
    default:
        UNIMPLEMENTED_TYPE("asComplex", x);
    }
    } else if(TYPEOF(x) == CHARSXP) {
    return Rf_ComplexFromString(x, &warn);
    }
    return z;
}


/* return the type (= "detailed mode") of the SEXP */
SEXP attribute_hidden do_typeof(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    checkArity(op, args);
    return ScalarString(type2str(TYPEOF(CAR(args))));
}

/* Define many of the <primitive> "is.xxx" functions :
   Note that  isNull, isNumeric, etc are defined in util.c or Rinlinedfuns.h
*/
SEXP attribute_hidden do_is(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    SEXP ans;
    checkArity(op, args);

    /* These are all builtins, so we do not need to worry about
       evaluating arguments in DispatchOrEval */
    if(PRIMVAL(op) >= 100 && PRIMVAL(op) < 200 &&
       isObject(CAR(args)) &&
       DispatchOrEval(call, op, CHAR(PRINTNAME(CAR(call))), /* ASCII */
              args, rho, &ans, 0,1))
    return(ans);

    PROTECT(ans = allocVector(LGLSXP, 1));
    switch (PRIMVAL(op)) {
    case NILSXP:    /* is.null */
    LOGICAL(ans)[0] = isNull(CAR(args));
    break;
    case LGLSXP:    /* is.logical */
    LOGICAL(ans)[0] = (TYPEOF(CAR(args)) == LGLSXP);
    break;
    case INTSXP:    /* is.integer */
    LOGICAL(ans)[0] = (TYPEOF(CAR(args)) == INTSXP)
        && !inherits(CAR(args), "factor");
    break;
    case REALSXP:   /* is.double == is.real */
    LOGICAL(ans)[0] = (TYPEOF(CAR(args)) == REALSXP);
    break;
    case CPLXSXP:   /* is.complex */
    LOGICAL(ans)[0] = (TYPEOF(CAR(args)) == CPLXSXP);
    break;
    case STRSXP:    /* is.character */
    LOGICAL(ans)[0] = (TYPEOF(CAR(args)) == STRSXP);
    break;
    case SYMSXP:    /* is.symbol === is.name */
    LOGICAL(ans)[0] = (TYPEOF(CAR(args)) == SYMSXP);
    break;
    case ENVSXP:    /* is.environment */
    LOGICAL(ans)[0] = (TYPEOF(CAR(args)) == ENVSXP);
    break;
    case VECSXP:    /* is.list */
    LOGICAL(ans)[0] = (TYPEOF(CAR(args)) == VECSXP ||
               TYPEOF(CAR(args)) == LISTSXP);
    break;
    case LISTSXP:   /* is.pairlist */
    LOGICAL(ans)[0] = (TYPEOF(CAR(args)) == LISTSXP ||
               TYPEOF(CAR(args)) == NILSXP);/* pairlist() -> NULL */
    break;
    case EXPRSXP:   /* is.expression */
    LOGICAL(ans)[0] = TYPEOF(CAR(args)) == EXPRSXP;
    break;
    case RAWSXP:    /* is.raw */
    LOGICAL(ans)[0] = (TYPEOF(CAR(args)) == RAWSXP);
    break;

    case 50:        /* is.object */
    LOGICAL(ans)[0] = OBJECT(CAR(args));
    break;
/* no longer used: is.data.frame is R code
    case 80:
    LOGICAL(ans)[0] = isFrame(CAR(args));
    break;
*/

    case 100:       /* is.numeric */
    LOGICAL(ans)[0] = isNumeric(CAR(args)) &&
        !isLogical(CAR(args));  /* isNumeric excludes factors */
    break;
    case 101:       /* is.matrix */
    LOGICAL(ans)[0] = isMatrix(CAR(args));
    break;
    case 102:       /* is.array */
    LOGICAL(ans)[0] = isArray(CAR(args));
    break;

    case 200:       /* is.atomic */
    switch(TYPEOF(CAR(args))) {
    case NILSXP:
        /* NULL is atomic (S compatibly), but not in isVectorAtomic(.) */
    case CHARSXP:
    case LGLSXP:
    case INTSXP:
    case REALSXP:
    case CPLXSXP:
    case STRSXP:
    case RAWSXP:
        LOGICAL(ans)[0] = 1;
        break;
    default:
        LOGICAL(ans)[0] = 0;
        break;
    }
    break;
    case 201:       /* is.recursive */
    switch(TYPEOF(CAR(args))) {
    case VECSXP:
    case LISTSXP:
    case CLOSXP:
    case ENVSXP:
    case PROMSXP:
    case LANGSXP:
    case SPECIALSXP:
    case BUILTINSXP:
    case DOTSXP:
    case ANYSXP:
    case EXPRSXP:
    case EXTPTRSXP:
#ifdef BYTECODE
    case BCODESXP:
#endif
    case WEAKREFSXP:
        LOGICAL(ans)[0] = 1;
        break;
    default:
        LOGICAL(ans)[0] = 0;
        break;
    }
    break;

    case 300:       /* is.call */
    LOGICAL(ans)[0] = TYPEOF(CAR(args)) == LANGSXP;
    break;
    case 301:       /* is.language */
    LOGICAL(ans)[0] = (TYPEOF(CAR(args)) == SYMSXP ||
               TYPEOF(CAR(args)) == LANGSXP ||
               TYPEOF(CAR(args)) == EXPRSXP);
    break;
    case 302:       /* is.function */
    LOGICAL(ans)[0] = isFunction(CAR(args));
    break;

    case 999:       /* is.single */
    errorcall(call, _("type \"single\" unimplemented in R"));
    default:
    errorcall(call, _("unimplemented predicate"));
    }
    UNPROTECT(1);
    return (ans);
}

/* What should is.vector do ?
 * In S, if an object has no attributes it is a vector, otherwise it isn't.
 * It seems to make more sense to check for a dim attribute.
 */

SEXP attribute_hidden do_isvector(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    SEXP ans, a;
    checkArity(op, args);
    if (!isString(CADR(args)) || LENGTH(CADR(args)) <= 0)
    errorcall_return(call, R_MSG_mode);

    PROTECT(ans = allocVector(LGLSXP, 1));
    if (streql(CHAR(STRING_ELT(CADR(args), 0)), "any")) { /* ASCII */
    LOGICAL(ans)[0] = isVector(CAR(args));/* from ./util.c */
    }
    else if (streql(CHAR(STRING_ELT(CADR(args), 0)), "numeric")) { /* ASCII */
    LOGICAL(ans)[0] = (isNumeric(CAR(args)) &&
               !isLogical(CAR(args)));
    }
    else if (streql(CHAR(STRING_ELT(CADR(args), 0)), /* ASCII */
            type2char(TYPEOF(CAR(args))))) {
    LOGICAL(ans)[0] = 1;
    }
    else
    LOGICAL(ans)[0] = 0;

    /* We allow a "names" attribute on any vector. */
    if (LOGICAL(ans)[0] && ATTRIB(CAR(args)) != R_NilValue) {
    a = ATTRIB(CAR(args));
    while(a != R_NilValue) {
        if (TAG(a) != R_NamesSymbol) {
        LOGICAL(ans)[0] = 0;
        break;
        }
        a = CDR(a);
    }
    }
    UNPROTECT(1);
    return (ans);
}

SEXP attribute_hidden do_isna(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    SEXP ans, dims, names, x;
    int i, n;

    checkArity(op, args);
    if (DispatchOrEval(call, op, "is.na", args, rho, &ans, 1, 1))
    return(ans);
    PROTECT(args = ans);
#ifdef stringent_is
    if (!isList(CAR(args)) && !isVector(CAR(args)))
    errorcall_return(call, "is.na " R_MSG_list_vec);

#endif
    x = CAR(args);
    n = length(x);
    PROTECT(ans = allocVector(LGLSXP, n));
    if (isVector(x)) {
    PROTECT(dims = getAttrib(x, R_DimSymbol));
    if (isArray(x))
        PROTECT(names = getAttrib(x, R_DimNamesSymbol));
    else
        PROTECT(names = getAttrib(x, R_NamesSymbol));
    }
    else dims = names = R_NilValue;
    switch (TYPEOF(x)) {
    case LGLSXP:
       for (i = 0; i < n; i++)
            LOGICAL(ans)[i] = (LOGICAL(x)[i] == NA_LOGICAL);
        break;
    case INTSXP:
    for (i = 0; i < n; i++)
        LOGICAL(ans)[i] = (INTEGER(x)[i] == NA_INTEGER);
    break;
    case REALSXP:
    for (i = 0; i < n; i++)
        LOGICAL(ans)[i] = ISNAN(REAL(x)[i]);
    break;
    case CPLXSXP:
    for (i = 0; i < n; i++)
        LOGICAL(ans)[i] = (ISNAN(COMPLEX(x)[i].r) ||
                   ISNAN(COMPLEX(x)[i].i));
    break;
    case STRSXP:
    for (i = 0; i < n; i++)
        LOGICAL(ans)[i] = (STRING_ELT(x, i) == NA_STRING);
    break;

/* Same code for LISTSXP and VECSXP : */
#define LIST_VEC_NA(s)                          \
    if (!isVector(s) || length(s) != 1)             \
        LOGICAL(ans)[i] = 0;                    \
    else {                              \
        switch (TYPEOF(s)) {                    \
        case LGLSXP:                        \
        case INTSXP:                        \
            LOGICAL(ans)[i] = (INTEGER(s)[0] == NA_INTEGER);    \
            break;                      \
        case REALSXP:                       \
            LOGICAL(ans)[i] = ISNAN(REAL(s)[0]);        \
            break;                      \
        case STRSXP:                        \
            LOGICAL(ans)[i] = (STRING_ELT(s, 0) == NA_STRING);  \
            break;                      \
        case CPLXSXP:                       \
            LOGICAL(ans)[i] = (ISNAN(COMPLEX(s)[0].r)       \
                       || ISNAN(COMPLEX(s)[0].i));  \
            break;                      \
        default:                        \
            LOGICAL(ans)[i] = 0;                \
        }                           \
    }

    case LISTSXP:
    for (i = 0; i < n; i++) {
        LIST_VEC_NA(CAR(x));
        x = CDR(x);
    }
    break;
    case VECSXP:
    for (i = 0; i < n; i++) {
        SEXP s = VECTOR_ELT(x, i);
        LIST_VEC_NA(s);
    }
    break;
    case RAWSXP:
    /* no such thing as a raw NA */
    for (i = 0; i < n; i++)
        LOGICAL(ans)[i] = 0;
    break;
    default:
    warningcall(call, _("%s() applied to non-(list or vector) of type '%s'"), 
            "is.na", type2char(TYPEOF(x)));
    for (i = 0; i < n; i++)
        LOGICAL(ans)[i] = 0;
    }
    if (dims != R_NilValue)
    setAttrib(ans, R_DimSymbol, dims);
    if (names != R_NilValue) {
    if (isArray(x))
        setAttrib(ans, R_DimNamesSymbol, names);
    else
        setAttrib(ans, R_NamesSymbol, names);
    }
    if (isVector(x))
    UNPROTECT(2);
    UNPROTECT(1);
    UNPROTECT(1); /*ans*/
    return ans;
}

SEXP attribute_hidden do_isnan(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    SEXP ans, dims, names, x;
    int i, n;

    checkArity(op, args);
    if (DispatchOrEval(call, op, "is.nan", args, rho, &ans, 1, 1))
    return(ans);

    PROTECT(args = ans);
#ifdef stringent_is
    if (!isList(CAR(args)) && !isVector(CAR(args)))
    errorcall_return(call, "is.nan " R_MSG_list_vec);
#endif
    x = CAR(args);
    n = length(x);
    PROTECT(ans = allocVector(LGLSXP, n));
    if (isVector(x)) {
    PROTECT(dims = getAttrib(x, R_DimSymbol));
    if (isArray(x))
        PROTECT(names = getAttrib(x, R_DimNamesSymbol));
    else
        PROTECT(names = getAttrib(x, R_NamesSymbol));
    }
    else dims = names = R_NilValue;
    switch (TYPEOF(x)) {
    case LGLSXP:
    case INTSXP:
    case STRSXP:
    case RAWSXP:
    for (i = 0; i < n; i++)
        LOGICAL(ans)[i] = 0;
    break;
    case REALSXP:
    for (i = 0; i < n; i++)
        LOGICAL(ans)[i] = R_IsNaN(REAL(x)[i]);
    break;
    case CPLXSXP:
    for (i = 0; i < n; i++)
        LOGICAL(ans)[i] = (R_IsNaN(COMPLEX(x)[i].r) ||
                   R_IsNaN(COMPLEX(x)[i].i));
    break;

/* Same code for LISTSXP and VECSXP : */

#define LIST_VEC_NAN(s)                         \
    if (!isVector(s) || length(s) != 1)             \
        LOGICAL(ans)[i] = 0;                    \
    else {                              \
        switch (TYPEOF(s)) {                    \
        case LGLSXP:                        \
        case INTSXP:                        \
        case STRSXP:                        \
            LOGICAL(ans)[i] = 0;                \
            break;                      \
        case REALSXP:                       \
            LOGICAL(ans)[i] = R_IsNaN(REAL(s)[0]);      \
            break;                      \
        case CPLXSXP:                       \
            LOGICAL(ans)[i] = (R_IsNaN(COMPLEX(s)[0].r) ||  \
                       R_IsNaN(COMPLEX(s)[0].i));   \
            break;                      \
        }                           \
    }

    case LISTSXP:
    for (i = 0; i < n; i++) {
        LIST_VEC_NAN(CAR(x));
        x = CDR(x);
    }
    break;
    case VECSXP:
    for (i = 0; i < n; i++) {
        SEXP s = VECTOR_ELT(x, i);
        LIST_VEC_NAN(s);
    }
    break;
    default:
    warningcall(call, _("%s() applied to non-(list or vector) of type '%s'"), 
            "is.nan", type2char(TYPEOF(x)));
    for (i = 0; i < n; i++)
        LOGICAL(ans)[i] = 0;
    }
    if (dims != R_NilValue)
    setAttrib(ans, R_DimSymbol, dims);
    if (names != R_NilValue) {
    if (isArray(x))
        setAttrib(ans, R_DimNamesSymbol, names);
    else
        setAttrib(ans, R_NamesSymbol, names);
    }
    if (isVector(x))
    UNPROTECT(2);
    UNPROTECT(1);
    UNPROTECT(1); /*ans*/
    return ans;
}

SEXP attribute_hidden do_isfinite(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    SEXP ans, x, names, dims;
    int i, n;
    checkArity(op, args);
    if (DispatchOrEval(call, op, "is.finite", args, rho, &ans, 0, 1))
    return(ans);
#ifdef stringent_is
    if (!isList(CAR(args)) && !isVector(CAR(args)))
    errorcall_return(call, "is.finite " R_MSG_list_vec);
#endif
    x = CAR(args);
    n = length(x);
    ans = allocVector(LGLSXP, n);
    if (isVector(x)) {
    dims = getAttrib(x, R_DimSymbol);
    if (isArray(x))
        names = getAttrib(x, R_DimNamesSymbol);
    else
        names = getAttrib(x, R_NamesSymbol);
    }
    else dims = names = R_NilValue;
    switch (TYPEOF(x)) {
    case LGLSXP:
    case INTSXP:
    for (i = 0; i < n; i++)
        LOGICAL(ans)[i] = (INTEGER(x)[i] != NA_INTEGER);
    break;
    case REALSXP:
    for (i = 0; i < n; i++)
        LOGICAL(ans)[i] = R_FINITE(REAL(x)[i]);
    break;
    case CPLXSXP:
    for (i = 0; i < n; i++)
        LOGICAL(ans)[i] = (R_FINITE(COMPLEX(x)[i].r) && R_FINITE(COMPLEX(x)[i].i));
    break;
    default:
    for (i = 0; i < n; i++)
        LOGICAL(ans)[i] = 0;
    }
    if (dims != R_NilValue)
    setAttrib(ans, R_DimSymbol, dims);
    if (names != R_NilValue) {
    if (isArray(x))
        setAttrib(ans, R_DimNamesSymbol, names);
    else
        setAttrib(ans, R_NamesSymbol, names);
    }
    return ans;
}

SEXP attribute_hidden do_isinfinite(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    SEXP ans, x, names, dims;
    double xr, xi;
    int i, n;
    checkArity(op, args);
    if (DispatchOrEval(call, op, "is.infinite", args, rho, &ans, 0, 1))
        return(ans);
#ifdef stringent_is
    if (!isList(CAR(args)) && !isVector(CAR(args)))
    errorcall_return(call, "is.infinite " R_MSG_list_vec);
#endif
    x = CAR(args);
    n = length(x);
    ans = allocVector(LGLSXP, n);
    if (isVector(x)) {
    dims = getAttrib(x, R_DimSymbol);
    if (isArray(x))
        names = getAttrib(x, R_DimNamesSymbol);
    else
        names = getAttrib(x, R_NamesSymbol);
    }
    else    dims = names = R_NilValue;
    switch (TYPEOF(x)) {
    case REALSXP:
    for (i = 0; i < n; i++) {
        xr = REAL(x)[i];
        if (ISNAN(xr) || R_FINITE(xr))
        LOGICAL(ans)[i] = 0;
        else
        LOGICAL(ans)[i] = 1;
    }
    break;
    case CPLXSXP:
    for (i = 0; i < n; i++) {
        xr = COMPLEX(x)[i].r;
        xi = COMPLEX(x)[i].i;
        if ((ISNAN(xr) || R_FINITE(xr)) && (ISNAN(xi) || R_FINITE(xi)))
        LOGICAL(ans)[i] = 0;
        else
        LOGICAL(ans)[i] = 1;
    }
    break;
    default:
    for (i = 0; i < n; i++)
        LOGICAL(ans)[i] = 0;
    }
    if (!isNull(dims))
    setAttrib(ans, R_DimSymbol, dims);
    if (!isNull(names)) {
    if (isArray(x))
        setAttrib(ans, R_DimNamesSymbol, names);
    else
        setAttrib(ans, R_NamesSymbol, names);
    }
    return ans;
}

SEXP attribute_hidden do_call(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    SEXP rest, evargs, rfun;

    PROTECT(rfun = eval(CAR(args), rho));
    if (!isString(rfun) || length(rfun) <= 0 ||
    streql(CHAR(STRING_ELT(rfun, 0)), "")) /* ASCII */
    errorcall_return(call, R_MSG_A1_char);
    PROTECT(rfun = install(translateChar(STRING_ELT(rfun, 0))));
    PROTECT(evargs = duplicate(CDR(args)));
    for (rest = evargs; rest != R_NilValue; rest = CDR(rest))
    SETCAR(rest, eval(CAR(rest), rho));
    rfun = LCONS(rfun, evargs);
    UNPROTECT(3);
    return (rfun);
}

SEXP attribute_hidden do_docall(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    SEXP c, fun, names, envir;
    int i, n;
    /* RCNTXT *cptr; */

    checkArity(op, args);

    fun = CAR(args);
    envir = CADDR(args);
    args = CADR(args);

    /* must be a string or a function */
    if( isString(fun) ) {
    if( length(fun) != 1 || CHAR(STRING_ELT(fun,0)) == '\0') /* ASCII */
        error(_("first argument must be a character string or a function"));
    } else if (!isFunction(fun) )
    error(_("first argument must be a character string or a function"));
    

    if (!isNull(args) && !isNewList(args))
    error(R_MSG_A2_list);

    if (!isEnvironment(envir))
    error(_("'envir' must be an environment"));

    n = length(args);
    names = getAttrib(args, R_NamesSymbol);

    PROTECT(c = call = allocList(n + 1));
    SET_TYPEOF(c, LANGSXP);
    if( isString(fun) )
        SETCAR(c, install(translateChar(STRING_ELT(fun, 0))));
    else
        SETCAR(c, fun);
    c = CDR(c);
    for (i = 0; i < n; i++) {
#ifndef NEW
        SETCAR(c, VECTOR_ELT(args, i));
#else
        SETCAR(c, mkPROMISE(VECTOR_ELT(args, i), rho));
        SET_PRVALUE(CAR(c), VECTOR_ELT(args, i)); */
#endif
        if (ItemName(names, i) != R_NilValue)
            SET_TAG(c, install(translateChar(ItemName(names, i))));
        c = CDR(c);
    }
    call = eval(call, envir);

    /*
    cptr = R_GlobalContext;
    while (cptr->nextcontext != NULL) {
        if (cptr->callflag & CTXT_FUNCTION ) {
        if(cptr->cloenv == rho)
           break;
    }
    }
    if( cptr->cloenv == rho )
        call = eval(call, cptr->sysparent);
    else
        error(_("do.call: could not find parent environment"));
    */

    UNPROTECT(1);
    return call;
}


/*
   do_substitute has two arguments, an expression and an environment
   (optional).  Symbols found in the expression are substituted with their
   values as found in the environment.  There is no inheritance so only
   the supplied environment is searched. If no environment is specified
   the environment in which substitute was called is used.  If the
   specified environment is R_GlobalEnv it is converted to R_NilValue, for
   historical reasons. In substitute(), R_NilValue signals that no
   substitution should be done, only extraction of promise expressions.
   Arguments to do_substitute should not be evaluated.
*/

SEXP substitute(SEXP lang, SEXP rho)
{
    SEXP t;
    switch (TYPEOF(lang)) {
    case PROMSXP:
    return substitute(PREXPR(lang), rho);
    case SYMSXP:
        if (rho != R_NilValue) {
        t = findVarInFrame3( rho, lang, TRUE);
        if (t != R_UnboundValue) {
        if (TYPEOF(t) == PROMSXP) {
            do {
            t = PREXPR(t);
            } while(TYPEOF(t) == PROMSXP);
            return t;
            }
            else if (TYPEOF(t) == DOTSXP)
            error(_("... used in an incorrect context"));
            if (rho != R_GlobalEnv)
            return t;
        }
    }
    return (lang);
    case LANGSXP:
    return substituteList(lang, rho);
    default:
    return (lang);
    }
}


/* Work through a list doing substitute on the
   elements taking particular care to handle '...' */

SEXP attribute_hidden substituteList(SEXP el, SEXP rho)
{
    SEXP h, p = R_NilValue, res = R_NilValue;

    if (isNull(el)) return el;

    while (el != R_NilValue) {
    /* walk along the pairlist, substituting elements.
       res is the result
       p is the current last element
       h is the element currently being processed
     */
    if (CAR(el) == R_DotsSymbol) {
        if (rho == R_NilValue)
        h = R_UnboundValue; /* so there is no substitution below */
        else
        h = findVarInFrame3(rho, CAR(el), TRUE);
        if (h == R_UnboundValue)
        h = LCONS(R_DotsSymbol, R_NilValue);
        else if (h == R_NilValue  || h == R_MissingArg)
        h = R_NilValue;
        else if (TYPEOF(h) == DOTSXP)
        h = substituteList(h, R_NilValue);
        else
        error(_("... used in an incorrect context"));
    } else {
        h = substitute(CAR(el), rho);
        if (isLanguage(el))
        h = LCONS(h, R_NilValue);
        else
        h = CONS(h, R_NilValue);
        SET_TAG(h, TAG(el));
    }
    if (h != R_NilValue) {
        if (res == R_NilValue)
        PROTECT(res = h);
        else
        SETCDR(p, h);
        /* now set 'p': dots might have expanded to a list of length > 1 */
        while (CDR(h) != R_NilValue) h = CDR(h);
        p = h;
    }
    el = CDR(el);
    }
    if(res != R_NilValue) UNPROTECT(1);
    return res;
}

SEXP attribute_hidden do_substitute(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    SEXP env, s, t;
    /* set up the environment for substitution */
    if (length(args) == 1)
    env = rho;
    else
    env = eval(CADR(args), rho);
    if (env == R_GlobalEnv) /* For historical reasons, don't substitute in R_GlobalEnv */
    env = R_NilValue;
    else if (TYPEOF(env) == VECSXP)
    env = NewEnvironment(R_NilValue, VectorToPairList(env), R_BaseEnv);
    else if (TYPEOF(env) == LISTSXP)
    env = NewEnvironment(R_NilValue, duplicate(env), R_BaseEnv);
    if (env != R_NilValue && TYPEOF(env) != ENVSXP)
    errorcall(call, _("invalid environment specified"));

    PROTECT(env);
    PROTECT(t = duplicate(args));
    SETCDR(t, R_NilValue);
    s = substituteList(t, env);
    UNPROTECT(2);
    return CAR(s);
}

SEXP attribute_hidden do_quote(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    checkArity(op, args);

    return(CAR(args));
}

typedef struct {
    char *s;
    SEXPTYPE sexp;
    Rboolean canChange;
} classType;

static classType classTable[] = {
    { "logical",    LGLSXP,    TRUE },
    { "integer",    INTSXP,    TRUE },
    { "double",     REALSXP,   TRUE },
    { "raw",        RAWSXP,    TRUE },
    { "complex",    CPLXSXP,   TRUE },
    { "character",  STRSXP,    TRUE },
    { "expression", EXPRSXP,   TRUE },
    { "list",       VECSXP,    TRUE },
    { "environment",    ENVSXP,    FALSE },
    { "char",       CHARSXP,   TRUE },
    { "externalptr",    EXTPTRSXP,  FALSE },
    { "weakref",    WEAKREFSXP, FALSE },
    { "name",       SYMSXP,    FALSE },

    { (char *)NULL, (SEXPTYPE)-1, FALSE}
};

static int class2type(const char *s)
{
    /* return the type if the class string is one of the basic types, else -1.
       Note that this is NOT str2type:  only certain types are defined to be basic
       classes; e.g., "language" is a type but many classes correspond to objects of
       this type.
    */
    int i; char *si;
    for(i = 0; ; i++) {
    si = classTable[i].s;
    if(!si)
        return -1;
    if(!strcmp(s, si))
        return i;
    }
    /* cannot get here return -1; */
}

/* set the class to value, and return the modified object.  This is
   NOT a primitive assignment operator , because there is no code in R
   that changes type in place. */
static SEXP R_set_class(SEXP obj, SEXP value, SEXP call)
{
    int nProtect = 0;
    if(isNull(value)) {
    setAttrib(obj, R_ClassSymbol, value);
    return obj;
    }
    if(TYPEOF(value) != STRSXP) {
    /* Beware: assumes value is protected, which it is
       in the only use below */
    PROTECT(value = coerceVector(duplicate(value), STRSXP));
    nProtect++;
    }
    if(length(value) > 1)
    setAttrib(obj, R_ClassSymbol, value);
    else if(length(value) == 0) {
    UNPROTECT(nProtect); nProtect = 0;
    error(_("invalid replacement object to be a class string"));
    }
    else {
    const char *valueString, *classString; int whichType;
    SEXP cur_class; SEXPTYPE valueType;
    valueString = CHAR(asChar(value)); /* ASCII */
    whichType = class2type(valueString);
    valueType = (whichType == -1) ? -1 : classTable[whichType].sexp;
    PROTECT(cur_class = R_data_class(obj, FALSE)); nProtect++;
    classString = CHAR(asChar(cur_class)); /* ASCII */
    /*  assigning type as a class deletes an explicit class attribute. */
    if(valueType != -1) {
        setAttrib(obj, R_ClassSymbol, R_NilValue);
        if(classTable[whichType].canChange) {
        PROTECT(obj = ascommon(call, obj, valueType));
        nProtect++;
        }
        else if(valueType != TYPEOF(obj))
        error(_("\"%s\" can only be set as the class if the object has this type; found \"%s\""),
              valueString, type2char(TYPEOF(obj)));
        /* else, leave alone */
    }
    else if(!strcmp("numeric", valueString)) {
        setAttrib(obj, R_ClassSymbol, R_NilValue);
        switch(TYPEOF(obj)) {
        case INTSXP: case REALSXP: break;
        default: PROTECT(obj = coerceVector(obj, REALSXP));
        nProtect++;
        }
    }
    /* the next 2 special cases mirror the special code in
     * R_data_class */
    else if(!strcmp("matrix", valueString)) {
        if(length(getAttrib(obj, R_DimSymbol)) != 2)
            error(_("invalid to set the class to matrix unless the dimension attribute is of length 2 (was %d)"),
         length(getAttrib(obj, R_DimSymbol)));
        setAttrib(obj, R_ClassSymbol, R_NilValue);
    }
    else if(!strcmp("array", valueString)) {
        if(length(getAttrib(obj, R_DimSymbol))<= 0)
            error(_("cannot set class to \"array\" unless the dimension attribute has length > 0"));
        setAttrib(obj, R_ClassSymbol, R_NilValue);
    }
    else { /* set the class but don't do the coercion; that's
          supposed to be done by an as() method */
        setAttrib(obj, R_ClassSymbol, value);
    }
    }
    UNPROTECT(nProtect);
    return obj;
}

SEXP attribute_hidden R_do_set_class(SEXP call, SEXP op, SEXP args, SEXP env)
{
    checkArity(op, args);
    return R_set_class(CAR(args), CADR(args), call);
}

SEXP attribute_hidden do_storage_mode(SEXP call, SEXP op, SEXP args, SEXP env)
{
    SEXP obj, value, ans;
    SEXPTYPE type;
    
    checkArity(op, args);
    obj = CAR(args);

    value = CADR(args);
    if (!isValidString(value) || STRING_ELT(value, 0) == NA_STRING)
    error(_("'value' must be non-null character string"));
    type = str2type(CHAR(STRING_ELT(value, 0)));
    if(type == (SEXPTYPE) -1) {
    /* For backwards compatibility we allow "real" and "single" */
    if(streql(CHAR(STRING_ELT(value, 0)), "real")) {
        error("use of 'real' is defunct: use 'double' instead");
    } else if(streql(CHAR(STRING_ELT(value, 0)), "single")) {
        error("use of 'single' is defunct: use mode<- instead");
    } else
        error(_("invalid value"));
    }
    if(TYPEOF(obj) == type) return obj;
    if(isFactor(obj))
    error(_("invalid to change the storage mode of a factor"));
    PROTECT(ans = coerceVector(obj, type));
    DUPLICATE_ATTRIB(ans, obj);
    UNPROTECT(1);
    return ans;
}