imcc.y

%{
/*
 * imcc.y
 *
 * Intermediate Code Compiler for Parrot.
 *
 * Copyright (C) 2002 Melvin Smith <melvin.smith@mindspring.com>
 * Copyright (C) 2002-2010, Parrot Foundation.
 *
 * Grammar of the PIR language parser.
 *
 *
 */

#include <string.h>
#include <stdio.h>
#include <stdlib.h>

#define _PARSER
#define PARSER_MAIN
#include "imc.h"
#include "parrot/dynext.h"
#include "pmc/pmc_callcontext.h"
#include "pbc.h"
#include "parser.h"
#include "optimizer.h"
#include "instructions.h"
#include "symreg.h"

/* prevent declarations of malloc() and free() in the generated parser. */
#define YYMALLOC
#define YYFREE(Ptr) do { /* empty */; } while (YYID (0))

#ifndef YYENABLE_NLS
#  define YYENABLE_NLS 0
#endif

#ifndef YYLTYPE_IS_TRIVIAL
#  define YYLTYPE_IS_TRIVIAL 0
#endif

/* HEADERIZER HFILE: compilers/imcc/imc.h */

/* HEADERIZER BEGIN: static */
/* Don't modify between HEADERIZER BEGIN / HEADERIZER END.  Your changes will be lost. */

static void add_pcc_named_arg(
    ARGMOD(imc_info_t *imcc),
    ARGMOD(SymReg *cur_call),
    ARGMOD(SymReg *name),
    ARGMOD(SymReg *value))
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        __attribute__nonnull__(3)
        __attribute__nonnull__(4)
        FUNC_MODIFIES(*imcc)
        FUNC_MODIFIES(*cur_call)
        FUNC_MODIFIES(*name)
        FUNC_MODIFIES(*value);

static void add_pcc_named_arg_var(
    ARGMOD(imc_info_t *imcc),
    ARGMOD(SymReg *cur_call),
    ARGMOD(SymReg *name),
    ARGMOD(SymReg *value))
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        __attribute__nonnull__(3)
        __attribute__nonnull__(4)
        FUNC_MODIFIES(*imcc)
        FUNC_MODIFIES(*cur_call)
        FUNC_MODIFIES(*name)
        FUNC_MODIFIES(*value);

static void add_pcc_named_param(
    ARGMOD(imc_info_t *imcc),
    ARGMOD(SymReg *cur_call),
    ARGMOD(SymReg *name),
    ARGMOD(SymReg *value))
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        __attribute__nonnull__(3)
        __attribute__nonnull__(4)
        FUNC_MODIFIES(*imcc)
        FUNC_MODIFIES(*cur_call)
        FUNC_MODIFIES(*name)
        FUNC_MODIFIES(*value);

static void add_pcc_named_result(
    ARGMOD(imc_info_t *imcc),
    ARGMOD(SymReg *cur_call),
    ARGMOD(SymReg *name),
    ARGMOD(SymReg *value))
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        __attribute__nonnull__(3)
        __attribute__nonnull__(4)
        FUNC_MODIFIES(*imcc)
        FUNC_MODIFIES(*cur_call)
        FUNC_MODIFIES(*name)
        FUNC_MODIFIES(*value);

static void add_pcc_named_return(
    ARGMOD(imc_info_t *imcc),
    ARGMOD(SymReg *cur_call),
    ARGMOD(SymReg *name),
    ARGMOD(SymReg *value))
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        __attribute__nonnull__(3)
        __attribute__nonnull__(4)
        FUNC_MODIFIES(*imcc)
        FUNC_MODIFIES(*cur_call)
        FUNC_MODIFIES(*name)
        FUNC_MODIFIES(*value);

static void adv_named_set(ARGMOD(imc_info_t *imcc), ARGIN(const char *name))
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        FUNC_MODIFIES(*imcc);

static void adv_named_set_u(
    ARGMOD(imc_info_t *imcc),
    ARGIN(const char *name))
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        FUNC_MODIFIES(*imcc);

static void begin_return_or_yield(ARGMOD(imc_info_t *imcc), int yield)
        __attribute__nonnull__(1)
        FUNC_MODIFIES(*imcc);

static void clear_state(ARGMOD(imc_info_t *imcc))
        __attribute__nonnull__(1)
        FUNC_MODIFIES(*imcc);

static void do_loadlib(ARGMOD(imc_info_t *imcc), ARGIN(const char *lib))
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        FUNC_MODIFIES(*imcc);

PARROT_WARN_UNUSED_RESULT
PARROT_CAN_RETURN_NULL
static Instruction* func_ins(
    ARGMOD(imc_info_t *imcc),
    ARGMOD(IMC_Unit *unit),
    ARGIN(SymReg *lhs),
    ARGIN(const char *op),
    ARGMOD(SymReg **r),
    int n,
    int keyv,
    int emit)
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        __attribute__nonnull__(3)
        __attribute__nonnull__(4)
        __attribute__nonnull__(5)
        FUNC_MODIFIES(*imcc)
        FUNC_MODIFIES(*unit)
        FUNC_MODIFIES(*r);

PARROT_WARN_UNUSED_RESULT
PARROT_CAN_RETURN_NULL
static Instruction * iINDEXFETCH(
    ARGMOD(imc_info_t *imcc),
    ARGMOD(IMC_Unit *unit),
    ARGIN(SymReg *r0),
    ARGIN(SymReg *r1),
    ARGIN(SymReg *r2))
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        __attribute__nonnull__(3)
        __attribute__nonnull__(4)
        __attribute__nonnull__(5)
        FUNC_MODIFIES(*imcc)
        FUNC_MODIFIES(*unit);

PARROT_WARN_UNUSED_RESULT
PARROT_CAN_RETURN_NULL
static Instruction * iINDEXSET(
    ARGMOD(imc_info_t *imcc),
    ARGMOD(IMC_Unit *unit),
    ARGIN(SymReg *r0),
    ARGIN(SymReg *r1),
    ARGIN(SymReg *r2))
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        __attribute__nonnull__(3)
        __attribute__nonnull__(4)
        __attribute__nonnull__(5)
        FUNC_MODIFIES(*imcc)
        FUNC_MODIFIES(*unit);

PARROT_WARN_UNUSED_RESULT
PARROT_CANNOT_RETURN_NULL
static Instruction * iLABEL(
    ARGMOD(imc_info_t *imcc),
    ARGMOD_NULLOK(IMC_Unit *unit),
    ARGMOD(SymReg *r0))
        __attribute__nonnull__(1)
        __attribute__nonnull__(3)
        FUNC_MODIFIES(*imcc)
        FUNC_MODIFIES(*unit)
        FUNC_MODIFIES(*r0);

PARROT_WARN_UNUSED_RESULT
PARROT_CAN_RETURN_NULL
static const char * inv_op(ARGIN(const char *op))
        __attribute__nonnull__(1);

PARROT_IGNORABLE_RESULT
PARROT_CANNOT_RETURN_NULL
static Instruction * iSUBROUTINE(
    ARGMOD(imc_info_t *imcc),
    ARGMOD_NULLOK(IMC_Unit *unit),
    ARGMOD(SymReg *r))
        __attribute__nonnull__(1)
        __attribute__nonnull__(3)
        FUNC_MODIFIES(*imcc)
        FUNC_MODIFIES(*unit)
        FUNC_MODIFIES(*r);

PARROT_IGNORABLE_RESULT
PARROT_CAN_RETURN_NULL
static Instruction * MK_I(
    ARGMOD(imc_info_t *imcc),
    ARGMOD(IMC_Unit *unit),
    ARGIN(const char *fmt),
    int n,
    ...)
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        __attribute__nonnull__(3)
        FUNC_MODIFIES(*imcc)
        FUNC_MODIFIES(*unit);

PARROT_WARN_UNUSED_RESULT
PARROT_CAN_RETURN_NULL
static Instruction* mk_pmc_const_named(
    ARGMOD(imc_info_t *imcc),
    ARGMOD(IMC_Unit *unit),
    ARGIN(const char *name),
    ARGMOD(SymReg *left),
    ARGIN(const char *constant))
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        __attribute__nonnull__(3)
        __attribute__nonnull__(4)
        __attribute__nonnull__(5)
        FUNC_MODIFIES(*imcc)
        FUNC_MODIFIES(*unit)
        FUNC_MODIFIES(*left);

PARROT_WARN_UNUSED_RESULT
PARROT_CANNOT_RETURN_NULL
static SymReg * mk_sub_address_fromc(
    ARGMOD(imc_info_t *imcc),
    ARGIN(const char *name))
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        FUNC_MODIFIES(*imcc);

PARROT_WARN_UNUSED_RESULT
PARROT_CANNOT_RETURN_NULL
static SymReg * mk_sub_address_u(
    ARGMOD(imc_info_t *imcc),
    ARGIN(const char *name))
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        FUNC_MODIFIES(*imcc);

static void set_lexical(
    ARGMOD(imc_info_t *imcc),
    ARGMOD(SymReg *r),
    ARGMOD(SymReg *name))
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        __attribute__nonnull__(3)
        FUNC_MODIFIES(*imcc)
        FUNC_MODIFIES(*r)
        FUNC_MODIFIES(*name);

#define ASSERT_ARGS_add_pcc_named_arg __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(imcc) \
    , PARROT_ASSERT_ARG(cur_call) \
    , PARROT_ASSERT_ARG(name) \
    , PARROT_ASSERT_ARG(value))
#define ASSERT_ARGS_add_pcc_named_arg_var __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(imcc) \
    , PARROT_ASSERT_ARG(cur_call) \
    , PARROT_ASSERT_ARG(name) \
    , PARROT_ASSERT_ARG(value))
#define ASSERT_ARGS_add_pcc_named_param __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(imcc) \
    , PARROT_ASSERT_ARG(cur_call) \
    , PARROT_ASSERT_ARG(name) \
    , PARROT_ASSERT_ARG(value))
#define ASSERT_ARGS_add_pcc_named_result __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(imcc) \
    , PARROT_ASSERT_ARG(cur_call) \
    , PARROT_ASSERT_ARG(name) \
    , PARROT_ASSERT_ARG(value))
#define ASSERT_ARGS_add_pcc_named_return __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(imcc) \
    , PARROT_ASSERT_ARG(cur_call) \
    , PARROT_ASSERT_ARG(name) \
    , PARROT_ASSERT_ARG(value))
#define ASSERT_ARGS_adv_named_set __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(imcc) \
    , PARROT_ASSERT_ARG(name))
#define ASSERT_ARGS_adv_named_set_u __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(imcc) \
    , PARROT_ASSERT_ARG(name))
#define ASSERT_ARGS_begin_return_or_yield __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(imcc))
#define ASSERT_ARGS_clear_state __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(imcc))
#define ASSERT_ARGS_do_loadlib __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(imcc) \
    , PARROT_ASSERT_ARG(lib))
#define ASSERT_ARGS_func_ins __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(imcc) \
    , PARROT_ASSERT_ARG(unit) \
    , PARROT_ASSERT_ARG(lhs) \
    , PARROT_ASSERT_ARG(op) \
    , PARROT_ASSERT_ARG(r))
#define ASSERT_ARGS_iINDEXFETCH __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(imcc) \
    , PARROT_ASSERT_ARG(unit) \
    , PARROT_ASSERT_ARG(r0) \
    , PARROT_ASSERT_ARG(r1) \
    , PARROT_ASSERT_ARG(r2))
#define ASSERT_ARGS_iINDEXSET __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(imcc) \
    , PARROT_ASSERT_ARG(unit) \
    , PARROT_ASSERT_ARG(r0) \
    , PARROT_ASSERT_ARG(r1) \
    , PARROT_ASSERT_ARG(r2))
#define ASSERT_ARGS_iLABEL __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(imcc) \
    , PARROT_ASSERT_ARG(r0))
#define ASSERT_ARGS_inv_op __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(op))
#define ASSERT_ARGS_iSUBROUTINE __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(imcc) \
    , PARROT_ASSERT_ARG(r))
#define ASSERT_ARGS_MK_I __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(imcc) \
    , PARROT_ASSERT_ARG(unit) \
    , PARROT_ASSERT_ARG(fmt))
#define ASSERT_ARGS_mk_pmc_const_named __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(imcc) \
    , PARROT_ASSERT_ARG(unit) \
    , PARROT_ASSERT_ARG(name) \
    , PARROT_ASSERT_ARG(left) \
    , PARROT_ASSERT_ARG(constant))
#define ASSERT_ARGS_mk_sub_address_fromc __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(imcc) \
    , PARROT_ASSERT_ARG(name))
#define ASSERT_ARGS_mk_sub_address_u __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(imcc) \
    , PARROT_ASSERT_ARG(name))
#define ASSERT_ARGS_set_lexical __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(imcc) \
    , PARROT_ASSERT_ARG(r) \
    , PARROT_ASSERT_ARG(name))
/* Don't modify between HEADERIZER BEGIN / HEADERIZER END.  Your changes will be lost. */
/* HEADERIZER END: static */


#define YYDEBUG 1
#define YYERROR_VERBOSE 1

/* Warning: parser is probably not reentrant */

/*
 * Choosing instructions for Parrot is pretty easy since many are
 * polymorphic.
 */


/*

=over 4

=item C<static Instruction * MK_I(imc_info_t *imcc, IMC_Unit *unit, const char
*fmt, int n, ...)>

build and emitb instruction by INS. fmt may contain:

  op %s, %s # comment

or just

  op

NOTE: Most usage of this function is with
imcc->cur_unit, but there are some
exceptions. Thus, we can't easily factorize that piece of
code.

=cut

 */

PARROT_IGNORABLE_RESULT
PARROT_CAN_RETURN_NULL
static Instruction *
MK_I(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit), ARGIN(const char *fmt), int n, ...)
{
    ASSERT_ARGS(MK_I)
    char opname[64];
    char *p;
    const char *q;
    va_list ap;
    SymReg *r[IMCC_MAX_FIX_REGS];
    int i;

    for (p = opname, q = fmt; *q && *q != ' ';)
        *p++ = *q++;
    *p = '\0';
    if (!*q)
        fmt = NULL;
    else
        fmt = ++q;
#ifdef OPDEBUG
    fprintf(stderr, "op '%s' format '%s' (%d)\n", opname, fmt?:"", n);
#endif
    va_start(ap, n);
    i = 0;
    for (i = 0; i < n; ++i) {
        r[i] = va_arg(ap, SymReg *);
    }
    va_end(ap);
    return INS(imcc, unit, opname, fmt, r, n, imcc->keyvec, 1);
}

/*

=item C<static Instruction* mk_pmc_const_named(imc_info_t *imcc, IMC_Unit *unit,
const char *name, SymReg *left, const char *constant)>

=cut

*/

PARROT_WARN_UNUSED_RESULT
PARROT_CAN_RETURN_NULL
static Instruction*
mk_pmc_const_named(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit),
    ARGIN(const char *name), ARGMOD(SymReg *left), ARGIN(const char *constant))
{
    ASSERT_ARGS(mk_pmc_const_named)
    SymReg *rhs;
    SymReg *r[3];
    char   *const_name;
    const int ascii       = (*constant == '\'' || *constant == '"');
    char   *unquoted_name = mem_sys_strdup(name + 1);
    size_t  name_length   = strlen(unquoted_name) - 1;

    unquoted_name[name_length] = 0;

    if (left->type == VTADDRESS) {      /* IDENTIFIER */
        if (imcc->state->pasm_file) {
            IMCC_fataly(imcc, EXCEPTION_SYNTAX_ERROR,
                        "Ident as PMC constant",
                        " %s\n", left->name);
        }
        left->type = VTIDENTIFIER;
        left->set = 'P';
    }
    r[0] = left;
    if (ascii) {
        /* strip delimiters */
        const_name = mem_sys_strdup(constant + 1);
        const_name[strlen(const_name) - 1] = 0;
    }
    else {
        const_name = mem_sys_strdup(constant);
    }

    if ((strncmp(unquoted_name, "Sub",       name_length) == 0)
    ||  (strncmp(unquoted_name, "Coroutine", name_length) == 0)) {
        rhs = mk_const(imcc, const_name, 'p');

        if (!ascii)
            rhs->type |= VT_ENCODED;

        rhs->usage    |= U_FIXUP | U_SUBID_LOOKUP;
    }
    else if (strncmp(unquoted_name, "LexInfo", name_length) == 0) {
        rhs = mk_const(imcc, const_name, 'l');
        if (!ascii)
            rhs->type |= VT_ENCODED;
        rhs->usage    |= U_FIXUP | U_LEXINFO_LOOKUP;
    }
    else {
        rhs = mk_const(imcc, const_name, 'P');
    }

    r[1]          = rhs;
    rhs->pmc_type = Parrot_pmc_get_type_str(imcc->interp,
        Parrot_str_new(imcc->interp, unquoted_name, name_length));

    mem_sys_free(unquoted_name);
    mem_sys_free(const_name);

    return INS(imcc, unit, "set_p_pc", "", r, 2, 0, 1);
}

/*

=item C<static Instruction* func_ins(imc_info_t *imcc, IMC_Unit *unit, SymReg
*lhs, const char *op, SymReg **r, int n, int keyv, int emit)>

=cut

*/

PARROT_WARN_UNUSED_RESULT
PARROT_CAN_RETURN_NULL
static Instruction*
func_ins(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit), ARGIN(SymReg *lhs),
        ARGIN(const char *op), ARGMOD(SymReg **r), int n, int keyv, int emit)
{
    ASSERT_ARGS(func_ins)
    int i;
    /* shift regs up by 1 */
    for (i = n - 1; i >= 0; --i)
        r[i+1] = r[i];
    r[0] = lhs;
    /* shift keyvec */
    keyv <<= 1;
    return INS(imcc, unit, op, "", r, n+1, keyv, emit);
}

/*

=item C<static void clear_state(imc_info_t *imcc)>

=cut

*/

static void
clear_state(ARGMOD(imc_info_t *imcc))
{
    ASSERT_ARGS(clear_state)
    imcc -> nargs = 0;
    imcc -> keyvec = 0;
}

/*

=item C<Instruction * INS_LABEL(imc_info_t *imcc, IMC_Unit *unit, SymReg *r0,
int emit)>

=cut

*/

PARROT_WARN_UNUSED_RESULT
PARROT_CANNOT_RETURN_NULL
Instruction *
INS_LABEL(ARGMOD(imc_info_t *imcc), ARGMOD_NULLOK(IMC_Unit *unit),
        ARGMOD(SymReg *r0), int emit)
{
    ASSERT_ARGS(INS_LABEL)

    Instruction * const ins = _mk_instruction("", "%s:", 1, &r0, 0);
    ins->type               = ITLABEL;
    r0->first_ins           = ins;

    if (emit)
        emitb(imcc, unit, ins);

    return ins;
}

/*

=item C<static Instruction * iLABEL(imc_info_t *imcc, IMC_Unit *unit, SymReg
*r0)>

=cut

*/

PARROT_WARN_UNUSED_RESULT
PARROT_CANNOT_RETURN_NULL
static Instruction *
iLABEL(ARGMOD(imc_info_t *imcc), ARGMOD_NULLOK(IMC_Unit *unit),
        ARGMOD(SymReg *r0))
{
    ASSERT_ARGS(iLABEL)
    Instruction * const i = INS_LABEL(imcc, unit, r0, 1);
    i->line               = imcc->line;

    clear_state(imcc);
    return i;
}

/*

=item C<static Instruction * iSUBROUTINE(imc_info_t *imcc, IMC_Unit *unit,
SymReg *r)>

=cut

*/

PARROT_IGNORABLE_RESULT
PARROT_CANNOT_RETURN_NULL
static Instruction *
iSUBROUTINE(ARGMOD(imc_info_t *imcc), ARGMOD_NULLOK(IMC_Unit *unit), ARGMOD(SymReg *r))
{
    ASSERT_ARGS(iSUBROUTINE)
    Instruction * const i = iLABEL(imcc, unit, r);
    i->type              |= ITPCCPARAM;

    r->type    = (r->type & VT_ENCODED) ? VT_PCC_SUB|VT_ENCODED : VT_PCC_SUB;
    r->pcc_sub = mem_gc_allocate_zeroed_typed(imcc->interp, pcc_sub_t);

    imcc->cur_call = r;
    i->line = imcc->line;

    add_namespace(imcc, unit);
    return i;
}

/*

=item C<static Instruction * iINDEXFETCH(imc_info_t *imcc, IMC_Unit *unit,
SymReg *r0, SymReg *r1, SymReg *r2)>

substr or X = P[key]

=cut

*/

PARROT_WARN_UNUSED_RESULT
PARROT_CAN_RETURN_NULL
static Instruction *
iINDEXFETCH(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit), ARGIN(SymReg *r0),
        ARGIN(SymReg *r1), ARGIN(SymReg *r2))
{
    ASSERT_ARGS(iINDEXFETCH)
    imcc -> keyvec |= KEY_BIT(2);
    return MK_I(imcc, unit, "set %s, %s[%s]", 3, r0, r1, r2);
}

/*

=item C<static Instruction * iINDEXSET(imc_info_t *imcc, IMC_Unit *unit, SymReg
*r0, SymReg *r1, SymReg *r2)>

substr or P[key] = X

=cut

*/

PARROT_WARN_UNUSED_RESULT
PARROT_CAN_RETURN_NULL
static Instruction *
iINDEXSET(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit), ARGIN(SymReg *r0),
        ARGIN(SymReg *r1), ARGIN(SymReg *r2))
{
    ASSERT_ARGS(iINDEXSET)
    if (r0->set == 'P') {
        imcc->keyvec |= KEY_BIT(1);
        MK_I(imcc, unit, "set %s[%s], %s", 3, r0, r1, r2);
    }
    else
        IMCC_fataly(imcc, EXCEPTION_SYNTAX_ERROR,
            "unsupported indexed set op\n");

    return NULL;
}

/*

=item C<static const char * inv_op(const char *op)>

=cut

*/

PARROT_WARN_UNUSED_RESULT
PARROT_CAN_RETURN_NULL
static const char *
inv_op(ARGIN(const char *op))
{
    ASSERT_ARGS(inv_op)
    int n;
    return get_neg_op(op, &n);
}

/*

=item C<Instruction * IMCC_create_itcall_label(imc_info_t *imcc)>

=cut

*/

PARROT_WARN_UNUSED_RESULT
PARROT_CANNOT_RETURN_NULL
Instruction *
IMCC_create_itcall_label(ARGMOD(imc_info_t *imcc))
{
    ASSERT_ARGS(IMCC_create_itcall_label)
    char         name[128];
    SymReg      *r;
    Instruction *i;

    snprintf(name, sizeof (name), "%cpcc_sub_call_%d", IMCC_INTERNAL_CHAR,
        imcc->cnr++);

    r       = mk_pcc_sub(imcc, name, 0);
    i       = iLABEL(imcc, imcc->cur_unit, r);
    i->type = ITCALL | ITPCCSUB;

    imcc->cur_call = r;

    return i;
}

/*

=item C<static SymReg * mk_sub_address_fromc(imc_info_t *imcc, const char
*name)>

=cut

*/

PARROT_WARN_UNUSED_RESULT
PARROT_CANNOT_RETURN_NULL
static SymReg *
mk_sub_address_fromc(ARGMOD(imc_info_t *imcc), ARGIN(const char *name))
{
    ASSERT_ARGS(mk_sub_address_fromc)
    /* name is a quoted sub name */
    SymReg *r;
    char   *name_copy;

    /* interpolate only if the first character is a double-quote */
    if (*name == '"') {
        STRING *unescaped = Parrot_str_unescape(imcc->interp, name, '"', NULL);
        name_copy         = Parrot_str_to_cstring(imcc->interp, unescaped);
    }
    else {
        name_copy = mem_sys_strdup(name);
        name_copy[strlen(name) - 1] = 0;
    }

    r = mk_sub_address(imcc, name_copy + 1);
    mem_sys_free(name_copy);

    return r;
}

/*

=item C<static SymReg * mk_sub_address_u(imc_info_t *imcc, const char *name)>

=cut

*/

PARROT_WARN_UNUSED_RESULT
PARROT_CANNOT_RETURN_NULL
static SymReg *
mk_sub_address_u(ARGMOD(imc_info_t *imcc), ARGIN(const char *name))
{
    ASSERT_ARGS(mk_sub_address_u)
    SymReg * const r = mk_sub_address(imcc, name);
    r->type         |= VT_ENCODED;

    return r;
}

/*

=item C<void IMCC_itcall_sub(imc_info_t *imcc, SymReg *sub)>

=cut

*/

void
IMCC_itcall_sub(ARGMOD(imc_info_t *imcc), ARGIN(SymReg *sub))
{
    ASSERT_ARGS(IMCC_itcall_sub)
    imcc->cur_call->pcc_sub->sub = sub;

    if (imcc->cur_obj) {
        if (imcc->cur_obj->set != 'P')
            IMCC_fataly(imcc, EXCEPTION_SYNTAX_ERROR, "object isn't a PMC");

        imcc->cur_call->pcc_sub->object = imcc->cur_obj;
        imcc->cur_obj = NULL;
    }
}


/*

=item C<static void begin_return_or_yield(imc_info_t *imcc, int yield)>

=cut

*/

static void
begin_return_or_yield(ARGMOD(imc_info_t *imcc), int yield)
{
    ASSERT_ARGS(begin_return_or_yield)
    Instruction *i;
    Instruction * const ins = imcc->cur_unit->instructions;
    char                name[128];

    if (!ins || !ins->symregs[0] || !(ins->symregs[0]->type & VT_PCC_SUB))
        IMCC_fataly(imcc, EXCEPTION_SYNTAX_ERROR,
                    "yield or return directive outside pcc subroutine\n");
    ins->symregs[0]->pcc_sub->yield = yield;
    snprintf(name, sizeof (name), yield ? "%cpcc_sub_yield_%d" : "%cpcc_sub_ret_%d",
            IMCC_INTERNAL_CHAR, imcc->cnr++);
    imcc->sr_return = mk_pcc_sub(imcc, name, 0);
    i = iLABEL(imcc, imcc->cur_unit, imcc->sr_return);
    i->type = yield ? ITPCCSUB | ITLABEL | ITPCCYIELD : ITPCCSUB | ITLABEL ;
    imcc->asm_state = yield ? AsmInYield : AsmInReturn;
}

/*

=item C<static void set_lexical(imc_info_t *imcc, SymReg *r, SymReg *name)>

=cut

*/

static void
set_lexical(ARGMOD(imc_info_t *imcc), ARGMOD(SymReg *r), ARGMOD(SymReg *name))
{
    ASSERT_ARGS(set_lexical)

    r->usage |= U_LEXICAL;

    if (name == r->reg)
        IMCC_fataly(imcc, EXCEPTION_SYNTAX_ERROR,
            "register %s already declared as lexical %s", r->name, name->name);

    /* chain all names in r->reg */
    name->reg    = r->reg;
    r->reg       = name;
    name->usage |= U_LEXICAL;
    r->use_count++;
}


/*

=item C<static void add_pcc_named_arg(imc_info_t *imcc, SymReg *cur_call, SymReg
*name, SymReg *value)>

=cut

*/

static void
add_pcc_named_arg(ARGMOD(imc_info_t *imcc), ARGMOD(SymReg *cur_call),
        ARGMOD(SymReg *name), ARGMOD(SymReg *value))
{
    ASSERT_ARGS(add_pcc_named_arg)
    name->type  |= VT_NAMED;

    add_pcc_arg(imcc, cur_call, name);
    add_pcc_arg(imcc, cur_call, value);
}

/*

=item C<static void add_pcc_named_arg_var(imc_info_t *imcc, SymReg *cur_call,
SymReg *name, SymReg *value)>

=cut

*/

static void
add_pcc_named_arg_var(ARGMOD(imc_info_t *imcc), ARGMOD(SymReg *cur_call),
        ARGMOD(SymReg *name), ARGMOD(SymReg *value))
{
    ASSERT_ARGS(add_pcc_named_arg_var)
    name->type |= VT_NAMED;
    add_pcc_arg(imcc, cur_call, name);
    add_pcc_arg(imcc, cur_call, value);
}

/*

=item C<static void add_pcc_named_result(imc_info_t *imcc, SymReg *cur_call,
SymReg *name, SymReg *value)>

=cut

*/

static void
add_pcc_named_result(ARGMOD(imc_info_t *imcc), ARGMOD(SymReg *cur_call),
        ARGMOD(SymReg *name), ARGMOD(SymReg *value))
{
    ASSERT_ARGS(add_pcc_named_result)
    name->type |= VT_NAMED;

    add_pcc_result(imcc, cur_call, name);
    add_pcc_result(imcc, cur_call, value);
}

/*

=item C<static void add_pcc_named_param(imc_info_t *imcc, SymReg *cur_call,
SymReg *name, SymReg *value)>

=cut

*/

static void
add_pcc_named_param(ARGMOD(imc_info_t *imcc), ARGMOD(SymReg *cur_call),
        ARGMOD(SymReg *name), ARGMOD(SymReg *value))
{
    ASSERT_ARGS(add_pcc_named_param)
    name->type |= VT_NAMED;

    add_pcc_arg(imcc, cur_call, name);
    add_pcc_arg(imcc, cur_call, value);
}

/*

=item C<static void add_pcc_named_return(imc_info_t *imcc, SymReg *cur_call,
SymReg *name, SymReg *value)>

=cut

*/

static void
add_pcc_named_return(ARGMOD(imc_info_t *imcc), ARGMOD(SymReg *cur_call),
        ARGMOD(SymReg *name), ARGMOD(SymReg *value))
{
    ASSERT_ARGS(add_pcc_named_return)
    name->type |= VT_NAMED;

    add_pcc_result(imcc, cur_call, name);
    add_pcc_result(imcc, cur_call, value);
}

/*

=item C<static void adv_named_set(imc_info_t *imcc, const char *name)>

=item C<static void adv_named_set_u(imc_info_t *imcc, const char *name)>

Sets the name of the current named argument.

C<adv_named_set_u> is the Unicode version of this function.

=cut

*/

static void
adv_named_set(ARGMOD(imc_info_t *imcc), ARGIN(const char *name))
{
    ASSERT_ARGS(adv_named_set)
    if (imcc->adv_named_id)
        IMCC_fataly(imcc, EXCEPTION_SYNTAX_ERROR,
                    "Named parameter with more than one name.\n");

    imcc->adv_named_id = mk_const(imcc, name, 'S');
}

static void
adv_named_set_u(ARGMOD(imc_info_t *imcc), ARGIN(const char *name))
{
    ASSERT_ARGS(adv_named_set_u)
    if (imcc->adv_named_id)
        IMCC_fataly(imcc, EXCEPTION_SYNTAX_ERROR,
                    "Named parameter with more than one name.\n");

    imcc->adv_named_id = mk_const(imcc, name, 'U');
}

/*

=item C<static void do_loadlib(imc_info_t *imcc, const char *lib)>

=cut

*/

static void
do_loadlib(ARGMOD(imc_info_t *imcc), ARGIN(const char *lib))
{
    ASSERT_ARGS(do_loadlib)
    STRING * const s = Parrot_str_unescape(imcc->interp, lib + 1, '"', NULL);
    PMC    * const lib_pmc = Parrot_dyn_load_lib(imcc->interp, s, NULL);
    if (PMC_IS_NULL(lib_pmc) || !VTABLE_get_bool(imcc->interp, lib_pmc)) {
        IMCC_fataly(imcc, EXCEPTION_LIBRARY_ERROR,
            "loadlib directive could not find library `%S'", s);
    }

    /* store non-dynoplib library deps here, dynoplibs are treated separately for now */
    /* TODO: This is very ugly and heavily nested. Can we avoid this? */
    if (!STRING_equal(imcc->interp,
            VTABLE_get_string(imcc->interp,
                VTABLE_getprop(imcc->interp, lib_pmc,
                    Parrot_str_new_constant(imcc->interp, "_type"))),
            Parrot_str_new_constant(imcc->interp, "Ops")))
        imcc_pbc_add_libdep(imcc, s);
}

/* HEADERIZER STOP */

%}

%union {
    IdList * idlist;
    int t;
    char * s;
    SymReg * sr;
    Instruction *i;
}

/* We need precedence for a few tokens to resolve a couple of conflicts */
%nonassoc LOW_PREC
%nonassoc '\n'
%nonassoc <t> PARAM

%token <t> SOL HLL TK_LINE TK_FILE
%token <t> GOTO ARG IF UNLESS PNULL SET_RETURN SET_YIELD
%token <t> ADV_FLAT ADV_SLURPY ADV_OPTIONAL ADV_OPT_FLAG ADV_NAMED ADV_ARROW
%token <t> ADV_INVOCANT ADV_CALL_SIG
%token <t> NAMESPACE DOT_METHOD
%token <t> SUB SYM LOCAL LEXICAL CONST ANNOTATE
%token <t> GLOBAL_CONST
%token <t> PLUS_ASSIGN MINUS_ASSIGN MUL_ASSIGN DIV_ASSIGN CONCAT_ASSIGN
%token <t> BAND_ASSIGN BOR_ASSIGN BXOR_ASSIGN FDIV FDIV_ASSIGN MOD_ASSIGN
%token <t> SHR_ASSIGN SHL_ASSIGN SHR_U_ASSIGN
%token <t> SHIFT_LEFT SHIFT_RIGHT INTV FLOATV STRINGV PMCV LOG_XOR
%token <t> RELOP_EQ RELOP_NE RELOP_GT RELOP_GTE RELOP_LT RELOP_LTE
%token <t> RESULT RETURN TAILCALL YIELDT GET_RESULTS
%token <t> POW SHIFT_RIGHT_U LOG_AND LOG_OR
%token <t> COMMA ESUB DOTDOT
%token <t> PCC_BEGIN PCC_END PCC_CALL PCC_SUB PCC_BEGIN_RETURN PCC_END_RETURN
%token <t> PCC_BEGIN_YIELD PCC_END_YIELD INVOCANT
%token <t> MAIN LOAD INIT IMMEDIATE POSTCOMP METHOD ANON OUTER NEED_LEX
%token <t> MULTI SUBTAG VTABLE_METHOD LOADLIB SUB_INSTANCE_OF SUBID
%token <t> NS_ENTRY
%token <s> LABEL
%token <t> EMIT EOM
%token <s> IREG NREG SREG PREG IDENTIFIER REG MACRO ENDM
%token <s> STRINGC INTC FLOATC USTRINGC
%token <s> PARROT_OP
%type <t> type hll_def return_or_yield comma_or_goto
%type <i> program
%type <i> class_namespace
%type <i> constdef sub emit pcc_ret pcc_yield
%type <i> compilation_units compilation_unit pmc_const pragma
%type <s> relop any_string assign_op  bin_op  un_op
%type <i> labels _labels label  statement sub_call
%type <i> pcc_sub_call
%type <sr> sub_param pcc_arg pcc_result pcc_args pcc_results sub_param_type_def
%type <sr> pcc_returns pcc_yields pcc_return pcc_call arg arglist the_sub multi_type
%type <sr> subtags
%type <t> argtype_list argtype paramtype_list paramtype
%type <t> pcc_return_many
%type <t> proto sub_proto sub_proto_list multi subtag multi_types outer
%type <t> vtable instanceof subid
%type <t> method ns_entry_name
%type <i> instruction assignment conditional_statement labeled_inst opt_label op_assign
%type <i> if_statement unless_statement
%type <i> func_assign get_results
%type <i> opt_invocant
%type <i> annotate_directive
%type <sr> target targetlist reg const stringc var result pcc_set_yield
%type <sr> keylist keylist_force _keylist key maybe_ns nslist _nslist
%type <sr> vars _vars var_or_i _var_or_i label_op sub_label_op sub_label_op_c
%type <i> pasmcode pasmline pasm_inst
%type <sr> pasm_args
%type <i> var_returns
%token <sr> VAR

%token <t> LINECOMMENT
%token <s> FILECOMMENT
%type <idlist> id_list id_list_id

%nonassoc CONCAT DOT

 /* %locations */
%pure_parser

%parse-param {void *yyscanner}
%lex-param   {void *yyscanner}
%parse-param {imc_info_t *imcc}
%lex-param   {imc_info_t *imcc}

%start program

/* In effort to make the grammar readable but not militaristic, please space indent
   code blocks on 10 col boundaries and keep indentation same for all code blocks
   in a rule. Indent rule tokens | and ; to 4th col and sub rules 6th col
 */

%%

program:
     compilation_units    { if (yynerrs) YYABORT; $$ = 0; }
   ;

compilation_units:
     compilation_unit
   | compilation_units compilation_unit
   ;

compilation_unit:
     class_namespace           { $$ = $1; }
   | constdef                  { $$ = $1; }
   | sub
         {
           $$ = $1;
           imc_close_unit(imcc, imcc->cur_unit);
           imcc->cur_unit = 0;
         }
   | emit
         {
           $$ = $1;
           imc_close_unit(imcc, imcc->cur_unit);
           imcc->cur_unit = 0;
         }
   | MACRO '\n'                { $$ = 0; }
   | pragma                    { $$ = 0; }
   | location_directive        { $$ = 0; }
   | '\n'                      { $$ = 0; }
   ;

pragma:
     hll_def         '\n'      { $$ = 0; }
   | LOADLIB STRINGC '\n'
         {
           $$ = 0;
           do_loadlib(imcc, $2);
           mem_sys_free($2);
         }
   ;

location_directive:
     TK_LINE INTC COMMA STRINGC '\n'
         {
           imcc->line = atoi($2);
           /* set_filename() frees the STRINGC */
           set_filename(imcc, $4);
         }
   | TK_FILE STRINGC '\n'
         {
           /* set_filename() frees the STRINGC */
           set_filename(imcc, $2);
         }
   ;

annotate_directive:
    ANNOTATE STRINGC COMMA const
        {
          /* We'll want to store an entry while emitting instructions, so just
           * store annotation like it's an instruction. */
          SymReg * const key = mk_const(imcc, $2, 'S');
          $$ = MK_I(imcc, imcc->cur_unit, ".annotate", 2, key, $4);
          mem_sys_free($2);
        }
    ;

hll_def:

     HLL STRINGC
         {
            STRING * const hll_name = Parrot_str_unescape(imcc->interp, $2 + 1, '"', NULL);
            Parrot_pcc_set_HLL(imcc->interp, CURRENT_CONTEXT(imcc->interp),
                Parrot_hll_register_HLL(imcc->interp, hll_name));

            imcc->cur_namespace = NULL;
            mem_sys_free($2);
            $$ = 0;
         }
   ;

constdef:
     CONST { imcc->is_def = 1; } type IDENTIFIER '=' const
         {
             mk_const_ident(imcc, $4, $3, $6, 1);
             mem_sys_free($4);
             imcc->is_def = 0;
         }
   ;

pmc_const:
     CONST { imcc->is_def = 1; } STRINGC var_or_i '=' any_string
         {
           $$ = mk_pmc_const_named(imcc, imcc->cur_unit, $3, $4, $6);
           mem_sys_free($3);
           mem_sys_free($6);
           imcc->is_def = 0;
         }
   ;
any_string:
     STRINGC
   | USTRINGC
   ;

pasmcode:
     pasmline
   | pasmcode pasmline
   ;

pasmline:
     labels  pasm_inst '\n'    { $$ = 0;  }
   | MACRO '\n'                { $$ = 0;  }
   | FILECOMMENT               { $$ = 0;  }
   | LINECOMMENT               { $$ = 0;  }
   | class_namespace           { $$ = $1; }
   | pmc_const
   | pragma
   ;

pasm_inst:                     { clear_state(imcc); }
     PARROT_OP pasm_args
         {
           $$ = INS(imcc, imcc->cur_unit, $2, 0, imcc->regs,
                    imcc->nargs, imcc -> keyvec, 1);
            mem_sys_free($2);
         }
   | PCC_SUB
         {
           imc_close_unit(imcc, imcc->cur_unit);
           imcc->cur_unit = imc_open_unit(imcc, IMC_PASM);
         }
     sub_proto LABEL
         {
           $$ = iSUBROUTINE(imcc, imcc->cur_unit, mk_sub_label(imcc, $4));
           imcc->cur_call->pcc_sub->pragma = $3;
           mem_sys_free($4);
         }
   | PNULL var
         {
           $$ = MK_I(imcc, imcc->cur_unit, "null", 1, $2);
         }
   | LEXICAL STRINGC COMMA REG
         {
           char   *name = mem_sys_strdup($2 + 1);
           SymReg *r    = mk_pasm_reg(imcc, $4);
           SymReg *n;
           name[strlen(name) - 1] = 0;
           n = mk_const(imcc, name, 'S');
           set_lexical(imcc, r, n);
           $$ = 0;
           mem_sys_free(name);
           mem_sys_free($2);
           mem_sys_free($4);
         }
   | /* none */ { $$ = 0;}
   ;

pasm_args:
     vars
   ;

emit:     /* EMIT and EOM tokens are used when compiling a .pasm file. */
     EMIT { imcc->cur_unit = imc_open_unit(imcc, IMC_PASM); }
     opt_pasmcode
     EOM
         {
           /* if (optimizer_level & OPT_PASM)
                         imc_compile_unit(interp, imcc->cur_unit);
                         emit_flush(interp);
           */
           $$ = 0;
         }
   ;

opt_pasmcode:
     /* empty */
  | pasmcode
  ;

class_namespace:
    NAMESPACE maybe_ns '\n'
         {
           int re_open = 0;
           $$ = 0;
           if (imcc->state->pasm_file && imcc->cur_namespace) {
               imc_close_unit(imcc, imcc->cur_unit);
               re_open = 1;
           }
           imcc->cur_namespace = $2;
           if (re_open)
               imcc->cur_unit = imc_open_unit(imcc, IMC_PASM);
         }
   ;

maybe_ns:
     '[' nslist ']' { $$ = $2; }
   | '[' ']'        { $$ = NULL; }
   ;

nslist:
         {
           imcc->nkeys    = 0;
         }
     _nslist
         {
           $$ = link_keys(imcc, imcc->nkeys, imcc->keys, 0);
         }
   ;

_nslist:
     stringc { imcc->keys[imcc->nkeys++] = $1; }
   | _nslist ';' stringc
         {
           imcc->keys[imcc->nkeys++] = $3;
           $$ = imcc->keys[0];
         }
   ;

sub:
     SUB
         {
           imcc->cur_unit = imc_open_unit(imcc, IMC_PCCSUB);
         }
     sub_label_op_c
         {
           iSUBROUTINE(imcc, imcc->cur_unit, $3);
         }
     sub_proto '\n'
        {
          imcc->cur_call->pcc_sub->pragma = $5;
          if (!imcc->cur_unit->instructions->symregs[0]->subid) {
            imcc->cur_unit->instructions->symregs[0]->subid =
                imcc->cur_unit->instructions->symregs[0];
          }
        }
     sub_body  ESUB            { $$ = 0; imcc->cur_call = NULL; }
   ;

sub_param:
   PARAM
   { imcc->is_def = 1; }
   sub_param_type_def '\n'
         {
           if (/* IMCC_INFO(interp)->cur_unit->last_ins->op
           ||  */ !(imcc->cur_unit->last_ins->type & ITPCCPARAM)) {
               SymReg *r;
               Instruction *i;
               char name[128];
               snprintf(name, sizeof (name), "%cpcc_params_%d",
                        IMCC_INTERNAL_CHAR, imcc->cnr++);
               r = mk_symreg(imcc, name, 0);
               r->type    = VT_PCC_SUB;
               r->pcc_sub = mem_gc_allocate_zeroed_typed(imcc->interp, pcc_sub_t);
               i = iLABEL(imcc, imcc->cur_unit, r);
               imcc->cur_call = r;
               i->type = ITPCCPARAM;
           }
           if (imcc->adv_named_id) {
                 add_pcc_named_param(imcc, imcc->cur_call,
                                     imcc->adv_named_id, $3);
                 imcc->adv_named_id = NULL;
           }
           else
               add_pcc_arg(imcc, imcc->cur_call, $3);
         }
   { imcc->is_def = 0; }
   ;

sub_param_type_def:
     type IDENTIFIER paramtype_list
         {
           if ($3 & VT_OPT_FLAG && $1 != 'I') {
               const char *type;
               switch ($1) {
                    case 'N': type = "num";     break;
                    case 'S': type = "string";  break;
                    case 'P': type = "pmc";     break;
                    default:  type = "strange"; break;
               }

               IMCC_fataly(imcc, EXCEPTION_SYNTAX_ERROR,
                   ":opt_flag parameter must be of type 'int', not '%s'", type);
           }
           if ($3 & VT_NAMED && !($3 & VT_FLAT) && !imcc->adv_named_id)
               adv_named_set(imcc, $2);
           $$ = mk_ident(imcc, $2, $1, VTIDENTIFIER);
           $$->type |= $3;
           mem_sys_free($2);
          }
   ;



multi:
     MULTI '(' multi_types ')' { $$ = 0; }
   ;

multi_types:
     /* empty */
         {
           add_pcc_multi(imcc, imcc->cur_call, NULL);
         }
   | multi_types COMMA multi_type
         {
           $$ = 0;
           add_pcc_multi(imcc, imcc->cur_call, $3);
         }
   | multi_type
         {
           $$ = 0;
           add_pcc_multi(imcc, imcc->cur_call, $1);
         }
   ;

multi_type:
     INTV        { $$ = mk_const(imcc, "INTVAL",   'S'); }
   | FLOATV      { $$ = mk_const(imcc, "FLOATVAL", 'S'); }
   | PMCV        { $$ = mk_const(imcc, "PMC",      'S'); }
   | STRINGV     { $$ = mk_const(imcc, "STRING",   'S'); }
   | IDENTIFIER
         {
           SymReg *r;
           if (strcmp($1, "_") != 0)
               r = mk_const(imcc, $1, 'S');
           else {
               r = mk_const(imcc, "PMC", 'S');
           }
           mem_sys_free($1);
           $$ = r;
         }
   | STRINGC
         {
           SymReg *r;
           if (strcmp($1, "\"_\"") == 0 || strcmp($1, "'_'") == 0)
               r = mk_const(imcc, "PMC", 'S');
           else {
               r = mk_const(imcc, $1, 'S');
           }
           mem_sys_free($1);
           $$ = r;
         }
   | '[' keylist ']'           { $$ = $2; }
   ;


subtag:
    SUBTAG '(' subtags ')' { $$ = 0; }
    ;

subtags:
   subtags COMMA STRINGC
         {
           SymReg * const r = mk_const(imcc, $3, 'S');
           add_pcc_flag_str(imcc, imcc->cur_call, r);
           mem_sys_free($3);
           $$ = r;
         }
   | STRINGC
         {
           SymReg * const r = mk_const(imcc, $1, 'S');
           add_pcc_flag_str(imcc, imcc->cur_call, r);
           mem_sys_free($1);
           $$ = r;
         }
   ;


outer:
     OUTER '(' STRINGC ')'
         {
           $$ = 0;
           imcc->cur_unit->outer = mk_sub_address_fromc(imcc, $3);
           mem_sys_free($3);
         }
    | OUTER '(' IDENTIFIER ')'
         {
           $$ = 0;
           imcc->cur_unit->outer = mk_const(imcc, $3, 'S');
           mem_sys_free($3);
         }
   ;

vtable:
     VTABLE_METHOD
         {
           $$ = P_VTABLE;
           imcc->cur_unit->vtable_name      = NULL;
           imcc->cur_unit->is_vtable_method = 1;
         }
   | VTABLE_METHOD '(' STRINGC ')'
         {
           $$ = P_VTABLE;
           imcc->cur_unit->vtable_name      = $3;
           imcc->cur_unit->is_vtable_method = 1;
         }
   ;

method:
     METHOD
         {
           $$ = P_METHOD;
           imcc->cur_unit->method_name = NULL;
           imcc->cur_unit->is_method   = 1;
         }
   | METHOD '(' any_string ')'
         {
           $$ = P_METHOD;
           imcc->cur_unit->method_name = $3;
           imcc->cur_unit->is_method   = 1;
         }
   ;

ns_entry_name:
    NS_ENTRY
         {
           $$ = P_NSENTRY;
           imcc->cur_unit->ns_entry_name     = NULL;
           imcc->cur_unit->has_ns_entry_name = 1;
         }
   | NS_ENTRY '(' any_string ')'
         {
           $$ = P_NSENTRY;
           imcc->cur_unit->ns_entry_name = $3;
           imcc->cur_unit->has_ns_entry_name = 1;
         }
   ;

instanceof:
     SUB_INSTANCE_OF '(' STRINGC ')'
         {
           $$ = 0;
           imcc->cur_unit->instance_of = $3;
         }
   ;

subid:
     SUBID
         {
           $$ = 0;
           imcc->cur_unit->subid = NULL;
         }
   | SUBID '(' any_string ')'
         {
           SymReg *r = mk_const(imcc, $3, 'S');
           $$ = 0;
           imcc->cur_unit->subid = r;
           imcc->cur_unit->instructions->symregs[0]->subid = r;
           mem_sys_free($3);
         }
   ;

sub_body:
     /* empty */
   |  statements
   ;

pcc_sub_call:
     PCC_BEGIN '\n'
         {
           char name[128];
           SymReg *r;
           Instruction *i;

           snprintf(name, sizeof (name), "%cpcc_sub_call_%d",
                   IMCC_INTERNAL_CHAR, imcc->cnr++);
           $<sr>$ = r = mk_pcc_sub(imcc, name, 0);
           /* this mid rule action has the semantic value of the
            * sub SymReg.
            * This is used below to append args & results
            */
           i = iLABEL(imcc, imcc->cur_unit, r);
           imcc->cur_call = r;
           i->type = ITPCCSUB;
         }
     pcc_args
     opt_invocant
     pcc_call
     opt_label
     pcc_results
     PCC_END { $$ = 0; imcc->cur_call = NULL; }
   ;

opt_label:
     /* empty */ { $$ = NULL; imcc->cur_call->pcc_sub->label = 0; }
   | label '\n'  { $$ = NULL; imcc->cur_call->pcc_sub->label = 1; }
   ;

opt_invocant:
     /* empty */       { $$ = NULL; }
   | INVOCANT var '\n' { $$ = NULL;  imcc->cur_call->pcc_sub->object = $2; }
   ;

sub_proto:
     /* empty */ { $$ = 0; }
   | sub_proto_list
   ;

sub_proto_list:
     proto                { $$ = $1; }
   | sub_proto_list proto { $$ = $1 | $2; }
   ;

proto:
     LOAD   {
                $$ = P_LOAD;
                /*
                SymReg * const r = mk_const(imcc, "load", 'S');
                add_pcc_flag_str(imcc, imcc->cur_call, r);
                $$ = r;
                */
            }
   | INIT   {
                $$ = P_INIT;
                /*
                SymReg * const r = mk_const(imcc, "load", 'S');
                add_pcc_flag_str(imcc, imcc->cur_call, r);
                $$ = r;
                */
            }
   | MAIN      { $$ = P_MAIN; }
   | IMMEDIATE { $$ = P_IMMEDIATE; }
   | POSTCOMP  { $$ = P_POSTCOMP; }
   | ANON      { $$ = P_ANON; }
   | NEED_LEX  { $$ = P_NEED_LEX; }
   | multi
   | subtag
   | outer
   | vtable
   | method
   | ns_entry_name
   | instanceof
   | subid
   ;

pcc_call:
     PCC_CALL var COMMA var '\n'
         {
           add_pcc_sub(imcc->cur_call, $2);
           add_pcc_cc(imcc->cur_call, $4);
         }
   | PCC_CALL var '\n'
         {
           add_pcc_sub(imcc->cur_call, $2);
         }


pcc_args:
     /* empty */               { $$ = 0; }
   | pcc_args pcc_arg '\n'
            {
                 if (imcc->adv_named_id) {
                     add_pcc_named_param(imcc, imcc->cur_call,
                                    imcc->adv_named_id, $2);
                     imcc->adv_named_id = NULL;
                 }
                 else
                     add_pcc_arg(imcc, imcc->cur_call, $2);
            }
   ;

pcc_arg:
     ARG arg { $$ = $2; }
   ;


pcc_results:
     /* empty */ { $$ = 0; }
   | pcc_results pcc_result '\n'
         {
           if ($2)
               add_pcc_result(imcc, imcc->cur_call, $2);
         }
   ;

pcc_result:
     RESULT target paramtype_list { $$ = $2; $$->type |= $3; }
   | LOCAL { imcc->is_def = 1; } type id_list_id
         {
           IdList * const l = $4;
           SymReg *ignored;
           ignored = mk_ident(imcc, l->id, $3, VTIDENTIFIER);
           UNUSED(ignored);
           imcc->is_def = 0;
           $$ = 0;
         }
   ;

paramtype_list:
     /* empty */               { $$ = 0; }
   | paramtype_list paramtype  { $$ = $1 | $2; }
   ;

paramtype:
     ADV_SLURPY                 { $$ = VT_FLAT;   }
   | ADV_OPTIONAL               { $$ = VT_OPTIONAL; }
   | ADV_OPT_FLAG               { $$ = VT_OPT_FLAG; }
   | ADV_NAMED                  { $$ = VT_NAMED; }
   | ADV_NAMED '(' STRINGC ')'  { adv_named_set(imcc, $3);   $$ = VT_NAMED; mem_sys_free($3); }
   | ADV_NAMED '(' USTRINGC ')' { adv_named_set_u(imcc, $3); $$ = VT_NAMED; mem_sys_free($3); }
   | ADV_CALL_SIG               { $$ = VT_CALL_SIG; }
   ;


pcc_ret:
     PCC_BEGIN_RETURN '\n'     { begin_return_or_yield(imcc, 0); }
     pcc_returns
     PCC_END_RETURN            { $$ = 0; imcc->asm_state = AsmDefault; }
   | pcc_return_many
         {
           imcc->asm_state = AsmDefault;
           $$ = 0;
         }
   ;

pcc_yield:
     PCC_BEGIN_YIELD '\n'      { begin_return_or_yield(imcc, 1); }
     pcc_yields
     PCC_END_YIELD             { $$ = 0; imcc->asm_state = AsmDefault; }
   ;

pcc_returns:
     /* empty */               { $$ = 0; }
   | pcc_returns '\n'
         {
           if ($1)
               add_pcc_result(imcc, imcc->sr_return, $1);
         }
   | pcc_returns pcc_return '\n'
         {
           if ($2)
               add_pcc_result(imcc, imcc->sr_return, $2);
         }
   ;

pcc_yields:
     /* empty */                { $$ = 0; }
   | pcc_yields '\n'
         {
           if ($1)
               add_pcc_result(imcc, imcc->sr_return, $1);
         }
   | pcc_yields pcc_set_yield '\n'
         {
           if ($2)
               add_pcc_result(imcc, imcc->sr_return, $2);
         }
   ;

pcc_return:
     SET_RETURN var argtype_list { $$ = $2; $$->type |= $3; }
   ;

pcc_set_yield:
     SET_YIELD var argtype_list  { $$ = $2; $$->type |= $3; }
   ;

pcc_return_many:
    return_or_yield  '('
        {
          if (imcc->asm_state == AsmDefault)
              begin_return_or_yield(imcc, $1);
        }
    var_returns  ')'
        {
          imcc->asm_state = AsmDefault;
          $$ = 0;
        }
  ;

return_or_yield:
     RETURN                    { $$ = 0; }
   | YIELDT                    { $$ = 1; }
   ;

var_returns:
     /* empty */               { $$ = 0; }
   | arg
         {
           if (imcc->adv_named_id) {
               add_pcc_named_return(imcc, imcc->sr_return,
                                    imcc->adv_named_id, $1);
               imcc->adv_named_id = NULL;
           }
           else
               add_pcc_result(imcc, imcc->sr_return, $1);
         }
   | STRINGC ADV_ARROW var
         {
            SymReg * const name = mk_const(imcc, $1, 'S');
            add_pcc_named_return(imcc, imcc->sr_return, name, $3);
         }
   | var_returns COMMA arg
         {
           if (imcc->adv_named_id) {
               add_pcc_named_return(imcc, imcc->sr_return,
                                    imcc->adv_named_id, $3);
               imcc->adv_named_id = NULL;
             }
             else
                 add_pcc_result(imcc, imcc->sr_return, $3);
         }
   | var_returns COMMA STRINGC ADV_ARROW var
         {
           SymReg * const name = mk_const(imcc, $3, 'S');
           add_pcc_named_return(imcc, imcc->sr_return, name, $5);
         }
   ;


statements:
     statement
   | statements statement
   ;

/* This is ugly. Because 'instruction' can start with PARAM and in the
 * 'pcc_sub' rule, 'pcc_params' is followed by 'statement', we get a
 * shift/reduce conflict on PARAM between reducing to the dummy
 * { clear_state(); } rule and shifting the PARAM to be used as part
 * of the 'pcc_params' (which is what we want). However, yacc syntax
 * doesn't propagate precedence to the dummy rules, so we have to
 * split out the action just so that we can assign it a precedence. */

helper_clear_state:
        { clear_state(imcc); } %prec LOW_PREC
   ;

statement:
     sub_param                 { $$ = 0; }
   | helper_clear_state
     instruction               { $$ = $2; }
   | MACRO '\n'                { $$ = 0; }
   | FILECOMMENT               { $$ = 0; }
   | LINECOMMENT               { $$ = 0; }
   | location_directive        { $$ = 0; }
   | annotate_directive        { $$ = $1; }
   ;

labels:
     /* none */ { $$ = NULL; }
   |  _labels
   ;

_labels:
     _labels label
   | label
   ;

label:
     LABEL
         {
             Instruction * const i = iLABEL(imcc, imcc->cur_unit,
                    mk_local_label(imcc, $1));
             mem_sys_free($1);
             $$ = i;
         }
   ;



instruction:
     labels labeled_inst '\n'  { $$ = $2; }
   | error '\n'
         {
           if (yynerrs >= PARROT_MAX_RECOVER_ERRORS) {
               IMCC_warning(imcc, "Too many errors. Correct some first.\n");
               YYABORT;
           }
           yyerrok;
         }
   ;

id_list :
     id_list_id
         {
           IdList* const l = $1;
           l->next = NULL;
           $$ = l;
         }

   | id_list COMMA id_list_id
         {
           IdList* const l = $3;
           l->next = $1;
           $$ = l;
         }
   ;

id_list_id :
     IDENTIFIER
         {
           IdList* const l = mem_gc_allocate_n_zeroed_typed(imcc->interp, 1, IdList);
           l->id           = $1;
           $$ = l;
         }
   ;

labeled_inst:
     assignment
   | conditional_statement
   | LOCAL { imcc->is_def = 1; } type id_list
         {
           IdList *l = $4;
           while (l) {
               IdList *l1;
               mk_ident(imcc, l->id, $3, VTIDENTIFIER);
               l1 = l;
               l  = l->next;
               mem_sys_free(l1->id);
               mem_sys_free(l1);
           }
           imcc->is_def = 0; $$ = 0;
         }
   | LEXICAL STRINGC COMMA target
         {
           SymReg *n;
           char   *name = mem_sys_strdup($2 + 1);
           name[strlen(name) - 1] = 0;
           n = mk_const(imcc, name, 'S');
           set_lexical(imcc, $4, n); $$ = 0;
           mem_sys_free($2);
           mem_sys_free(name);
         }
   | LEXICAL USTRINGC COMMA target
         {
           SymReg *n = mk_const(imcc, $2, 'U');
           set_lexical(imcc, $4, n); $$ = 0;
           mem_sys_free($2);
         }
   | CONST { imcc->is_def = 1; } type IDENTIFIER '=' const
         {
           mk_const_ident(imcc, $4, $3, $6, 0);
           imcc->is_def = 0;
           mem_sys_free($4);
         }

   | pmc_const
   | GLOBAL_CONST { imcc->is_def = 1; } type IDENTIFIER '=' const
         {
           mk_const_ident(imcc, $4, $3, $6, 1);
           imcc->is_def = 0;
           mem_sys_free($4);
         }
   | TAILCALL sub_call
         {
           $$ = NULL;
           imcc->cur_call->pcc_sub->tailcall = 1;
           imcc->cur_call = NULL;
         }
   | GOTO label_op
         {
            $$ = MK_I(imcc, imcc->cur_unit, "branch", 1, $2);
         }
   | PARROT_OP vars
         {
           $$ = INS(imcc, imcc->cur_unit, $1, 0, imcc->regs, imcc->nargs,
                    imcc->keyvec, 1);
           mem_sys_free($1);
         }
   | PNULL var    { $$ = MK_I(imcc, imcc->cur_unit, "null", 1, $2); }
   | sub_call     { $$ = 0; imcc->cur_call = NULL; }
   | pcc_sub_call { $$ = 0; }
   | pcc_ret
   | pcc_yield
   | /* none */   { $$ = 0;}
   ;

type:
     INTV    {$$ = 'I'; }
   | FLOATV  { $$ = 'N'; }
   | STRINGV { $$ = 'S'; }
   | PMCV    { $$ = 'P'; }
   ;

assignment:
     target '=' var
            { $$ = MK_I(imcc, imcc->cur_unit, "set", 2, $1, $3);  }
   | target '=' un_op var
            { $$ = MK_I(imcc, imcc->cur_unit, $3, 2, $1, $4);  }
   | target '=' var bin_op var
            { $$ = MK_I(imcc, imcc->cur_unit, $4, 3, $1, $3, $5); }
   | target '=' var '[' keylist ']'
            { $$ = iINDEXFETCH(imcc, imcc->cur_unit, $1, $3, $5); }
   | target '[' keylist ']' '=' var
            { $$ = iINDEXSET(imcc, imcc->cur_unit, $1, $3, $6); }
     /* Subroutine call the short way */
   | target  '=' sub_call
         {
           add_pcc_result(imcc, $3->symregs[0], $1);
           imcc->cur_call = NULL;
           $$ = 0;
         }
   | '('
         {
           $<i>$ = IMCC_create_itcall_label(imcc);
         }
     targetlist  ')' '=' the_sub '(' arglist ')'
         {
           IMCC_itcall_sub(imcc, $6);
           imcc->cur_call = NULL;
         }
   | get_results
   | op_assign
   | func_assign
   | target '=' PNULL
         {
           $$ = MK_I(imcc, imcc->cur_unit, "null", 1, $1);
         }
   ;

/* C++ hates implicit casts from string constants to char *, so be explicit */
un_op:
     '!'                       { $$ = (char *)"not"; }
   | '~'                       { $$ = (char *)"bnot"; }
   | '-'                       { $$ = (char *)"neg"; }
   ;

bin_op:
     '-'                       { $$ = (char *)"sub"; }
   | '+'                       { $$ = (char *)"add"; }
   | '*'                       { $$ = (char *)"mul"; }
   | '/'                       { $$ = (char *)"div"; }
   | '%'                       { $$ = (char *)"mod"; }
   | FDIV                      { $$ = (char *)"fdiv"; }
   | POW                       { $$ = (char *)"pow"; }
   | CONCAT                    { $$ = (char *)"concat"; }
   | RELOP_EQ                  { $$ = (char *)"iseq"; }
   | RELOP_NE                  { $$ = (char *)"isne"; }
   | RELOP_GT                  { $$ = (char *)"isgt"; }
   | RELOP_GTE                 { $$ = (char *)"isge"; }
   | RELOP_LT                  { $$ = (char *)"islt"; }
   | RELOP_LTE                 { $$ = (char *)"isle"; }
   | SHIFT_LEFT                { $$ = (char *)"shl"; }
   | SHIFT_RIGHT               { $$ = (char *)"shr"; }
   | SHIFT_RIGHT_U             { $$ = (char *)"lsr"; }
   | LOG_AND                   { $$ = (char *)"and"; }
   | LOG_OR                    { $$ = (char *)"or"; }
   | LOG_XOR                   { $$ = (char *)"xor"; }
   | '&'                       { $$ = (char *)"band"; }
   | '|'                       { $$ = (char *)"bor"; }
   | '~'                       { $$ = (char *)"bxor"; }
   ;


get_results:
     GET_RESULTS
         {
           $<i>$ = IMCC_create_itcall_label(imcc);
           $<i>$->type &= ~ITCALL;
           $<i>$->type |= ITRESULT;
         }
     '(' targetlist  ')' {  $$ = 0; }
   ;



op_assign:
     target assign_op var
         { $$ = MK_I(imcc, imcc->cur_unit, $2, 2, $1, $3); }
   | target CONCAT_ASSIGN var
         {
             if ($1->set == 'P')
                 $$ = MK_I(imcc, imcc->cur_unit, "concat", 2, $1, $3);
             else
                 $$ = MK_I(imcc, imcc->cur_unit, "concat", 3, $1, $1, $3);
         }
   ;

assign_op:
     PLUS_ASSIGN               { $$ = (char *)"add"; }
   | MINUS_ASSIGN              { $$ = (char *)"sub"; }
   | MUL_ASSIGN                { $$ = (char *)"mul"; }
   | DIV_ASSIGN                { $$ = (char *)"div"; }
   | MOD_ASSIGN                { $$ = (char *)"mod"; }
   | FDIV_ASSIGN               { $$ = (char *)"fdiv"; }
   | BAND_ASSIGN               { $$ = (char *)"band"; }
   | BOR_ASSIGN                { $$ = (char *)"bor"; }
   | BXOR_ASSIGN               { $$ = (char *)"bxor"; }
   | SHR_ASSIGN                { $$ = (char *)"shr"; }
   | SHL_ASSIGN                { $$ = (char *)"shl"; }
   | SHR_U_ASSIGN              { $$ = (char *)"lsr"; }
   ;


func_assign:
   target '=' PARROT_OP pasm_args
       {
        $$ = func_ins(imcc, imcc->cur_unit, $1, $3, imcc -> regs,
                      imcc -> nargs, imcc -> keyvec, 1);
         mem_sys_free($3);
       }
   ;

the_sub:
     IDENTIFIER { $$ = mk_sub_address(imcc, $1);       mem_sys_free($1); }
     | STRINGC  { $$ = mk_sub_address_fromc(imcc, $1); mem_sys_free($1); }
     | USTRINGC { $$ = mk_sub_address_u(imcc, $1);     mem_sys_free($1); }
   | target
         {
           $$ = $1;
           if ($1->set != 'P')
               IMCC_fataly(imcc, EXCEPTION_SYNTAX_ERROR, "Sub isn't a PMC");
         }
   | target DOT sub_label_op
        {
            /* disallow bareword method names; SREG name constants are fine */
            const char * const name = $3->name;
            if (!($3->type & VTREG)) {
                if (*name != '\'' || *name != '\"')
                    IMCC_fataly(imcc, EXCEPTION_SYNTAX_ERROR,
                        "Bareword method name '%s' not allowed in PIR",
                        $3->name);
            }

            imcc->cur_obj = $1;
            $$ = $3;
        }
   | target DOT USTRINGC
         {
            imcc->cur_obj = $1;
            $$ = mk_const(imcc, $3, 'U');
            mem_sys_free($3);
         }
   | target DOT STRINGC
         {
            imcc->cur_obj = $1;
            $$ = mk_const(imcc, $3, 'S');
            mem_sys_free($3);
         }
   | target DOT target
        {
            imcc->cur_obj = $1;
            $$ = $3;
        }
   ;


sub_call:
     the_sub
         {
           $<i>$ = IMCC_create_itcall_label(imcc);
           IMCC_itcall_sub(imcc, $1);
         }
     '(' arglist ')' { $$ = $<i>2; }
   ;

arglist:
     /* empty */ { $$ = 0; }
   | arglist COMMA arg
         {
           $$ = 0;
           if (imcc->adv_named_id) {
               add_pcc_named_arg(imcc, imcc->cur_call, imcc->adv_named_id, $3);
               imcc->adv_named_id = NULL;
           }
           else
               add_pcc_arg(imcc, imcc->cur_call, $3);
         }
   | arg
         {
           $$ = 0;
           if (imcc->adv_named_id) {
               add_pcc_named_arg(imcc, imcc->cur_call, imcc->adv_named_id, $1);
               imcc->adv_named_id = NULL;
           }
           else
               add_pcc_arg(imcc, imcc->cur_call, $1);
         }
   | arglist COMMA STRINGC ADV_ARROW var
         {
           $$ = 0;
           add_pcc_named_arg(imcc, imcc->cur_call, mk_const(imcc, $3, 'S'), $5);
           mem_sys_free($3);
         }
   | var ADV_ARROW var
         {
           $$ = 0;
           add_pcc_named_arg_var(imcc, imcc->cur_call, $1, $3);
         }
   | STRINGC ADV_ARROW var
         {
           $$ = 0;
           add_pcc_named_arg(imcc, imcc->cur_call,
                mk_const(imcc, $1, 'S'), $3);
           mem_sys_free($1);
         }
   ;

arg:
     var argtype_list { $$ = $1; $$->type |= $2; }
   ;

argtype_list:
     /* empty */               { $$ = 0; }
   | argtype_list argtype      { $$ = $1 | $2; }
   ;

argtype:
     ADV_FLAT                  { $$ = VT_FLAT;     }
   | ADV_NAMED                 { $$ = VT_NAMED;    }
   | ADV_CALL_SIG              { $$ = VT_CALL_SIG; }

   | ADV_NAMED '(' USTRINGC ')'
        {
            adv_named_set_u(imcc, $3);
            mem_sys_free($3);
            $$ = 0;
        }
   | ADV_NAMED '(' STRINGC  ')'
        {
            adv_named_set(imcc, $3);
            mem_sys_free($3);
            $$ = 0;
        }
   ;

result:
     target paramtype_list     { $$ = $1; $$->type |= $2; }
   ;

targetlist:
     targetlist COMMA result
         {
           $$ = 0;
           if (imcc->adv_named_id) {
               add_pcc_named_result(imcc, imcc->cur_call, imcc->adv_named_id, $3);
               imcc->adv_named_id = NULL;
           }
           else
               add_pcc_result(imcc, imcc->cur_call, $3);
         }
   | targetlist COMMA STRINGC ADV_ARROW target
         {
            add_pcc_named_result(imcc, imcc->cur_call,
                    mk_const(imcc, $3, 'S'), $5);
            mem_sys_free($3);
         }
   | result
         {
           $$ = 0;
           if (imcc->adv_named_id) {
               add_pcc_named_result(imcc, imcc->cur_call, imcc->adv_named_id, $1);
               imcc->adv_named_id = NULL;
           }
           else
               add_pcc_result(imcc, imcc->cur_call, $1);
         }
   | STRINGC ADV_ARROW target
         {
           add_pcc_named_result(imcc, imcc->cur_call, mk_const(imcc, $1, 'S'), $3);
           mem_sys_free($1);
         }
   | /* empty */                { $$ = 0; }
   ;

conditional_statement:
     if_statement               { $$ = $1; }
   | unless_statement           { $$ = $1; }
   ;

unless_statement:
     UNLESS var relop var GOTO label_op
         {
           $$ = MK_I(imcc, imcc->cur_unit, inv_op($3), 3, $2, $4, $6);
         }
   | UNLESS PNULL var GOTO label_op
         {
           $$ = MK_I(imcc, imcc->cur_unit, "unless_null", 2, $3, $5);
         }
   | UNLESS var comma_or_goto label_op
         {
           $$ = MK_I(imcc, imcc->cur_unit, "unless", 2, $2, $4);
         }
   ;

if_statement:
     IF var comma_or_goto label_op
         {
           $$ = MK_I(imcc, imcc->cur_unit, "if", 2, $2, $4);
         }
   | IF var relop var GOTO label_op
         {
           $$ = MK_I(imcc, imcc->cur_unit, $3, 3, $2, $4, $6);
         }
   | IF PNULL var GOTO label_op
         {
           $$ = MK_I(imcc, imcc->cur_unit, "if_null", 2, $3, $5);
         }
   ;

comma_or_goto:
     COMMA                     { $$ = 0; }
   | GOTO                      { $$ = 0; }
   ;

relop:
     RELOP_EQ                  { $$ = (char *)"eq"; }
   | RELOP_NE                  { $$ = (char *)"ne"; }
   | RELOP_GT                  { $$ = (char *)"gt"; }
   | RELOP_GTE                 { $$ = (char *)"ge"; }
   | RELOP_LT                  { $$ = (char *)"lt"; }
   | RELOP_LTE                 { $$ = (char *)"le"; }
   ;

target:
     VAR
   | reg
   ;

vars:
     /* empty */               { $$ = NULL; }
   | _vars                     { $$ = $1; }
   ;

_vars:
     _vars COMMA _var_or_i     { $$ = imcc->regs[0]; }
   | _var_or_i
   ;

_var_or_i:
     var_or_i                  { imcc->regs[imcc->nargs++] = $1; }
   | target '[' keylist ']'
         {
           imcc -> regs[imcc->nargs++] = $1;
           imcc -> keyvec |= KEY_BIT(imcc->nargs);
           imcc -> regs[imcc->nargs++] = $3;
           $$ = $1;
         }
   | '[' keylist_force ']'
         {
           imcc -> regs[imcc->nargs++] = $2;
           $$ = $2;
         }
   ;
sub_label_op_c:
     sub_label_op
   | STRINGC  { $$ = mk_sub_address_fromc(imcc, $1); mem_sys_free($1); }
   | USTRINGC { $$ = mk_sub_address_u(imcc, $1);     mem_sys_free($1); }
   ;

sub_label_op:
     IDENTIFIER { $$ = mk_sub_address(imcc, $1); mem_sys_free($1); }
   | PARROT_OP  { $$ = mk_sub_address(imcc, $1); mem_sys_free($1); }
   ;

label_op:
     IDENTIFIER { $$ = mk_label_address(imcc, $1); mem_sys_free($1); }
   | PARROT_OP  { $$ = mk_label_address(imcc, $1); mem_sys_free($1); }
   ;

var_or_i:
     label_op
   | var
   ;

var:
     target
   | const
   ;

keylist:
         {
           imcc->nkeys    = 0;
         }
     _keylist
         {
           $$ = link_keys(imcc, imcc->nkeys, imcc->keys, 0);
         }
   ;

keylist_force:
         {
           imcc->nkeys = 0;
         }
     _keylist
         {
           $$ = link_keys(imcc,
                          imcc->nkeys,
                          imcc->keys, 1);
         }
   ;

_keylist:
     key { imcc->keys[imcc->nkeys++] = $1; }
   | _keylist ';' key
         {
           imcc->keys[imcc->nkeys++] = $3;
           $$ = imcc->keys[0];
         }
   ;

key:
     var
         {
           $$ = $1;
         }
   ;

reg:
     IREG  { $$ = mk_symreg(imcc, $1, 'I'); }
   | NREG  { $$ = mk_symreg(imcc, $1, 'N'); }
   | SREG  { $$ = mk_symreg(imcc, $1, 'S'); }
   | PREG  { $$ = mk_symreg(imcc, $1, 'P'); }
   | REG   { $$ = mk_pasm_reg(imcc, $1); mem_sys_free($1); }
   ;

stringc:
     STRINGC  { $$ = mk_const(imcc, $1, 'S'); mem_sys_free($1); }
   | USTRINGC { $$ = mk_const(imcc, $1, 'U'); mem_sys_free($1); }
   ;

const:
     INTC     { $$ = mk_const(imcc, $1, 'I'); mem_sys_free($1); }
   | FLOATC   { $$ = mk_const(imcc, $1, 'N'); mem_sys_free($1); }
   | stringc  { $$ = $1; }
   ;

/* The End */
%%

/* I need this prototype somewhere... */
char *yyget_text(yyscan_t yyscanner);

/* I do not like this function, but, atm, it is the only way I can
 * make the code in yyerror work without segfault on some specific
 * cases.
 */
/* int yyholds_char(yyscan_t yyscanner); */

int yyerror(void *yyscanner, ARGMOD(imc_info_t *imcc), const char *s)
{
    /* If the error occurr in the end of the buffer (I mean, the last
     * token was already read), yyget_text will return a pointer
     * outside the bison buffer, and thus, not "accessible" by
     * us. This means it may segfault. */
    const char * const chr = yyget_text((yyscan_t)yyscanner);

    /* IMCC_fataly(imcc, EXCEPTION_SYNTAX_ERROR, s); */
    /* --- This was called before, not sure if I should call some
           similar function that does not die like this one. */

    /* Basically, if current token is a newline, it mean the error was
     * before the newline, and thus, line is the line *after* the
     * error. Instead of duplicating code for both cases (the 'newline' and
     * non-newline case, do the test twice; efficiency is not important when
     * we have an error anyway. */
    if (!at_eof(yyscanner)) {
        IMCC_warning(imcc, "error:imcc:%s", s);

        /* don't print the current token if it is a newline */
        if (*chr != '\n')
            IMCC_warning(imcc, " ('%s')", chr);

        IMCC_print_inc(imcc);
    }

    /* scanner is at EOF; just to be sure, don't print "current" token */
    else {
        IMCC_warning(imcc, "error:imcc:%s", s);
        IMCC_print_inc(imcc);
    }

    return 0;
}

/*

=back

 */
/*
 * Local variables:
 *   c-file-style: "parrot"
 * End:
 * vim: expandtab shiftwidth=4 cinoptions='\:2=2' :
 */