implement $invocant: syntax
[p5sagit/Function-Parameters.git] / Parameters.xs
index 1dda3ad..2031f0b 100644 (file)
@@ -83,7 +83,8 @@ enum {
        FLAG_NAME_OK      = 0x01,
        FLAG_ANON_OK      = 0x02,
        FLAG_DEFAULT_ARGS = 0x04,
-       FLAG_CHECK_NARGS  = 0x08
+       FLAG_CHECK_NARGS  = 0x08,
+       FLAG_INVOCANT     = 0x10
 };
 
 DEFSTRUCT(KWSpec) {
@@ -156,9 +157,6 @@ static int kw_flags(pTHX_ const char *kw_ptr, STRLEN kw_len, KWSpec *spec) {
 }
 
 
-#include "toke_on_crack.c.inc"
-
-
 static void free_defspec(pTHX_ void *vp) {
        DefaultParamSpec *dp = vp;
        op_free(dp->init);
@@ -216,11 +214,237 @@ enum {
        MY_ATTR_SPECIAL = 0x04
 };
 
+static void my_sv_cat_c(pTHX_ SV *sv, U32 c) {
+       char ds[UTF8_MAXBYTES + 1], *d;
+       d = uvchr_to_utf8(ds, c);
+       if (d - ds > 1) {
+               sv_utf8_upgrade(sv);
+       }
+       sv_catpvn(sv, ds, d - ds);
+}
+
+static bool my_is_uni_xidfirst(pTHX_ UV c) {
+       U8 tmpbuf[UTF8_MAXBYTES + 1];
+       uvchr_to_utf8(tmpbuf, c);
+       return is_utf8_xidfirst(tmpbuf);
+}
+
+static bool my_is_uni_xidcont(pTHX_ UV c) {
+       U8 tmpbuf[UTF8_MAXBYTES + 1];
+       uvchr_to_utf8(tmpbuf, c);
+       return is_utf8_xidcont(tmpbuf);
+}
+
+static SV *my_scan_word(pTHX_ bool allow_package) {
+       bool at_start, at_substart;
+       I32 c;
+       SV *sv = sv_2mortal(newSVpvs(""));
+       if (lex_bufutf8()) {
+               SvUTF8_on(sv);
+       }
+
+       at_start = at_substart = TRUE;
+       c = lex_peek_unichar(0);
+
+       while (c != -1) {
+               if (at_substart ? my_is_uni_xidfirst(aTHX_ c) : my_is_uni_xidcont(aTHX_ c)) {
+                       lex_read_unichar(0);
+                       my_sv_cat_c(aTHX_ sv, c);
+                       at_substart = FALSE;
+                       c = lex_peek_unichar(0);
+               } else if (allow_package && !at_substart && c == '\'') {
+                       lex_read_unichar(0);
+                       c = lex_peek_unichar(0);
+                       if (!my_is_uni_xidfirst(aTHX_ c)) {
+                               lex_stuff_pvs("'", 0);
+                               break;
+                       }
+                       sv_catpvs(sv, "'");
+                       at_substart = TRUE;
+               } else if (allow_package && (at_start || !at_substart) && c == ':') {
+                       lex_read_unichar(0);
+                       if (lex_peek_unichar(0) != ':') {
+                               lex_stuff_pvs(":", 0);
+                               break;
+                       }
+                       lex_read_unichar(0);
+                       c = lex_peek_unichar(0);
+                       if (!my_is_uni_xidfirst(aTHX_ c)) {
+                               lex_stuff_pvs("::", 0);
+                               break;
+                       }
+                       sv_catpvs(sv, "::");
+                       at_substart = TRUE;
+               } else {
+                       break;
+               }
+               at_start = FALSE;
+       }
+
+       return SvCUR(sv) ? sv : NULL;
+}
+
+static SV *my_scan_parens_tail(pTHX_ bool keep_backslash) {
+       I32 c, nesting;
+       SV *sv;
+       line_t start;
+
+       start = CopLINE(PL_curcop);
+
+       sv = sv_2mortal(newSVpvs(""));
+       if (lex_bufutf8()) {
+               SvUTF8_on(sv);
+       }
+
+       nesting = 0;
+       for (;;) {
+               c = lex_read_unichar(0);
+               if (c == EOF) {
+                       CopLINE_set(PL_curcop, start);
+                       return NULL;
+               }
+
+               if (c == '\\') {
+                       c = lex_read_unichar(0);
+                       if (c == EOF) {
+                               CopLINE_set(PL_curcop, start);
+                               return NULL;
+                       }
+                       if (keep_backslash || (c != '(' && c != ')')) {
+                               sv_catpvs(sv, "\\");
+                       }
+               } else if (c == '(') {
+                       nesting++;
+               } else if (c == ')') {
+                       if (!nesting) {
+                               break;
+                       }
+                       nesting--;
+               }
+
+               my_sv_cat_c(aTHX_ sv, c);
+       }
+
+       return sv;
+}
+
+static void my_check_prototype(pTHX_ const SV *declarator, SV *proto) {
+       char *start, *r, *w, *end;
+       STRLEN len;
+
+       /* strip spaces */
+       start = SvPV(proto, len);
+       end = start + len;
+
+       for (w = r = start; r < end; r++) {
+               if (!isSPACE(*r)) {
+                       *w++ = *r;
+               }
+       }
+       *w = '\0';
+       SvCUR_set(proto, w - start);
+       end = w;
+       len = end - start;
+
+       if (!ckWARN(WARN_ILLEGALPROTO)) {
+               return;
+       }
+
+       /* check for bad characters */
+       if (strspn(start, "$@%*;[]&\\_+") != len) {
+               SV *dsv = newSVpvs_flags("", SVs_TEMP);
+               warner(
+                       packWARN(WARN_ILLEGALPROTO),
+                       "Illegal character in prototype for %"SVf" : %s",
+                       SVfARG(declarator),
+                       SvUTF8(proto)
+                               ? sv_uni_display(
+                                       dsv,
+                                       proto,
+                                       len,
+                                       UNI_DISPLAY_ISPRINT
+                               )
+                               : pv_pretty(dsv, start, len, 60, NULL, NULL,
+                                       PERL_PV_ESCAPE_NONASCII
+                               )
+               );
+               return;
+       }
+
+       for (r = start; r < end; r++) {
+               switch (*r) {
+                       default:
+                               warner(
+                                       packWARN(WARN_ILLEGALPROTO),
+                                       "Illegal character in prototype for %"SVf" : %s",
+                                       SVfARG(declarator), r
+                               );
+                               return;
+
+                       case '_':
+                               if (r[1] && !strchr(";@%", *r)) {
+                                       warner(
+                                               packWARN(WARN_ILLEGALPROTO),
+                                               "Illegal character after '_' in prototype for %"SVf" : %s",
+                                               SVfARG(declarator), r
+                                       );
+                                       return;
+                               }
+                               break;
+
+                       case '@':
+                       case '%':
+                               if (r[1]) {
+                                       warner(
+                                               packWARN(WARN_ILLEGALPROTO),
+                                               "prototype after '%c' for %"SVf": %s",
+                                               *r, SVfARG(declarator), r + 1
+                                       );
+                                       return;
+                               }
+                               break;
+
+                       case '\\':
+                               r++;
+                               if (strchr("$@%&*", *r)) {
+                                       break;
+                               }
+                               if (*r == '[') {
+                                       r++;
+                                       for (; r < end && *r != ']'; r++) {
+                                               if (!strchr("$@%&*", *r)) {
+                                                       break;
+                                               }
+                                       }
+                                       if (*r == ']' && r[-1] != '[') {
+                                               break;
+                                       }
+                               }
+                               warner(
+                                       packWARN(WARN_ILLEGALPROTO),
+                                       "Illegal character after '\\' in prototype for %"SVf" : %s",
+                                       SVfARG(declarator), r
+                               );
+                               return;
+
+                       case '$':
+                       case '*':
+                       case '&':
+                       case ';':
+                       case '+':
+                               break;
+               }
+       }
+}
+
 static int parse_fun(pTHX_ OP **pop, const char *keyword_ptr, STRLEN keyword_len, const KWSpec *spec) {
        SV *declarator;
        I32 floor_ix;
        int save_ix;
        SV *saw_name;
+       OP **prelude_sentinel;
+       int did_invocant_decl;
+       SV *invocant;
        AV *params;
        DefaultParamSpec *defaults;
        int args_min, args_max;
@@ -228,7 +452,6 @@ static int parse_fun(pTHX_ OP **pop, const char *keyword_ptr, STRLEN keyword_len
        OP **attrs_sentinel, *body;
        unsigned builtin_attrs;
        STRLEN len;
-       char *s;
        I32 c;
 
        declarator = sv_2mortal(newSVpvn(keyword_ptr, keyword_len));
@@ -239,9 +462,7 @@ static int parse_fun(pTHX_ OP **pop, const char *keyword_ptr, STRLEN keyword_len
 
        /* function name */
        saw_name = NULL;
-       s = PL_parser->bufptr;
-       if ((spec->flags & FLAG_NAME_OK) && (len = S_scan_word(aTHX_ s, TRUE))) {
-               saw_name = sv_2mortal(newSVpvn_flags(s, len, PARSING_UTF ? SVf_UTF8 : 0));
+       if ((spec->flags & FLAG_NAME_OK) && (saw_name = my_scan_word(aTHX_ TRUE))) {
 
                if (PL_parser->expect != XSTATE) {
                        /* bail out early so we don't predeclare $saw_name */
@@ -261,10 +482,9 @@ static int parse_fun(pTHX_ OP **pop, const char *keyword_ptr, STRLEN keyword_len
                        builtin_attrs |= MY_ATTR_SPECIAL;
                }
 
-               lex_read_to(s + len);
                lex_read_space(0);
        } else if (!(spec->flags & FLAG_ANON_OK)) {
-               croak("I was expecting a function name, not \"%.*s\"", (int)(PL_parser->bufend - s), s);
+               croak("I was expecting a function name, not \"%.*s\"", (int)(PL_parser->bufend - PL_parser->bufptr), PL_parser->bufptr);
        } else {
                sv_catpvs(declarator, " (anon)");
        }
@@ -276,7 +496,14 @@ static int parse_fun(pTHX_ OP **pop, const char *keyword_ptr, STRLEN keyword_len
        /* create outer block: '{' */
        save_ix = S_block_start(aTHX_ TRUE);
 
+       /* initialize synthetic optree */
+       Newx(prelude_sentinel, 1, OP *);
+       *prelude_sentinel = NULL;
+       SAVEDESTRUCTOR_X(free_ptr_op, prelude_sentinel);
+
        /* parameters */
+       did_invocant_decl = 0;
+       invocant = NULL;
        params = NULL;
        defaults = NULL;
        args_min = 0;
@@ -306,11 +533,10 @@ static int parse_fun(pTHX_ OP **pop, const char *keyword_ptr, STRLEN keyword_len
                                lex_read_unichar(0);
                                lex_read_space(0);
 
-                               s = PL_parser->bufptr;
-                               if (!(len = S_scan_word(aTHX_ s, FALSE))) {
+                               if (!(param = my_scan_word(aTHX_ FALSE))) {
                                        croak("In %"SVf": missing identifier", SVfARG(declarator));
                                }
-                               param = sv_2mortal(newSVpvf("%c%.*s", sigil, (int)len, s));
+                               sv_insert(param, 0, 0, &sigil, 1);
                                if (saw_slurpy) {
                                        croak("In %"SVf": I was expecting \")\" after \"%"SVf"\", not \"%"SVf"\"", SVfARG(declarator), SVfARG(saw_slurpy), SVfARG(param));
                                }
@@ -320,40 +546,92 @@ static int parse_fun(pTHX_ OP **pop, const char *keyword_ptr, STRLEN keyword_len
                                        args_max = -1;
                                        saw_slurpy = param;
                                }
-                               av_push(params, SvREFCNT_inc_simple_NN(param));
-                               lex_read_to(s + len);
-                               lex_read_space(0);
 
+                               lex_read_space(0);
                                c = lex_peek_unichar(0);
 
-                               if (!(c == '=' && (spec->flags & FLAG_DEFAULT_ARGS))) {
-                                       if (sigil == '$' && !defaults) {
-                                               args_min++;
+                               assert(param_count >= 1);
+
+                               if (c == ':') {
+                                       if (invocant) {
+                                               croak("In %"SVf": invalid double invocants %"SVf", %"SVf"", SVfARG(declarator), SVfARG(invocant), SVfARG(param));
+                                       }
+                                       if (param_count != 1) {
+                                               croak("In %"SVf": invocant %"SVf" must be first in parameter list", SVfARG(declarator), SVfARG(param));
+                                       }
+                                       if (!(spec->flags & FLAG_INVOCANT)) {
+                                               croak("In %"SVf": invocant %"SVf" not allowed here", SVfARG(declarator), SVfARG(param));
+                                       }
+                                       if (sigil != '$') {
+                                               croak("In %"SVf": invocant %"SVf" can't be a %s", SVfARG(declarator), SVfARG(param), sigil == '@' ? "array" : "hash");
                                        }
-                               } else if (sigil != '$') {
-                                       croak("In %"SVf": %s %"SVf" can't have a default value", SVfARG(declarator), sigil == '@' ? "array" : "hash", SVfARG(saw_slurpy));
-                               } else {
-                                       DefaultParamSpec *curdef;
 
                                        lex_read_unichar(0);
                                        lex_read_space(0);
 
-                                       Newx(curdef, 1, DefaultParamSpec);
-                                       curdef->next = NULL;
-                                       curdef->limit = param_count;
-                                       curdef->name = param;
-                                       curdef->init = NULL;
-                                       SAVEDESTRUCTOR_X(free_defspec, curdef);
+                                       args_max--;
+                                       param_count--;
+                                       invocant = param;
+                               } else {
+                                       av_push(params, SvREFCNT_inc_simple_NN(param));
+
+                                       if (c == '=' && (spec->flags & FLAG_DEFAULT_ARGS)) {
+                                               DefaultParamSpec *curdef;
 
-                                       curdef->next = *pdefaults_tail;
-                                       *pdefaults_tail = curdef;
-                                       pdefaults_tail = &curdef->next;
+                                               if (sigil != '$') {
+                                                       croak("In %"SVf": %s %"SVf" can't have a default value", SVfARG(declarator), sigil == '@' ? "array" : "hash", SVfARG(saw_slurpy));
+                                               }
 
-                                       /* let perl parse the default parameter value */
-                                       curdef->init = parse_termexpr(0);
+                                               lex_read_unichar(0);
+                                               lex_read_space(0);
 
-                                       lex_read_space(0);
-                                       c = lex_peek_unichar(0);
+                                               /* my $self;  # in scope for default argument */
+                                               if (!invocant && !did_invocant_decl && SvTRUE(spec->shift)) {
+                                                       OP *var;
+
+                                                       var = newOP(OP_PADSV, OPf_MOD | (OPpLVAL_INTRO << 8));
+                                                       var->op_targ = pad_add_name_sv(spec->shift, 0, NULL, NULL);
+
+                                                       *prelude_sentinel = op_append_list(OP_LINESEQ, *prelude_sentinel, newSTATEOP(0, NULL, var));
+
+                                                       did_invocant_decl = 1;
+                                               }
+
+                                               Newx(curdef, 1, DefaultParamSpec);
+                                               curdef->next = NULL;
+                                               curdef->limit = param_count;
+                                               curdef->name = param;
+                                               curdef->init = NULL;
+                                               SAVEDESTRUCTOR_X(free_defspec, curdef);
+
+                                               curdef->next = *pdefaults_tail;
+                                               *pdefaults_tail = curdef;
+                                               pdefaults_tail = &curdef->next;
+
+                                               /* let perl parse the default parameter value */
+                                               curdef->init = parse_termexpr(0);
+
+                                               lex_read_space(0);
+                                               c = lex_peek_unichar(0);
+                                       } else {
+                                               if (sigil == '$' && !defaults) {
+                                                       args_min++;
+                                               }
+                                       }
+                               }
+
+                               /* my $param; */
+                               {
+                                       OP *var;
+
+                                       var = newOP(OP_PADSV, OPf_MOD | (OPpLVAL_INTRO << 8));
+                                       var->op_targ = pad_add_name_sv(param, 0, NULL, NULL);
+
+                                       *prelude_sentinel = op_append_list(OP_LINESEQ, *prelude_sentinel, newSTATEOP(0, NULL, var));
+                               }
+
+                               if (param_count == 0) {
+                                       continue;
                                }
 
                                if (c == ',') {
@@ -388,11 +666,11 @@ static int parse_fun(pTHX_ OP **pop, const char *keyword_ptr, STRLEN keyword_len
                        lex_stuff_pvs(":", 0);
                        c = ':';
                } else {
-                       proto = sv_2mortal(newSVpvs(""));
-                       if (!S_scan_str(aTHX_ proto, FALSE, FALSE)) {
+                       lex_read_unichar(0);
+                       if (!(proto = my_scan_parens_tail(aTHX_ FALSE))) {
                                croak("In %"SVf": prototype not terminated", SVfARG(declarator));
                        }
-                       S_check_prototype(aTHX_ declarator, proto);
+                       my_check_prototype(aTHX_ declarator, proto);
                        lex_read_space(0);
                        c = lex_peek_unichar(0);
                }
@@ -419,14 +697,10 @@ static int parse_fun(pTHX_ OP **pop, const char *keyword_ptr, STRLEN keyword_len
                        for (;;) {
                                SV *attr;
 
-                               s = PL_parser->bufptr;
-                               if (!(len = S_scan_word(aTHX_ s, FALSE))) {
+                               if (!(attr = my_scan_word(aTHX_ FALSE))) {
                                        break;
                                }
 
-                               attr = sv_2mortal(newSVpvn_flags(s, len, PARSING_UTF ? SVf_UTF8 : 0));
-
-                               lex_read_to(s + len);
                                lex_read_space(0);
                                c = lex_peek_unichar(0);
 
@@ -439,11 +713,14 @@ static int parse_fun(pTHX_ OP **pop, const char *keyword_ptr, STRLEN keyword_len
                                                attr = NULL;
                                        }
                                } else {
-                                       SV *sv = sv_2mortal(newSVpvs(""));
-                                       if (!S_scan_str(aTHX_ sv, TRUE, TRUE)) {
+                                       SV *sv;
+                                       lex_read_unichar(0);
+                                       if (!(sv = my_scan_parens_tail(aTHX_ TRUE))) {
                                                croak("In %"SVf": unterminated attribute parameter in attribute list", SVfARG(declarator));
                                        }
+                                       sv_catpvs(attr, "(");
                                        sv_catsv(attr, sv);
+                                       sv_catpvs(attr, ")");
 
                                        lex_read_space(0);
                                        c = lex_peek_unichar(0);
@@ -485,7 +762,6 @@ static int parse_fun(pTHX_ OP **pop, const char *keyword_ptr, STRLEN keyword_len
                );
        }
 
-
        if (builtin_attrs & MY_ATTR_LVALUE) {
                CvLVALUE_on(PL_compcv);
        }
@@ -496,127 +772,146 @@ static int parse_fun(pTHX_ OP **pop, const char *keyword_ptr, STRLEN keyword_len
                CvSPECIAL_on(PL_compcv);
        }
 
-       /* munge */
-       {
-               OP *prelude = NULL;
+       if (!invocant) {
+               invocant = spec->shift;
+
+               /* my $self;  # wasn't needed yet */
+               if (SvTRUE(invocant) && !did_invocant_decl) {
+                       OP *var;
 
-               /* my $self = shift; */
-               if (SvTRUE(spec->shift)) {
-                       OP *const var = newOP(OP_PADSV, OPf_WANT_SCALAR | (OPpLVAL_INTRO << 8));
-                       var->op_targ = pad_add_name_sv(spec->shift, 0, NULL, NULL);
+                       var = newOP(OP_PADSV, OPf_MOD | (OPpLVAL_INTRO << 8));
+                       var->op_targ = pad_add_name_sv(invocant, 0, NULL, NULL);
 
-                       prelude = newASSIGNOP(OPf_STACKED, var, 0, newOP(OP_SHIFT, 0));
-                       prelude = newSTATEOP(0, NULL, prelude);
+                       *prelude_sentinel = op_append_list(OP_LINESEQ, *prelude_sentinel, newSTATEOP(0, NULL, var));
+               }
+       }
+
+       /* min/max argument count checks */
+       if (spec->flags & FLAG_CHECK_NARGS) {
+               if (SvTRUE(invocant)) {
+                       args_min++;
+                       if (args_max != -1) {
+                               args_max++;
+                       }
                }
 
-               /* min/max argument count checks */
-               if (spec->flags & FLAG_CHECK_NARGS) {
-                       if (args_min > 0) {
-                               OP *chk, *cond, *err, *croak;
+               if (args_min > 0) {
+                       OP *chk, *cond, *err, *croak;
 
-                               err = newSVOP(OP_CONST, 0,
-                                             newSVpvf("Not enough arguments for %"SVf, SVfARG(declarator)));
+                       err = newSVOP(OP_CONST, 0,
+                                     newSVpvf("Not enough arguments for %"SVf, SVfARG(declarator)));
 
-                               croak = newCVREF(OPf_WANT_SCALAR,
-                                                newGVOP(OP_GV, 0, gv_fetchpvs("Carp::croak", 0, SVt_PVCV)));
-                               err = newUNOP(OP_ENTERSUB, OPf_STACKED,
-                                             op_append_elem(OP_LIST, err, croak));
+                       croak = newCVREF(OPf_WANT_SCALAR,
+                                        newGVOP(OP_GV, 0, gv_fetchpvs("Carp::croak", 0, SVt_PVCV)));
+                       err = newUNOP(OP_ENTERSUB, OPf_STACKED,
+                                     op_append_elem(OP_LIST, err, croak));
 
-                               cond = newBINOP(OP_LT, 0,
-                                               newAVREF(newGVOP(OP_GV, 0, PL_defgv)),
-                                               newSVOP(OP_CONST, 0, newSViv(args_min)));
-                               chk = newLOGOP(OP_AND, 0, cond, err);
+                       cond = newBINOP(OP_LT, 0,
+                                       newAVREF(newGVOP(OP_GV, 0, PL_defgv)),
+                                       newSVOP(OP_CONST, 0, newSViv(args_min)));
+                       chk = newLOGOP(OP_AND, 0, cond, err);
 
-                               prelude = op_append_list(OP_LINESEQ, prelude, newSTATEOP(0, NULL, chk));
-                       }
-                       if (args_max != -1) {
-                               OP *chk, *cond, *err, *croak;
+                       *prelude_sentinel = op_append_list(OP_LINESEQ, *prelude_sentinel, newSTATEOP(0, NULL, chk));
+               }
+               if (args_max != -1) {
+                       OP *chk, *cond, *err, *croak;
 
-                               err = newSVOP(OP_CONST, 0,
-                                             newSVpvf("Too many arguments for %"SVf, SVfARG(declarator)));
+                       err = newSVOP(OP_CONST, 0,
+                                     newSVpvf("Too many arguments for %"SVf, SVfARG(declarator)));
 
-                               croak = newCVREF(OPf_WANT_SCALAR,
-                                                newGVOP(OP_GV, 0, gv_fetchpvs("Carp::croak", 0, SVt_PVCV)));
-                               err = newUNOP(OP_ENTERSUB, OPf_STACKED,
-                                             op_append_elem(OP_LIST, err, croak));
+                       croak = newCVREF(OPf_WANT_SCALAR,
+                                        newGVOP(OP_GV, 0, gv_fetchpvs("Carp::croak", 0, SVt_PVCV)));
+                       err = newUNOP(OP_ENTERSUB, OPf_STACKED,
+                                     op_append_elem(OP_LIST, err, croak));
 
-                               cond = newBINOP(OP_GT, 0,
-                                               newAVREF(newGVOP(OP_GV, 0, PL_defgv)),
-                                               newSVOP(OP_CONST, 0, newSViv(args_max)));
-                               chk = newLOGOP(OP_AND, 0, cond, err);
+                       cond = newBINOP(OP_GT, 0,
+                                       newAVREF(newGVOP(OP_GV, 0, PL_defgv)),
+                                       newSVOP(OP_CONST, 0, newSViv(args_max)));
+                       chk = newLOGOP(OP_AND, 0, cond, err);
 
-                               prelude = op_append_list(OP_LINESEQ, prelude, newSTATEOP(0, NULL, chk));
-                       }
+                       *prelude_sentinel = op_append_list(OP_LINESEQ, *prelude_sentinel, newSTATEOP(0, NULL, chk));
                }
+       }
 
-               /* my (PARAMS) = @_; */
-               if (params && av_len(params) > -1) {
-                       SV *param;
-                       OP *init_param, *left, *right;
-
-                       left = NULL;
-                       while ((param = av_shift(params)) != &PL_sv_undef) {
-                               OP *const var = newOP(OP_PADSV, OPf_WANT_LIST | (OPpLVAL_INTRO << 8));
-                               var->op_targ = pad_add_name_sv(param, 0, NULL, NULL);
-                               SvREFCNT_dec(param);
-                               left = op_append_elem(OP_LIST, left, var);
-                       }
+       /* $self = shift; */
+       if (SvTRUE(invocant)) {
+               OP *var, *shift;
+
+               var = newOP(OP_PADSV, OPf_WANT_SCALAR);
+               var->op_targ = pad_findmy_sv(invocant, 0);
 
-                       left->op_flags |= OPf_PARENS;
-                       right = newAVREF(newGVOP(OP_GV, 0, PL_defgv));
-                       init_param = newASSIGNOP(OPf_STACKED, left, 0, right);
-                       init_param = newSTATEOP(0, NULL, init_param);
+               shift = newASSIGNOP(OPf_STACKED, var, 0, newOP(OP_SHIFT, 0));
+               *prelude_sentinel = op_append_list(OP_LINESEQ, *prelude_sentinel, newSTATEOP(0, NULL, shift));
+       }
 
-                       prelude = op_append_list(OP_LINESEQ, prelude, init_param);
+       /* (PARAMS) = @_; */
+       if (params && av_len(params) > -1) {
+               SV *param;
+               OP *init_param, *left, *right;
+
+               left = NULL;
+               while ((param = av_shift(params)) != &PL_sv_undef) {
+                       OP *const var = newOP(OP_PADSV, OPf_WANT_LIST);
+                       var->op_targ = pad_findmy_sv(param, 0);
+                       SvREFCNT_dec(param);
+                       left = op_append_elem(OP_LIST, left, var);
                }
 
-               /* defaults */
-               {
-                       OP *gen = NULL;
-                       DefaultParamSpec *dp;
+               left->op_flags |= OPf_PARENS;
+               right = newAVREF(newGVOP(OP_GV, 0, PL_defgv));
+               init_param = newASSIGNOP(OPf_STACKED, left, 0, right);
+               init_param = newSTATEOP(0, NULL, init_param);
 
-                       for (dp = defaults; dp; dp = dp->next) {
-                               OP *init = dp->init;
-                               OP *var, *args, *cond;
+               *prelude_sentinel = op_append_list(OP_LINESEQ, *prelude_sentinel, init_param);
+       }
 
-                               /* var = `$,name */
-                               var = newOP(OP_PADSV, 0);
-                               var->op_targ = pad_findmy_sv(dp->name, 0);
+       /* defaults */
+       {
+               OP *gen = NULL;
+               DefaultParamSpec *dp;
 
-                               /* init = `,var = ,init */
-                               init = newASSIGNOP(OPf_STACKED, var, 0, init);
+               for (dp = defaults; dp; dp = dp->next) {
+                       OP *init = dp->init;
+                       OP *var, *args, *cond;
 
-                               /* args = `@_ */
-                               args = newAVREF(newGVOP(OP_GV, 0, PL_defgv));
+                       /* var = `$,name */
+                       var = newOP(OP_PADSV, 0);
+                       var->op_targ = pad_findmy_sv(dp->name, 0);
 
-                               /* cond = `,args < ,index */
-                               cond = newBINOP(OP_LT, 0, args, newSVOP(OP_CONST, 0, newSViv(dp->limit)));
+                       /* init = `,var = ,init */
+                       init = newASSIGNOP(OPf_STACKED, var, 0, init);
 
-                               /* init = `,init if ,cond */
-                               init = newLOGOP(OP_AND, 0, cond, init);
+                       /* args = `@_ */
+                       args = newAVREF(newGVOP(OP_GV, 0, PL_defgv));
 
-                               /* gen = `,gen ; ,init */
-                               gen = op_append_list(OP_LINESEQ, gen, newSTATEOP(0, NULL, init));
+                       /* cond = `,args < ,index */
+                       cond = newBINOP(OP_LT, 0, args, newSVOP(OP_CONST, 0, newSViv(dp->limit)));
 
-                               dp->init = NULL;
-                       }
+                       /* init = `,init if ,cond */
+                       init = newLOGOP(OP_AND, 0, cond, init);
 
-                       prelude = op_append_list(OP_LINESEQ, prelude, gen);
+                       /* gen = `,gen ; ,init */
+                       gen = op_append_list(OP_LINESEQ, gen, newSTATEOP(0, NULL, init));
+
+                       dp->init = NULL;
                }
 
-               /* finally let perl parse the actual subroutine body */
-               body = parse_block(0);
+               *prelude_sentinel = op_append_list(OP_LINESEQ, *prelude_sentinel, gen);
+       }
 
-               /* add '();' to make function return nothing by default */
-               /* (otherwise the invisible parameter initialization can "leak" into
-                  the return value: fun ($x) {}->("asdf", 0) == 2) */
-               if (prelude) {
-                       body = newSTATEOP(0, NULL, body);
-               }
+       /* finally let perl parse the actual subroutine body */
+       body = parse_block(0);
 
-               body = op_append_list(OP_LINESEQ, prelude, body);
+       /* add '();' to make function return nothing by default */
+       /* (otherwise the invisible parameter initialization can "leak" into
+          the return value: fun ($x) {}->("asdf", 0) == 2) */
+       if (*prelude_sentinel) {
+               body = newSTATEOP(0, NULL, body);
        }
 
+       body = op_append_list(OP_LINESEQ, *prelude_sentinel, body);
+       *prelude_sentinel = NULL;
+
        /* it's go time. */
        {
                OP *const attrs = *attrs_sentinel;
@@ -643,7 +938,7 @@ static int parse_fun(pTHX_ OP **pop, const char *keyword_ptr, STRLEN keyword_len
                        attrs,
                        body
                );
-               *pop = NULL;
+               *pop = newOP(OP_NULL, 0);
                return KEYWORD_PLUGIN_STMT;
        }
 }
@@ -674,14 +969,15 @@ BOOT:
 WARNINGS_ENABLE {
        HV *const stash = gv_stashpvs(MY_PKG, GV_ADD);
        /**/
-       newCONSTSUB(stash, "FLAG_NAME_OK", newSViv(FLAG_NAME_OK));
-       newCONSTSUB(stash, "FLAG_ANON_OK", newSViv(FLAG_ANON_OK));
+       newCONSTSUB(stash, "FLAG_NAME_OK",      newSViv(FLAG_NAME_OK));
+       newCONSTSUB(stash, "FLAG_ANON_OK",      newSViv(FLAG_ANON_OK));
        newCONSTSUB(stash, "FLAG_DEFAULT_ARGS", newSViv(FLAG_DEFAULT_ARGS));
-       newCONSTSUB(stash, "FLAG_CHECK_NARGS", newSViv(FLAG_CHECK_NARGS));
+       newCONSTSUB(stash, "FLAG_CHECK_NARGS",  newSViv(FLAG_CHECK_NARGS));
+       newCONSTSUB(stash, "FLAG_INVOCANT",     newSViv(FLAG_INVOCANT));
        newCONSTSUB(stash, "HINTK_KEYWORDS", newSVpvs(HINTK_KEYWORDS));
-       newCONSTSUB(stash, "HINTK_FLAGS_", newSVpvs(HINTK_FLAGS_));
-       newCONSTSUB(stash, "HINTK_SHIFT_", newSVpvs(HINTK_SHIFT_));
-       newCONSTSUB(stash, "HINTK_ATTRS_", newSVpvs(HINTK_ATTRS_));
+       newCONSTSUB(stash, "HINTK_FLAGS_",   newSVpvs(HINTK_FLAGS_));
+       newCONSTSUB(stash, "HINTK_SHIFT_",   newSVpvs(HINTK_SHIFT_));
+       newCONSTSUB(stash, "HINTK_ATTRS_",   newSVpvs(HINTK_ATTRS_));
        /**/
        next_keyword_plugin = PL_keyword_plugin;
        PL_keyword_plugin = my_keyword_plugin;