compile.c

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#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <ctype.h>
#include "p2.h"
#include "internal.h"
#include "ast.h"
#include "opcodes.h"
#include "asm.h"
#ifdef WITH_EXTERN
#include <dlfcn.h>
#endif

#define PN_ASM1(ins, _a)     f->asmb = (PN)potion_asm_op(P, (PNAsm *)f->asmb, (u8)ins, (int)_a, 0)
#define PN_ASM2(ins, _a, _b) f->asmb = (PN)potion_asm_op(P, (PNAsm *)f->asmb, (u8)ins, (int)_a, (int)_b)

const struct {
  const char *name;
  const u8 args;
} potion_ops[] = {
  {"noop", 0}, {"move", 2}, {"loadk", 2}, {"loadpn", 2}, {"self", 1},
  {"newtuple", 2}, {"gettuple", 2}, {"settuple", 2}, {"getlocal", 2}, {"setlocal", 2},
  {"getupval", 2}, {"setupval", 2}, {"global", 2}, {"gettable", 2},
  {"settable", 2}, {"newlick", 2}, {"getpath", 2}, {"setpath", 2},
  {"add", 2}, {"sub", 2}, {"mult", 2}, {"div", 2}, {"mod", 2}, {"pow", 2},
  {"not", 1}, {"cmp", 2}, {"eq", 2}, {"neq", 2}, {"lt", 2}, {"lte", 2},
  {"gt", 2}, {"gte", 2}, {"bitn", 2}, {"bitl", 2}, {"bitr", 2}, {"def", 2},
  {"bind", 2}, {"msg", 2}, {"jump", 1}, {"test", 2}, {"testjmp", 2},
  {"notjmp", 2}, {"named", 2}, {"call", 2}, {"callset", 2}, {"tailcall", 2},
  {"return", 1}, {"proto", 2}, {"class", 2}, {"debug", 2}
};

PN potion_proto_tree(Potion *P, PN cl, PN self) {
  return PN_PROTO(self)->tree;
}

PN potion_proto_call(Potion *P, PN cl, PN self, PN args) {
  return potion_vm(P, self, P->lobby, args, 0, NULL);
}

PN potion_sig_string(Potion *P, PN cl, PN sig) {
  PN out = potion_byte_str(P, "");
  if (PN_IS_TUPLE(sig)) {
    int nextdef = 0;
    struct PNTuple * volatile t = ((struct PNTuple *)potion_fwd(sig));
    if (t->len != 0) {
      PN_SIZE i, comma=0;
      for (i = 0; i < t->len; i++) {
    PN v = (PN)t->set[i];
    if (PN_IS_INT(v)) {
          // currently types are still encoded as NUM, TODO: support VTABLE also
      int c = PN_INT(v); comma=0;
      if (c == '.')      // is end
        pn_printf(P, out, ".");
      else if (c == '|') // is optional
        pn_printf(P, out, "|");
      else if (c == ':') { nextdef = 1;
        pn_printf(P, out, ":"); // is default
      }
      else {
        if (comma++) pn_printf(P, out, ",");
        if (nextdef) { nextdef = 0;
          pn_printf(P, out, "=");
          potion_bytes_obj_string(P, out, v);
        } else
          pn_printf(P, out, "=%c", c);
      }
    } else {
      if (comma++) pn_printf(P, out, ",");
      if (nextdef)
        { nextdef = 0; pn_printf(P, out, "="); }
      potion_bytes_obj_string(P, out, v);
    }}}}
  return PN_STR_B(out);
}

PN potion_proto_string(Potion *P, PN cl, PN self) {
  vPN(Proto) t = (struct PNProto *)self;
  int x = 0;
  PN_SIZE num = 1;
  PN_SIZE numcols;
  PN out = potion_byte_str(P, "; function definition");
  #ifdef JIT_DEBUG
  pn_printf(P, out, ": %p; %u bytes\n", t, PN_FLEX_SIZE(t->asmb));
  #else
  pn_printf(P, out, ": %u bytes\n", PN_FLEX_SIZE(t->asmb));
  #endif
  if (t->name)
    pn_printf(P, out, "; %s(", PN_STR_PTR(t->name));
  else
    pn_printf(P, out, "; (");
  potion_bytes_obj_string(P, out, potion_sig_string(P, cl, t->sig));
  pn_printf(P, out, ") %ld registers\n", PN_INT(t->stack));
  PN_TUPLE_EACH(t->paths, i, v, {
    pn_printf(P, out, ".path /");
    v = PN_TUPLE_AT(t->values, PN_INT(v));
    potion_bytes_obj_string(P, out, v);
    pn_printf(P, out, " ; %u\n", i);
  });
  PN_TUPLE_EACH(t->locals, i, v, {
    pn_printf(P, out, ".local ");
    potion_bytes_obj_string(P, out, v);
    pn_printf(P, out, " ; %u\n", i);
  });
  PN_TUPLE_EACH(t->upvals, i, v, {
    pn_printf(P, out, ".upval ");
    potion_bytes_obj_string(P, out, v);
    pn_printf(P, out, " ; %u\n", i);
  });
  PN_TUPLE_EACH(t->values, i, v, {
    pn_printf(P, out, ".value ");
    potion_bytes_obj_string(P, out, v);
    pn_printf(P, out, " ; %u\n", i);
  });
  PN_TUPLE_EACH(t->protos, i, v, {
    potion_bytes_obj_string(P, out, v);
  });
  numcols = (int)ceil(log10(PN_FLEX_SIZE(t->asmb) / sizeof(PN_OP)));
  for (x = 0; x < PN_FLEX_SIZE(t->asmb) / sizeof(PN_OP); x++) {
    const int commentoffset = 20;
    int width = pn_printf(P, out, "[%*u] %-8s %d",
      numcols, num, potion_ops[PN_OP_AT(t->asmb, x).code].name, PN_OP_AT(t->asmb, x).a);

    if (potion_ops[PN_OP_AT(t->asmb, x).code].args > 1)
      width += pn_printf(P, out, " %d", PN_OP_AT(t->asmb, x).b);

    if (width < commentoffset)
      pn_printf(P, out, "%*s", commentoffset - width, "");
    else
      pn_printf(P, out, " ");

    // TODO: Byte code listing: instead of using tabs, pad with spaces to make everything line up
    switch (PN_OP_AT(t->asmb, x).code) {
      case OP_JMP:
        pn_printf(P, out, "; to %d", num + PN_OP_AT(t->asmb, x).a + 1);
        break;
      case OP_NOTJMP:
      case OP_TESTJMP:
        pn_printf(P, out, "; to %d", num + PN_OP_AT(t->asmb, x).b + 1);
        break;
      case OP_LOADPN:
        pn_printf(P, out, "; ");
        potion_bytes_obj_string(P, out, PN_OP_AT(t->asmb, x).b);
        break;
      case OP_LOADK:
        pn_printf(P, out, "; ");
        potion_bytes_obj_string(P, out, PN_TUPLE_AT(t->values, PN_OP_AT(t->asmb, x).b));
        break;
      case OP_SETLOCAL:
      case OP_GETLOCAL:
        pn_printf(P, out, "; ");
        potion_bytes_obj_string(P, out, PN_TUPLE_AT(t->locals, PN_OP_AT(t->asmb, x).b));
        break;
    }
    pn_printf(P, out, "\n");
    num++;
  }
  //pn_printf(P, out, "\n");
  pn_printf(P, out, "; function end\n");
  return PN_STR_B(out);
}

#define PN_REG(f, reg) \
  if (reg >= PN_INT(f->stack)) \
    f->stack = PN_NUM(reg + 1)
#ifdef P2XXX
// uses global PN_SRC(t)
#define PN_ARG(n, reg) \
  if (PN_PART(t->a[n]) == AST_LIST && PN_PART(PN_TUPLE_AT(PN_S(t->a[n],0), 0)) == AST_EXPR) { \
    PN test = PN_S(PN_TUPLE_AT(PN_S(t->a[n],0), 0), 0);         \
    if (!PN_IS_NIL(test)) {                     \
      DBG_c("list (expr %s) => %s\n", AS_STR(test), AS_STR(test));  \
      PN_TUPLE_EACH(test, i, v, {                   \
      potion_source_asmb(P, f, loop, 0, PN_SRC(v), reg); });    \
    }                                   \
  } else {                              \
    potion_source_asmb(P, f, loop, 0, t->a[n], reg);            \
  }
#else
#define PN_ARG(n, reg) \
  if (PN_PART(t->a[n]) == AST_EXPR && PN_PART(PN_TUPLE_AT(PN_S(t->a[n],0), 0)) == AST_LIST) { \
    PN test = PN_S(PN_TUPLE_AT(PN_S(t->a[n],0), 0), 0);         \
    if (!PN_IS_NIL(test)) {                     \
      DBG_c("expr (list %s) => %s\n", AS_STR(test), AS_STR(test));  \
      PN_TUPLE_EACH(test, i, v, {                   \
      potion_source_asmb(P, f, loop, 0, PN_SRC(v), reg); });    \
    }                                   \
  } else {                              \
    potion_source_asmb(P, f, loop, 0, t->a[n], reg);            \
  }
#endif
#define PN_BLOCK(reg, blk, sig) ({ \
  PN block = potion_send(blk, PN_compile, (PN)f, sig); \
  PN_SIZE num = PN_PUT(f->protos, block); \
  DBG_c("protos => %u\n", num); \
  PN_ASM2(OP_PROTO, reg, num); \
  PN_TUPLE_EACH(((struct PNProto *)block)->upvals, i, v, { \
    PN_SIZE numup = PN_GET(f->upvals, v); \
    DBG_c("upvals %s <= %d\n", AS_STR(v), (int)numup); \
    if (numup != PN_NONE) PN_ASM2(OP_GETUPVAL, reg, numup); \
    else                  PN_ASM2(OP_GETLOCAL, reg, PN_GET(f->locals, v)); \
  }); \
})
#define PN_UPVAL(name) ({ \
  PN_SIZE numl = PN_GET(f->locals, name); \
  DBG_c("locals %s <= %d\n", AS_STR(name), (int)numl); \
  PN_SIZE numup = PN_NONE; \
  if (numl == PN_NONE) { \
    numup = PN_GET(f->upvals, name); \
    if (numup == PN_NONE) { \
      DBG_c("upvals %s <= -1\n", AS_STR(name)); \
      vPN(Proto) up = f; \
      int depth = 1; \
      while (PN_IS_PROTO(up->source)) { \
        up = (struct PNProto *)up->source; \
        if (PN_NONE != (numup = PN_GET(up->locals, name))) break; \
        depth++; \
      } \
      DBG_c("locals %s <= %d\n", AS_STR(name), (int)numup); \
      if (numup != PN_NONE) { \
        up = f; \
        while (depth--) { \
          up->upvals = PN_PUSH(up->upvals, name); \
      DBG_c("upvals %s =>\n", AS_STR(name)); \
          up = (struct PNProto *)up->source; \
        } \
      } \
      numup = PN_GET(f->upvals, name); \
      DBG_c("upvals %s <= %d\n", AS_STR(name), (int)numup); \
    } \
  } \
  numup; \
})
#define PN_ARG_TABLE(args, reg, inc) potion_arg_asmb(P, f, loop, args, &reg, inc)
#define SRC_TUPLE_AT(src,i)  PN_SRC(PN_TUPLE_AT(PN_S(src,0), i))
#define PN_ASM_DEBUG(REG, T) REG = potion_source_debug(P, f, T, REG)

u8 potion_source_debug(Potion *P, struct PNProto * volatile f, struct PNSource * volatile t, u8 reg) {
  static PNType lineno = 0;
  if ((P->flags & EXEC_DEBUG) && t && t->loc.lineno != lineno && t->loc.lineno > 0) {
    PN_SIZE num = PN_PUT(f->debugs, (PN)t);
    PN_ASM2(OP_DEBUG, reg, num);
    lineno = t->loc.lineno;
    DBG_c("debug %s :%d\n", PN_STR_PTR(potion_send(t, PN_name)), lineno);
  }
  return reg;
}

#define MAX_JUMPS 1024
struct PNLoop {
  int bjmps[MAX_JUMPS];
  int cjmps[MAX_JUMPS];

  int bjmpc;  
  int cjmpc;  
};

void potion_source_asmb(Potion *, struct PNProto * volatile, struct PNLoop *, PN_SIZE, struct PNSource * volatile, u8);

void potion_arg_asmb(Potion *P, struct PNProto * volatile f, struct PNLoop *loop, PN args, u8 *reg, int inc) {
  if (args != PN_NIL) {
    if (PN_PART(args) == AST_LIST) {
      args = PN_S(args,0);
      if (!PN_IS_NIL(args)) {
        u8 freg = *reg, sreg = *reg + PN_TUPLE_LEN(args) + 1;
    DBG_c("ARGLIST %d %d\n", freg, sreg);
        PN_TUPLE_EACH(args, i, v, {
          if (inc) {
            (*reg)++;
            if (PN_PART(v) == AST_ASSIGN) {
              vPN(Source) lhs = PN_SRC(PN_S(v,0));
          potion_source_asmb(P, f, loop, 0, PN_SRC(v)->a[1], sreg + 1);
              if (lhs->part == AST_EXPR && PN_TUPLE_LEN(PN_S(lhs,0)) == 1)
              {
                lhs = SRC_TUPLE_AT(lhs, 0);
        PN_ASM_DEBUG(sreg, lhs);
                if (lhs->part == AST_MSG || lhs->part == AST_VALUE) {
                  PN_OP op; op.a = PN_S(lhs,0); //12 bit!
                  if (!PN_IS_PTR(PN_S(lhs,0)) && PN_S(lhs,0) == op.a) {
                    PN_ASM2(OP_LOADPN, sreg, PN_S(lhs,0));
                  } else {
                    PN_SIZE num = PN_PUT(f->values, PN_S(lhs,0));
                    DBG_c("values %d %s => %d\n", sreg, AS_STR(lhs->a[0]), (int)num);
                    PN_ASM2(OP_LOADK, sreg, num);
                  }
                  lhs = NULL;
                }
              }

              if (lhs != NULL)
                potion_source_asmb(P, f, loop, 0, lhs, sreg);

              PN_ASM2(OP_NAMED, freg - 1, sreg + 1);
              PN_REG(f, sreg + 1);
            } else
              potion_source_asmb(P, f, loop, 0, PN_SRC(v), *reg);
          } else
            potion_source_asmb(P, f, loop, 0, PN_SRC(v), *reg);
        });
      }
    } else {
      if (inc) (*reg)++;
      potion_source_asmb(P, f, loop, 0, PN_SRC(args), *reg);
    }
  } else {
    if (inc) (*reg)++;
    PN_ASM_DEBUG(*reg, PN_SRC(args));
    PN_ASM2(OP_LOADPN, *reg, args);
  }
}

void potion_source_asmb(Potion *P, struct PNProto * volatile f, struct PNLoop *loop, PN_SIZE count,
                        struct PNSource * volatile t, u8 reg) {
  //PN fname = 0;
  PN_REG(f, reg);
  PN_ASM_DEBUG(reg, t);
  switch (t->part) {
    case AST_CODE:
    case AST_BLOCK:
      if (PN_S(t,0) != PN_NIL) {
        DBG_c("%s %u %s\n", t->part == AST_CODE?"code":"block", reg,
          t->part == AST_CODE?"":AS_STR(PN_S(t,0)));
        PN_TUPLE_EACH(PN_S(t,0), i, v, {
          potion_source_asmb(P, f, loop, 0, PN_SRC(v), reg);
        });
      }
    break;

    case AST_EXPR:
      if (PN_S(t,0) != PN_NIL) {
    PN e = PN_S(t,0);
        DBG_c("expr %u %s\n", reg, AS_STR(e));
        PN_TUPLE_EACH(e, i, v, {
      potion_source_asmb(P, f, loop, i, PN_SRC(v), reg);
        });
      }
    break;

    case AST_PROTO:
      PN_BLOCK(reg, PN_S(t,1), PN_S(t,0));
    break;

    case AST_VALUE: {
      vPN(Source) a = PN_S_(t,0);
      PN_OP op; op.a = PN_S(t,0); // but 12bit only
      if (!PN_IS_PTR(a) && (PN)a == (PN)op.a) {
        PN_ASM2(OP_LOADPN, reg, PN_S(t,0));
      } else if (a != PN_NIL && PN_IS_PTR(a)
                 && PN_PART(a) == AST_LICK && PN_PART(a->a[0]) == AST_MSG) {
        vPN(Source) msg = a->a[0];
        PN tpl = PN_S(msg, 0);
        // locals or upvals. locals alone broke nbody
        PN_SIZE num = PN_UPVAL(tpl);
        u8 opcode =  OP_GETUPVAL;
        PN key = PN_S(PN_TUPLE_AT(a->a[1]->a[0], 0), 0);
        if (num == PN_NONE) {
          num = PN_PUT(f->locals, tpl);
          DBG_c("locals %s => %d\n", AS_STR(tpl), (int)num);
          opcode = OP_GETLOCAL;
        }
        PN_ASM2(opcode, reg, num);
        if (PN_VTYPE(key) == PN_TSTRING) { // a[k] a variable
          num = PN_PUT(f->locals, key);
          DBG_c("locals %s => %d\n", PN_STR_PTR(key), (int)num);
          PN_ASM2(OP_GETLOCAL, reg+1, num);
          num = reg+1;
          DBG_c("gettuple %d %d %s[%s]\n", reg, num, PN_STR_PTR(tpl), PN_STR_PTR(key));
          PN_ASM2(OP_GETTUPLE, reg, num | ASM_TPL_IMM);
          PN_REG(f, reg + 1);
        } else { // a[0] constant, could to be optimized in jit
          assert(PN_VTYPE(key) == PN_TSOURCE && PN_PART(key) == AST_VALUE);
          PN k = PN_S(key, 0);
          if (PN_IS_INT(k)) {
            if (PN_INT(k) >= ASM_TPL_IMM || PN_INT(k) < 0) {
              num = PN_PUT(f->values, k);
              PN_ASM2(OP_LOADK, reg+1, num);
              DBG_c("values %ld => %d\n", PN_INT(k), (int)num);
              num = reg + 1;
              PN_REG(f, reg + 1);
            } else {
              num = PN_INT(k);
            }
            DBG_c("gettuple %d %d %s[%ld]\n", reg, num, PN_STR_PTR(tpl), PN_INT(k));
            PN_ASM2(OP_GETTUPLE, reg, num);
          } else {
            num = PN_PUT(f->values, k); // op.b has 12 bits
            PN_ASM2(OP_LOADK, reg+1, num);
            DBG_c("values \"%s\" => %d\n", PN_STR_PTR(k), (int)num);
            num = reg+1;
            DBG_c("gettable %d %d %s[\"%s\"]\n", reg, num, PN_STR_PTR(tpl), PN_STR_PTR(k));
            PN_ASM2(OP_GETTABLE, reg, num);
            PN_REG(f, reg + 1);
          }
        }
      } else {
        PN_SIZE num = PN_PUT(f->values, (PN)a);
    DBG_c("values %d %s => %d\n", reg, AS_STR(a), (int)num);
        PN_ASM2(OP_LOADK, reg, num);
      }
      if (PN_S(t,1) != PN_NIL && a->part != AST_LICK) {
        u8 breg = reg;
        PN_ASM1(OP_SELF, ++breg);
        PN_ARG_TABLE(PN_S(t,1), breg, 1);
        if (PN_S(t,2) != PN_NIL) {
          breg++;
          PN_BLOCK(breg, PN_S(t,2), PN_NIL);
        }
        DBG_c("; call %d %d VALUE\n", reg, breg);
        PN_ASM2(OP_CALL, reg, breg);
      }
    }
    break;

    case AST_ASSIGN: {
      vPN(Source) lhs = t->a[0];
      PN_SIZE num = PN_NONE, c = count;
      u8 opcode = OP_GETUPVAL, breg = reg;

      if (lhs->part == AST_EXPR) {
        unsigned long i = 0;
        c = PN_TUPLE_LEN(PN_S(lhs,0)) - 1;
        DBG_c("assign expr [%lu]\n", (_PN)c);
        for (i = 0; i < c; i++) {
          potion_source_asmb(P, f, loop, i, SRC_TUPLE_AT(lhs, i), reg);
        };
        lhs = SRC_TUPLE_AT(lhs, c);
    PN_ASM_DEBUG(reg, lhs);
      }

      if (lhs->part == AST_MSG || lhs->part == AST_QUERY) {
#ifndef P2
        char first_letter = PN_STR_PTR(PN_S(lhs,0))[0];
#endif
    DBG_c("assign %s '%s'\n", lhs->part == AST_MSG?"msg":"query",
          AS_STR(PN_S(lhs,0)));
    /* globals are different in potion and p2 */
#ifndef P2
        if ((first_letter & 0x80) == 0 && isupper((unsigned char)first_letter)) {
          num = PN_PUT(f->values, PN_S(lhs,0));
      DBG_c("values %d %s => %d\n", breg, AS_STR(lhs->a[0]), (int)num);
          PN_ASM2(OP_LOADK, breg, num);
          opcode = OP_GLOBAL;
          num = ++breg;
        } else
#endif
    if (c == 0) {
          num = PN_UPVAL(PN_S(lhs,0));
          if (num == PN_NONE) {
            num = PN_PUT(f->locals, PN_S(lhs,0));
        DBG_c("locals %s => %d\n", AS_STR(lhs->a[0]), (int)num);
            opcode = OP_GETLOCAL;
#if 0 // store func names
        if (lhs->part == AST_MSG) {
          PN rhs = PN_TUPLE_AT(f->locals, num);
          PN fname = PN_S(lhs,0);
          DBG_c("getlocal %s %ld = %s\n",
                PN_STR_PTR(fname), PN_INT(num), AS_STR(rhs));
            }
#endif
          }
        } else {
          num = PN_PUT(f->values, PN_S(lhs,0));
      DBG_c("values %d %s => %d\n", breg+1, AS_STR(lhs->a[0]), (int)num);
          PN_ASM2(OP_LOADK, ++breg, num);
          opcode = OP_DEF;
          num = ++breg;
        }
      } else if (lhs->part == AST_PATH || lhs->part == AST_PATHQ) {
        DBG_c("assign %s\n", lhs->part == AST_PATH?"path":"pathq");
        num = PN_PUT(f->values, PN_S(lhs,0));
    DBG_c("values %d %s => %d\n", breg+1, AS_STR(lhs->a[0]), (int)num);
        if (c == 0) {
          PN_PUT(f->paths, PN_NUM(num));
      DBG_c("paths %d\n", (int)num);
          PN_ASM1(OP_SELF, reg);
        }
        PN_ASM2(OP_LOADK, ++breg, num);
        opcode = OP_GETPATH;
        num = ++breg;
      }

      if (num == PN_NONE)
        potion_syntax_error(P, t, "Assignment to illegal variable");
      else if (lhs->a[1] != PN_NIL) {
        breg = reg;
        PN_ASM2(opcode, ++breg, num);
        DBG_c("; callset %d %d ASSIGN\n", reg, breg);
        PN_ASM2(OP_CALLSET, reg, breg);
        PN_ARG_TABLE(PN_S(lhs,1), breg, 1);
        // TODO: no block allowed here?
        potion_source_asmb(P, f, loop, 0, t->a[1], ++breg);
        DBG_c("; call %d %d ASSIGN\n", reg, breg);
        PN_ASM2(OP_CALL, reg, breg);
      } else {
        potion_source_asmb(P, f, loop, 0, t->a[1], breg);
        if (opcode == OP_GETUPVAL) {
          if (lhs->part == AST_QUERY) {
            PN_ASM2(OP_GETUPVAL, breg, num);
            PN_ASM2(OP_TESTJMP, breg, 1);
          }
          PN_ASM2(OP_SETUPVAL, reg, num);
        } else if (opcode == OP_GETLOCAL) {
          if (lhs->part == AST_QUERY) {
            PN_ASM2(OP_GETLOCAL, breg, num);
            PN_ASM2(OP_TESTJMP, breg, 1);
          } else {
            DBG_c("setlocal %d %d\n", reg, (int)num);
            PN_ASM2(OP_SETLOCAL, reg, num);
          }
        } else if (opcode == OP_GETPATH) {
          if (lhs->part == AST_PATHQ) {
            PN_ASM2(OP_GETPATH, reg, num);
            PN_ASM2(OP_TESTJMP, reg, 1);
          }
          PN_ASM2(OP_SETPATH, reg, num);
        } else {
          PN_ASM2(opcode, reg, num);
        }
      }
      PN_REG(f, breg);
    }
    break;

    case AST_INC: {
      u8 breg = reg;
      vPN(Source) lhs = t->a[0];
      PN_SIZE num = PN_UPVAL(PN_S(lhs,0));
      u8 opcode = OP_SETUPVAL;
      if (num == PN_NONE) {
        num = PN_PUT(f->locals, PN_S(lhs,0));
    DBG_c("locals %s => %d\n", AS_STR(lhs->a[0]), (int)num);
        opcode = OP_SETLOCAL;
      }

      if (opcode == OP_SETUPVAL)
        PN_ASM2(OP_GETUPVAL, reg, num);
       else if (opcode == OP_SETLOCAL)
        PN_ASM2(OP_GETLOCAL, reg, num);
      if (PN_IS_INT(PN_S(t,1))) {
        breg++;
        PN_ASM2(OP_MOVE, breg, reg);
      }
      PN_ASM2(OP_LOADPN, breg + 1, (PN_S(t,1) | PN_FINTEGER));
      PN_ASM2(OP_ADD, breg, breg + 1);
      PN_ASM2(opcode, breg, num);
      PN_REG(f, breg + 1);
    }
    break;

    case AST_CMP: case AST_EQ: case AST_NEQ:
    case AST_GT: case AST_GTE: case AST_LT: case AST_LTE:
    case AST_PLUS: case AST_MINUS: case AST_TIMES: case AST_DIV:
    case AST_REM:  case AST_POW:   case AST_BITL:  case AST_BITR: {
      PN_ARG(0, reg);
      PN_ARG(1, reg + 1);
      switch (t->part) {
        case AST_CMP:   PN_ASM2(OP_CMP, reg, reg + 1);  break;
        case AST_EQ:    PN_ASM2(OP_EQ,  reg, reg + 1);  break;
        case AST_NEQ:   PN_ASM2(OP_NEQ, reg, reg + 1);  break;
        case AST_GTE:   PN_ASM2(OP_GTE, reg, reg + 1);  break;
        case AST_GT:    PN_ASM2(OP_GT, reg, reg + 1);   break;
        case AST_LT:    PN_ASM2(OP_LT, reg, reg + 1);   break;
        case AST_LTE:   PN_ASM2(OP_LTE, reg, reg + 1);  break;
        case AST_PLUS:  PN_ASM2(OP_ADD, reg, reg + 1);  break;
        case AST_MINUS: PN_ASM2(OP_SUB, reg, reg + 1);  break;
        case AST_TIMES: PN_ASM2(OP_MULT, reg, reg + 1); break;
        case AST_DIV:   PN_ASM2(OP_DIV, reg, reg + 1);  break;
        case AST_REM:   PN_ASM2(OP_REM, reg, reg + 1);  break;
        case AST_POW:   PN_ASM2(OP_POW, reg, reg + 1);  break;
        case AST_BITL:  PN_ASM2(OP_BITL, reg, reg + 1); break;
        case AST_BITR:  PN_ASM2(OP_BITR, reg, reg + 1); break;
      }
    }
    break;

    case AST_NOT: case AST_WAVY:
      PN_ARG(0, reg);
      PN_ASM2(t->part == AST_WAVY ? OP_BITN : OP_NOT, reg, reg);
    break;

    case AST_AND: case AST_OR: {
      int jmp;
      PN_ARG(0, reg);
      jmp = PN_OP_LEN(f->asmb);
      PN_ASM2(t->part == AST_AND ? OP_NOTJMP : OP_TESTJMP, reg, 0);
      PN_ARG(1, reg);
      PN_OP_AT(f->asmb, jmp).b = (PN_OP_LEN(f->asmb) - jmp) - 1;
    }
    break;

    // TODO: this stuff is ugly and repetitive. replace by compiler macros for control structures
    case AST_MSG:
    case AST_QUERY: {
      u8 breg = reg;
      int arg = (PN_S(t,1) != PN_NIL);
      int call = (PN_S(t,2) != PN_NIL || arg);
      PN ifconst = PN_NONE;
#ifdef P2
      if (t->part == AST_MSG && PN_S(t,0) == PN_use) {
#  if 0
        PN use = PN_TUPLE_AT(PN_S(t,1), 0);
        PN name = PN_TUPLE_AT(PN_S(t,1), 1);
        PN list = potion_tuple_at(P,0,PN_S(t,1),2);
        PN class = potion_require(P, name); //TODO name to file
        if (use == PN_use) potion_send(class, PN_STR("import"), list);
        else if (use == PN_no) potion_send(class, PN_STR("unimport"), list);
        else potion_fatal("Internal error: use or no");
#  endif
      }
      else
#endif
      if (t->part == AST_MSG && PN_S(t,0) == PN_if) {
        int jmp; breg++;
#ifdef P2
    if (!t->a[2]) { // rhs ifexpr: missing block
          DBG_c("expr (msg if, (cond)), block => expr (msg if, (cond), block)\n");
          if (P->flags & MODE_P2) {
            //TODO
            breg++;
            break;
          } else {
            potion_syntax_error(P, t,
                "%s statement used as expr only valid with use p2;", "if");
          }
    }
#endif
        if (t->a[1]->part == AST_VALUE && !t->a[1]->a[1]) {
          ifconst = PN_S(t->a[1], 0);
          if (PN_TEST1(ifconst)) {
            DBG_c("if (true) {block} => block\n");
            potion_source_asmb(P, f, loop, 0, t->a[2], reg);
          } else {
            DBG_c("if (false) {block} => \n");
          }
        } else {
          ifconst = PN_NONE;
          PN_ARG_TABLE(PN_S(t,1), breg, 0);
          jmp = PN_OP_LEN(f->asmb);
          PN_ASM2(OP_NOTJMP, breg, 0);
          potion_source_asmb(P, f, loop, 0, t->a[2], reg);
          PN_OP_AT(f->asmb, jmp).b = (PN_OP_LEN(f->asmb) - jmp) - 1;
    }
      } else if (t->part == AST_MSG && PN_S(t,0) == PN_elsif) {
        int jmp1 = PN_OP_LEN(f->asmb), jmp2; breg++;
        // true ifconst: ignore. use only 1st if
#ifdef P2
    if (!t->a[2]) { // rhs ifexpr: missing block
          DBG_c("expr (msg elsif, (cond)), block => expr (msg elsif, (cond), block)\n");
          if (P->flags & MODE_P2) {
            //TODO
            breg++;
            break;
          } else {
            potion_syntax_error(P, t,
                "%s statement used as expr only valid with use p2;", "elsif");
          }
    }
#endif
        if (ifconst != PN_NONE && PN_TEST1(ifconst)) {
          DBG_c("elsif (...) {block} => [false]\n");
        } else if (t->a[1]->part == AST_VALUE && !t->a[1]->a[1]) {
          ifconst = PN_S(t->a[1], 0);
          if (!PN_TEST1(ifconst)) {
            DBG_c("elsif (true) {block} => block\n");
            potion_source_asmb(P, f, loop, 0, t->a[2], reg);
          } else {
            DBG_c("elsif (false) {block} =>\n");
          }
        }
        else {
          PN_ASM2(OP_TESTJMP, breg, 0);
          PN_ARG_TABLE(PN_S(t,1), breg, 0);
          jmp2 = PN_OP_LEN(f->asmb);
          PN_ASM2(OP_NOTJMP, breg, 0);
          potion_source_asmb(P, f, loop, 0, t->a[2], reg);
          PN_OP_AT(f->asmb, jmp1).b = (PN_OP_LEN(f->asmb) - jmp1) - 1;
          PN_OP_AT(f->asmb, jmp2).b = (PN_OP_LEN(f->asmb) - jmp2) - 1;
        }
      } else if (t->part == AST_MSG && PN_S(t,0) == PN_else) {
        int jmp = PN_OP_LEN(f->asmb); breg++;
#ifdef P2
    if (!t->a[2]) { // rhs ifexpr: missing block
          DBG_c("expr (msg else), block => expr (msg else, block)\n");
          if (P->flags & MODE_P2) {
            //TODO
            break;
          } else {
            potion_syntax_error(P, t,
                "%s statement used as expr only valid with use p2;", "else");
          }
    }
#endif
        if (ifconst != PN_NONE) {
          if (!PN_TEST1(ifconst)) {
            DBG_c("else {block} => block [false]\n");
            potion_source_asmb(P, f, loop, 0, t->a[2], reg);
          } else {
            DBG_c("else {block} => [true]\n");
          }
        }
        else {
          PN_ASM2(OP_TESTJMP, breg, 0);
          potion_source_asmb(P, f, loop, 0, t->a[2], reg);
          PN_OP_AT(f->asmb, jmp).b = (PN_OP_LEN(f->asmb) - jmp) - 1;
        }
        PN_ASM2(OP_TESTJMP, breg, 0);
        potion_source_asmb(P, f, loop, 0, t->a[2], reg);
        PN_OP_AT(f->asmb, jmp).b = (PN_OP_LEN(f->asmb) - jmp) - 1;
      } else if (t->part == AST_MSG && PN_S(t,0) == PN_class) {
        u8 breg = reg;
        if (count == 0)
          PN_ASM1(OP_SELF, reg);
        if (PN_S(t,2) != PN_NIL) {
      vPN(Source) blk = PN_S_(t,2);
          // TODO: a hack to make sure constructors always return self
          if (PN_S(blk, 0) == PN_NIL)
            blk->a[0] = PN_SRC(PN_AST(CODE, PN_NIL, blk->loc.lineno, blk->line));
          PN ctor = PN_S(blk, 0);
          PN_PUSH(ctor, PN_AST(EXPR, PN_TUP(PN_AST(MSG,
        PN_STRN("self", 4), blk->loc.lineno, 0)),
                    blk->loc.lineno, blk->line));
          breg++;
          PN_BLOCK(breg, (PN)blk, PN_S(t,1));
        }
        PN_ASM2(OP_CLASS, reg, breg);
#ifdef WITH_EXTERN
      } else if (t->part == AST_MSG && PN_S(t,0) == PN_extern) { // ffi
        //u8 breg = reg;
    int i, arity;
        PN msg = PN_S(t,1);
    char *name = PN_STR_PTR(PN_S(PN_TUPLE_AT(msg,0),0));
    //defer dlsym to run-time to see load, or require load at BEGIN time?
    //PN_ASM2(OP_LOADPN, breg++, name);
    PN_F sym = (PN_F)dlsym(RTLD_DEFAULT, name);
    DBG_c("extern %s => dlsym %p\n", name, sym);
    if (!sym) {
      fprintf(stderr, "* extern %s not found. You may need to load a library first\n",
              name);
          PN_ASM2(OP_LOADPN, reg, PN_NIL);
        } else {
          // TODO: create a ffi wrapper to translate the args and return value
          struct PNProto* cl = PN_CALLOC_N(PN_TPROTO, struct PNProto, 0);
          cl->source = PN_NIL;
          cl->stack = PN_NUM(1);
          cl->protos = cl->paths = cl->locals = cl->upvals = cl->values = PN_TUP0();
          cl->tree = (PN)t;
          cl->asmb = (PN)potion_asm_new(P);
          cl->name = PN_S(PN_TUPLE_AT(msg,0),0);
          cl->jit = (PN_F)sym;
      PN sig = PN_TUPLE_LEN(msg) ? PN_TUPLE_AT(msg, 1) : PN_TUP0();
      cl->sig = sig;
      arity = cl->arity = potion_sig_arity(P, sig);
          for (i=0; i < arity; i++) {
        if (PN_TUPLE_LEN(msg) > 1) {
          // TODO set argtype translators
              PN arg = PN_TUPLE_AT(sig, i);
              if (arg == PN_STR("N") || arg == PN_STR("int") || arg == PN_STR("long")) {
                DBG_c("extern %s %d-th arg => PN_INT(N)\n", name, i);
                //insert PN_INT >>1 at runtime
                //PN_ASM2(OP_LOADPN, breg++, arg);
              } else if (arg == PN_STR("S") || arg == PN_STR("char*")) {
                DBG_c("extern %s %d-th arg => PN_STR_PTR(S)\n", name, i);
                // insert call to potion_str_ptr at runtime
                //PN_ASM2(OP_LOADPN, breg++, arg);
              } else {
                fprintf(stderr, "* unknown extern %s argument type qualifier\n",
                        PN_STR_PTR(arg));
              }
        }
        // maybe add code to check and fill in defaults?
      }
          // TODO insert code to transform return values
      cl->asmb = (PN)potion_asm_op(P, (PNAsm *)cl->asmb, OP_RETURN, reg, 0);
          PN_ASM2(OP_PROTO, reg, PN_PUT(f->protos, (PN)cl));
          //PN_ASM2(OP_EXTERN, reg, breg);
        }
#endif
      } else if (t->part == AST_MSG && (PN_S(t,0) == PN_while || PN_S(t,0) == PN_loop)) {
        int jmp1 = 0, jmp2 = PN_OP_LEN(f->asmb); breg++;
        struct PNLoop l; l.bjmpc = 0; l.cjmpc = 0;
        int i;
        if (PN_S(t,0) == PN_while) {
          PN_ARG_TABLE(PN_S(t,1), breg, 0);
          jmp1 = PN_OP_LEN(f->asmb);
          PN_ASM2(OP_NOTJMP, breg, 0);
        } else if (PN_S(t,1) || !t->a[2]) {
      //warn or skip to allow a method named loop? for aio we want loop methods
      //fprintf(stderr, "* loop takes no args, just a block");
      goto loopfunc;
    }
        if (!t->a[2]) {
          if (PN_S(t,0) == PN_while)
            return potion_syntax_error(P, t, "Missing while body");
          else
            return potion_syntax_error(P, t, "Missing loop body");
        }
        potion_source_asmb(P, f, &l, 0, t->a[2], reg);
        PN_ASM1(OP_JMP, (jmp2 - PN_OP_LEN(f->asmb)) - 1);
        if (PN_S(t,0) == PN_while) {
          PN_OP_AT(f->asmb, jmp1).b = (PN_OP_LEN(f->asmb) - jmp1) - 1;
        }
        for (i = 0; i < l.bjmpc; i++) {
          PN_OP_AT(f->asmb, l.bjmps[i]).a = (PN_OP_LEN(f->asmb) - l.bjmps[i]) - 1;
        }
        for (i = 0; i < l.cjmpc; i++) {
          PN_OP_AT(f->asmb, l.cjmps[i]).a = (jmp2 - l.cjmps[i]) - 1;
        }
      } else if (t->part == AST_MSG && PN_S(t,0) == PN_return) {
        //if (!t->a[1])
        //    return potion_syntax_error(P, t, "Missing return value");
        PN_ARG_TABLE(PN_S(t,1), reg, 0);
        PN_ASM1(OP_RETURN, reg);
      } else if (t->part == AST_MSG && PN_S(t,0) == PN_break) {
        if (loop != NULL) {
          loop->bjmps[loop->bjmpc++] = PN_OP_LEN(f->asmb);
          PN_ASM1(OP_JMP, 0);
        } else {
          potion_syntax_error(P, t, "'break' outside of loop");
        }
      } else if (t->part == AST_MSG && PN_S(t,0) == PN_continue) {
        if (loop != NULL) {
          loop->cjmps[loop->cjmpc++] = PN_OP_LEN(f->asmb);
          PN_ASM1(OP_JMP, 0);
        } else {
          potion_syntax_error(P, t, "'continue' outside of loop");
        }
      } else if (t->part == AST_MSG && PN_S(t,0) == PN_self) {
        PN_ASM1(OP_SELF, reg);
      } else {
        // TODO lookup if macro
      loopfunc: ;
    u8 opcode = OP_GETUPVAL;
        PN_SIZE num = PN_NONE;
        PN v = PN_S(t,0);
        if (count == 0 && t->part == AST_MSG) {
          num = PN_UPVAL(v);
          if (num == PN_NONE) {
            num = PN_GET(f->locals, v);
        DBG_c("locals %s <= %d\n", AS_STR(v), (int)num);
            opcode = OP_GETLOCAL;
          }
        }

        if (num == PN_NONE && PN_S(t,0) != PN_NIL) {
          u8 oreg = ++breg;
          int jmp = 0;
          num = PN_PUT(f->values, PN_S(t,0));
      DBG_c("values %d %s => %d\n", reg, AS_STR(t->a[0]), (int)num);
          if (count == 0) {
            PN_ASM1(OP_SELF, oreg);
          } else {
            PN_ASM2(OP_MOVE, oreg, reg);
          }
          PN_ASM2(OP_LOADK, reg, num);
          if (PN_S(t,2) != PN_NIL && (PN_PART(PN_S(t,2)) == AST_MSG)) {
            vPN(Source) t2 = PN_S_(t,2); //typed message (MSG LIST|NIL TYPE)
            DBG_c("typed %s %s\n", AS_STR(t->a[0]), AS_STR(t2));
            //TODO type should already exist at compile-time. check native or user type
            num = PN_PUT(f->values, PN_S(t2,0));
            PN_ASM2(OP_LOADK, reg, num);
            PN_ASM2(OP_BIND, reg, breg);
          } else {
            PN_ASM2(((PN_S(t,1) != PN_NIL || PN_S(t,2) != PN_NIL) ? OP_MSG : OP_BIND), reg, breg);
          }
          if (t->part == AST_QUERY && PN_S(t,1) != PN_NIL) {
            jmp = PN_OP_LEN(f->asmb);
            PN_ASM2(OP_NOTJMP, reg, 0);
          }
#define LOAD_ARG() PN_ARG_TABLE(PN_S(t,1), breg, 1)
          if (arg) {
            u8 part1 = PN_PART(PN_S(t,1));
            if (part1 == AST_VALUE || (part1 == AST_LIST && PN_S(t,2) == PN_NIL)) {
              LOAD_ARG();
            }
          }
          if (PN_S(t,2) != PN_NIL && (PN_PART(PN_S(t,2)) == AST_PROTO)) {
            vPN(Source) t2 = PN_S_(t,2);
            breg++;
            PN_BLOCK(breg, PN_S(t2,1), PN_S(t2,0));
          } else {
            if (PN_S(t,1) == PN_NIL && PN_S(t,2) == PN_NIL)
              LOAD_ARG();
            if (PN_S(t,2) != PN_NIL && PN_PART(PN_S(t,2)) == AST_BLOCK) {
              breg++;
              PN_BLOCK(breg, PN_S(t,2), PN_S(t,1));
            }
          }
#undef LOAD_ARG
          if (t->part == AST_MSG) {
        DBG_c("; call %d %d MSG\n", reg, breg);
            PN_ASM2(OP_CALL, reg, breg);
          } else {
            if (PN_S(t,1) != PN_NIL) {
          DBG_c("; call %d %d !MSG\n", reg, breg);
              PN_ASM2(OP_CALL, reg, breg);
              PN_OP_AT(f->asmb, jmp).b = (PN_OP_LEN(f->asmb) - jmp) - 1;
            } else {
              PN_ASM2(OP_TEST, reg, breg);
            }
          }
        } else {
          if (num != PN_NONE)
            PN_ASM2(opcode, reg, num);
          if (call) {
            PN_ASM1(OP_SELF, ++breg);
            PN_ARG_TABLE(PN_S(t,1), breg, 1);
            if (PN_S(t,2) != PN_NIL) {
              breg++;
              PN_BLOCK(breg, PN_S(t,2), PN_NIL);
            }
            DBG_c("; call %d %d\n", reg, breg);
            PN_ASM2(OP_CALL, reg, breg);
          }
        }
      }
      PN_REG(f, breg);
    }
    break;

    case AST_PATH:
    case AST_PATHQ: {
      PN_SIZE num = PN_PUT(f->values, PN_S(t,0));
      DBG_c("values %d %s => %d\n", reg, AS_STR(t->a[0]), (int)num);
      if (count == 0) {
        PN_PUT(f->paths, PN_NUM(num));
    DBG_c("paths %d\n", (int)num);
        PN_ASM1(OP_SELF, reg);
      }
      PN_ASM2(OP_LOADK, reg + 1, num);
      PN_ASM2(OP_GETPATH, reg, reg + 1);
      if (t->part == AST_PATHQ)
        PN_ASM2(OP_TEST, reg, reg);
      PN_REG(f, reg + 1);
    }
    break;

    case AST_LICK: {
      u8 breg = reg;
      PN_SIZE num = PN_PUT(f->values, PN_S(t,0));
      DBG_c("values %d %s => %d\n", reg, AS_STR(t->a[0]), (int)num);
      PN_ASM2(OP_LOADK, reg, num);
      if (PN_S(t,1) != PN_NIL)
        potion_source_asmb(P, f, loop, 0, t->a[1], ++breg);
      else if (PN_S(t,2) != PN_NIL)
        PN_ASM2(OP_LOADPN, ++breg, PN_NIL);
      if (PN_S(t,2) != PN_NIL)
        potion_source_asmb(P, f, loop, 0, t->a[2], ++breg);
      PN_ASM2(OP_NEWLICK, reg, breg);
      PN_REG(f, breg);
    }
    break;

    case AST_LIST:
      PN_ASM1(OP_NEWTUPLE, reg);
      if (PN_S(t,0) != PN_NIL) {
        PN_TUPLE_EACH(PN_S(t,0), i, v, {
      PN_ASM_DEBUG(reg, PN_SRC(v));
          if (PN_PART(v) == AST_ASSIGN) { //potion only: (k=v, ...)
        vPN(Source) lhs = PN_SRC(PN_S(v,0));
            if (lhs->part == AST_EXPR && PN_TUPLE_LEN(PN_S(lhs,0)) == 1)
            {
              lhs = SRC_TUPLE_AT(lhs, 0);
              if (lhs->part == AST_MSG) {
        PN_ASM_DEBUG(reg, lhs);
                PN_SIZE num = PN_PUT(f->values, PN_S(lhs,0));
        DBG_c("values %d %s => %d\n", reg+1, AS_STR(lhs->a[0]), (int)num);
                PN_ASM2(OP_LOADK, reg + 1, num);
                lhs = NULL;
              }
            }

            if (lhs != NULL)
              potion_source_asmb(P, f, loop, 0, lhs, reg + 1);

            potion_source_asmb(P, f, loop, 0, PN_SRC(v)->a[1], reg + 2);
            PN_ASM2(OP_SETTABLE, reg, reg + 2);
            PN_REG(f, reg + 2);
          } else {
            potion_source_asmb(P, f, loop, 0, PN_SRC(v), reg + 1);
            PN_ASM2(OP_SETTUPLE, reg, reg + 1);
            PN_REG(f, reg + 1);
          }
        });
      }
    break;
  }
}

#define SIG_EXPR_MSG(name,expr)         \
  if (expr->part == AST_EXPR) {         \
    vPN(Source) t = SRC_TUPLE_AT(expr, 0);  \
    if (t->part == AST_MSG) {           \
      name = PN_S(t,0);             \
      PN_PUT(f->locals, name);          \
      DBG_c("locals %s\n", PN_STR_PTR(name));   \
      sig = PN_PUSH(sig, name);         \
    }                       \
  } else { name = PN_NIL; }

PN potion_sig_compile(Potion *P, vPN(Proto) f, PN src) {
  vPN(Source) t = PN_SRC(src);
#ifdef P2
  // already parsed to tuple
  PN sig = PN_S(t,0);
  if (!sig)
    sig = PN_TUP0();
  else
    PN_TUPLE_EACH(sig, i, v, {
      if (PN_IS_STR(v)) { // assign string default to a local
        PN_PUT(f->locals, v);
        DBG_c("locals %s\n", PN_STR_PTR(v));
      }});
#else
  PN sig = PN_TUP0();
  if (t->part == AST_LIST && PN_S(t,0) != PN_NIL) {
    //PN_TUPLE_EACH(PN_S(t,0), i, v, {
    ({ struct PNTuple * volatile __tv = ((struct PNTuple *)potion_fwd(PN_S(t,0)));
      if (__tv->len != 0) {
        DBG_c("--- sig compile ---\n");
    PN_SIZE i;
    for (i = 0; i < __tv->len; i++) {
      struct PNSource *v = PN_SRC(__tv->set[i]);
      {
      vPN(Source) expr = PN_SRC(v);
      PN name = 0;
      SIG_EXPR_MSG(name, expr)
      if (expr->part == AST_VALUE) {
        vPN(Source) lhs = expr->a[0];
    PN v = PN_S(lhs,0);
    if (PN_IS_STR(v)) {
      DBG_c("sig: lhs value, computed name %s\n", AS_STR(v));
          PN_PUT(f->locals, v);
      DBG_c("locals %s\n", PN_STR_PTR(v));
      sig = PN_PUSH(sig, v);
    } else {
      potion_syntax_error(P, t,
              "in signature: value %s as argument name", AS_STR(v));
    }
      } else if (expr->part == AST_PIPE) { //x|y => (pipe (expm x) (expm y))
    vPN(Source) lhs = expr->a[0];
    vPN(Source) rhs = expr->a[1];
    PN name2 = 0;
    SIG_EXPR_MSG(name, lhs);
    sig = PN_PUSH(sig, PN_NUM('|'));
    SIG_EXPR_MSG(name2, rhs);
    DBG_c("; (%s | %s)\n", AS_STR(name), AS_STR(name2));
      } else if (expr->part == AST_ASSIGN) { //x=o => (assign (expm x) (expm o))
        vPN(Source) lhs = expr->a[0];
    vPN(Source) rhs = expr->a[1];
        if (lhs->part == AST_EXPR && PN_TUPLE_LEN(PN_S(lhs,0)) == 1) {
      SIG_EXPR_MSG(name, lhs);
          lhs = SRC_TUPLE_AT(lhs, 0);
      DBG_c("; (%s ", AS_STR(name));
    }
        else if (lhs->part == AST_PIPE) {
      //x|y=o => (assign (pipe (expm x) (expm y)) (expm o))
      SIG_EXPR_MSG(name, lhs->a[0]);
      sig = PN_PUSH(sig, PN_NUM('|'));
      rhs = lhs->a[1];
      DBG_c("; (%s | ", AS_STR(name));
    } else {
      potion_syntax_error(P, t, "in signature: unexpected AST %s", AS_STR(lhs));
    }
    if (rhs->part == AST_EXPR && PN_TUPLE_LEN(rhs->a[0]) == 1) {
      rhs = SRC_TUPLE_AT(rhs, 0);
      if (rhs->part == AST_MSG) {
        PN v = PN_NUM(PN_STR_PTR(PN_S(rhs,0))[0]); // = type. TODO: one-char => VTABLE
        DBG_c("%s)\n", AS_STR(v));
        sig = PN_PUSH(sig, v);
      }
        } else if (rhs->part == AST_ASSIGN && rhs->a[0]->part == AST_PIPE) {
          //x=N|y=o => (assign (pipe (expm x) (expm y)) (expm o))
          lhs = PN_S_(PN_S_(rhs, 0), 0);
      if (lhs->part == AST_EXPR && SRC_TUPLE_AT(lhs,0)->part == AST_MSG) {
        PN v = PN_NUM(PN_STR_PTR((PN)SRC_TUPLE_AT(lhs,0)->a[0])[0]); // = type. TODO: one-char => VTABLE
        DBG_c("%s)\n", AS_STR(v));
        sig = PN_PUSH(sig, v);
      }
      sig = PN_PUSH(sig, PN_NUM('|'));
      SIG_EXPR_MSG(name, rhs->a[0]->a[1]);
          rhs = rhs->a[1];
      if (rhs->part == AST_EXPR && SRC_TUPLE_AT(rhs,0)->part == AST_MSG) {
            PN v = PN_S(SRC_TUPLE_AT(rhs,0),0);
        v = PN_NUM(PN_STR_PTR(v)[0]); // = type. TODO: one-char => VTABLE
        DBG_c("%s)\n", AS_STR(v));
        sig = PN_PUSH(sig, v);
          }
    } else if (rhs->part == AST_VALUE) {    // :=default
      PN v = PN_S(rhs,0);
      DBG_c(": %s)\n", AS_STR(v));
      sig = PN_PUSH(PN_PUSH(sig, PN_NUM(':')), v);
    } else {
      potion_syntax_error(P, t, "in signature: unexpected AST %s", AS_STR(expr));
    }
      }
    }}}
    });
  }
#endif
  return sig;
}
#undef SRC_TUPLE_AT
#undef SIG_EXPR_MSG

PN potion_source_compile(Potion *P, PN cl, PN self, PN source, PN sig) {
  vPN(Proto) f;
  vPN(Source) t = (struct PNSource *)self;

  switch (t->part) {
    case AST_CODE:
    case AST_BLOCK: break;
    default: return PN_NIL; // TODO: error
  }
  f = PN_ALLOC(PN_TPROTO, struct PNProto);
  f->source = source;
  f->stack = PN_NUM(1);
  f->protos = PN_TUP0();
  f->paths = PN_TUP0();
  f->locals = PN_TUP0();
  f->upvals = PN_TUP0();
  f->values = PN_TUP0();
  f->debugs = PN_TUP0();
  f->tree = self;
  DBG_c("-- compile --\n");
  f->sig = (sig == PN_NIL ? PN_TUP0() : potion_sig_compile(P, f, sig));
  f->asmb = (PN)potion_asm_new(P);
  f->name = PN_NIL;

  potion_source_asmb(P, f, NULL, 0, t, 0);
  PN_ASM1(OP_RETURN, 0);

  f->localsize = PN_TUPLE_LEN(f->locals);
  f->upvalsize = PN_TUPLE_LEN(f->upvals);
  f->pathsize = PN_TUPLE_LEN(f->paths);
  return (PN)f;
}

PN potion_proto_clone(Potion *P, PN cl, PN self) {
  vPN(Proto) f = (struct PNProto *)self;
  vPN(Proto) n = PN_ALLOC(PN_TPROTO, struct PNProto);
  PN PN_clone = PN_STR("clone");
  PNAsm * volatile asmb;
  PN len;

  //TODO extern protos
  n->name = f->name;
  n->source = f->source;
  n->stack = f->stack;
  n->protos = potion_send(PN_clone, f->protos);
  n->paths  = potion_send(PN_clone, f->paths);
  n->locals = potion_send(PN_clone, f->locals);
  n->upvals = potion_send(PN_clone, f->upvals);
  n->values = potion_send(PN_clone, f->values);
  n->debugs = potion_send(PN_clone, f->debugs);
  n->tree   = f->tree;
  n->localsize = f->localsize;
  n->upvalsize = f->upvalsize;
  n->pathsize = f->pathsize;
  n->sig = PN_IS_TUPLE(f->sig) ? potion_send(PN_clone, f->sig) : f->sig;

  len = ((PNAsm *)f->asmb)->len;
  PN_FLEX_NEW(asmb, PN_TBYTES, PNAsm, len);
  PN_MEMCPY_N(asmb->ptr, ((PNAsm *)f->asmb)->ptr, u8, len);
  asmb->len = len;
  n->asmb = (PN)asmb;

  return (PN)n;
}

#define READ_U8(ptr) ({u8 rpu = *ptr; ptr += sizeof(u8); rpu;})
#define READ_PN(pn, ptr) ({PN rpn = *(PN *)ptr; ptr += pn; rpn;})
#define READ_CONST(pn, ptr) ({ \
    PN val = READ_PN(pn, ptr); \
    if (PN_IS_PTR(val)) { \
      if (val & 2) { \
        size_t len = ((val ^ 2) >> 4) - 1; \
        val = potion_strtod(P, (char *)ptr, len); \
        ptr += len; \
      } else { \
        size_t len = (val >> 4) - 1; \
        val = PN_STRN((char *)ptr, len); \
        ptr += len; \
      } \
    } \
    val; \
  })

#define READ_TUPLE(ptr) \
  long i = 0, count = READ_U8(ptr); \
  PN tup = potion_tuple_with_size(P, (PN_SIZE)count); \
  for (; i < count; i++)
#define READ_VALUES(pn, ptr) ({ \
    READ_TUPLE(ptr) PN_TUPLE_AT(tup, i) = READ_CONST(pn, ptr); \
    tup; \
  })
#define READ_PROTOS(pn, ptr) ({ \
    READ_TUPLE(ptr) PN_TUPLE_AT(tup, i) = potion_proto_load(P, (PN)f, pn, &(ptr)); \
    tup; \
  })

// TODO: this byte string is volatile, need to avoid using ptr
PN potion_proto_load(Potion *P, PN up, u8 pn, u8 **ptr) {
  PN len = 0;
  PNAsm * volatile asmb = NULL;
  vPN(Proto) f = PN_ALLOC(PN_TPROTO, struct PNProto);
  // TODO extern protos
  f->name = READ_CONST(pn, *ptr);
  f->source = READ_CONST(pn, *ptr);
  if (f->source == PN_NIL) f->source = up;
  f->sig = READ_VALUES(pn, *ptr);
  f->stack = READ_CONST(pn, *ptr);
  f->values = READ_VALUES(pn, *ptr);
  f->paths = READ_VALUES(pn, *ptr);
  f->locals = READ_VALUES(pn, *ptr);
  f->upvals = READ_VALUES(pn, *ptr);
  f->protos = READ_PROTOS(pn, *ptr);
  f->debugs = PN_TUP0();

  len = READ_PN(pn, *ptr);
  PN_FLEX_NEW(asmb, PN_TBYTES, PNAsm, len);
  PN_MEMCPY_N(asmb->ptr, *ptr, u8, len);
  asmb->len = len;

  f->asmb = (PN)asmb;
  f->localsize = PN_TUPLE_LEN(f->locals);
  f->upvalsize = PN_TUPLE_LEN(f->upvals);
  f->pathsize  = PN_TUPLE_LEN(f->paths);
  *ptr += len;
  return (PN)f;
}

// TODO: "load" from a stream
PN potion_source_load(Potion *P, PN cl, PN buf) {
  u8 *ptr;
  vPN(BHeader) h = (struct PNBHeader *)PN_STR_PTR(buf);
  // check for compiled binary first
  if ((size_t)PN_STR_LEN(buf) <= sizeof(struct PNBHeader) ||
      strncmp((char *)h->sig, POTION_SIG, 4) != 0)
    return PN_NIL;

  ptr = h->proto;
  return potion_proto_load(P, PN_NIL, h->pn, &ptr);
}

// TODO: switch to dump methods
#define WRITE_U8(un, ptr) ({*ptr = (u8)un; ptr += sizeof(u8);})
#define WRITE_PN(pn, ptr) ({*(PN *)ptr = pn; ptr += sizeof(PN);})
#define WRITE_CONST(val, ptr) ({ \
    if (PN_IS_STR(val)) { \
      PN count = (PN_STR_LEN(val)+1) << 4; \
      WRITE_PN(count, ptr); \
      PN_MEMCPY_N(ptr, PN_STR_PTR(val), char, PN_STR_LEN(val)); \
      ptr += PN_STR_LEN(val); \
    } else if (PN_IS_DBL(val)) { \
      PN str = potion_num_string(P, PN_NIL, val); \
      PN count = ((PN_STR_LEN(str)+1) << 4) | 2; \
      WRITE_PN(count, ptr); \
      PN_MEMCPY_N(ptr, PN_STR_PTR(str), char, PN_STR_LEN(str)); \
      ptr += PN_STR_LEN(str); \
    } else { \
      PN cval = (PN_IS_PTR(val) ? PN_NIL : val); \
      WRITE_PN(cval, ptr); \
    } \
  })
#define WRITE_TUPLE(tup, ptr) \
  long i = 0, count = PN_TUPLE_LEN(tup); \
  WRITE_U8(count, ptr); \
  for (; i < count; i++)
#define WRITE_VALUES(tup, ptr) ({ \
    WRITE_TUPLE(tup, ptr) WRITE_CONST(PN_TUPLE_AT(tup, i), ptr); \
  })
#define WRITE_PROTOS(tup, ptr) ({ \
    WRITE_TUPLE(tup, ptr) ptr += potion_proto_dumpbc(P, PN_TUPLE_AT(tup, i), \
        out, (char *)ptr - PN_STR_PTR(out)); \
  })

long potion_proto_dumpbc(Potion *P, PN proto, PN out, long pos) {
  vPN(Proto) f = (struct PNProto *)proto;
  char *start = PN_STR_PTR(out) + pos;
  u8 *ptr = (u8 *)start;
  //TODO extern (by name)
  WRITE_CONST(f->name, ptr);
  WRITE_CONST(f->source, ptr);
  WRITE_VALUES(f->sig, ptr);
  WRITE_CONST(f->stack, ptr);
  WRITE_VALUES(f->values, ptr);
  WRITE_VALUES(f->paths, ptr);
  WRITE_VALUES(f->locals, ptr);
  WRITE_VALUES(f->upvals, ptr);
  WRITE_PROTOS(f->protos, ptr);
  WRITE_PN(PN_FLEX_SIZE(f->asmb), ptr);
  PN_MEMCPY_N(ptr, ((PNFlex *)f->asmb)->ptr, u8, PN_FLEX_SIZE(f->asmb));
  ptr += PN_FLEX_SIZE(f->asmb);
  return (char *)ptr - start;
}

// Low TODO: dump to a stream (if we have not enough memory)
PN potion_source_dumpbc(Potion *P, PN cl, PN proto, PN options) {
  PN pnb = potion_bytes(P, 8192);
  struct PNBHeader h;
  DBG_c("compile bc\n");
  PN_MEMCPY_N(h.sig, POTION_SIG, u8, 4);
  h.major = POTION_MAJOR;
  h.minor = POTION_MINOR;
  h.vmid = POTION_VMID;
  h.pn = (u8)sizeof(PN);

  PN_MEMCPY(PN_STR_PTR(pnb), &h, struct PNBHeader);
  PN_STR_LEN(pnb) = (long)sizeof(struct PNBHeader) +
    potion_proto_dumpbc(P, proto, pnb, sizeof(struct PNBHeader));
  return pnb;
}

PN potion_source_dump(Potion *P, PN cl, PN self, PN backend, PN options) {
  if (backend == PN_STRN("bc", 2))
    return potion_source_dumpbc(P, cl, self, options);
#ifndef SANDBOX
  char *cb = PN_STR_PTR(backend);
  if (potion_load(P, P->lobby, self, potion_strcat(P, "compile/", cb))) {
    DBG_c("loaded compile/%s\n", cb);
    DBG_c("Source dump%s(%s)\n", cb, PN_IS_STR(options) ? PN_STR_PTR(options) : "");
    return potion_send(self, potion_strcat(P, "dump", cb), options);
  } else {
    fprintf(stderr, "** failed loading the compile/%s module\n", cb);
    return PN_NIL;
  }
#else
  potion_fatal("external compilers disabled with SANDBOX");
#endif
}

PN potion_run(Potion *P, PN code, int jit) {
#ifndef POTION_JIT_TARGET
  if (jit) {
    fprintf(stderr, "** potion not compiled with JIT\n");
    jit = 0;
  }
#endif
 if (jit) {
    PN cl = potion_closure_new(P, (PN_F)potion_jit_proto(P, code), PN_NIL, 1);
    PN_CLOSURE(cl)->data[0] = code;
    return PN_PROTO(code)->jit(P, cl, P->lobby);
  } else {
    return potion_vm(P, code, P->lobby, PN_NIL, 0, NULL);
  }
}

PN potion_eval(Potion *P, PN bytes) {
  PN code = (PN_TYPE(bytes) == PN_TSOURCE)
    ? bytes
    : potion_parse(P, bytes, "<eval>");
  if (PN_TYPE(code) != PN_TSOURCE) return code;
  code = potion_send(code, PN_compile, PN_NIL, PN_NIL);
  return potion_run(P, code, P->flags & EXEC_JIT);
}

void potion_compiler_init(Potion *P) {
  PN pro_vt = PN_VTABLE(PN_TPROTO);
  PN src_vt = PN_VTABLE(PN_TSOURCE);
  potion_method(pro_vt, "call", potion_proto_call, "args=u");
  potion_method(pro_vt, "tree", potion_proto_tree, 0);
  potion_method(pro_vt, "string", potion_proto_string, 0);
  potion_method(pro_vt, "clone", potion_proto_clone, 0);
  potion_method(src_vt, "compile", potion_source_compile, "source=a,sig=u");
  potion_method(src_vt, "dump", potion_source_dump, "backend=S|options=S");
  potion_method(src_vt, "dumpbc", potion_source_dumpbc, "|options=S");
}