path: root/model.cpp

#include "consts.h"
#include "model.h"
#include "types.h"
#include "exc.h"
#include "gc.h"

#include <cstdio>

static const int REPR_STACK_SIZE = 262144;
extern EmptyList *empty_list;
extern GarbageCollector gc;
typedef set<EvalObj*> EvalObjAddrHash;

/** Maintain the current in-stack objects to detect circular structures */
static EvalObjAddrHash hash;
/** The stack for building external representation string */
static ReprCons *repr_stack[REPR_STACK_SIZE];

FrameObj::FrameObj(FrameType _ftype) : ftype(_ftype) {}

EmptyList::EmptyList() : Pair(NULL, NULL) {}

ReprCons *EmptyList::get_repr_cons() { return new ReprStr("()"); }

bool FrameObj::is_parse_bracket() {
    return ftype & CLS_PAR_BRA;
}

EvalObj::EvalObj(int _otype) : 
FrameObj(CLS_EVAL_OBJ), otype(_otype) {
    /** To notify GC when an EvalObj is constructed */
    gc_rec = gc.join(this);
}

EvalObj::~EvalObj() {
    /** To notify GC when an EvalObj is destructed */
    gc.quit(this);
}

bool EvalObj::is_container() {
    return otype & CLS_CONTAINER;
}

void EvalObj::prepare(Pair *pc) {}

bool EvalObj::is_simple_obj() {
    return otype & CLS_SIM_OBJ;
}

bool EvalObj::is_sym_obj() {
    return otype & CLS_SYM_OBJ;
}

bool EvalObj::is_opt_obj() {
    return otype & CLS_OPT_OBJ;
}

bool EvalObj::is_pair_obj() {
    /** an empty list is not a pair obj */
    return this != empty_list && (otype & CLS_PAIR_OBJ);
}

bool EvalObj::is_num_obj() {
    return otype & CLS_NUM_OBJ;
}

bool EvalObj::is_bool_obj() {
    return otype & CLS_BOOL_OBJ;
}

bool EvalObj::is_str_obj() {
    return otype & CLS_STR_OBJ;
}

bool EvalObj::is_prom_obj() {
    return otype & CLS_PROM_OBJ;
}

bool EvalObj::is_vect_obj() {
    return otype & CLS_VECT_OBJ;
}

int EvalObj::get_otype() {
    return otype;
}

bool EvalObj::is_true() {
    /** will be override by `BoolObj` */
    return true;
}

string EvalObj::ext_repr() {
    // TODO: Performance improvement
    // (from possibly O(n^2logn) to strictly O(nlogn))
    // O(n^2logn) because the potential string concatenate
    // cost
    hash.clear();
    ReprCons **top_ptr = repr_stack;
    *top_ptr++ = this->get_repr_cons();
    EvalObj *obj;
    hash.insert(this);
    while (!(*repr_stack)->done)
    {
        if ((*(top_ptr - 1))->done)
        {
            top_ptr -= 2;
            obj = (*top_ptr)->next((*(top_ptr + 1))->repr);
            delete *(top_ptr + 1);
            if (obj)
            {
                *(++top_ptr) = obj->get_repr_cons();
                EvalObj *ptr = (*top_ptr)->ori;
                if (ptr)
                {
                    if (hash.count(ptr))
                    {
                        delete *top_ptr;
                        *top_ptr = new ReprStr("#inf#");
                    }
                    else hash.insert(ptr);
                }
            }
            else
            {
                hash.erase((*top_ptr)->ori);    // poping from stack
                ReprCons *p = *top_ptr;
                *top_ptr = new ReprStr(p->repr);
                delete p;
            }
        }
        else
        {
            top_ptr--;
            obj = (*top_ptr)->next("");
            if (obj)
            {
                *(++top_ptr) = obj->get_repr_cons();
                EvalObj *ptr = (*top_ptr)->ori;
                if (ptr)
                {
                    if (hash.count(ptr))
                    {
                        delete *top_ptr;
                        *top_ptr = new ReprStr("#inf#");
                    }
                    else hash.insert(ptr);      // push into stack
                }
            }
            else
            {
                ReprCons *p = *top_ptr;
                *top_ptr = new ReprStr(p->repr);
                delete p;
            }
        }
        top_ptr++;
    }
    string res = (*repr_stack)->repr;
    if (this->is_pair_obj())
        res = "(" + res + ")";
    delete *repr_stack;
    return res;
}

ParseBracket::ParseBracket(unsigned char _btype) :
FrameObj(CLS_SIM_OBJ | CLS_PAR_BRA), btype(_btype) {}

UnspecObj::UnspecObj() : EvalObj(CLS_SIM_OBJ) {}

ReprCons *UnspecObj::get_repr_cons() {
    return new ReprStr("#<Unspecified>");
}


Container::Container(int otype, bool override) : 
EvalObj(otype | (override ? 0 : CLS_CONTAINER)) {}