#pragma once

#define TYPE(x) ((x).type)

#define CONS(x) ((x).value.consCell)
#define CAR(x) (((x).value.consCell)->car)
#define CDR(x) (((x).value.consCell)->cdr)
#define SYM(x) ((x).value.symbol)
#define BOOL(x) ((x).value.boolean)
#define ERR(x) ((x).value.err)

#define PROC(x) ((x).value.proc)
#define PROC_TYPE(x) ((x).value.proc->type)
#define PROC_BUILTIN(x) ((x).value.proc->value.builtin)
#define PROC_COMP_ARGS(x) ((x).value.proc->value.compound.args)
#define PROC_COMP_BODY(x) ((x).value.proc->value.compound.body)

#define NUM(x) ((x).value.num)
#define NUM_TYPE(x) ((x).value.num.type)
#define NUM_NUMER(x) ((x).value.num.value.fraction.numerator)
#define NUM_DENOM(x) ((x).value.num.value.fraction.denominator)
#define NUM_REAL(x) ((x).value.num.value.real)

typedef enum
{
	nilObject,
	consObject,
	numberObject,
	symbolObject,
	procedureObject,
	boolObject,
	errorObject
} dataType;

typedef enum
{
	improperListError,
	typeError,
	unrecognizedSymbolError,
	notApplicableError,
	divisionByZeroError,
	argumentNumberError,
	maxRecursionDepthError,
	syntaxError
} error;

typedef enum
{
	fractionNum,
	realNum
} numType;

typedef enum
{
	builtinProc,
	compoundProc
} procType;

typedef struct number number;
typedef struct object object;
typedef struct cons cons;
typedef struct procedure procedure;

struct number
{
	numType type;
	union
	{
		long double real;
		struct
		{
			long long int numerator;
			long long int denominator;
		} fraction;
	} value;
};

struct object
{
	dataType type;
	union
	{
		error err;
		char *symbol;
		cons *consCell;
		number num;
		procedure *proc;
		int boolean;
	} value;
};

struct cons
{
	object car;
	object cdr;
};

struct procedure
{
	procType type;
	union
	{
		object (*builtin)(object);
		struct
		{
			object args;
			object body;
		} compound;
	} value;
};

int isSpecialForm(char *symbol);
int properList(object list);
int listLength(object list);
void deleteObject(object input);
object copyObject(object input);


object longlongToNumber(long long int input);
object shortenFractionNum(object a);
object exactToInexactNum(object a);
object inexactToExactNum(object a);
object plusNum(object a, object b);
object minusNum(object a);
object timesNum(object a, object b);
object inverseNum(object a);

procedure *createProcedure();