shithub: pprolog

ref: ee65a81ee5b0112ba4480619ca672c569fb28b45
dir: /dat.h/

#define PrecedenceLevels 1200

typedef struct Operator Operator;
typedef struct Term Term;
typedef struct Binding Binding;
typedef struct Goal Goal;
typedef struct Choicepoint Choicepoint;
typedef struct Clause Clause;
typedef struct Predicate Predicate;
typedef struct Module Module;
typedef int (*Builtin)(Term *, Binding **, Module *);

struct Operator
{
	int type;
	int level;
	Rune *spelling;
	Operator *next;
};

struct Term
{
	int tag;

	Rune *text;
	int arity;
	Term *next;
	Term *children;
	vlong ival;
	double dval;
	uvlong clausenr;
};

struct Binding
{
	Rune *name;
	uvlong nr; /* Unique number for each clause. Every time a clause is used, it gets a new number. */
	Term *value;
	Binding *next;
};

struct Goal
{
	Term *goal;
	Module *module; /* What module is this goal to be evaluated in? */
	Term *catcher; /* When this is non-nil, the goal is a catch frame, goal is the recovery. */
	Goal *next;
};

struct Choicepoint
{
	Goal *goalstack;
	Clause *alternative;
	Binding *altbindings;
	uvlong id; /* Unique number for each clause. Used to know where to cut to. */
	Module *currentmodule;
	Choicepoint *next;
};

struct Clause
{
	Term *head;
	Term *body;
	uvlong clausenr;
	Clause *next;
};

struct Predicate
{
	Rune *name;
	int arity;
	int public;
	int builtin; /* All the predicates from the system module are builtin */
	int dynamic;
	Clause *clauses;
	Predicate *next;
};

struct Module
{
	/* What about imports */
	Rune *name;
	Predicate *predicates;
	Operator *operators[PrecedenceLevels];
	Module *next;
};

/* Operator types */
enum {
	Xf	= 1<<0, /* 1 */
	Yf	= 1<<1, /* 2 */
	Xfx	= 1<<2, /* 4 */
	Xfy	= 1<<3, /* 8 */
	Yfx	= 1<<4, /* 16 */
	Fy	= 1<<5, /* 32 */
	Fx	= 1<<6, /* 64 */
};

/* Sorted so that a lower value means it comes earlier in the standard ordering */
enum {
	VariableTerm,
	FloatTerm,
	IntegerTerm,
	AtomTerm,
	CompoundTerm,
};

int debug;

/* Flags */
enum {
	DoubleQuotesChars,
	DoubleQuotesCodes,
	DoubleQuotesAtom,
};

int flagdoublequotes;

/* State of the running system */
Choicepoint *choicestack;
Goal *goalstack;
Module *modules;
Module *systemmodule; /* The module for the builtins. Everything has access to those */
Module *usermodule; /* The default module for user defined predicates */
uvlong clausenr;
Binding *replbindings; /* The bindings used by the repl */
Term *replquery; /* The currently active repl query */