path: root/e-util/e-sexp.h

/*
  generic s-exp evaluator class
*/
#ifndef _E_SEXP_H
#define _E_SEXP_H

#include <setjmp.h>
#include <time.h>
#include <glib.h>

#ifdef E_SEXP_IS_GTK_OBJECT
#include <gtk/gtkobject.h>
#endif

#ifdef E_SEXP_IS_GTK_OBJECT
#define E_SEXP(obj)         GTK_CHECK_CAST (obj, e_sexp_get_type (), ESExp)
#define E_SEXP_CLASS(klass) GTK_CHECK_CLASS_CAST (klass, e_sexp_get_type (), ESExpClass)
#define FILTER_IS_SEXP(obj)      GTK_CHECK_TYPE (obj, e_sexp_get_type ())
#else
#define E_SEXP(obj)         ((struct _ESExp *)(obj))
#define E_SEXP_CLASS(klass)     ((struct _ESExpClass *)(klass))
#define FILTER_IS_SEXP(obj)      (1)
#endif

typedef struct _ESExp      ESExp;
typedef struct _ESExpClass ESExpClass;

typedef struct _ESExpSymbol ESExpSymbol;
typedef struct _ESExpResult ESExpResult;
typedef struct _ESExpTerm ESExpTerm;

typedef struct _ESExpResult *(ESExpFunc)(struct _ESExp *sexp,
                           int argc,
                           struct _ESExpResult **argv,
                           void *data);

typedef struct _ESExpResult *(ESExpIFunc)(struct _ESExp *sexp,
                            int argc,
                            struct _ESExpTerm **argv,
                            void *data);
enum _ESExpResultType {
    ESEXP_RES_ARRAY_PTR=0,  /* type is a ptrarray, what it points to is implementation dependant */
    ESEXP_RES_INT,      /* type is a number */
    ESEXP_RES_STRING,   /* type is a pointer to a single string */
    ESEXP_RES_BOOL,     /* boolean type */
    ESEXP_RES_TIME,     /* time_t type */
    ESEXP_RES_UNDEFINED /* unknown type */
};

struct _ESExpResult {
    enum _ESExpResultType type;
    union {
        GPtrArray *ptrarray;
        int number;
        char *string;
        int bool;
        time_t time;
    } value;
};

enum _ESExpTermType {
    ESEXP_TERM_INT  = 0,    /* integer literal */
    ESEXP_TERM_BOOL,    /* boolean literal */
    ESEXP_TERM_STRING,  /* string literal */
    ESEXP_TERM_TIME,    /* time_t literal (number of seconds past the epoch) */
    ESEXP_TERM_FUNC,    /* normal function, arguments are evaluated before calling */
    ESEXP_TERM_IFUNC,   /* immediate function, raw terms are arguments */
    ESEXP_TERM_VAR,     /* variable reference */
};

struct _ESExpSymbol {
    int type;       /* ESEXP_TERM_FUNC or ESEXP_TERM_VAR */
    char *name;
    void *data;
    union {
        ESExpFunc *func;
        ESExpIFunc *ifunc;
    } f;
};

struct _ESExpTerm {
    enum _ESExpTermType type;
    union {
        char *string;
        int number;
        int bool;
        time_t time;
        struct {
            struct _ESExpSymbol *sym;
            struct _ESExpTerm **terms;
            int termcount;
        } func;
        struct _ESExpSymbol *var;
    } value;
};



struct _ESExp {
#ifdef E_SEXP_IS_GTK_OBJECT
    GtkObject object;
#else
    int refcount;
#endif
    GScanner *scanner;  /* for parsing text version */
    ESExpTerm *tree;    /* root of expression tree */

    /* private stuff */
    jmp_buf failenv;
    char *error;

    /* TODO: may also need a pool allocator for term strings, so we dont lose them
       in error conditions? */
    struct _EMemChunk *term_chunks;
    struct _EMemChunk *result_chunks;
};

struct _ESExpClass {
#ifdef E_SEXP_IS_GTK_OBJECT
    GtkObjectClass parent_class;
#endif
};

#ifdef E_SEXP_IS_GTK_OBJECT
guint       e_sexp_get_type     (void);
#endif
ESExp          *e_sexp_new      (void);
#ifndef E_SEXP_IS_GTK_OBJECT
void        e_sexp_ref      (ESExp *f);
void        e_sexp_unref        (ESExp *f);
#endif
void        e_sexp_add_function     (ESExp *f, int scope, char *name, ESExpFunc *func, void *data);
void        e_sexp_add_ifunction    (ESExp *f, int scope, char *name, ESExpIFunc *func, void *data);
void        e_sexp_add_variable     (ESExp *f, int scope, char *name, ESExpTerm *value);
void        e_sexp_remove_symbol    (ESExp *f, int scope, char *name);
int     e_sexp_set_scope    (ESExp *f, int scope);

void        e_sexp_input_text   (ESExp *f, const char *text, int len);
void        e_sexp_input_file   (ESExp *f, int fd);


int     e_sexp_parse        (ESExp *f);
ESExpResult    *e_sexp_eval     (ESExp *f);

ESExpResult    *e_sexp_term_eval    (struct _ESExp *f, struct _ESExpTerm *t);
ESExpResult    *e_sexp_result_new   (struct _ESExp *f, int type);
void        e_sexp_result_free  (struct _ESExp *f, struct _ESExpResult *t);

/* used in normal functions if they have to abort, to free their arguments */
void        e_sexp_resultv_free (struct _ESExp *f, int argc, struct _ESExpResult **argv);

/* utility functions for creating s-exp strings. */
void        e_sexp_encode_bool  (GString *s, gboolean state);
void        e_sexp_encode_string    (GString *s, const char *string);

/* only to be called from inside a callback to signal a fatal execution error */
void        e_sexp_fatal_error  (struct _ESExp *f, char *why, ...);

/* return the error string */
const char     *e_sexp_error        (struct _ESExp *f);

#endif /* _E_SEXP_H */