NAME

src/spf_vtable.c - Parrot sprintf

DESCRIPTION

Implements the two families of functions Parrot_sprintf may use to retrieve arguments.

Var args Functions

static STRING *getchr_va: Gets a char out of the va_list in obj and returns it as a Parrot STRING.; size is unused.
static HUGEINTVAL getint_va: Gets an integer out of the va_list in obj and returns it as a Parrot STRING.; size is an enum spf_type_t value which indicates the storage type of the integer.
static UHUGEINTVAL getuint_va: Gets an unsigned integer out of the va_list in obj and returns it as a Parrot STRING.; size is an enum spf_type_t value which indicates the storage type of the integer.
static HUGEFLOATVAL getfloat_va: Gets an floating-point number out of the va_list in obj and returns it as a Parrot STRING.; size is an enum spf_type_t value which indicates the storage type of the number.
static STRING *getstring_va: Gets an string out of the va_list in obj and returns it as a Parrot STRING.; size is an enum spf_type_t value which indicates the storage type of the string.
static void *getptr_va: Gets a void * out of the va_list in obj and returns it.; size is unused.

PMC Functions

static STRING *getchr_pmc: Same as getchr_va() except that a vtable is used to get the value from obj.
static HUGEINTVAL getint_pmc: Same as getint_va() except that a vtable is used to get the value from obj.
static UHUGEINTVAL getuint_pmc: Same as getuint_va() except that a vtable is used to get the value from obj.
static HUGEFLOATVAL getfloat_pmc: Same as getfloat_va() except that a vtable is used to get the value from obj.
static STRING *getstring_pmc: Same as getstring_va() except that a vtable is used to get the value from obj.
static void *getptr_pmc: Same as getptr_va() except that a vtable is used to get the value from obj.

HISTORY

When I was first working on this implementation of sprintf, I ran into a problem. I wanted to re-use the implementation for a Parrot bytecode-level sprintf, but that couldn't be done, since it used va_* directly. For a while I thought about generating two versions of the source with a Perl script, but that seemed like overkill. Eventually I came across this idea -- pass in a specialized vtable with methods for extracting things from the arglist, whatever it happened to be. This is the result.

TODO

In the future, it may be deemed desirable to similarly vtable-ize appending things to the string, allowing for faster PIO_printf() &c, as well as a version that writes directly to a C string. However, at this point neither of those is needed.