HolyC basics¶

This is enough HolyC to read and modify the examples. For the full language, see the hcc docs at holyc-lang.com. The language comes from TempleOS, and hcc implements most of it.

Types¶

HolyC	C equivalent	Notes
`U0`	`void`
`Bool`	`_Bool`	`TRUE`, `FALSE`
`U8` / `I8`	`uint8_t` / `int8_t`	`U8 *` is a string
`U16` / `I16`, `U32` / `I32`
`U64` / `I64`	`uint64_t` / `int64_t`	`I64` is the default integer
`F64`	`double`	the default float
`F32`	`float`	hcc extension; needed for OpenGL data

Functions¶

U0 Move(Player *p, I64 dx, I64 dy = 0)
{
  p->x += dx;
  p->y += dy;
}

Default arguments are allowed. A function called with no arguments can drop the parentheses (Main;), though the examples always write them.

A function must be declared before it's used. Either define it higher in the file or add a prototype:

I64 Later(I64 a);

Classes¶

class is a C struct. There are no methods, but single inheritance works:

class Actor
{
  I64 x, y;
};

class Bat : Actor
{
  I64 vx, vy;
};

Fields can share a line (I64 x, y;). Globals can't. Write one global per line. See Compiler quirks.

Printing¶

"plain text\n";
"%s is %d years old\n", name, age;
U8 *s = MStrPrint("%d,%d", x, y);    // allocates; Free(s) later
StrPrint(buf, "score %d", score);    // into an existing buffer

In a print statement, %d only formats 32 bits; use %ld for larger values. StrPrint and MStrPrint take %d for any size. See Compiler quirks.

Memory¶

MAlloc, CAlloc (zeroed), Free, MemSet, MemCpy. There's no garbage collector.

Maths¶

Use the C maths library names: sin, cos, tan, sqrt, floor, atan2, pow. The TempleOS spellings (Sqrt, Floor) don't exist in hcc.

Programs and Main¶

hcc starts at Main. It can return U0 or I32 and can take (I32 argc, U8 **argv):

I32 Main(I32 argc, U8 **argv)
{
  if (argc > 1)
    "first argument: %s\n", argv[1];
  return 0;
}

Includes and defines¶

#include "../common/canvas.HC"   // relative to this file
#define WIDTH 320
#ifdef IS_LINUX
#endif
#ifjit
  "running under the JIT\n";
#endif

hcc defines IS_LINUX or IS_MACOS for the target, and __HCC_JIT__ or __HCC_AOT__ depending on how it's running. #ifjit and #ifaot are shorthand for checking those.

What's missing¶

No ternary operator (a ? b : c). Use if.
No struct keyword. Use class.
No function-like macros. #define SQ(x) ((x) * (x)) crashes hcc 0.0.15 with a segfault instead of giving an error. Write a function.

The first two fail with a normal compile error. The bugs that compile but misbehave are listed in Compiler quirks.