HolyC reference · TempleOS

Overview

HolyC is the one language of TempleOS. It is compiled just in time, so there is no separate build step: a file you #include is compiled and run, and a line typed at the prompt is compiled and run the same way. It looks like C with different edges.

"Hello, world!\n";   // a string statement prints

Types

Integer and float types say their size. I64 is the default integer.

Name	Meaning
`U0`	void, no value
`I8, U8`	8 bit signed, unsigned
`I16, U16`	16 bit
`I32, U32`	32 bit
`I64, U64`	64 bit
`F64`	64 bit float (there is no 32 bit float)
`Bool`	true or false, stored in a byte

Functions

No main. Parameters can have defaults. A call with no arguments can drop the parentheses.

U0 Count(I64 n=3)
{
  I64 i;
  for (i=0;i<n;i++)
    "Line %d\n",i;
}
Count;      // n is 3
Count(5);

Strings and printing

A string literal used as a statement prints, and extra arguments after a comma are format arguments. A $ starts a DolDoc command in a string, so a literal dollar sign is written $$.

"x = %d, name = %s\n",x,name;
Print("Total: $$%d\n",total);

Operators

Differences from C that surprise people:

Comparisons chain: 5<x<10 means x is between 5 and 10.
` is the power operator: 2`3 is 8.
Shifts and power bind tighter than multiplication, so parenthesise when mixing.

if (5<x<10)
  "in range\n";
"%d\n",2`3;

Classes

A class is a struct. It can contain nested classes and unions, and a class can be used as a base to share a leading set of members.

class Pt
{
  I64 x,y;
};
Pt p;
p.x=3; p.y=4;

Control flow

if, for, while, do and switch work as in C. switch has a bracketed sub-switch form, start: and end:, for shared setup and teardown. try, catch and throw raise and handle errors.

try {
  throw('Oops');
} catch {
  "caught\n";
  Fs->catch_except=TRUE;
}

Also worth knowing

Everything runs at ring 0 in one address space. A bad pointer can take the system down, so a VM is the safe place to experiment.
The assembler is built in and takes asm blocks.
DolDoc is the document format that source files, the editor and the shell share, so a source file can hold pictures and links.

This reference is a summary written for this site. For exact behaviour, read the system source and the pages listed under Docs. Snippets are untested sketches.

HolyC reference.