tt — Tiny Template Transpiler

Overview

tt is a tiny C++ utility that converts .h.tt template files into .h files by alternating between raw byte output and inline C/C++ code.

It is designed for generating C/C++ source or headers that embed raw data safely as byte strings while still allowing logic, macros, or hand-written code inline.

Core Idea

• % is used as a mode toggle
• Text outside % blocks is treated as raw data
• Text inside % blocks is treated as C/C++ code
• Raw data is emitted as escaped hex bytes via an OUT() macro

RAW TEXT % C/C++ CODE % MORE RAW TEXT

Example

Input (index.h.tt)

Hello world
%
// some C/C++ code
#define X 42
%
Goodbye

Output (index.h)

OUT("\x48\x65\x6c\x6c\x6f\x20\x77\x6f\x72\x6c\x64\x0a", 12);
// some C/C++ code;
OUT("\x47\x6f\x6f\x64\x62\x79\x65", 7);

• Raw text is converted to \xNN byte sequences
• Code blocks are copied verbatim (with ; appended)

Building

make build

This produces:

./bin/tt

Usage

./bin/tt index.h.tt

• Input files must end with .tt
• Output file name is derived by stripping the suffix

index.h.tt → index.h

Template Rules

• % toggles between data mode and code mode
• Processing starts in data mode
• Every % flips the mode
• No nesting — intentionally simple

Requirements

• C++17-compatible compiler
• Tested with g++

Assumptions

• An OUT(const char*, size_t) macro or function exists
• Newlines are preserved as raw bytes
• No attempt is made to be clever or safe beyond byte-accuracy

Philosophy

• Small
• Predictable
• Hackable
• Build-system friendly

If it feels like something you’d write at 2am inside Emacs, it’s working.

License

Do whatever you want. If it breaks, you get to keep both pieces.