ccpp — a tiny toy C preprocessor

Features (initial):

• Supports simple object-like #define NAME VALUE macros (no args)
• Replaces identifiers in code, skipping string literals and comments
• Reads from a file path or stdin; writes to stdout

Usage:

• Build: make -C ccpp
• Test: make -C ccpp test
• Run: ./ccpp/ccpp [input.c] > output.c

Header scans:

• Linux (curated): make -C ccpp test-linux-core-headers
• Linux (broad): make -C ccpp test-linux-headers (see Makefile for variants)
• macOS (C/Unix only): make -C ccpp test-macos-c-unix-headers

Limitations (by design for now):

• No #include, conditionals, or function-like macros
• No macro redefinition/undef tracking beyond last definition wins
• Block comments are skipped at a basic level; nested comments not supported

Pragmas:

• #pragma once is honored internally to avoid duplicate includes.
• Other #pragma directives are suppressed in output by default. Set CCPP_PRESERVE_PRAGMAS=1 to pass them through unchanged.