Command-Line Interface

Thorn provides a single unified binary that acts as both a meta-build generator and a reverse decompiler.

Usage Syntax

USAGE:
    thorn [spec]
    thorn build [-f spec] [--out-dir dir] [--engine ninja|make|both]
                [--compiler cc] [--ar ar]
    thorn decompile <build.ninja|Makefile> [-o out.thorn]
    thorn help | version

Commands & Subcommands

Default / build Command

Evaluates the specification file (build.thorn or a custom spec) and emits the selected backend files.

# Evaluate build.thorn in current directory
thorn

# Evaluate custom spec file positionally
thorn myproject.thorn

# Explicit build command with output directory and engine override
thorn build -f custom.thorn --out-dir out/artifacts --engine ninja

Options:

• [spec], -f, --file <spec>
  Path to the specification file. Defaults to build.thorn if omitted.
• -o, --out-dir <dir>
  Destination directory for generated build files (build.ninja, Makefile) and build artifacts. Defaults to current working directory (.).
• -e, --engine <ninja|make|both>
  Override the target build engine(s) to emit:
  • ninja: Emit only build.ninja.
  • make: Emit only Makefile.
  • both: Emit both backends simultaneously.
    Note: Can also be defined inside the specification via engine.backend("...").
• --compiler <cc>
  Specify the C compiler executable (e.g. gcc, clang, cc, tcc). Precedence: --compiler flag > CC environment variable > system default cc. Thorn validates that the compiler exists in PATH before writing rules.
• --ar <ar>
  Specify the archiver executable (e.g. ar, llvm-ar) used for static library archives. Precedence: --ar flag > AR environment variable > system default ar.

decompile Command

Parses an existing Ninja file or Makefile and synthesizes an idiomatic, equivalent build.thorn specification.

# Decompile build.ninja and print to standard output
thorn decompile build.ninja

# Decompile Makefile directly to a specification file
thorn decompile Makefile -o build.thorn

Options:

• -o, --out <path>
  Output destination file for the recovered specification. If omitted, the recovered spec is written to standard output.

Informational Commands

• thorn version / -v, --version: Print version information (thorn 0.3.0).
• thorn help / -h, --help: Display usage summary and help text.