How it works

Reflection.Emit needs a JIT, and the Native AOT front-end has none. ilrepl is therefore two processes.

ilrepl (Native AOT)                          ilrepl-host (framework-dependent)
┌──────────────────────────────┐   JSON-RPC  ┌──────────────────────────────┐
│ command line                 │  over stdio │ type and member resolution   │
│ Hex1b terminal UI            │ ──────────▶ │ stack simulation             │
│ batch mode                   │ ◀────────── │ Reflection.Emit compilation  │
│ transcript and completion    │             │ the session                  │
└──────────────────────────────┘             └──────────────────────────────┘

The front-end owns the transcript, completion, and rendering. The host owns the session and returns the transcript lines each input produced. They talk JSON-RPC with StreamJsonRpc over the host’s standard streams. Console output from a cell is captured inside the host, so the channel is never mixed with what the cell prints.

The same engine runs in the browser on the live session page, where the .NET runtime is compiled to WebAssembly and the Hex1b UI renders into xterm.js. Nothing there talks to a server.

The cell

Every line is validated against a replayable model of the cell: declared locals and arguments, the instructions, the labels, the open exception blocks, and the simulated stack. When the cell runs, the accepted lines are replayed against a fresh MethodBuilder, so generic parameters bind to the method that is emitted and the same cell can compile more than once, for ret and for .save.

Compiled cells are AssemblyBuilder types with one static Run method returning object. The epilogue boxes a value type left on the stack. Vararg cells get a standard-convention wrapper, because reflection cannot invoke a vararg method directly.

Projects

Project	Purpose
IlRepl.Protocol	The transcript model, the completion catalog, and the JSON-RPC contract.
IlRepl.Engine	Parsing, resolution, simulation, compilation, the session, and the REPL core.
IlRepl.Host	Serves the engine over standard streams.
IlRepl.Tui	The Hex1b widgets: transcript, prompt with completion palette, status bar.
IlRepl	The tool: command line, host client, batch mode.
IlRepl.Wasm	The browser build used by the docs.