Vulpin REPL

An interactive REPL for Vulpin. Keeps a single VM alive for the whole session — variables, functions and labels persist across inputs — and includes live, as-you-type syntax highlighting, multi-line block support (?...;, @...&, F...~, etc.), and a handful of REPL-only commands.

Build

The REPL links directly against Vulpin's own VM/parser (vm.c/vm.h), vendored as a plain clone rather than committed here, so grab that first:

git clone https://github.com/vulpin-lang/Vulpin vendor/Vulpin

Then build:

cd repl
make            # -> ./vulpin-repl
make clean

Requires gcc and GNU readline (used only for history storage, e.g. on Arch: sudo pacman -S readline; on Debian/Ubuntu: sudo apt install libreadline-dev).

Usage

./repl/vulpin-repl              # start an interactive session
./repl/vulpin-repl script.vul   # load & run a file first, then drop into the REPL
./repl/vulpin-repl --debug      # dump the parsed AST for every accepted input
./repl/vulpin-repl -e 'G 1+2'   # run one snippet non-interactively and exit

Inside the REPL, write Vulpin exactly as you would in a .vul file — see the Vulpin README for the language itself. A few examples:

vul> x=5
vul> G x
5
vul> @ i < 3
  ...> G i
  ...> i=i+1
  ...> &
0
1
2

Multi-line constructs (?/:/;, @/&, O/&, F/~, T/C/Y, W/V/N/Z) are detected automatically — the prompt switches to ...> until the block is closed, then the whole thing runs at once.

REPL commands

Command	Effect
:help	show the command list
:vars	list variables assigned so far, with their current values
:load <file>	parse & run a .vul file into the current session
:debug	toggle AST dump for each accepted input
:reset	start a fresh VM, clearing all state
:abort	discard a pending, not-yet-closed multi-line input
:quit / :q	exit

Editing

The input line has its own raw-mode editor (not GNU readline) so it can recolor tokens live as you type: Left/Right/Home/End/Delete/Backspace, Ctrl-A/Ctrl-E/Ctrl-K, Up/Down for history, Ctrl-C to clear the current line, Ctrl-D on an empty line to exit. History persists across sessions in ~/.vulpin_history.

Colors are used automatically when stdout is a terminal, and skipped automatically when piped (e.g. in scripts or tests).