repl

Yup Shell (yupsh)

An interactive shell — a REPL — for the gloo-foo ecosystem. It composes the gloo-foo/framework typed-stream pipeline out of the gloo-foo/cmd-* command modules, giving a familiar shell interface backed entirely by type-safe Go commands — no external processes for the core tools.

The prompt is yup>; the program is yupsh (Yup Shell, like bash/fish).

Pages

• Usage — running the shell, the input model, examples
• Commands — the command catalogue and what is/isn’t wired
• Architecture — how a line becomes a pipeline; adding a command
• Development — the quality gate, integration tests, contributing

Features

• Typed-stream pipelines — every stage is a gloo.Command[[]byte, []byte], composed with | and run through the framework’s RunContext.
• Source and filter commands — sources (echo, seq, ls, find, yes, emit) start a pipeline; filters (grep, wc, sort, …) transform it.
• Unix-style flags — wc -l, grep -v, head -n 10, cut -d , -f 2, the GNU head -5/tail -3 shorthand — translated to each command’s typed options.
• Shell expansion — globbing (*, ?, […]) and ~ expand against the filesystem; quotes suppress expansion; non-matching globs stay literal.
• File or stdin input — file arguments on the first command are opened as the pipeline’s input; otherwise input is read from stdin.
• Interactive history & editing — on a TTY, up/down history and in-line editing via golang.org/x/term; piped input uses plain scanning.
• Built-ins — help, version, clear, exit/quit, and # comments.

Install

go install github.com/yupsh/repl/yupsh@latest

Installs a yupsh binary to $GOPATH/bin (or $HOME/go/bin).

Quick start

yupsh REPL v0.2.0
Yup Shell — a typed-stream REPL over gloo-foo/framework and cmd-* commands.
Type 'help' for commands, 'exit' to quit.

yup> echo hello world
hello world
yup> seq 1 10 | grep -v 5 | head -n 3
1
2
3
yup> wc -l *.go