yaegi

Usage

Run Go source under the embedded yaegi interpreter (a pure-Go implementation of the Go language, v0.16.1). Stdlib only — no cgo, no module fetches. Each invocation runs in a fresh interpreter; nothing persists between calls.

Primary form — full program via stdin

Pass args: ["run"] and send a complete package main program on stdin. This is the cleanest form: only your program's output is returned.

{ "args": ["run"], "stdin": "package main\nimport "fmt"\nfunc main(){ fmt.Println("hi") }" }

Quick one-liner — -e

Pass args: ["-e", "<statements>"] to evaluate statements in an implicit main. fmt is preloaded; additional import statements are NOT permitted in this mode.

{ "args": ["-e", "for i:=0;i<3;i++ { fmt.Println(i) }"] }

Other subcommands

yaegi version → prints "0.16.1" yaegi help [cmd] → usage info yaegi test [path] → run test funcs in a package yaegi extract pkgs... → generate wrapper file for a package

Pitfalls

• Stdin with NO args drops into a REPL-style mode that echoes expression values and a trailing pointer. Always pass ["run"] when sending a full program on stdin.
• run -e <src> also leaks a trailing pointer to stdout. Use plain -e for snippets, or run + stdin for full programs.
• In -e mode, put each statement on its own line; semicolons inside one -e string can confuse the parser around imports.