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REPL

Running gopy with no script drops into the interactive prompt. The banner matches CPython's:

gopy 0.12.0 (3.14.0+) [go1.26 darwin/arm64]
Type "help", "copyright", "credits" or "license" for more information.
>>>

Behaviour​

Each line is parsed in mode="single". Expression statements print their value via sys.displayhook, so

>>> 2 + 2
4

is real output, not a print call.

A blank line ends a multi-line block. The classic continuation prompt is ... :

>>> def double(x):
...     return x * 2
...
>>> double(21)
42

History​

gopy uses myreadline/ for line editing. The history file path is the same one CPython uses: $XDG_STATE_HOME/python_history, falling back to ~/.python_history.

Hooks​

The REPL respects sys.displayhook, sys.excepthook, and sys.__interactivehook__. Replacing displayhook is the canonical way to customise how repr-style output is rendered.

>>> import sys
>>> def loud(value):
...     if value is None: return
...     print(f"=> {value!r}")
>>> sys.displayhook = loud
>>> 1 + 1
=> 2

Soft and hard exits​

Ctrl-D on an empty line exits cleanly. Ctrl-C raises KeyboardInterrupt at the current prompt and clears the in-progress buffer. exit() and quit() are real functions that raise SystemExit.