Hy representations

New in version 0.13.0.

hy.contrib.hy-repr is a module containing a single function. To import it, say:

(import [hy.contrib.hy-repr [hy-repr]])

To make the Hy REPL use it for output, invoke Hy like so:

$ hy --repl-output-fn=hy.contrib.hy-repr.hy-repr


Usage: (hy-repr x)

This function is Hy’s equivalent of Python’s built-in repr. It returns a string representing the input object in Hy syntax.

=> (hy-repr [1 2 3])
'[1 2 3]'
=> (repr [1 2 3])
'[1, 2, 3]'

If the input object has a method __hy-repr__, it will be called instead of doing anything else.

=> (defclass C [list] [__hy-repr__ (fn [self] "cuddles")])
=> (hy-repr (C))

When hy-repr doesn’t know how to handle its input, it falls back on repr.

Like repr in Python, hy-repr can round-trip many kinds of values. Round-tripping implies that given an object x, (eval (read-str (hy-repr x))) returns x, or at least a value that’s equal to x.