[Python-ideas] new operators via backquoting (original) (raw)

Chris Rebert cvrebert at gmail.com
Wed Jan 3 01:07:31 CET 2007

In Haskell, foo baz bar means (baz foo bar), which translates to baz(foo, bar) in Python. This allows Haskell programmers to use functions as infix operators. If I recall correctly, in Py3k, enclosing something in backticks will no longer cause it to be repr()-ed, leaving the backtick without a meaning in Python.

Thus, I propose one of the following as the new use for the backtick (`): [Note: In both, the characters between the backticks must be a valid Python identifier.]

(A) baz is treated as an operator, named "baz", just as / is "div". foo baz bar thus causes python to try to call foo.baz(bar), and failing that, bar.rbaz(foo), and if both those fail, raise TypeError. This is, if I understand correctly, how the builtin operators work.

(B) baz is a special way to call a callable. foo baz bar is translated to baz(foo, bar) with the standard lookup rules for resolving "baz"

Example use cases, stolen from Haskell: The Craft of Functional Programming: 2 max 5 => 5 7 cons tail => ConsCell(val=7, next=tail) matrix1 crossproduct matrix2 => cross-product of the matrices [1, 2, 3] zip ['a', 'b', 'c'] => [[1, 'a'], [2, 'c'], [3, 'c']]

I believe that this would improve the readability of code, such as Numeric, without going off the deep end and offering programmable syntax.

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