On 1/2/07, Chris Rebert wrote:

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.

Right. I removed that back in August at the Google sprint. 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.

Big -1 from me. I hate this feature from Haskell. It is a step towards programmable syntax and I think that's just a messy. And having it become a magic method that is called instead of just some function that takes two arguments really sends us down that road. -Brett

On 1/2/07, Chris Rebert wrote:

Thus, I propose one of the following as the new use for the backtick (`):

You're missing one of the main reasons for removing the backtick syntax in the first place: the character itself causes trouble by looking too much like a regular quote (depending on your font), is routinely mangled by typesetting software (as every Python book author can testify), and requires a four-finger chord on Swiss keyboards. No new uses for it will be accepted in Python 3000 no matter how good the idea. -- --Guido van Rossum (home page: http://www.python.org/~guido/)