AlternateLambdaSyntax

As it stands, Guido van Rossum has suggested that lambda forms will disappear in ["Python3.0"]. This started a number of threads on comp.lang.python suggesting alternate syntaxes for lambda in the hopes that one of them might be more amenable to GvR's tastes. This pages summarizes these suggestions:

Current Syntax

   1 lambda a, b, c:f(a) + o(b) - o(c)
   2 lambda x: x * x
   3 lambda : x
   4 lambda *a, **k: x.bar(*a, **k)
   5 ((lambda x=x, a=a, k=k: x(*a, **k)) for x, a, k in funcs_and_args_list)

New Syntaxes

Args Before Expression

Nick Coghlan: def-to syntax [1]

   1 (def (a, b, c) to f(a) + o(b) - o(c))
   2 (def (x) to x * x)
   3 (def () to x)
   4 (def (*a, **k) to x.bar(*a, **k))
   5 ((def (x=x, a=a, k=k) to x(*a, **k)) for x, a, k in funcs_and_args_list)

Nick Coghlan: def-arrow syntax [1]

   1 (def (a, b, c) -> f(a) + o(b) - o(c))
   2 (def (x) -> x * x)
   3 (def () -> x)
   4 (def (*a, **k) -> x.bar(*a, **k))
   5 ((def (x=x, a=a, k=k) -> x(*a, **k)) for x, a, k in funcs_and_args_list)

Alex Martelli: def-as syntax [2]

   1 (def (a, b, c) as f(a) + o(b) - o(c))
   2 (def (x) as x * x)
   3 (def () as x)
   4 (def (*a, **k) as x.bar(*a, **k))
   5 ((def (x=x, a=a, k=k) as x(*a, **k)) for x, a, k in funcs_and_args_list)

Dave Benjamin: fun syntax [7]

   1 (fun(a, b, c): f(a) + o(b) - o(c))
   2 (fun(x): x * x)
   3 (fun(): x)
   4 (fun(*a, **k): x.bar(*a, **k))
   5 ((fun(x=x, a=a, k=k): x(*a, **k)) for x, a, k in funcs_and_args_list)

Expression Before Args

Nick Coghlan: for syntax [6]

   1 (f(a) + o(b) - o(c) for (a, b, c))
   2 (x * x for (x))
   3 (x for ())
   4 (x.bar(*a, **k) for (*a, **k))
   5 ((x(*a, **k) for (x=x, a=a, k=k)) for x, a, k in funcs_and_args_list)

Robert Brewer: for (no-parens) syntax [3]

   1 (f(a) + o(b) - o(c) for a, b, c)
   2 (x * x for x)
   3 (x for ())
   4 (x.bar(*a, **k) for *a, **k)
   5 ((x(*a, **k) for (x=x, a=a, k=k)) for x, a, k in funcs_and_args_list)

Nick Coghlan: def-from syntax [4]

   1 (def f(a) + o(b) - o(c) from (a, b, c))
   2 (def x * x from (x))
   3 (def x from ())
   4 (def x.bar(*a, **k) from (*a, **k))
   5 ((def x(*a, **k) from (x=x, a=a, k=k)) for x, a, k in funcs_and_args_list)

Michael Spencer: from-args syntax [5]

   1 (f(a) + o(b) - o(c) from args(a, b, c))
   2 (x * x from args(x))
   3 (x from args())
   4 (x.bar(*a, **k) from args(*a, **k))
   5 ((x(*a, **k) from args(x=x, a=a, k=k)) for x, a, k in funcs_and_args_list)

Michael Spencer: for-args syntax [5]

   1 (f(a) + o(b) - o(c) for args(a, b, c))
   2 (x * x for args(x))
   3 (x for args())
   4 (x.bar(*a, **k) for args(*a, **k))
   5 ((x(*a, **k) for args()) for x, a, k in funcs_and_args_list)

Bengt Richter: colon-function-application syntax [9]

   1 (:f(a) + o(b) - o(c))(a, b, c)
   2 (:x*x)(X)
   3 (:x)()
   4 (:x.bar(*a, **k))(*a, **k)
   5 ((:x(*a, **k))(x=x, a=a, k=k) for x, a, k in funcs_and_args_list)

Page

User

Current Syntax

New Syntaxes

Args Before Expression

Expression Before Args

References