Re: ideas for lambda syntax

[oliver <oliver.schoenborn@...>]

Thanks for coming back to the original topic of the thread. I must say, MoonScript has a very nice syntax in general. It has the expressivity of Python but seems able to keep the underlying simplicity and versatility of Lua. 

On Sat, Apr 13, 2013 at 5:03 AM, steve donovan <steve.j.donovan@gmail.com> wrote:

To return to Oliver's question, I think short-function syntax makes particular sense with _interactive_ work. For instance, Francesco Abbate's gsl-shell[1] uses the |x| x+1 short form popularised by metalua to great effect, since one's often creating short functions.

The point is that interactive usage requires finger-friendly syntax that you would not necessarily want in formal code, much as in English contractions like "it's" are not so appropriate in reports.

There are a number of ways to get that informal style. You can use metalua itself interactively.  Or use LuaMacro, which does not care about which Lua version is used:

LuaMacro $ lua52 luam -i

Lua 5.2.2  Copyright (C) 1994-2013 Lua.org, PUC-Rio

Lua Macro 2.3.0 Copyright (C) 2007-2011 Steve Donovan

> f = \x(x+1)

> = f(2)

3

LM defines a short function form based on a suggestion by lhf (a lexical macro system isn't clever enough to do |x|...)

Or even use a full-blown Lua-based language like MoonScript, which is particularly friendly for interactive work because the call operator has a very low precedence

$ mooni

MoonScript version 0.2.3

Note: use backslash at line end to start a block

> f = (x) -> x+1

> f 2

3

mooni is an experimental interactive version [2]. Sometimes problems make more sense with a more appropriate notation!

steve d.

[1] http://www.nongnu.org/gsl-shell/doc/intro.html

[2] 'luarocks --from=http://rocks.moonscript.org install mooni'.  If you don't have Git, then first grab moonscript using regular luarocks server.