Re: Are parenthesis-free calls a Good? (was Re: patch: C-style string
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- Subject: Re: Are parenthesis-free calls a Good? (was Re: patch: C-style string
- From: Doug Rogers <rogers@...>
- Date: 2008年1月31日 11:10:06 -0500
alex.mania@iinet.net.au wrote:
> Not quite.
> f "A" .. "B"
> will raise a syntax error, presumably to reduce confusion.
As was pointed out in another thread, this does not produce a syntax
error but rather a run-time error. And only if 'f "A"' does not return a
string:
$ lua
Lua 5.1.2 Copyright (C) 1994-2007 Lua.org, PUC-Rio
> f = function(s) return s .. '*' end
> print(f "a" .. "b")
a*b
> g = function(s) return 4 end
> print(g "a" .. "b")
4b
> h = function(s) return end
> print(h "a" .. "b")
stdin:1: attempt to concatenate a nil value
stack traceback:
stdin:1: in main chunk
[C]: ?
>
Note that the second one (g) succeeds only because Lua runs tostring()
on the number returned by g(); that's another debate for another day.
Doug
--
Innovative Concepts, Inc. www.innocon.com 703-893-2007 x220