Re: [Xotcl] Passing a switch non-positional argument
Created by hypermail2xowiki importer, last modified by Stefan Sobernig 02 Jan 2017, at 11:15 PM
From: Gustaf Neumann <neumann_at_wu-wien.ac.at>
Date: Thu, 02 Mar 2006 02:32:56 +0100
Kurt,
passing around the actual values of the non-positional arguments
with next or with a forwarder is already very conveniant, but this
was not your question.
Passing unary non-pos arguments to some explicit method invocations
is some typing work, but straightforward. Passing a switch is painful.
Your example can be made somewhat shorter
eval my p1 [expr {$sw? "-sw" : ""}] [list -opt $opt]
list is needed to protect the value of opt, if it contains e.g.
a $, spaces etc. But still, the preceding eval reminds me on the days
of otcl and does not win a beauty contest.
For your example, i would tend to use boolean non-pos-args instead.
We introduced the 0-argument switch mostly for oacs, which
uses a similar construct already for it's ad_proc. When one defines
in xotcl a public/private method with boolean, as in
SomeClass method -private true foo {x y } ....
this looks rather stupid compared to
SomeClass method -private foo {x y } ....
However, in many other situations, the notation with
the boolean argument as in
obj -someflag on
or
obj -debug true
looks from the aesthetical point of view quite ok to me.
-gustaf neumann
Date: Thu, 02 Mar 2006 02:32:56 +0100
Kurt,
passing around the actual values of the non-positional arguments
with next or with a forwarder is already very conveniant, but this
was not your question.
Passing unary non-pos arguments to some explicit method invocations
is some typing work, but straightforward. Passing a switch is painful.
Your example can be made somewhat shorter
eval my p1 [expr {$sw? "-sw" : ""}] [list -opt $opt]
list is needed to protect the value of opt, if it contains e.g.
a $, spaces etc. But still, the preceding eval reminds me on the days
of otcl and does not win a beauty contest.
For your example, i would tend to use boolean non-pos-args instead.
We introduced the 0-argument switch mostly for oacs, which
uses a similar construct already for it's ad_proc. When one defines
in xotcl a public/private method with boolean, as in
SomeClass method -private true foo {x y } ....
this looks rather stupid compared to
SomeClass method -private foo {x y } ....
However, in many other situations, the notation with
the boolean argument as in
obj -someflag on
or
obj -debug true
looks from the aesthetical point of view quite ok to me.
-gustaf neumann
