'''Background'''

TIP #144 ''Argument Expansion Syntax''
[http://www.tcl.tk/cgi-bin/tct/tip/144.html]
(and the earlier TIP #103 ''Argument Expansion Command''
[http://www.tcl.tk/cgi-bin/tct/tip/103.html])
proposes to add syntax to Tcl to perform argument expansion in a safe
and efficient manner.

For example, instead of having to write:

 eval [linsert $args 0 exec $program]

The TIP would allow one to say:

 exec $program {}$args

where the leading '''{}''' indicates that the remainder of the
word shall be parsed as a list (after applying the usual substitution rules),
and each element of the list is passed as a separate argument to the command.

Naturally, there has been a great deal of discussion about what
syntax should be used to indicate argument expansion.  The two
most popular options seem to be {} and ` (backquote).

The main advantage of the {} syntax is that it can be added to
Tcl 8.5 without breaking backwards-compatibility,
as such usage is currently a syntax error.
Any other option would have to wait until Tcl 9.0.

A similar poll was conducted on the tcl-core mailing list. The result
is on the [Argument Expansion Poll Summary] page.

'''Poll'''

The purpose of this poll is to get a feel for the Tcl community's
preferences regarding the proposed syntaxes.
The poll is in two parts: the first asks which syntax would be preferable
''if backwards compatibility were not an issue''.
The second asks if the backwards-compatible syntax would be
acceptable if it meant the feature could be introduced earlier.

Please vote by signing your name or initials after the proposed option.

Discussion moved to [DISCUSSION: Argument Expansion Syntax]

'''Part 1: which syntax do you prefer?'''

''Option 1: leading {}'':
[Vince], [RS], [Roy Terry], [Jeffrey Hobbs], [EB]

''Option 2: leading `'':
[Joe English], [Jacob Levy], [David Welton], [ramsan], [lv], [SO], [US]

''Option 3: other (please specify)'':
   * ''leading {expand}'' [DGP], [Daniel Steffen], [MS], [KBK], [Peter Spjuth], [de], [Donald Arseneau]
   * ''leading @'': [Larry Smith]
   * ''$(<whatever you want expanded>)'': [Larry Smith], [Steve Redler IV] ''([EB]: This syntax can't be used, this is an empty array name dereference, used in [stooop], for example)''
   * ''[[expand <whatever you want expanded>]]'' If someone can do it: [Steve Redler IV], [MAK]
   * ''^^$foo and ^^[[foo]]'' : [Setok]
   * Added functionality to Tcl that allows "macro" commands: commands can edit the calling command line. Dangerous in a semi-Tclish fashion. F.ex.  file join [[expand $MyList]] : [Setok]

''Option 4: neither'':
marc, THIRION

''Option 5: anything, just give me the functionality'':
[KPV], [ulis]

'''Part 2: Is {} acceptable for Tcl 8.5?'''

''Yes, {} is acceptable'': [DGP], [Vince], [Daniel Steffen], [RS], [KBK], [Peter Spjuth], [Roy Terry], [EB]

''Yes, ` is acceptable (never mind the slight chance of breakage)'': [lv], [US]

''Yes, $() is acceptable'': [Larry Smith], [Steve Redler IV]

''Yes, anything is acceptable'': [KPV], [ulis]

''No, wait until Tcl 9 to add the feature'':
[Joe English], [Jacob Levy], marc, THIRION, [SO], [Setok]

''No, we do not need this functionality'':
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