modern Tcl and correct quoting

[Lawrence Velázquez]

On Jun 12, 2013, at 6:18 PM, Poor Yorick <org.macosforge.lists.macports-dev at pooryorick.com> wrote:

> [eval] concatenates its arguments and passes them through the interpreter again
> to be parsed and executed as a script.  This results in double substitution.
> Here's an example from the patch:
> 
>    $workername eval "package ifneeded $pkgName $pkgVers {$pkgLoadScript}"
> 
> The first issue with this is that if, e.g., $pkgName contained a space, the
> constructed script would no longer be syntactically correct, as it would pass
> too many arguments to [package ifneeded].  The second issue is that simply
> putting braces around a substituted variable like $pkgLoadScript is not
> guaranteed to result in a well-formed single value.  If $pkgLoadScript contains
> a left or right curly bracket, or if it ends in a backslash, the script will be
> corrupted.  .  The robust way to write the line above is like this:
> 
> 	$workername eval [list package ifneeded $pkgName $pkgVers $pkgLoadScript]
> 
> http://wiki.tcl.tk/1535 has more details.


Is there a material difference between using list here and doing something like this?

    $workername eval {package ifneeded $pkgName $pkgVers $pkgLoadScript}

vq