TCL use a variable to contain list of arguments for format command

The “format” command expects separate arguments, not a list. You can use this syntax:

puts [format $fmt {*}$valList]

The “{*}” syntax expands the list into separate arguments to a command.

Good catch David.  Not a lot of people using the {*} syntax in Cloverleaf but it a very valuable command for your toolbox.  It was added in Tcl 8.5.  See below for usage and examples.

https://wiki.tcl-lang.org/page/%7B%2A%7D

The “{*}” syntax explains how to write this the way you originally proposed, but I thought of another way to do this that may be simpler. Instead of dynamically building the format string and using that to generate the output string, it may be easier to dynamically generate the output string. Something like this:

set v1 A
set v2 B
set valList { C D E }
set outVal [format “%-40.40s %-7.7s ” $v1 $v2]
foreach v $valList {
append outVal [format “%-10.10s” $v]
}
puts $outVal

• This reply was modified 3 years, 11 months ago by David Barr.
• This reply was modified 3 years, 11 months ago by David Barr.

Lots of ways in Tcl to do the same things.  For example:

set fmt “%-40.40s %-7.7s %-10.10s %-10.10s %-10.10s”
set valList “A  B  C  D  E”
set cmd {format $fmt}

foreach var $valList {set cmd [concat $cmd $var]}

echo [eval $cmd]

I would still prefer the {*} paradigm.

The {*} was created because eval can be a pain at times