Variable in curly bracket double quote tcl - tcl

Question

I am working this script I want script to replace the second line of my session.mvw file so I am asking input "name" if I enter 2222 as input I expect the second line of my session.mvw file as {GRAPHIC_FILE_1 = "E:/ge work/hyperview scripting/222.rst"}
but instead its only giving
{GRAPHIC_FILE_1 = "E:/ge work/hyperview scripting/${name}.rst"}.
puts "Enter your name: "
#flush stdout set name [gets stdin]
set in [open session.mvw r]
# get the path to the parent directory
set hostDir [file dirname session.mvw]
set tempfile "$hostDir/temp2.txt"
# open/create a temp file
set out [open $tempfile w]
set count 0
while { [eof $in] != 1 } {
gets $in line
#set firstItem [lindex $line 0] incr count
# a match has been found...
if {$count == 2 } {
puts $out {GRAPHIC_FILE_1 = "E:/ge work/hyperview scripting/${name}.rst"}
} elseif {$count == 3} {
puts $out {GRAPHIC_FILE_1 = "E:/ge work/hyperview scripting/${name}.rst"}
} else {
puts $out $line
}
}
close $in
close $out
close $hostDir
# over-write the existing file
#file rename -force $tempfile session_file.mvw

Answer 1

Tcl's got a general rule that it doesn't do substitutions inside braces. That's usually exactly the right thing. However, in this case you need something a bit more. For these sorts of cases, there's the subst command which does do those substitutions:
puts $out [subst {GRAPHIC_FILE_1 = "E:/ge work/hyperview scripting/${name}.rst"}]
(Note: If you're generating Tcl code with subst, you're probably doing it wrong. Not that this is what you're doing in this case, but still it's a warning to all readers…)

Answer 2

If you want to have braces around the value, you could do this
puts $out [list "GRAPHIC_FILE_1 = \"E:/ge work/hyperview scripting/${name}.rst\""]
or this
puts $out "{GRAPHIC_FILE_1 = \"E:/ge work/hyperview scripting/${name}.rst\"}"
both of which print the string
{GRAPHIC_FILE_1 = "E:/ge work/hyperview scripting/222.rst"}