Problems generating a command

[marcyboy]

Hi just trying to get to grips with tcl.

I am having to use the Oracle version and it is difficult to understand what version I am using. (using the OMB extension set)

However, I am trying to open a file for reading by passing in the file name as a argument from the tcl script.

this all works OK

but when I try to open the file

set file_id [open $my_file_fqn w]

it fails I then tried to eval by

cmd [list "set file_id [open " $my_file_fqn w]]

eval $cmd

even when I separate it out it seems to put curley braces around the [


Any thoughts on this?

Is there a much easier way? Someone must have had to do this at sometime

many thanks

 

[Bong]

What if you use the file name directly? That is, instead of the value of the variable, "my_file_fqn", use the explicit file name. If that works, then somehow the variable is not set properly and I would suspect scope.

_________________
Bob Rashkin

 

[marcyboy]

Thnks Bong

dynamic file creation

I am making progress

this works:

# escape the [] as the parser still tries to subst the
# internal commands
set cmd1 [subst {\[open $my_big_file w\]}]
# list puts curley braces around so I used concat
#
set cmd2 [concat set file_id $cmd1]
eval $cmd2
puts $file_id "My big words"
close $file_id

but now the $file id seems to take over as stdout when called form UNIX!!

I havn't given up yet

I need to work out what happens to the stdout

 

[marcyboy]

managed to get this proc to work nicely
If anyone finds it of use.

It's a bit clunky and if anyone has a sleeker version let me know

proc dmic_file {file_fqn file_type} {
set cmd1 [subst {\[open $file_fqn $file_type\]}]
set cmd2 [concat set channel $cmd1]
eval $cmd2
global file_id
set file_id $channel
}

set my_big_file "/tmp/my_big_file.txt"

eval dmic_file $my_big_file w

puts $file_id "my big words"

close $file_id