how to update tcl variable value in file using tcl?

Question

I have 2 tcl file, in data.tcl file i am keeping flag bits and test.tcl file work based on the flag value . I need to reset the flag value in data.tcl after every test . could you please help me to do the same. I tried the following code but its not working

data.tcl file contains flag variable:

set mac 1 
set xmac 0 
set fea 0

test.tcl script file which has a function to set flag values to 1 or 0 :

  set testcase mac 
  set fp [open "data.tcl" r+] 

  while { [gets $fp data] >= 0 } { 
    set var $data 
    if { [lindex $var 1] == $testcase } { 
       set fp1 [open "data.tcl" w+] 
       while { [gets $fp1 data1] >= 0 } { 
            set var1 $data1 
            if { [lindex $var1 1] == $testcase } { 
            set [lindex $var1 2] 0 
            } 
        close $fp1 
     } 

  close $fp 
   }   
 } 

close $fp

I have tried the above code but I am not able to update the value of the variable. Please do help on this.

I am writing automation script, where test runs if the particular flag bit is set to one in data.tcl file. After completing the first task, I need to reset the MAC flag value to 0 and I need to set xmac flag file 1 and remaining flags to 0.

before running test script flag values in data.tcl

set mac 1 
set xmac 0 
set fea 0 
set fea1 0

after 1st run: expected content of data.tcl file:

  set mac 0 
  set xmac 1 
  set fea 0 
  set fea1 0

after 2nd run: expected content of data.tcl file:

  set mac 0 
  set xmac 0 
  set fea 1 
  set fea1 0

after 3rd run: expected content of data.tcl file:

  set mac 0 
  set xmac 0 
  set fea 0 
  set fea1 1

Hope you guys got my requirement.

Your update to the question is fundamentally different from the original question, and your current 'attempt' at the problem does not address your updated requirements.Please make a new question highlighting the clear requirements and your attempt at those requirements — Jerry, Jan 11 '18 at 08:07

score 1 · Accepted Answer · answered Jan 10 '18 at 09:23

Opening the file with the w+ flag doesn't mean the values in the file will change if you simply set a few value (and set [lindex $var1 2] 0 is likely not doing what you think it's doing). You have to puts the new value(s). I'd advise putsing the modified content to a different file and then rename it. Something like this possibly:

set testcase mac 
set fp [open "data.tcl" r]
set fp1 [open "data_temp.tcl" w]

while {[gets $fp data] >= 0} { 
  if {[lindex $data 1] == $testcase} {
    # Change this line's 2nd element to 0
    lset data 2 0
  }
  # Write the line to the temp file
  puts $fp1 $data
}

close $fp
close $fp1

# Delete the old file
file delete -force data.tcl
# Rename the temp file to the old name
file rename -force data_temp.tcl data.tcl

On Tcl before 8.4 (if that's the case, you should upgrade if possible), you can use set data [lreplace $data 2 2 0] instead of lset data 2 0

Thank you, it fixed the issue . – Nagesh HS Jan 10 '18 at 10:05 — Nagesh HS, Jan 10 '18 at 10:05

how to update tcl variable value in file using tcl?

1 Answers1