Question

I have the following code where I’m trying to match data on a single line into different variables via the regexp function.
The number of data (on the input line) and then of variable names in regexp function can vary, that’s why I use $varLine (which is previously processed in my real code).

set in_stim "13 1 1 0 1 0 0 0 2 03"
set regex {^(\d+)\s([01])\s([01])\s([01])\s([01])\s([01])\s([01])\s([01])\s(\d+)\s(\d+)}
set varLine "sig1 sig2 sig3 sig4 sig5 sig6 sig7 sig8 sig8"
regexp $regex $in_stim whole sig0 $varLine
puts "sig0: $sig0"
puts $sig1

When I am executing it, I get the following error ($sig0 is correctly displayed):

    sig0: 13

    can't read "sig1": no such variable
    while executing
"puts $sig1"

If I manually substitute $varLine into the regexp line, the error disappears:

set in_stim "13 1 1 0 1 0 0 0 2 03"
set regex {^(\d+)\s([01])\s([01])\s([01])\s([01])\s([01])\s([01])\s([01])\s(\d+)\s(\d+)}
regexp $regex $in_stim whole sig0 sig1 sig2 sig3 sig4 sig5 sig6 sig7 sig8 sig8
puts $sig0
puts $sig1

I get the following correct output:

13
1

Does anyone see mistakes in my code or could help?
Thanks!

Answer 1

The issue is that the regexp command doesn’t take a list of variables to store submatches into as one argument, but rather as many arguments.

The simplest method of working around this is to expand the variable list:

regexp $regex $in_stim whole sig0 {*}$varLine