You can use regexp here Bob. You can also use the string commands. The problem with regexp is making sure to escape any special characters.
For example, if you know the field separator is * and the element separator is ~, you can define a pattern like:
set pat {ISA*.*?~IEA.*?~}
Then get all of the ISA .. IEA in a list like:
set list [regexp -all -inline — $pat $msg]
I sometimes prefer to use the string commands. string commands in Tcl are highly optimized and you don’t have to worry about special characters
First find start and end locations and put in a list of pairs
This assumes you have extracted the field, component and element separators into variables
set locList {}; set offset 0
set ndx [string first “ISA$fldSep” $msg $offset”
while {$ndx >= 0} {
lappend locList $ndx
incr offset 4 ;# Step past last ISA
set ndx [string first “ISA$fldSep” $msg $offset]
if {$ndx >= 0} {
lappend locList [expr $ndx – 1]
}
}
# Now put end as end of last one if any
if {![lempty $locList} {lappend locList end}
# Now you can extract your ISA .. IEA
set msgList {}
foreach {start end} $loclist {
lappend msgList [string range $msg $start $end]
}
I hope you get the idea here. You could combine these steps but I find it more self documenting this way.
FWIW, according to Jeff Hobbs at Active State, there is no command you can execute that is more optimized than the string commands.
Hope this helps
Charlie
