##Eskil Plugin : Swap sides of contents
#
# This plugin swaps data between files. A fairly useless thing.
# This is to test and exemplify how to use yield in a plugin.
# Example file for a plugin.
# A plugin's first line must start exactly like this one.
# The text after : is the summary you can get at the command line
# A plugin must define this procedure to do the job.
# side: left or right
# chi: An input channel for reading the original file.
# cho: An output channel for writing the processed file.
proc PreProcess {side chi cho} {
if {[info commands yield] eq ""} {
puts $cho "Swap plugin must be run with Tcl 8.6 or newer"
return 1
}
# Read all data from both sides
set ::data($side) [read $chi]
yield
# Output data from other side
if {$side eq "left"} {
puts $cho $::data(right)
} else {
puts $cho $::data(left)
}
# Signal that the file after processing should be used both
# for comparison and for displaying.
return 1
}