gnuplot - Changing title within loop -

i using gnuplot 5.0, , have data set plot using

key1 = 'some title multiple words' key2 = 'some other descriptive title ' key3 = '...and third title' plot for[i=1:3] datafile index i-1 using 1:2 lines title eval('key'.i) 

this not working, have different string multiple words each curve. using words() , word() not work. so, how can change title in plot-for command?

gnuplot 5.0 introduces limited support using quoted strings word , words:

keys = '"some title multiple words" '.\        '"some other descriptive title" '.\        '"...and third title"' plot for[i=1:3] i*x lines title word(keys, i)