The book is the structure that orders the graphical queue elements (GQEs). It is a 2-dimensional array, addressed by a slot number and a subindex. SCAN, ARRAYs and the like have a non-zero slot number and a subindex that is zero. TEXTs, TAGs, etc. share the slot number with the SCAN they belong to. Apart from the indices GQEs have names. The functions book_name(), book_slot() and book_subindex() return the book information.
#!/usr/bin/perl -w use strict; use Spectra; Spectra::delete(); Spectra::Gra_command( " create t1 0 10 100"); Spectra::cls(); print "\n"; print " book_name(1) = " . Spectra::book_name( "1") . "\n"; print " book_name(t1) = " . Spectra::book_name( "t1") . "\n"; print " book_slot(t1) = " . Spectra::book_slot( "t1") . "\n"; print " book_slot(1) = " . Spectra::book_slot( "1") . "\n"; print " book_subindex(t1) = " . Spectra::book_subindex( "t1") . "\n"; print "---\n\n"; # # the output: # book_name(1) = T1 # book_name(t1) = T1 # book_slot(t1) = 1 # book_slot(1) = 1 # book_subindex(t1) = 0