Data update

Task/Substring/Pluto/substring.pluto

@@ -0,0 +1,26 @@
+require "uchar"
+
+local s  = uchar.of("αβγδεζηθ")
+local n = 3
+local m = 3
+local kc = "δ"   -- known character
+local ks = "δε"  -- known string
+-- For reference.
+print("Index of characters:  12345678")
+print($"Complete string:      {s}")
+-- Starting from n characters in and of m length
+print($"Start {n}, length {m}:    {s:sub(n, n + m - 1)}")
+-- Starting from n characters in, up to the end of the string
+print($"Start {n}, to end:      {s:sub(n)}")
+-- Whole string minus last character.
+print($"All but last:         {s:sub(1, -2)}")
+-- Starting from a known character within the string and of m length.
+local dx = s:find(kc)
+if dx then
+    print($"Start '{kc}', length {m}:  {s:sub(dx, dx + m - 1)}")
+end
+-- Starting from a known substring within the string and of m length.
+local sx = s:find(ks)
+if sx then
+    print($"Start '{ks}', length {m}: {s:sub(sx, sx + m - 1)}")
+end