From c80ccdd7bae68d04204192ef7ce9a4d893040d93 Mon Sep 17 00:00:00 2001
From: Nathaniel Wesley Filardo <nwf@cs.jhu.edu>
Date: Fri, 16 Dec 2016 00:59:54 -0500
Subject: [PATCH] New morse module

---
 morse/morse.lua     | 80 +++++++++++++++++++++++++++++++++++++++++++++
 morse/morsetest.lua |  6 ++++
 2 files changed, 86 insertions(+)
 create mode 100644 morse/morse.lua
 create mode 100644 morse/morsetest.lua

diff --git a/morse/morse.lua b/morse/morse.lua
new file mode 100644
index 0000000..7676893
--- /dev/null
+++ b/morse/morse.lua
@@ -0,0 +1,80 @@
+-- utilities for handling morse code
+local malpha =
+ { [30] = '33333' -- 0
+ , [31] = '13333'
+ , [32] = '11333'
+ , [33] = '11133'
+ , [34] = '11113'
+ , [35] = '11111'
+ , [36] = '31111'
+ , [37] = '33111'
+ , [38] = '33311'
+ , [39] = '33331' -- 9
+ , [97] = '13' -- a
+ , [98] = '3111'
+ , [99] = '3131'
+ , [100] = '311'
+ , [101] = '1'
+ , [102] = '1131'
+ , [103] = '331'
+ , [104] = '1111'
+ , [105] = '11'
+ , [106] = '1333' -- j
+ , [107] = '313'
+ , [108] = '1311'
+ , [109] = '33'
+ , [110] = '31'
+ , [111] = '333'
+ , [112] = '1331'
+ , [113] = '3313'
+ , [114] = '131'
+ , [115] = '111'
+ , [116] = '3' -- t
+ , [117] = '113'
+ , [118] = '1113'
+ , [119] = '133'
+ , [120] = '3113'
+ , [121] = '3133'
+ , [122] = '3311' -- z
+ }
+
+return function (istr)
+  local function fail() return nil end
+  local strix = 0 -- last character of istr moved to cstr
+  local chix = 0 -- last position of ch shifted out
+  local on = false
+  local cstr
+
+  local function nextcstr()
+    cstr = nil; chix = 0;
+    if strix < istr:len() then
+      strix = strix + 1 
+      local b = istr:sub(strix,strix):lower():byte(1)
+      cstr = malpha[b] or '666'
+    end
+  end
+
+  local function nextt()
+    if on then
+     on = false
+     if chix  < cstr:len() then return 1, false end
+     nextcstr()
+     return (cstr and 3), false
+    elseif chix < cstr:len() then
+      chix = chix + 1
+      local c = cstr:sub(chix,chix)
+      if c == ' ' then return 7, false end
+      on = true
+      return tonumber(cstr:sub(chix,chix)), true
+    else return nil
+    end
+  end
+
+  nextcstr() -- prime pump
+
+  -- cb takes: on/off, duration in dits (1,3,7)
+  return function(cb)
+    local t,p = nextt()
+    if t then cb(t,p); return true else return false end
+  end
+end
diff --git a/morse/morsetest.lua b/morse/morsetest.lua
new file mode 100644
index 0000000..18e2f8c
--- /dev/null
+++ b/morse/morsetest.lua
@@ -0,0 +1,6 @@
+morse = dofile("morse/morse.lua")
+
+function tm(str)
+  local m = morse(str)
+  while m(print) do end
+end
-- 
2.50.1