Philipp Gesang  committed 802d993

[doc] completed documentation

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File doc/context/third/enigma/enigma_manual.tex

-\useurl [codebook]   []
-\useurl [luatex-web] []
-\useurl [chickenize] []
+\useurl [chickenize]    []
+\useurl [codebook]      []
+\useurl [key_procedure] []
+\useurl [luatex-web]    []
+\useurl [rotor_wirings] []
+\useurl [wp:day_key]    []
+        []              [\hyphenatedurl{\#Key_setting}]
+\useurl [wp:ring]       []
+        []              [\hyphenatedurl{\#The_ring_setting}]
 \startdocsection[title=Loading the Module/Package]
-  \TODO{instuctions for plain, latex + ctx}
   The intention is for the \modulename{Enigma} codebase to integrate
   with the three most popular (as of 2012) \TEX\ formats:
   problem translating between coding styles.
   Those familiar with \CONTEXT\ might, therefore, skip the following
   paragraphs and continue directly with the next section on
-  \at{page}[sec:opts].
+  \at{page}[sec:opts].%
   The package is loaded as usual. For \PLAIN, issue a
   placeholder for a list of \emph{assignments}, i.\,e. pairs of
   \emph{key=value} statements by means of which all further parameters
   are specified.
-  A list of possible parameters can be found in the next section,
+  The possible parameters are listed in the next section,
   examples of their effects will be given further below in the section
   on functionality (see \at{page}[sec:fun]).%
-    If you grasp the concept of paired \type{\define<foo>} --
+    If you grasp the concept of paired \type{\define<foo>} \endash\space
     \type{\setup<foo>} macros, then congratulations are in order:
     you qualify for migration from your current macro package to
 \startdocsection[title=Options Explained,reference=sec:opts]
+At the moment, the \texmacro{setupenigma} macro in any format  accepts
+the following parameters.
+% \startpostponing[+2]%% messes up floats -- why?
+  \placefigure[right]{Usage example for the \PLAIN\ format.}{
+    % \framed[align=right,frameoffset=1em]{%
+    \framed[align=right,frameoffset=1em,frame=off]{%
+      \startlatextyping[before=,after=,]
+      \input {enigma}
+      %% Definition ··········· %%
+      \defineenigma {encryption}
+      %% Setup ················ %%
+      \setupenigma  {encryption} {
+        other_chars = no,
+        day_key = I II III
+                  01 01 01,
+        rotor_setting = aaa,
+        verbose = 1,
+      }
+      %% Usage ················ %%
+      \startencryption
+        aaaaa aaaaa aaaaa
+        aaaaa aaaaa aaaaa 
+      \stopencryption
+      \startencryption
+        Nobody in Poland is going
+        to be able to read this,
+        har har!
+      \stopencryption
+      \bye
+      \stoplatextyping
+    }
+  }
+% \stoppostponing
+  \setuptolerance[tolerant]%% it’s crowded in here due to the float
   \def\item#1#2{% 1 name, 2 type
   \item{verbose}{integer} Controls overall verbosity level (\emph{global}!).
-\TODO{day key syntax, rotor settings strings etc.}
+%% day key
+To state the obvious, the value of \identifier{day_key} serves as the
+\emph{day key} for encryption. An Enigma day key ordinarily consists of
+(1) a list of the the rotor configuration,
+(2) the ring settings, and
+(3) the plugboard connections.
+Together these have the denotation \emph{day key}, because they are
+meant to be supplied in special code books by central authority, one for
+each day.\footnote{%
+  Read about the historical directives for daily key renewal at
+  \from[key_procedure]; also, don’t miss the explanation on Wikipedia:
+  \from[wp:day_key].
+In the \modulename{Enigma} setup, the day key starts
+with a triple of Roman numerals ({\sc i} to {\sc v}) describing which
+of the five rotors is located in which of the three slots.
+(e.\,g. \type{I VI II}).\footnote{%
+  For the individual wirings of the five rotors see
+  \from[rotor_wirings], as well as the implementation below at
+  \at{page}[listing:rotor_wiring].
+Its next part is the ring setting, a triple of two-digit integers that
+are the amount by which the internal wiring of each rotor has been
+shifted (\type{03 23 11}). As the Enigma encrypts only the letters of
+the Latin alphabet, sane values range from one (first position: no
+shift) to twenty six.\footnote{%
+  Consult \from[wp:ring] for an introduction into the ring mechanics.
+The third section specifies which pairs of letters are substituted by
+each other by means of plugboard connections (\type{NI CE GO LD ...}).
+There can be zero to thirteen of these redirections, thus the presence
+of this section is entirely optional.
+Also part of the \identifier{day_key}, but not mentioned yet, is the
+choice of the \emph{reflector}.
+It may be specified as one of the three letters \type{A}, \type{B} and
+\type{C} as the first item. If no reflector is requested explicitly, the
+machine defaults to \type{B}, which is actually the only one of the
+three models that had been in widespread use
+(see below on \at{page}[listing:reflector] for the wirings).
+Initialization is not complete without a \identifier{rotor_setting}.
+This is a triple of letters, each representing the initial state of
+one rotor (e.\,g. \type{fkd}). Historically this was not part of the day
+key but supposed to be chosen at random by the operating signal officer.
 %%% other_chars
+% The option \identifier{other_chars} determines how the machine -- in our
+% Unicode-aware times -- should behave when it encounters a non-Latin
+% letter. For the time being it can either remove them from the input
+% (value \emph{no}) or pass them through unmodified (\emph{yes}). Note
+% that this is independent of the \emph{preprocessing} of characters like
+% punctuation and umlauts, which is done automatically.
+% (See below \at{page}[listing:preproc] for the internal substitution
+% list.)
 Most documents don’t naturally adhere to the machine-imposed restriction
 to the 26 letters of the Latin alphabet. The original encipherment
 directives comprised substitution tables to compensate for a set of
 This will result in the thoroughly scrambled string
+\typ{omribshpwfrfjovkntgqgi abbkhjpxmhdztapkatwrvf}.
 Then, use the same settings you encrypted the text with in your

File doc/context/third/enigma/examples/enigma-example-context.tex

 \defineenigma [nilsettings]
 \setupenigma  [nilsettings] [ %% a machine with vanilla settings
   other_chars = no,
-  day_key = B I II III 01 01 01,
+  day_key = I II III 01 01 01,
   rotor_setting = aaa,
   verbose = 3,

File tex/context/third/enigma/enigma.lua

 local KERN_NODE                    = node and nodeid"kern"
 local DISC_NODE                    = node and nodeid"disc"
-local IGNORE_NODES = {
+local IGNORE_NODES = node and {
 --[GLUE_NODE] = true,
   [KERN_NODE] = true,
 --[DISC_NODE] = true,
+} or { }
     q = 17, r = 18, s = 19, t = 20, u = 21, v = 22, w = 23, x = 24,
     y = 25, z = 26,
+The five rotors to simulate.\reference[listing:rotor_wiring]{}
+Their wirings are created from strings at runtime, see below the
+function \luafunction{get_rotors}.
-    Wirings are created from strings at runtime.
   alpha_sorted = "abcdefghijklmnopqrstuvwxyz"
   raw_rotor_wiring = {
-\placetable[here][]{The three reflectors and their substitution
+\placetable[here][listing:reflector]{The three reflectors and their substitution
   local p_init = P{
     init               = V"whitespace"^-1 * Ct(V"do_init"),
-    do_init            = V"reflector"  * V"whitespace"
+    do_init            = (V"reflector" * V"whitespace")^-1
                        * V"rotors"     * V"whitespace"
                        * V"ring"
                        * (V"whitespace" * V"plugboard")^-1
     emit(1, pprint_machine_step, machine.step,
+The day key is entrusted to the function \luafunction{handle_day_key}.
+If the day key is the empty string or \type{nil}, it will ask for a key
+on the terminal. (Cf. below, \at{page}[listing:ask_for_day_key].)
+Lesson: don’t forget providing day keys in your setups when running in
+batch mode.
   local handle_day_key handle_day_key = function (dk, name, old)
     local result
     if not dk or dk == "" then
       dk = ask_for_day_key(name, old)
     result = lpegmatch(p_init, dk)
+    result.reflector = result.reflector or "b"
     -- If we don’t like the key we’re going to ask again. And again....
     return result or handle_day_key(nil, name, dk)
 If the machine setting lacks key settings then we’ll go ahead and ask
 the user directly, hence the function \luafunction{ask_for_day_key}.
 We abort after three misses lest we annoy the user \dots

File tex/context/third/enigma/t-enigma.mkvi

 %D \stopdocsection
 %D \startdocsection[title=Setup]
       local enigma = thirddata.enigma
       local current_args =
 %D All the logic is at the Lua end, not much to see here …
 %D \stopparagraph
     \catcodetable \txtcatcodes
-      \enigma_setup{#args}%
+      \enigma_setup_indeed{#args}%
-  \dodoubleempty\do_setup_enigma%
+  \dodoubleempty\enigma_setup%
 %D \stopdocsection