C ENCRYP-- Encrypt password
C
C Declarations
C
SUBROUTINE ENCRYP(INW,OUTW)
IMPLICIT INTEGER (A-Z)
INCLUDE 'dparam.for'
CHARACTER*8 INW,OUTW,KEYW
INTEGER UINW(8),UKEYW(8)
DATA KEYW/'ECOVXRMS'/


ICHARA=ICHAR('A')-1 ! character base.
UINWS=0 ! unbiased inw sum.
UKEYWS=0 ! unbiased keyw sum.
J=1 ! pointer in keyword.
DO 100 I=1,8 ! unbias, compute
sums.
UKEYW(I)=ICHAR(KEYW(I:I))-ICHARA ! strip ascii.
IF(ICHAR(INW(J:J)).LE.ICHARA) J=1 ! recycle on bad.
UINW(I)=ICHAR(INW(J:J))-ICHARA
UKEYWS=UKEYWS+UKEYW(I)
UINWS=UINWS+UINW(I)
J=J+1
100 CONTINUE


USUM=MOD(UINWS,8)+(8*MOD(UKEYWS,8)) ! compute mask.
DO 200 I=1,8
J=(UINW(I).XOR.UKEYW(I).XOR.USUM).AND.31
USUM=MOD(USUM+1,32)
IF(J.GT.26) J=MOD(J,26)
OUTW(I:I)=CHAR(MAX0(1,J)+ICHARA)
200 CONTINUE
RETURN


END

To decide what indexed text is the encryption of (x - an indexed text):
let keyw be {5, 3, 15, 22, 24, 18, 13, 19};
let outw be an indexed text;
let uinws be 0;
let usum be 0;
let inw be a list of numbers;
let i be 1;
let j be 1;
change outw to "[8 spaces]";
let len be the number of characters in x;
while i is at most 8 begin;
  if j is greater than len, change j to 1;
  let a be character number j in x;
  if a matches the regular expression "<^A-Z>", change j to 1;
  let a be character number j in x;
  let b be the alphabet position of a;
  add b to inw;
  increase uinws by b;
  increase i by 1;
  increase j by 1;
end while;
change usum to (the remainder after dividing uinws by 8) + 56;
change i to 1;
while i is at most 8 begin;
  let c be entry i of inw;
  let b be entry i of keyw;
  change j to the twiddle of c and b and usum;
  change j to the remainder after dividing j by 32;
  if j is greater than 26, change j to the remainder after dividing j by 26;
  change a to character number j in the alphabet;
  replace character number i in outw with a;
  change usum to the remainder after dividing (usum + 1) by 32;
  increase i by 1;
end while;
decide on outw.

To decide what number is the twiddle of (a - a number) and (b - a number) and (c - a number):
  (- xor(xor({a},{b}),{c}) -).

To decide which number is the alphabet position of (n - an indexed text):
if n is "A", decide on 1;
if n is "B", decide on 2;
if n is "C", decide on 3;
if n is "D", decide on 4;
if n is "E", decide on 5;
if n is "F", decide on 6;
if n is "G", decide on 7;
if n is "H", decide on 8;
if n is "I", decide on 9;
if n is "J", decide on 10;
if n is "K", decide on 11;
if n is "L", decide on 12;
if n is "M", decide on 13;
if n is "N", decide on 14;
if n is "O", decide on 15;
if n is "P", decide on 16;
if n is "Q", decide on 17;
if n is "R", decide on 18;
if n is "S", decide on 19;
if n is "T", decide on 20;
if n is "U", decide on 21;
if n is "V", decide on 22;
if n is "W", decide on 23;
if n is "X", decide on 24;
if n is "Y", decide on 25;
if n is "Z", decide on 26.

The alphabet is an indexed text variable.  The alphabet is always "ABCDEFGHIJKLMNOPQRSTUVWXYZ".

Incanting is an action applying to one topic.  Understand "incant [text]" as incanting.
Check incanting:
if endgame flag is true, say "[one of]Sorry, only one incantation to a customer.[or]Incantations are useless once you have gotten this far[at random]" instead.

Carry out incanting:
let i be the number of words in the topic understood;
  let a be word number one in the topic understood;
  change a to "[a in upper case]";
  let b be word number two in the topic understood;
  change b to "[b in upper case]";
if i is 1 begin;
  if the player is not in Crypt of the Implementors, say "That spell has no obvious effect." instead;
  if not in darkness, say  "That spell has no obvious effect." instead;
  if the player is carrying something lit, say "That spell has no obvious effect." instead;
  let b be character number 1 in a;
  if b matches the regular expression "<^A-Z>", say "Sorry, your secret word must begin with a letter." instead;
  say "A hollow voice replies '[encryption of a]'";
  change the score to 621;
  change endgame flag to true;
  move the battery-powered brass lantern to the player;
  move the sword to the player;
  move the player to Top of Stairs.
else if i is 2;
 let c be character number one in a;
  let d be character number one in b;
 if c matches the regular expression "<^A-Z>", say "That spell has no obvious effect." instead;
  if d matches the regular expression "<^A-Z>", say "That spell has no obvious effect.";
  let e be the encryption of a;
  let f be the encryption of b;
  if e is b, skip to the endgame instead;
  if f is a, skip to the endgame instead;
  say "That spell has no obvious effect.";
else;
  say "That spell has no obvious effect.";
end if.

Is the WTF in the actual implementation of the algorithm, or is it the programming language? On a first glance, the Inform code is much easier to read than the Fortran code (that is without having ever used either language), and I'm impressed that this kind of computation is even possible in Inform. 

This reminds me of the the Shakespeare Programming Language, but Inform is actually productive. Very cool.

Nandurius:

Is the WTF in the actual implementation of the algorithm, or is it the programming language? On a first glance, the Inform code is much easier to read than the Fortran code (that is without having ever used either language), and I'm impressed that this kind of computation is even possible in Inform. 

This reminds me of the the Shakespeare Programming Language, but Inform is actually productive. Very cool.

 The programming language is not the WTF -- it makes sense to use a programming language for writing Z-code text adventures for implementing a text adventure.

 The WTF is using a bunch of ifs to get the alphabet position rather than a select case. Other than that, the rest of code is actually pretty goodl

Compared to what a FORTRAN-to-C compiler would generate this actually looks more readable. A very nice example of how Inform 7 rocks, even if it tends to hyperverbosity.

samanddeanus:

 The WTF is using a bunch of ifs to get the alphabet position rather than a select case. Other than that, the rest of code is actually pretty goodl

Inform 7 doesn't seem to have a general purpose switch statement, as far as I can tell, so the only way I can see you'd get it much better is by using "otherwise" (else). Sure, you can drop down to Inform 6 code and just put a block in there, but they might not have wanted to do that.

(Granted, I haven't really worked with either version of Inform.)

j6cubic:

A very nice example of how Inform 7 rocks, even if it tends to hyperverbosity.

It looks decidedly less verbose than ordinary C# + .Net

samanddeanus:

Carry out incanting:
let i be the number of words in the topic understood;
  let a be word number one in the topic understood;
  change a to "[a in upper case]";
  let b be word number two in the topic understood;
  change b to "[b in upper case]";

Good God, that looks like an unholy love-child of code from Graham Nelson and Eric S. Raymond. No, wait, if ESR was involved, this would have more proto-anci-fennoscandonian rune-poemtry. I don't know if Futhark works in these forums, so here's a reasonable approximation of what I pictured...

Før værilþy, We šalt chantt,
inne ðeus wenne øeure harþs wert fyl øf joye,
ánde fyl øf zeale ánde fyl øf brevry førre fáþer-landynn:
  værilþy šalt be "i", numbyr be øf wordes inne topícyn knéwnstød;
  værilþy šalt be "á", þe word fyrst, by Odin, offe topícyn knéwnstød;...

Okay, joking aside, the obvious question: Is there a reason why the implementation has to use this particular encryption method? Why can't it use something that would be, uh, more Inform-friendly?

(Edit: Okay I didn't read the code before writing the above AltGr-orgy, so it's not an exact dupe, but I guess I made the point =)

WWWWolf:

Okay, joking aside, the obvious question: Is there a reason why the implementation has to use this particular encryption method? Why can't it use something that would be, uh, more Inform-friendly?