Data commit

Task/Substitution-cipher/Lambdatalk/substitution-cipher.lambdatalk

@@ -0,0 +1,52 @@
+{def small_ascii {S.map fromCharCode {S.serie 33 122}}}
+-> small_ascii
+
+{S.length {small_ascii}} = 90
+
+{def substitution
+
+ {def substitution.r
+  {lambda {:w :n :s :i}
+   {if {> :i :n}
+    then
+    else {let { {:s :s} {:c {W.char2code {A.get :i :w}}}
+              } {if {and {>= :c 33} {<= :c 122}}
+                 then {W.code2char {+ 33 {% {+ :c {- :s 33}} 90}}}
+                 else {if {= :c 248} then :c else}}
+         }{substitution.r :w :n :s {+ :i 1}} }}}
+
+ {lambda {:s :w}
+  {let { {:s :s} {:w {S.replace \s by ` in :w}}
+       } {S.replace `
+                 by space
+                 in {substitution.r {A.split :w}
+                                    {- {W.length :w} 1}
+                                    :s
+                                    0}} }}}
+-> substitution
+
+1) intitial text:
+
+{def txt
+Veni, Vidi, Vici is a Latin phrase popularly attributed to Julius Caesar who, according to Appian, used the phrase
+in a letter to the Roman Senate around 47 BC after he had achieved a quick victory in his short war against
+Pharnaces II of Pontus at the Battle of Zela.
+} -> txt
+
+2) choose the shift:
+
+{def shift 13}
+-> shift // valid in [0...90] except 5 10 15 29 30 50 53 70 74
+
+3) encoding the text
+
+ {substitution {shift} {txt}}
+-> cr!v9mcvqv9mcvpvmv&mnmYn'v!m#u%n&rm#"#(yn%y,mn''%vo('rqm'"mW(yv(&mPnr&n%m*u"9mnpp"%qv!tm'"mN##vn!9m(&rqm'urm#u%n&rmv!mnmyr''r%m'"m'urm_"zn!m r!n'rmn%"
+(!qmADmOPmns'r%murmunqmnpuvr)rqmnm$(vpxm)vp'"%,mv!muv&m&u"%'m*n%mntnv!&'m]un%!npr&mVVm"sm]"!'(&mn'm'urmOn''yrm"smgryn;
+
+4) decoding the text
+
+ {substitution {- 90 {shift}} {substitution {shift} {txt}}}
+-> Veni, Vidi, Vici is a Latin phrase popularly attributed to Julius Caesar who, according to Appian, used the phrase
+in a letter to the Roman Senate around 47 BC after he had achieved a quick victory in his short war against
+Pharnaces II of Pontus at the Battle of Zela.