adding docs for 24 game

extra/24-game/24-game-docs.factor

@@ -0,0 +1,67 @@
+USING: help.markup help.syntax math kernel ;
+IN: 24-game
+
+HELP: play-game ( -- )
+{ $description "Starts the game!" }
+{ $examples
+    { $unchecked-example
+        "USE: 24-game"
+        "play-game"
+        "{ 8 2 1 2 }\n"
+        "Commands: { + - * / rot swap q }\n"
+        "swap\n"
+        "{ 8 2 2 1 }\n"
+        "Commands: { + - * / rot swap q }\n"
+        "-\n"
+        "{ 8 2 1 }\n"
+        "Commands: { + - * / rot swap q }\n"
+        "+\n"
+        "{ 8 3 }\n"
+        "Commands: { + - * / swap q }\n"
+        "*\n"
+        "You WON!"
+    }
+} ;
+
+HELP: 24-able ( -- vector )
+{ $values { "vector" "vector of 4 integers" } }
+{ $description
+    "Produces a vector with 4 integers. With the following condition: "
+    "If these integers were directly on the stack, one can process them into 24, "
+    "just using the provided commands and the 4 numbers. The Following are the "
+    "provided commands: "
+    { $link + } ", " { $link - } ", " { $link * } ", "
+    { $link / } ", and " { $link swap } "."
+}
+{ $examples
+    { $example
+        "USE: 24-game"
+        "24-able vector-24-able?"
+        "t"
+    }
+    { $notes { $link 24-able? } " is used in " { $link 24-able } "." }
+} ;
+
+HELP: 24-able? ( quad -- t/f )
+{ $values
+    { "quad" "vector of 4 integers" }
+    { "t/f" "a boolean" }
+}
+{ $description
+    "Tells if it is possible to win 24-game if it was initiated "
+    "with this sequence."
+} ;
+
+HELP: build-quad ( -- array )
+{ $values
+    { "vector" "an array of 4 numbers" }
+}
+{ $description "Builds an array of 4 random numbers." } ;
+ARTICLE: "24-game" "The Game of 24"
+"A classic math game, where one attempts to create 24, by applying "
+"arithmetical operations and some shuffle words to a stack of 4 numbers. "
+{ $subsection play-game }
+{ $subsection 24-able }
+{ $subsection 24-able? }
+{ $subsection build-quad } ;
+ABOUT: "24-game"