Pokemon prolog

Because prolog can be awesome when you have to work with databases.

Installation

You will need swipl and node.js (for generating databases). Probably git and bash too.

If you are on linux, you should probably be able to install these tools by using your favorite package manager. On Windows, you will probably have to install them manually (sorry (a)). I strongly advise you to use Cygwin (but not for node) : it includes the right packages for swipl, git and bash.

Once you have all of this, just go into your home folder then type the following commands :

$> git clone git@github.com:arcanis/trivia.pokemon-prolog
$> cd trivia.pokemon-prolog
$> bin/generate-database
$> bin/start

You will have access to a new shell in which you will be able to type prolog commands. Pklib and pktools will be already loaded in the environment.

About Prolog

Backtracking

One of the key features of prolog is its ability to backtrack. It means that it will return every result which could match a predicate, replacing variables by the possible value. For example :

foo(a).
foo(b).

Will generate two facts named foo, which says basically that foo(a) is true, and foo(b) is true.

Now, if you try this in your terminal :

?- foo(X).
X = a;
X = b;

You will see that prolog has found two possible results for X : a or b.

It is a very useful feature, and it can be intensively used to iterate over almost any data providen by this library.

Predicates API

pkdb

Pkdb is the main data source. It contains everything about the pokeworld.

• pkdb:type_atomic(Type)

  Checks if Type is a type. It can also be used to backtrack over every type.

• pkdb:type_ratio(Attack, Defense, Result)

  Computes the ratio of an attack of type Attack over a pokemon of type Defense.

• pkdb:species_atomic(Species)

  Checks if Species is a pokemon species. It can also be used to backtrack over every pokemon species.

• pkdb:species_type(Species, Type)

  Checks if Species is of type Type. It can also be used to backtrack over every type of a species, or to get the species of a certain type.

• pkdb:species_evolution(Species, Evolution)

  Checks if Evolution is the evolution of Species. It can also be used to backtrack over every next-stage evolution of a species, or to get the pre-evolution of a species.

• pkdb:species_stat(Species, Stat, Value)

  Returns into Value the value of the stat Stat of the pokemon Species.

• pkdb:stat_atomic(Stat)

  Checks if Stat is a valid stat name. It can also be used to backtrack over every stat name.

  The current stats are hp, atk, def, spa (spe. atk), spd (spe. def) and spe (speed).

pklib

Pklib is a little library which gives you helper functions for some complex requests.

• pklib:type_ratio(Attack, Defense, Result)

  This predicate will compute into Result the ratio of an attack of type Attack over a pokemon of type Defense.

  As opposed to pkdb:type_ratio/3, this function accepts lists as parameter (to deal with composite defense type).

  Currently Defense cannot have more than two items, and Attack a single one.

  Example

  ?- pklib:type_ratio(X, [water, flying], Result), Result >= 2.0.
  X = [electric],
  Result = 4.0 ;
  X = [rock],
  Result = 2.0 ;
  

• pklib:species_evolutionary_line_root(Species, Result)

  This predicate will return into Result the base species of the evolutionary line Species.

  Example

  ?- pklib:species_evolutionary_line_root(ivysaur, X).
  X = bulbasaur.
  

• pklib:species_evolutionary_line(Species, Result)

  This predicate will return into Result the entire evolutionary line of Species.

  It also works with branched evolutionary lines.

  Example

  ?- pklib:species_evolutionary_line(cascoon, X).
  X = [wurmple, silcoon, beautifly] ;
  X = [wurmple, cascoon, dustox] ;
  

• pklib:species_evolutions(Species, Result)

  This predicate will return into Result the possible evolutions of Species.

  It also works with branched evolutionary lines.

  Example

  ?- pklib:species_evolutions(wurmple, X).
  X = [silcoon, beautifly] ;
  X = [cascoon, dustox] ;
  
  ?- pklib:species_evolutions(cascoon, X).
  X = [dustox] ;
  

• pklib:species_total_stats(Species, Result)

  This predicate will compute into Result the sum of all the stats of a species.

  Example

  ?- pklib:species_total_stats(Result, 200).
  Result = magikarp ;
  Result = feebas ;
  
  ?- pklib:species_total_stats(Result, 700).
  Result = kyurem_black ;
  Result = kyurem_white ;
  

More examples

Atk stat of all Eevee's evolutions

?- pkdb:species_evolution(eevee, Evolution), pkdb:species_stat(Evolution, atk, Atk).

SpAtk stat of every fully evolved fire pokemon

?- pkdb:species_atomic(Species), pkdb:species_type(Species, fire), \+ pkdb:species_evolution(Species, _), pkdb:species_stat(Species, spa, SpAtk).

Future

• Add moar functions to the API. Any idea of what could be useful ? Open an issue !
• Add moves into the database. With their power and precision. Probably some effects too (such as parallizis, burning, etc), but adding more will be hard.
• Write a script to compute an optimal team when battling a specific other team (I never really played 'hardcore', so I will need help of smogon players on this).
• If you have nice examples, open an issue and I will add it in the section (and credit you :).