--- title: Render the board - Implementing Chess with Ruby for beginners slug: render-the-board-implementing-chess-with-ruby-for-beginners published_at: 2021-05-28 23:29:52 +0000 updated_at: 2026-03-04 20:14:13 +0000 summary: description: In this series we're building a basic terminal based Chess game with Ruby for beginners with the goal of discussing various object oriented concepts. In this episode we create a factory method for creating a pre-configured board. * Factory methods * Single responsibility principle - create a BoardRendererText class rather than printing directly from the board class Playlist: https://www.youtube.com/playlist?list=PLS6F722u-R6LZxh7mvEUvZKshcH6KSNhr Code: https://replit.com/@CJAvilla/chess#main.rb tags: [Implement chess with Ruby] views: 772 author: CJ Avilla url: https://www.cjav.dev/videos/render-the-board-implementing-chess-with-ruby-for-beginners youtube_url: https://www.youtube.com/watch?v=B4FU0oO0uOw youtube_id: B4FU0oO0uOw embed_url: https://www.youtube.com/embed/B4FU0oO0uOw thumbnail_url: https://i.ytimg.com/vi/B4FU0oO0uOw/hqdefault.jpg type: video --- # Render the board - Implementing Chess with Ruby for beginners *Published: May 28, 2021* *Views: 772* ## Watch [Watch on YouTube](https://www.youtube.com/watch?v=B4FU0oO0uOw) [![Render the board - Implementing Chess with Ruby for beginners](https://i.ytimg.com/vi/B4FU0oO0uOw/hqdefault.jpg)](https://www.youtube.com/watch?v=B4FU0oO0uOw) ## Description In this series we're building a basic terminal based Chess game with Ruby for beginners with the goal of discussing various object oriented concepts. In this episode we create a factory method for creating a pre-configured board. * Factory methods * Single responsibility principle - create a BoardRendererText class rather than printing directly from the board class Playlist: https://www.youtube.com/playlist?list=PLS6F722u-R6LZxh7mvEUvZKshcH6KSNhr Code: https://replit.com/@CJAvilla/chess#main.rb ## Transcript hey you're back welcome back again to uh some more chess so in the last episode we talked about pieces we built out a lot of pieces uh and in our testing our board while we have a basic board set up it's spitting out in a really nasty way so what we want to do in this episode is build a tool that will render our board into the terminal so what we're going to do is we're actually going to build a separate class for rendering our board our board class should really only be responsible for maintaining the internal representation and having a little bit of validation logic so we're actually going to separate this out into a separate class we're going to create a new class called um maybe like board like terminal or like cli board renderer or something like that board render boardrender.rb like technically you could build renderers that would take in an instance of the board and render it as html or render it as like plain text for the terminal actually that's what we should call it board render plain text we'll just call it text board render render text okay and so this is going to be class board renderer text and it's responsible for knowing how to take in a board and render it as text in a way that we could like look at the text of it and know that we're talking about chess here so we're going to initialize with an instance of the board class and we're going to say board is equal to board and then we're going to have a method here called render and this is going to return the string representation of the board that is going to look nice hopefully we'll see so what we want to do is say maybe board um yeah we can make this a reader so adder reader board we want to say board dot grid dot um let's see so in this case um i'm wondering if we should just do like eight dot times do and that'll give us the row and then eight times do column just to like iterate over because we know that this is going to be a chess board this would only work for chess boards otherwise we would need to like reach into the board and figure out stuff about its grid but i think we might be able to do this so every time there's a new row maybe we want to like put like um a line or something and then for each column in the row we want to i think use print and we want to print out the value at that row and column so now we want to say like board at the location row and column and i i don't know let's just see uh let's just see how that works we might also need like after we've printed out all of those we probably want like puts just like a normal new line so now we want to take this board renderer text come back over here instead of just printing out the grid for the board we're going to initialize a new one of these with our board and then we'll say renderer is this thing and then we'll say renderer let's let's say uh text board and we'll say text or dot render and we'll puts it out and just see what this looks like it's a little bit of trial and error here so pawn on line four it's getting the wrong number of arguments oops all right run let's see what we get uninitialize constant because we haven't required it yet so we're going to want to require everything that's that's in there so i think we can actually do something like um oh gosh i think it's like durr well yeah instead of like fighting with it i think it's probably easiest just to like put in the answer um okay but we're gonna need yeah we're gonna need like the rest of these rook uh knight king queen uh did we get them all bishop okay so we've got bishop board renderer i'm going to make these alphabetical order so we want this one at the very top the reason i'm doing alphabetical order is just so i can look at the file list on the left and really quickly read through and see that we've done all of these correctly we can make this a little smaller and we've got our board then we've got our king then knight then pawn then queen then rook okay i think we're good all right let's see what we can do now so we run this oh wow look at that that looks pretty neat let's go back to our board class and we want to actually make this 8x8 and uh initially let's just start off with like an array so this is this is interesting so we say array.new and i think if we pass in eight i think it'll create eight so let's just actually this um irb i'm gonna say array dot new and that'll give us back a new array and if we say array.new and we pass in an element that'll give us that many uh items and then i think we can pass this a block that will run for each element and then i think we can also say array.new let's see if that works okay so that'll give us an array of arrays eight arrays of arrays array.new and then we can just assume that something else is setting it up one thing that we might want to do is implement a factory method for initializing a board which would create a board and also set it up as like a brand new board so let's do that now i'm actually just going to remove this so a factory method is a class method that generally creates instances of those classes for you so instead of calling like board new we'll call board dot setup chess or something like or board dot start chess and that will create a board and set it up for a new game of chess so we could set it up for it's playing like eight queens or some other some other game so we could say like def self dot um start chess and what this will do is it'll create a new instance of the board so we can actually say like self.new and that'll be like our board and then we want to put all the pieces on the board so i'm going to require all of the pieces just the pieces not the board itself and not this so in replit you can hold down command and click and it'll give you like multiple cursors that's a nice handy feature so now we can say like board at um okay how do we want to do this so we want to we want to create eight pawns and eight yeah so eight pawns we want to say like eight dot times do board at one and then so that'll be the column 1c is equal to pawn.new and we'll pass in black i think i believe this should create um eight pawns and put them on the first row at each of the columns and then we can come back over to main and say like board dot start chess and that should do some stuff and then give us back a board that is initialized and all right so board renderer line 9 8 times do what is going on here no implicit conversion of array into integer ah so i think that yeah so we didn't actually like populate the array here in our board right we created eight new arrays but those arrays don't actually have elements yet so i think that's what we need to do is make it eight arrays with empty no okay let's see so board renderer text on line 12 for board renderer text line 12 printing the board of row and column so let's puts um or p r and c and see where it's failing zero zero okay so board at zero zero we're getting back huh implicit conversion of array into integer so initialize with board what's going on here ah start chess okay so board dot start chess this was a factory method it's supposed to return the instance and right now it's returning the array so we need to actually say board at the end here okay so we can say run and oh awesome okay we're getting closer we are definitely getting closer our board renderer we don't need to print this out anymore instead we just need to print the actual things that are there and okay fantastic this is looking so good okay so in addition to our like symbol that we're printing out let's also print a space so i'm just going to use string interpolation here to put in the value of the the piece that's at that position and then i'm adding a space here so it adds a space after it let's see if that's enough to give us some wiggle room okay oh fantastic all right so we've got everything set up online um yep on this first line and then we have space space and then we're actually i don't know where the other why we're not printing the other lines oh wow okay so some something in the rendering here i have to like scroll a little bit for that to work um that's okay all right so if we go back to our board class we want to do this same thing but instead of line on on line one we want to put on line seven i think and this is going to be our white pieces um i don't actually know for sure if like which side of the board they show up on or if that even matters um but now we've got some white pieces at the bottom that's fantastic actually i think this is six which is seven when we're zero indexed so i think yeah i think we want six there okay we are starting to see a chess board take shape here uh folks okay so this is super cool all right so the next thing that we want to do is um let's add the pawns and or the rooks and knights and all that stuff so uh okay so let's see so if we wanted to do board at uh zero zero that is going to be a rook rook.new and i think that's going to be black and um okay so we can do like uh yeah so we want zero and seven dot each do and that's going to be our row um or maybe it doesn't matter we can we don't have to get too fancy all right so we've got a we've got a rook on either end so 0 and 7 should give us a rook and then we also want the same thing but with white ones here wait 0 oops i put the 0 in the wrong spot 0 and seven and then down here we're gonna have seven and zero and seven i think that should give us the rooks in the right spots um okay sort of getting warmer uh i think what's happening is that where there's no where there's no piece here we're only printing out one space instead of multiple spaces which is i think that's um i think that's all right let's go back to our board renderer and if this is nil um yep so we might say like if if the position is nil at on the board here so let's say peace is this if piece dot nil then we want to print like two spaces otherwise we'll print the whole thing and later on we can talk about the null object pattern which is helpful for things like this but for now we should be able to just get away with something simple like that so we run and now our rooks are in the right spots at least oh look on both ends okay fantastic all right let's keep going i think we also want to put like print a full line at the very bottom just to like give the board a little bit more dimension all right so we go back to our board here and we're still sort of setting things up um what i was thinking of doing was like saying like zero comma black and seven comma white dot each do and then what we can do is destructure each of those arrays so we're going to iterate over each of these subarrays and we're going to be emitted like this array element but what we can do is if we put inside of parentheses we can destructure that array into the like row and color and i'm going to move this over a bit since we don't need too much space here and what that does is that buys us this row right and then this is the color and i think that will make it so that we only have to do this like that and if we run it again i believe okay cool we're showing up in the same spots so this should totally work and i think we can iterate just like this to create the other pieces also so what's one in from the rook i think that's the the knight so we'll copy these and paste them and i think we want to go one and six and these are going to be night queen and the queen okay so the king and the king all right so they're facing each other i don't know if there's like technical reasons why they need to be like right next to each other but at this point we now have a factory method that creates a new instance of the board so calling self.news creating a new instance of the board so now because we started the method with self dot that means that it's available on the class level so back here we can call board dot start chess instead of board dot new right so where we have board renderer.txt.new that initializes an instance but new is not really a factory method it's just like the built-in constructor constructor function and so here we created a factory method that would start our board with the default configuration for chess now if we wanted to we could come back here and create another start like constructor function that we or a factory function factory method factory function whatever for creating a board that just had like one element on it or whatever um what's nice about this is that when the board is created it's empty it doesn't have anything on it's just nil right and so technically if we wanted to we could say board.new and this would just create an empty board for us and if we wanted to then we could just place one piece in one specific position and feel like play around with it and see where it goes without needing to like change the internals of the board to like delete all the pieces or remove all the pieces or make moves so start chess is a factory method on the board class which is super helpful for rendering out or like setting up the board and then we created this board renderer that takes in an instance of the board and helps us print it out so those are kind of the two things that i wanted to cover in this episode uh hopefully that's useful and uh yeah these factory methods are are really handy for constructing or doing like setup stuff that you might need and especially useful if you wanted to create like separate several different ways of constructing instances yep so that's it if you enjoyed this episode great awesome if you if you give it a thumbs up then other folks will be able to find it and i'd really appreciate that and uh yeah otherwise i'll see you in the next one [Music] cheers --- [Back to all videos](https://www.cjav.dev/videos) --- ## Hey Agent, thanks for visiting! 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