Design a text editor

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    Design a text editor including its UI.

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    This is a really a big topic.

    1. platform.
      is this a text editor in 3d engine , browser or desktop ?
      if it is in a 3d egnine, you may need to consider how to render the font.
      if it is a browser based, the textarea tag is not that powerful, so you may need to consider to expand of it.
    2. features
      What kind of features of this editor support ?
      1. Undo/Redo you need track the history by a stack, you can cache all the history state of the text, but what if the text is so big ? Therefore you need to cache the diff about each change, however, if the user type "hello world", cache the each world or each char ?
      2. Cusor and Multi cusor. Insert into the cusor. the basic idea is we can split the file into seveval lines, then we can use the col/row to track where the cusor is, then when you insert a char at the cusor, this is really a insert an element into an array. Image if we open a big file, this will be very slow, because you will need to move the char one by one. It will be worse if you need to render the font or you need render typesetting of the text, you may need to recalculate everything. Therefore you need a data strcuture here to speed up the insertion and deletion. Rope will be an option here, it like binary tree, split a large string by different pieces, so you don't need to move all the char, just move those at the same leaf.
      3. Selection and Copy Paste. If you select lines of text, you will need to compute all the leaf in our rope, and need to consider how to rebalance the tree.
      4. Search. Well trie will be the option here.
      5. Grammer highlight. First you will need a parser here. and the text editor should have api that support render the font in differnt color. If we are designing something target to the browser, we should not use textarea anymore, in this case, all the text should be render as a html file, the cusor should be an element in that html, we render it by caculating the position.
      6. Plugins system. You will need to support a script language in your editor. and provide some api about things like uodo/redo, get the text, change the format of selected text etc.
      7. Decoding/Encoding. You will need to select right charset based on the file automatically, otherwise you will have wrong data show on the screen.
      8. Typesetting.
      9. Support markup/lex

    Well that what i got so far.

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    @facetothefate its a real interview question that failed me :)

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    I am so sorry.

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    @facetothefate That's a great thought process. This gives a good big picture. At this point, Any interviewer will take part of problem such as how you will implement Trie and go deeper into interview.

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    This post is deleted!

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