Ruvim Text Editor Implementation

Implementation

Ruby + C Code.

Buffer

Bidirectional Linked List

Each character is a node in the list. A separate array can be mantained with the length, start, and end of the line.

Pros:

Fast Insert/Remove Operations
Easy to Implement
Each Character node can contain additional information
Other types of nodes can be used (Format, Special characters, etc)

Cons:

Not Memory efficient for large files.
Regex Search hard to implement.
Slow Loading

User Interface

Panel Alignment

Panel alignment is done keeping a Client constant containing the coordinates of a box describing the current available space in the screen.

Window Events

Update: Called when keyboard, mouse event or when the user resizes the terminal window.
Refresh: Signal Windows to refresh.
Redraw: Called when window needs to be completely redrawn.

Cursor Movement

Possible movements are:

Character: Up, Down, Left, Right
Word: Next, Previous
Line: Beggining, End, Next, Previous
Paragraph

API

Our Editor will have an API to allow programmers to write scripts and macros.

Mappings

Ruby's blocks are the perfect way to store editor macros.

Event Handling

Editor Features

Handling TABS

Handling TABS is simple. To Move forward we can simply used the formula tabsize - x % tabsize to count the number of spaces occupied by the TAB character. Moving Backwards is a bit more complicated. We need to count the space occupied by the text from the start of the line to the previous character.

Plugin System

Plugin module keeps track of plugins. There are two kinds of plugins:

Application Plugins: Global plugins available to the application class ($ruvim).
Editor Plugins: Editor Plugins constructed everytime a new editor instance is created