CS-521 Homework (editor)
In this assignment you will compare two implementations of storing text files:
• One continuous string (newline char as separator).
• List of strings where each string represents a line
Each of these representations has to be implemented as a separate set of functions and, of course, with separate Python file For each implementation, you will write editor functions to move the “cursor”. In each representation, you use a cursor to represent the current position. For example, for (1) the cursor is just the position (index). For (2), the cursor is a pair: the index of the line and the position within the corresponding line string. Finally, for (3) the cursor is a pointer to the node (containing the line) and the position within that line.
Write (and test) the following 10 functions (names are taken from old vi editor) for each implementation
• cmd_h: move cursor one character to the left
• cmd_I: move cursor one character to the right
• cmd_j: move cursor vertically up one line
• cmd_k: move cursor vertically down one line
• cmd_X: delete the character to the left of the cursor
• cmd_D: remove on current line from cursor to the end
• cmd_dd: delete current line and move cursor to the beginning of next line
• cmd_ddp: transpose two adjacent lines
• cmd_n: search for next occurrence of a string (assume that string to be searched is fully in one line.
• cmd_wq: write your representation as text file and save it
Think of and implement any other 5 functions (your choice)
For testing, you will read the following “nerdy” poem (from the “Zen of Python”) into your “file representation”.
Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
After each command, print the contents of your file with character ‘^’ as cursor.
Example: your initial configuration is
^Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
After executing cmd_n(‘better”), your representation should print:
Beautiful is ^better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.