CSC1002代写、代做Python编程设计

日期：2025-05-07 10:58

CSC1002 – Computational Laboratory

Console-Based Editor - Multi-Line - 2025

OVERVIEW

In this assignment, you are going to design and develop a simple, basic console-based editor to support

multi-line editing. Unlike the modern, advanced editor such as Microsoft Word which provides users

with a sophisticated editing environment, utilizing the high-resolution of the graphical screen together

with the mouse and the keyboard to position and adjust any text and figures displayed on the screen,

giving us the WYSIWYG (What-You-See-Is-What-You-Get) experience.

In the early days, lacking access to a rich graphical display and mouse, the functionality of editors was

limited, providing only a much simpler user interface, usually console-based. Editing was carried out

based on simple text commands entered via the keyboard, commands such as inserting (i) and

appending (a) a text string, positioning the editor cursor one character position to the left (h), one

character position to the right (l), one-word position forwards (w), one-word position backwards (b), and

so on.

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CSC1002 – Computational Laboratory

SCOPE

1. Complete all the following editor commands:

• NOTE: Refer to the section “Specific Spec” for more information on particular

requirements and the section “Assumptions” for any conditions for which the program

is designed and implemented.

2. Case-sensitive commands - all editor commands are case-sensitive, for example, the capital

letter ‘A’ does not equal the lowercase letter ‘a’.

3. Command types - most commands are single-letter (in lower case) commands (such as ?, $, x, ^,

…etc), while some are two-letter (such as dw). Most commands do not require extra input,

while a few do, such as insert (i) and append (a).

4. Command prompt (>) - The prompt is a single character string ‘>’ by calling input(‘>’). See the

screenshots on the first page.

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5. Command Syntax - “Command[Text]”, where “Command” is one of the commands shown in

step 1, “Text” applies only to commands requiring extra input such as insert (i) and append (a).

Any commands whose description includes a substring enclosed in “<>” brackets require extra

input “Text”. “LineNo” is an integer value indicating the line number to which the line cursor

position is set.

6. Command Parsing - the user types a single command and then presses the return key to

continue. Parse each command string according to “Command Syntax” to ensure that the input

string matches EXACTLY one of the commands from step 1, including the extra input “Text” if

required. When invalid input is entered, simply display another prompt as illustrated in the

following screenshot.

a. Examples of valid command input:

i. “$”

ii. “^”

iii. “h”

iv. “l”

v. “ahello world”

vi. “i hello world “

b. Examples of invalid command input:

i. “ $”

ii. “ ?”

iii. “? “

iv. “ ahello world”

v. “i”

7. Command Execution - the editor will repeatedly prompt the user to enter an editor command,

parse the input according to the “Command Syntax”, execute the command (if valid), and then

output the latest editor content (even there are no changes to the content) on the display

console (except for commands ‘?’ and ‘q’, see Note follows). After the editor content is

displayed, the editor will display another prompt (‘>’) on a new line. Refer to the section

“Sample Output” for more examples.

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CSC1002 – Computational Laboratory

Note: when the help command (?) is entered, output only the help menu as shown in step 1;

when the quit command (‘q’) is entered, terminate the program.

NOTE:

• Keep your entire source code in ONE SINGLE file.

• Use only Python modules as specified in the “Permitted Modules” section.

• In your design stick ONLY to functions, in other words, no class objects of your own.

o Furthermore, the lines of code containing the sub-function(s) defined within another

function will be counted as part of the parent function.

o NOTE: Failure to adhere to the instructions outlined in the assignment handout will

result in a 50% reduction in the coding style score.

SPECIFIC SPEC

1. Editor content - the editor shows its content, if any, as a single or multiple lines of text string

constructed by one or multiple Insert/Append/Paste commands. If the row cursor is enabled, it

shows its position in a color such as green. If the line cursor is enabled, the content will be

shifted one space to the right to show line cursor as a ‘*’ symbol. When the editor program

initially starts, its content is empty. Refer to the section “Sample Output” for more examples.

2. Row cursor - it’s used to show where the cursor is on the current row if not empty. In other

words, the cursor will appear on printable characters including space. The cursor is shown by

wrapping a character with a pair of escape character strings such as “\033[42m” and “\033[0m”.

For example, given a string “hello world”, to show the green cursor at the position of the letter

‘e’, this is the string to print: “h” + “\033[42m” + “e” + “\033[0m” + “llo world”.

3. Insert - the given string “Text” will be inserted to the left of the cursor and the cursor position

will be changed to the beginning of the “Text” string.

4. Append - the given string “Text” will be inserted to the right of the current cursor position and

the cursor position will be changed to the end of the “Text” string.

5. Delete word - delete all characters from the cursor position to the beginning of the next word or

to the end of the line. When all characters are deleted, the line becomes empty. Refer to the

following figures for an illustration.

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CSC1002 – Computational Laboratory

6. Delete Character - delete the character at cursor. When all characters are deleted, the line

becomes empty.

7. Cursor left and right - when repositioning the cursor to the left or right, one or multiple

positions, and if the cursor is already at the far left or far right position, leave the cursor where it

is.

8. Undo - it’s used to reverse the action of the last valid command, including change(s), if any,

made to the editor content and/or the cursor (row, line) position(s). Once a command is

undone, it’s no longer available for future Undo and Repeat. If multiple consecutive undo

commands are executed, each will undo one command at a time in the reverse order that the

commands were originally executed. For example, given the last 2 valid commands are “ahello”

followed by “a world”, the first undo command will reverse the “a world”, and the second

consecutive undo command will reverse “ahello”. Commands such as “s” and “?’ are not

candidates for Undo as they do not make any changes to the editor content, the same applies to

Repeat command. Refer to the following figure for an illustration.

9. Repeat - The “Repeat” command is used to re-execute the last valid command and it offers the

convenience of sparing the user from retyping it again. Commands “u”, “?”, and “s” are not

candidates for the “Repeat” command as these commands do not directly update the editor

content. For example, consider the command sequence: “ahello”, “a world”, “?”, “s” and “u”. If

the command “r” is subsequently entered multiple times, each Repeat command will always re execute “ahello”. Refer to step “Undo followed by Repeat” for another illustration.

10. Undo followed by Repeat - In this case, the “Undo” is not considered as the last command and

the "Repeat" command is used to target the command immediately preceding the "Undo"

command, not the most recent action performed. Any command entered prior to the "Undo"

will be re-executed upon triggering the "Repeat" command. Refer to the following figure for an

illustration.

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CSC1002 – Computational Laboratory

11. b command - it moves the cursor to the beginning of the word to the left of the cursor, provided

that such a word exists; if no such word exists, the cursor remains stationary. If the cursor is

positioned within a word, it will be placed at the first letter of that word. Refer to the following

figure for an illustration.

12. w command - it moves the cursor to the beginning of the word to the right of the cursor,

provided that such a word exists; if no such word exists, the cursor remains stationary.

13. Word - a word is defined as a sequence of consecutive characters including punctuation but not

white space, in other words, any group of characters without spaces is considered a single word,

even if it includes punctuation marks. Refer to the following figure for an illustration.

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CSC1002 – Computational Laboratory

14. Line Copy - it’s used to copy or duplicate the content of the current line, including newly

inserted empty lines. The copied line is then pasted into the editor content using the Paste

command. Only one copied line is kept at a time, in other words, subsequent “Line Copy” will

replace the cached line with the content of the current line. When the editor’s content is

empty, the Line Copy command will not perform any action.

15. Line cursor - it’s used to show the current row being edited by prefixing it with a character ‘*’,

while other rows are shown with a single space. Refer to the following figure(s) for an

illustration.

16. Cursor up and down - when repositioning the cursor to the line either above or below and if its

length is shorter, position the cursor to the end of the line (similar to ‘$’). If the cursor is already

on the first or the last line, do not jump the cursor from top to bottom and vice versa, in other

words, leave the row cursor where it is. Refer to the following figure(s) for an illustration.

17. Empty Line insert Above/Below - it inserts an empty row above or below the current line and

adjusts the line cursor accordingly. Refer to the following figure(s) for an illustration.

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CSC1002 – Computational Laboratory

18. Line Paste Above/Below - it pastes the last copied line(s) above or below the current line and

adjusts the line cursor accordingly. Adjust the row cursor position as if it was re-positioned by

having it moved up or down from the current line to the pasted line. Refer to the following

figure(s) for an illustration.

19. Line Delete - delete the current line and adjusts the line and row cursors accordingly. Refer to

the following figure(s) for an illustration.

CSC1002 – 2025 Winter By Kinley Lam

CSC1002 – Computational Laboratory

ASSUMPTIONS

1. The goal of this assignment is to illustrate the benefits of “Problem Decomposition”, “Clean

Coding” and “Refactoring”, all together achieving high code readability to ease logic expansion

and keep high maintainability, therefore, it’s not aimed at designing a complex, general-purpose

editor for handling large editing content.

2. It’s assumed that the length of each line is kept within a reasonable length so that each line can

be stored directly using the standard Python ‘str’ type. The number of lines is also kept within a

reasonable number so that all lines can be kept in one standard Python list and the lines can be

efficiently updated using the standard list and str operations such as append, insert, slicing,

cloning, …etc.

3. Each test case is designed to evaluate the functionality and correctness of your program, rather

than its speed, performance and memory usage. Each test case consists of multiple editing

commands with short “Text” and small “Repeater” values.

4. The text editor is required to handle only regular English characters, thus additional unicode

support, if any, is unnecessary.

STARTUP OPTIONS

Not applicable

SKILLS

In this assignment, you will be trained on the use of the followings:

• Refactoring - logic reuse or simplification based on the existing logic.

• Variable scope: global, local and function parameters.

• Coding Styles (naming convention, meaningful names, comments, doc_string, …etc)

• Problem Decomposition, Clean Code, Top-Down Design

• Functions (with parameters and return) for program structure and logic decomposition

• Standard objects (strings, numbers & lists)

• Variable Scope

CSC1002 – 2025 Winter By Kinley Lam

CSC1002 – Computational Laboratory

PERMITTED MODULES

Only the following Python module(s) is allowed to be used:

• re (regular expression)

DELIVERABLES

Program source code (A3_School_StudentID.py), where School is SSE, SDS, SME, HSS, FE, LHS, MED and

StudentID is your 9-digit student ID.

For instance, a student from SME with student ID “119010001” will name the Python file as follows:

• A3_SME_119010001.py:

Ensure that your source file is saved in standard, regular UTF-8 encoding format. On the status bar of

Visual Studio Code, you can view the current encoding format as follows:

On an occasion, the encoding scheme is set to UTF-8 with BOM as follows:

The presence of the Byte Order Mark (BOM) could be due to copying from websites, older version of

editor, file conversion from other sources, default encoding setting, and so on.

Confirm the encoding scheme is UTF-8 and the file name is correct, then submit the plain program file to

the corresponding assignment folder. A deduction of 5% will be penalized if the file is incorrectly named

or in wrong encoding format.

TIPS & HINTS

• Apply problem decomposition, Clean Code and Refactoring as illustrated during classes.

• Beware of variable scope as you might keep a few variables as global such as current editor

content, cursor position, undo buffer, and so on.

• Refer to Python website for program styles and naming conventions (PEP 8)

CSC1002 – 2025 Winter By Kinley Lam

CSC1002 – Computational Laboratory

SAMPLE OUTPUT

Note: please also refer to the first assignment for more sample output.

CSC1002 – 2025 Winter By Kinley Lam

CSC1002 – Computational Laboratory

MARKING CRITERIA

• Coding Styles – overall program structure including layout, comments, white spaces, naming

convention, variables, indentation, functions with appropriate parameters and return.

• Program Correctness – whether or the program works 100% as per Scope.

• User Interaction – how informative and accurate information is exchanged between your

program and the player.

• Readability counts – programs that are well structured and easy to follow using functions to

break down complex problems into smaller cleaner generalized functions are preferred over a

function embracing a complex logic with many nested conditions and branches! In other words,

a design with a clean architecture and high readability is the predilection for the course

objectives over efficiency. The logic in each function should be kept simple and short, and it

should be designed to perform a single task and be generalized with parameters as needed.

• KISS approach – Keep It Simple and Straightforward.

• Balance approach – you are not required to come up with a very optimized solution. However,

take a balance between readability and efficiency with good use of program constructs.

DUE DATE

May 5th, 2025, 11:59PM

ITEMS PERCENTAGE REMARKS

CODING STYLES 30%-40% 0% IF PROGRAM DOESN’T RUN

FUNCTIONALITY 60%-70% REFER TO SCOPE

CSC1002 – 2025 Winter By Kinley Lam