Text Statistics

This document describes the text statistics feature that displays real-time word, character, and line counts in the status bar.

Overview

The text statistics feature provides instant feedback about document metrics as users type. Statistics are displayed in the status bar, updating in real-time whenever the content changes.

Architecture

Module Structure

src/editor/
├── mod.rs           # Exports TextStats
├── stats.rs         # TextStats struct and counting algorithms
├── line_numbers.rs  # Reused count_lines() function
└── widget.rs        # Editor widget

TextStats Struct

The TextStats struct holds all document metrics:

pub struct TextStats {
    pub words: usize,              // Word count
    pub characters: usize,         // Characters including spaces
    pub characters_no_spaces: usize, // Characters excluding spaces
    pub lines: usize,              // Line count
    pub paragraphs: usize,         // Paragraph count
}

Counting Algorithms

Word Count

Words are defined as sequences of non-whitespace characters separated by whitespace:

text.split_whitespace().count()

Note: This means Chinese/Japanese text without spaces between words will be counted as fewer words than expected.

Character Count

Two counts are provided:

• With spaces: Total character count including all whitespace
• Without spaces: Characters excluding whitespace

Line Count

Uses the existing count_lines() function from line_numbers.rs:

• Empty text = 1 line
• Non-empty text = number of newline characters + 1

Paragraph Count

Paragraphs are non-empty text blocks separated by blank lines:

• Consecutive non-blank lines are one paragraph
• One or more blank lines separate paragraphs

Integration

Status Bar Display

Statistics appear in the status bar alongside the cursor position:

Ready          150 words | 892 chars | 25 lines     Ln 1, Col 1

Real-Time Updates

Statistics are recalculated on every frame for the active tab's content. The single-pass algorithm ensures minimal performance impact.

API

Creating Stats

use crate::editor::TextStats;

let stats = TextStats::from_text("Hello, World!");
println!("{}", stats.format_compact()); // "2 words | 13 chars | 1 lines"

Formatting Options

• format_compact() - Concise: "150 words | 892 chars | 25 lines"
• format_detailed() - Full: "150 words | 892 chars (743 no spaces) | 25 lines | 5 paragraphs"

Helper Functions

Standalone functions for individual metrics:

use crate::editor::stats::{count_words, count_characters, count_paragraphs};

let words = count_words("Hello World"); // 2
let chars = count_characters("Hello World"); // 11
let paragraphs = count_paragraphs("Para 1\n\nPara 2"); // 2

Performance

The TextStats::from_text() method uses a single-pass algorithm that:

1. Iterates through each character once
2. Tracks word boundaries
3. Tracks paragraph boundaries
4. Counts all metrics simultaneously

This ensures O(n) time complexity where n is the text length.

Testing

31 unit tests cover:

• Empty text handling
• Single word/line/paragraph cases
• Multiple paragraphs
• Unicode text
• Whitespace-only text
• Edge cases (trailing newlines, mixed whitespace)
• Formatting functions

Run tests:

cargo test stats

Future Enhancements

Potential improvements:

• Reading time estimate (words per minute)
• Selection-based statistics
• CJK word segmentation for accurate Asian language word counts
• Sentence count
• Average word length