Thai Number Text (Rust)

A minimal, no_std-compatible Rust crate for converting numbers to Thai textual representations.

Zero dependencies by default.

Features

• Integer and float conversion to Thai text
• Thai Baht currency formatting
• Accounting-style wording (ถ้วน suffix)
• Three Et (เอ็ด) modes: Colloquial, RoyalInstitute, Military
• Large number support (ล้านล้าน, ล้านล้านล้าน, ล้านล้านล้านล้าน...)
• String input for arbitrarily large numbers (beyond i64::MAX)
• Scientific notation support (9.22 × 10^37)
• #![no_std] compatible (uses alloc only)
• Optional serde support

Installation

[dependencies]
thai-number-text = "1.0.0"

Feature Flags

Usage

Basic Usage

use thai_number_text::{to_text_i64, to_text_f64, to_baht, ThaiTextOptions};

let opts = ThaiTextOptions::new();

// Integers
assert_eq!(to_text_i64(21, &opts), "ยี่สิบเอ็ด");
assert_eq!(to_text_i64(101, &opts), "หนึ่งร้อยหนึ่ง"); // Standard: no เอ็ด

// Floats
assert_eq!(to_text_f64(0.123, &opts), "ศูนย์จุดหนึ่งสองสาม");

// Currency
assert_eq!(to_baht(100.50, &opts), "หนึ่งร้อยบาทห้าสิบสตางค์");

Et Modes (เอ็ด)

use thai_number_text::{to_text_i64, EtMode, ThaiTextOptions};

// Colloquial (default): เอ็ด only when tens digit exists
// This is the common everyday usage in Thailand
let opts = ThaiTextOptions::new();
assert_eq!(to_text_i64(11, &opts), "สิบเอ็ด");        // has tens digit
assert_eq!(to_text_i64(101, &opts), "หนึ่งร้อยหนึ่ง");   // no tens digit
assert_eq!(to_text_i64(111, &opts), "หนึ่งร้อยสิบเอ็ด"); // has tens digit

// RoyalInstitute (ราชบัณฑิตยสภา): Always use เอ็ด for trailing 1
// This is the formal/official Thai language standard
let opts = ThaiTextOptions::royal_institute();
assert_eq!(to_text_i64(101, &opts), "หนึ่งร้อยเอ็ด");
assert_eq!(to_text_i64(1001, &opts), "หนึ่งพันเอ็ด");

// Military: Never use เอ็ด
// Used in Thai military communications for clarity
let opts = ThaiTextOptions::military();
assert_eq!(to_text_i64(11, &opts), "สิบหนึ่ง");
assert_eq!(to_text_i64(21, &opts), "ยี่สิบหนึ่ง");

Large Numbers

use thai_number_text::{to_text_i64, ThaiTextOptions};

let opts = ThaiTextOptions::new();

// Million (ล้าน)
assert_eq!(to_text_i64(1_000_000, &opts), "หนึ่งล้าน");

// Trillion (ล้านล้าน)
assert_eq!(to_text_i64(1_000_000_000_000, &opts), "หนึ่งล้านล้าน");

// Quintillion (ล้านล้านล้าน) - handles up to i64::MAX
let result = to_text_i64(i64::MAX, &opts);
// "เก้าล้านล้านล้าน..."

Accounting Style

use thai_number_text::{to_baht, ThaiTextOptions};

let opts = ThaiTextOptions::accounting();
assert_eq!(to_baht(100.50, &opts), "หนึ่งร้อยบาทห้าสิบสตางค์ถ้วน");

String Input (Arbitrarily Large Numbers)

use thai_number_text::{to_text_str, ThaiTextOptions};

let opts = ThaiTextOptions::new();

// Basic string input
assert_eq!(to_text_str("21", &opts).unwrap(), "ยี่สิบเอ็ด");
assert_eq!(to_text_str("0.5", &opts).unwrap(), "ศูนย์จุดห้า");

// Scientific notation strings
assert_eq!(to_text_str("1e6", &opts).unwrap(), "หนึ่งล้าน");
assert_eq!(to_text_str("1.5e10", &opts).unwrap(), "หนึ่งหมื่นห้าพันล้าน");

// Beyond i64::MAX (10^24)
let result = to_text_str("1000000000000000000000000", &opts).unwrap();
// "หนึ่งล้านล้านล้านล้าน"

Scientific Notation

use thai_number_text::{to_text_scientific, ThaiTextOptions};

let opts = ThaiTextOptions::new();

// 9.22 × 10^37
assert_eq!(
    to_text_scientific(9.22, 37, &opts),
    "เก้าจุดสองสอง คูณ สิบยกกำลังสามสิบเจ็ด"
);

// Negative exponent: 5.5 × 10^-3
assert_eq!(
    to_text_scientific(5.5, -3, &opts),
    "ห้าจุดห้า คูณ สิบยกกำลังลบสาม"
);

Thai Language Rules

API

// Direct functions (smallest code size)
pub fn to_text_i64(n: i64, opts: &ThaiTextOptions) -> String;
pub fn to_text_f64(n: f64, opts: &ThaiTextOptions) -> String;
pub fn to_baht(amount: f64, opts: &ThaiTextOptions) -> String;

// Generic wrapper
pub fn to_text<N: Into<ThaiNumber>>(n: N, opts: &ThaiTextOptions) -> String;

// String input (arbitrarily large numbers)
pub fn to_text_str(s: &str, opts: &ThaiTextOptions) -> Result<String, ParseError>;

// Scientific notation
pub fn to_text_scientific(mantissa: f64, exponent: i64, opts: &ThaiTextOptions) -> String;

// Options
pub enum EtMode { Colloquial, RoyalInstitute, Military }
pub struct ThaiTextOptions { et_mode: EtMode, accounting_style: bool }

Run Demo

cargo run --example demo --features std

License

This project is MIT licensed (see LICENSE), maintaining the same license as the original work.