Add convert_currency

Author: wannaphong

docs/api/ancient.rst

@@ -6,4 +6,5 @@ pythainlp.ancient
 Modules
 -------
 
-.. autofunction:: aksonhan_to_current
+.. autofunction:: aksonhan_to_current
+.. autofunction:: convert_currency

pythainlp/ancient/__init__.py

@@ -6,6 +6,7 @@
 Ancient versions of the Thai language
 """
 
-__all__ = ["aksonhan_to_current"]
+__all__ = ["aksonhan_to_current", "convert_currency"]
 
 from pythainlp.ancient.aksonhan import aksonhan_to_current
+from pythainlp.ancient.currency import convert_currency

pythainlp/ancient/currency.py

@@ -0,0 +1,40 @@
+# -*- coding: utf-8 -*-
+# SPDX-FileCopyrightText: 2016-2025 PyThaiNLP Project
+# SPDX-FileType: SOURCE
+# SPDX-License-Identifier: Apache-2.0
+
+def convert_currency(value: float, from_unit: str) -> dict:
+    """
+    Convert ancient Thai currency to other units
+
+    :param float value: value
+    :param str from_unit: currency unit \
+        ('เบี้ย', 'อัฐ', 'ไพ', 'เฟื้อง', 'สลึง', 'บาท', 'ตำลึง', 'ชั่ง')
+    :return: Thai currency
+    :rtype: dict
+    """
+    conversion_factors_to_att = {
+        'เบี้ย': 1,
+        'อัฐ': 100,  # 1 อัฐ = 100 เบี้ย
+        'ไพ': 2 * 100,  # 1 ไพ = 2 อัฐ
+        'เฟื้อง': 4 * 2 * 100,  # 1 เฟื้อง = 4 ไพ
+        'สลึง': 2 * 4 * 2 * 100,  # 1 สลึง = 2 เฟื้อง
+        'บาท': 4 * 2 * 4 * 2 * 100,  # 1 บาท = 4 สลึง
+        'ตำลึง': 4 * 4 * 2 * 4 * 2 * 100,  # 1 ตำลึง = 4 บาท
+        'ชั่ง': 20 * 4 * 4 * 2 * 4 * 2 * 100,  # 1 ชั่ง = 20 ตำลึง
+    }
+
+    if from_unit not in conversion_factors_to_att:
+        raise NotImplementedError(
+            f"Currency unit '{from_unit}' is not support."
+        )
+
+    # start from 'อัฐ'
+    value_in_att = value * conversion_factors_to_att[from_unit]
+
+    # Calculate values ​​in other units
+    results = {}
+    for unit, factor in conversion_factors_to_att.items():
+        results[unit] = value_in_att / factor
+
+    return results

tests/core/test_ancient.py

@@ -5,7 +5,7 @@
 
 import unittest
 
-from pythainlp.ancient import aksonhan_to_current
+from pythainlp.ancient import aksonhan_to_current, convert_currency
 
 
 class AncientTestCase(unittest.TestCase):
@@ -23,3 +23,25 @@ def test_aksonhan_to_current(self):
         self.assertEqual(aksonhan_to_current("หลงง"), "หลัง")
         self.assertEqual(aksonhan_to_current("บงงคบบ"), "บังคับ")
         self.assertEqual(aksonhan_to_current("สรรเพชญ"), "สรรเพชญ")
+
+    def test_convert_currency(self):
+        self.assertEqual(
+            convert_currency(80, "บาท")["ตำลึง"],
+            20.0
+        )
+        self.assertEqual(
+            convert_currency(80, "บาท")["ชั่ง"],
+            1.0
+        )
+        self.assertEqual(
+            convert_currency(80, "บาท")["บาท"],
+            80.0
+        )
+        self.assertEqual(
+            convert_currency(1,"ชั่ง")["บาท"],
+            80.0
+        )
+        self.assertEqual(
+            convert_currency(1,"ชั่ง")["ชั่ง"],
+            1.0
+        )