LangString Python Library
Project description
LangString Python Library
The LangString Python Library offers a powerful and intuitive way to represent strings with associated language metadata. Designed with the intent to simplify language-specific string management, this library encapsulates a string with its language information, allowing for advanced linguistic operations and clear representations.
📦 PyPI Package: The library is conveniently available as a PyPI package, allowing users to easily import it into other Python projects.
📚 Documentation: For inquiries and further information, please refer to the comprehensive docstring-generated documentation available for this project.
Contents
- LangString Python Library
LangString Overview
LangString is a powerful Python library inspired by the RDF's idea of language tagging. It offers a streamlined approach to handle multilingual data in Python.
Benefits of LangStrings
-
Context: Knowing the language of a text is crucial for processing and presentation.
-
User Experience: For apps with global users, displaying data in a user's language improves their experience. LangStrings make this process efficient.
-
Data Consistency: With LangStrings, multilingual data has a standard format, reducing complexity.
-
Tailored Operations: Having the language info allows for specialized actions, especially in fields like NLP.
Practical Use of LangStrings
Consider the value of LangStrings in real-world scenarios:
- Greeting Users:
# English vs Japanese greeting
greeting_en = LangString(text="Hello", lang="en")
greeting_ja = LangString(text="こんにちは", lang="ja")
print(greeting_en.to_string()) # "Hello"@en
print(greeting_ja.to_string()) # "こんにちは"@ja
- Multilingual Product Names:
# Eiffel Tower in English and French
eiffel_en = LangString(text="Eiffel Tower", lang="en")
eiffel_fr = LangString(text="Tour Eiffel", lang="fr")
print(eiffel_en.to_string()) # "Eiffel Tower"@en
print(eiffel_fr.to_string()) # "Tour Eiffel"@fr
LangString Class - Usage Examples
The LangString
class in the langstring_lib
module encapsulates a string with its associated language information.
- Initialization
# Create a LangString object with only text
simple_string = LangString("Hello, world!")
# Create a LangString object with text and language information
english_greeting = LangString("Hello, world!", "en")
If an invalid language tag is used or non-string type is provided, appropriate warnings and errors will be raised:
# This will log a warning because 'invalid-lang' is not a valid language tag
invalid_lang = LangString("Hello, world!", "invalid-lang")
# This will raise a TypeError since the text is not a string
try:
invalid_text_type = LangString(12345)
except TypeError as e:
print(f"Error: {e}") # Outputs an error message if the input is not a string
Control Options for LangString
The LangString
class is designed to work with text strings and their associated language tags, offering enhanced functionality and control over how these strings are handled and validated. This control is achieved through a set of flags defined in the LangStringControl
class, using the LangStringFlag
enumeration. These flags allow for dynamic configuration of LangString
behavior, enabling customization to fit various application needs.
Available Flags
-
ENSURE_TEXT
: When enabled, this flag ensures that thetext
field of aLangString
object is not empty. An attempt to create aLangString
with an emptytext
field will raise aValueError
. -
ENSURE_ANY_LANG
: This flag mandates the presence of a non-empty language tag in thelang
field of aLangString
. If enabled, creating aLangString
with an emptylang
field will result in aValueError
. -
ENSURE_VALID_LANG
: Enabling this flag requires that thelang
field of aLangString
contains a valid language code. Invalid language codes will lead to aValueError
uponLangString
creation. -
VERBOSE_MODE
: This flag activates verbose logging. When enabled, any warnings or informational messages related toLangString
operations, such as the use of empty strings or invalid language tags, are logged for better traceability and debugging.
Setting and Retrieving Flags
Flags can be set globally and will affect the behavior of all LangString
instances within the application. To set a flag, use:
LangStringControl.set_flag(LangStringFlag.<FLAG_NAME>, <True/False>)
To check the current state of a flag:
current_state = LangStringControl.get_flag(LangStringFlag.<FLAG_NAME>)
Example Usage
from langstring import LangString, LangStringControl, LangStringFlag
# Enable the ENSURE_TEXT flag
LangStringControl.set_flag(LangStringFlag.ENSURE_TEXT, True)
# Attempting to create a LangString with an empty text will raise an error
try:
lang_str = LangString("", "en")
except ValueError as e:
print(e) # Output: "ENSURE_TEXT enabled: Langstring's 'text' field cannot receive empty string."
# Disable the ENSURE_TEXT flag
LangStringControl.set_flag(LangStringFlag.ENSURE_TEXT, False)
# Now, creating a LangString with an empty text will succeed
lang_str = LangString("", "en")
- Converting the LangString Object to String
The LangString
class provides two methods to convert the object into its string representation, to_string()
and __str__()
:
english_greeting = LangString("Hello, world!", "en")
# Using the to_string() method
print(english_greeting.to_string()) # Outputs: "Hello, world!"@en
# Using the __str__() method (which is implicitly called when using Python's built-in str() function)
print(str(english_greeting)) # Outputs: "Hello, world!"@en
The string representation will include the text encapsulated in double quotes. If a language is associated with the text, it will be appended after the text, preceded by an "@" symbol.
MultiLangString: Handling Multiple Translations
While LangString
manages one string-language pair, MultiLangString
holds several translations of a string. This is useful for keeping various translations of a term within one object.
For instance, if you have a product with multiple language names:
from langstring import MultiLangString
product_names = MultiLangString({
"en": "Smartphone",
"fr": "Smartphone",
"es": "Teléfono inteligente",
"de": "Smartphone"
})
print(product_names.get_lang("es")) # Teléfono inteligente
MultiLangString Control Options
MultiLangString
provides granular controls for handling situations where there are multiple entries with the same language tag. This behavior is defined by the MULTIPLE_ENTRIES_CONTROLS
configuration.
Available Controls
-
ALLOW
:- Description: Permits multiple entries with the same language tag. However, it ensures that no duplicate texts for the same language tag are added.
- Usage: Beneficial in situations where multiple translations or interpretations of a term in the same language are valid.
-
OVERWRITE
:- Description: If an entry with the same language tag already exists, this control will overwrite the existing entry with the new value.
- Usage: Useful in scenarios where you want to ensure that there's only one entry per language and are okay with updating existing values.
-
BLOCK_WARN
:- Description: Blocks the addition of a
LangString
if a matching language tag already exists and logs a warning. - Usage: Recommended for cases where you want to prevent duplicate entries but only want a log warning instead of a halt in operations.
- Description: Blocks the addition of a
-
BLOCK_ERROR
:- Description: Blocks the addition of a
LangString
if a matching language tag is present and raises an error. - Usage: Useful when ensuring data integrity is paramount, and you want to halt the operation if a duplicate entry is encountered.
- Description: Blocks the addition of a
When setting the control
property of a MultiLangString
instance, it is essential to provide a valid control strategy. If an invalid strategy is supplied, the system will raise a ValueError
highlighting the acceptable control values.
To utilize these controls, configure the desired behavior when initializing the MultiLangString
object or updating its entries.
Usage Examples for the MultiLangString Class
- Initialization
You can initialize a MultiLangString
object by passing in multiple LangString
objects and specifying control and preferred language properties:
from langstring import LangString, MultiLangString
english_greeting = LangString("Hello", "en")
french_greeting = LangString("Bonjour", "fr")
# Initializing MultiLangString with two LangString objects
multi_lang_str = MultiLangString(english_greeting, french_greeting, control="ALLOW", preferred_lang="en")
- Add Method
Use the add
method to add a new LangString
object to the MultiLangString
:
lang_str3 = LangString("Hola", "es")
multi_lang_str.add_langstring(lang_str3)
- Getting a Specific Language String
To retrieve a language string for a specific language:
english_strings = multi_lang_str.get_langstring("en") # Returns list of English strings
- Getting the Preferred Language String
Retrieve the language string for the preferred language:
preferred_string = multi_lang_str.get_pref_langstring() # Returns the string for the preferred language
- Removing a Specific LangString
Remove a specific LangString
object from the MultiLangString
:
multi_lang_str.remove_langstring(lang_str3) # Removes the Spanish string
- Removing All Strings for a Specific Language
Remove all LangString
objects associated with a specific language:
multi_lang_str.remove_language("es") # Removes all Spanish strings
- Converting to String
You can convert a MultiLangString
object to a string representation:
str_representation = multi_lang_str.to_string()
print(str_representation) # Outputs: '"Hello"@en, "Bonjour"@fr'
- Converting to List of Strings
Convert the MultiLangString
to a list of strings:
list_representation = multi_lang_str.to_string_list()
print(list_representation) # Outputs: ['"Hello"@en', '"Bonjour"@fr']
- Getting the Length
Determine the number of LangString
objects in a MultiLangString
:
length = len(multi_lang_str) # Outputs: 2
- String Representation
"Obtain a user-friendly string representation of the MultiLangString
. This representation is ideal for displaying the content of the MultiLangString
object in a readable format, suitable for user interfaces or textual outputs. The str()
method is used to achieve this."
print(str(multi_lang_str)) # Outputs: '"Hello"@en, "Bonjour"@fr'
- Representation Method
Use the repr()
method to get a formal, detailed string representation of the MultiLangString
object. This output is more technical, showing the exact state of the object, which is particularly useful for debugging and development purposes. It provides a clear view of the internal structure and data of the MultiLangString
."
print(repr(multi_lang_str)) # Outputs a detailed, technical representation of the object
This is useful for understanding the current state of a MultiLangString
object.
Remember, the MultiLangString
class is designed to handle multiple language strings, allowing you to manage multilingual text strings effectively and efficiently.
Getting Started
Installation
Install with:
pip install langstring
Then, encapsulate strings with their language tags as shown in the examples above.
Importing and Using the Library
After installation, you can use the LangString
and MultiLangString
classes in your project. Simply import the classes and start encapsulating strings with their language tags.
from langstring import LangString, MultiLangString
Example Usage of LangString
# Creating a LangString object for an English greeting
greeting_en = LangString("Hello", "en")
# Printing the LangString object, which shows the text and its language tag
print(greeting_en) # Output: "Hello"@en
Example Usage of MultiLangString
# Create LangString objects for greetings in English and Spanish
greeting_en = LangString("Hello", "en")
greeting_es = LangString("Hola", "es")
# Use MultiLangString to combine them. The 'control' parameter determines how duplicate language tags are handled.
combined_greeting = MultiLangString(greeting_en, greeting_es, control="ALLOW")
# Fetch and print a greeting based on language
# Note: The `get_langstring` method returns a list, so we'll take the first item if available
spanish_greetings = combined_greeting.get_langstring("es")
if spanish_greetings:
print(spanish_greetings[0]) # Outputs: "Hola"@es
else:
print("No greeting found for the specified language.")
# Retrieve the preferred language's greeting (defaults to English in this example)
preferred_greeting = combined_greeting.get_pref_langstring()
if preferred_greeting:
print(preferred_greeting) # Outputs: "Hello"@en
else:
print("No greeting found for the preferred language.")
Comparison and Hashing
Both the LangString
and the MultiLangString
classes support comparison and hashing operations, making it easier to compare and manage these objects in data structures like sets and dictionaries.
LangString
Equality and Inequality
__eq__
: Checks if twoLangString
objects are equal (bothtext
andlang
attributes are the same).__ne__
: Checks if twoLangString
objects are not equal.
from langstring import LangString
ls1 = LangString("Hello", "en")
ls2 = LangString("Hello", "en")
ls3 = LangString("Hola", "es")
# Equality
print(ls1 == ls2) # Output: True
print(ls1 == ls3) # Output: False
# Inequality
print(ls1 != ls2) # Output: False
print(ls1 != ls3) # Output: True
Hashing
__hash__
: Generates a hash value for aLangString
object, allowing it to be used in sets and as dictionary keys.
from langstring import LangString
ls1 = LangString("Hello", "en")
ls2 = LangString("Hello", "en")
ls3 = LangString("Hola", "es")
# Using LangString objects in a set
lang_strings = {ls1, ls2, ls3}
print(len(lang_strings)) # Output: 2 (since ls1 and ls2 are equal)
# Using LangString as dictionary keys
lang_dict = {ls1: "Greeting in English", ls3: "Greeting in Spanish"}
print(lang_dict[ls1]) # Output: "Greeting in English"
MultiLangString
Equality and Inequality
__eq__
: Checks if twoMultiLangString
objects are equal. Equality is determined based on the content of thelangstrings
attribute, which holds the multilingual data. Thepreferred_lang
andcontrol
attributes are not considered in this comparison.
from multilangstring import MultiLangString, LangString
mls1 = MultiLangString(LangString("Hello", "en"), LangString("Hola", "es"))
mls2 = MultiLangString(LangString("Hello", "en"), LangString("Hola", "es"))
mls3 = MultiLangString(LangString("Bonjour", "fr"))
# Equality
print(mls1 == mls2) # Output: True
print(mls1 == mls3) # Output: False
Hashing
__hash__
: Generates a hash value for aMultiLangString
object, allowing it to be used in sets and as dictionary keys. The hash is computed based on thelangstrings
attribute.
from multilangstring import MultiLangString, LangString
mls1 = MultiLangString(LangString("Hello", "en"), LangString("Hola", "es"))
mls2 = MultiLangString(LangString("Hello", "en"), LangString("Hola", "es"))
mls3 = MultiLangString(LangString("Bonjour", "fr"))
# Using MultiLangString objects in a set
multi_lang_strings = {mls1, mls2, mls3}
print(len(multi_lang_strings)) # Output: 2 (since mls1 and mls2 are equal)
# Using MultiLangString as dictionary keys
multi_lang_dict = {mls1: "Greetings in English and Spanish", mls3: "Greeting in French"}
print(multi_lang_dict[mls1]) # Output: "Greetings in English and Spanish"
Code Testing
The code provided has undergone rigorous testing to ensure its reliability and correctness. The tests can be found in the 'tests' directory of the project. To run the tests, navigate to the project root directory and execute the following command:
langstring> pytest .\tests
Changelog and Future Development
Version 1.3.0 - [To be developed: Translations for MultiLangString (Expected)]
Version 1.2.0 - [To be developed: MultiLangStringControl and MultiLangStringFlags (Expected)]
Version 1.1.0 - [Released: LangStringControl and LangStringFlags]
New Features
-
LangStringControl: A new class introduced to manage the configuration settings for language strings dynamically. This addition allows for global settings that affect the behavior of
LangString
instances throughout your application. -
LangStringFlags: An enumeration (
LangStringFlag
) that defines various configuration flags. These flags provide enhanced control over theLangString
class, enabling behaviors such as:ENSURE_TEXT
: Ensures that thetext
field inLangString
is not empty.ENSURE_ANY_LANG
: Requires a non-empty language tag inLangString
.ENSURE_VALID_LANG
: Enforces the use of valid language codes inLangString
.VERBOSE_MODE
: Activates verbose logging for operations, aiding in debugging and monitoring.
Enhancements
- Improved validation and error handling in
LangString
based on the new control flags. - Enhanced logging capabilities with the integration of the
VERBOSE_MODE
flag, providing better insights into the library's operations.
Usage
These new features can be utilized to fine-tune the behavior of LangString
objects in various scenarios, making the library more adaptable to specific requirements. For detailed usage examples, refer to the Control Options for LangString section.
How to Contribute
Reporting Issues
- If you encounter a bug or wish to suggest a feature, please open a new issue.
- If you notice any discrepancies in the documentation created with the aid of AI, feel free to report them by opening an issue.
Code Contributions
- Fork the project repository and create a new feature branch for your work:
git checkout -b feature/YourFeatureName
. - Make and commit your changes with descriptive commit messages.
- Push your work back up to your fork:
git push origin feature/YourFeatureName
. - Submit a pull request to propose merging your feature branch into the main project repository.
Test Contributions
- Enhance the project's reliability by adding new tests or improving existing ones.
General Guidelines
- Ensure your code follows our coding standards.
- Update the documentation as necessary.
- Make sure your contributions do not introduce new issues.
We appreciate your time and expertise in contributing to this project!
Dependencies
This project can be set up using either Poetry or requirements.txt
. Both are kept in sync to ensure consistency in dependencies.
Using Poetry
Poetry is used for easy management of dependencies and packaging. To install the dependencies with Poetry, first install Poetry if you haven't already, and then run:
poetry install
This will install all the dependencies as specified in pyproject.toml
.
Using requirements.txt
If you prefer not to use Poetry, a requirements.txt
file is also provided. You can install the dependencies using pip:
pip install -r requirements.txt
This is a straightforward way to set up the project if you are accustomed to using pip and traditional requirements files.
License
This project is licensed under the Apache License 2.0. See the LICENSE file for details.
Author
This project is an initiative of the Semantics, Cybersecurity & Services (SCS) Group at the University of Twente, The Netherlands. The main developer is:
Feel free to reach out using the provided links. For inquiries, contributions, or to report any issues, you can open a new issue on this repository.
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