Scalendar - Scala Calendar Utility

A command-line calendar utility similar to ncal, written in Scala.

Features

• Display current month calendar
• Display specific month and year
• Display entire year calendar
• Leap year support
• Internationalization (i18n) support - Month names, day names, and error messages in multiple languages
• Clean, formatted output similar to traditional Unix cal/ncal utilities
• Configurable localization via command-line options

Usage

Basic Usage

# Display current month
sbt run

# Display help
sbt "runMain scalendar.ScalendarApp --help"

# Display specific month in current year (e.g., March)
sbt "runMain scalendar.ScalendarApp --month 3"

# Display specific month and year (e.g., March 2024)
sbt "runMain scalendar.ScalendarApp --month 3 --year 2024"

# Display entire current year
sbt "runMain scalendar.ScalendarApp --year-view"

# Display specific year
sbt "runMain scalendar.ScalendarApp --year-view --year 2024"

# Display calendar in Spanish
sbt "runMain scalendar.ScalendarApp --month 3 --year 2024 --locale es"

# Display calendar in French  
sbt "runMain scalendar.ScalendarApp --month 3 --year 2024 --locale fr"

Command Line Options

• --help or -h: Show usage information
• --year-view or -y: Display entire year calendar
• --month <int>: Specify month (1-12) to display
• --year <int>: Specify year to display
• --locale <string> or -l: Set locale for internationalization (e.g., 'es' for Spanish, 'fr' for French)

Examples

Display March 2024 in English (default):

    March 2024
Su Mo Tu We Th Fr Sa
                1  2
 3  4  5  6  7  8  9
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
31

Display March 2024 in Spanish:

    Marzo 2024
Do Lu Ma Mi Ju Vi Sa
                1  2
 3  4  5  6  7  8  9
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
31

Display March 2024 in French:

    Mars 2024
Di Lu Ma Me Je Ve Sa
                1  2
 3  4  5  6  7  8  9
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
31

Internationalization Support

Scalendar supports multiple languages through Java's ResourceBundle system. The following languages are currently supported:

• English (en) - Default
• Spanish (es) - Español
• French (fr) - Français

Supported Locales

Use the --locale or -l option to specify a language:

# English (default)
sbt "run --month 3 --year 2024"

# Spanish
sbt "run --month 3 --year 2024 --locale es"

# French
sbt "run --month 3 --year 2024 --locale fr"

Adding New Languages

To add support for a new language:

1. Create a new properties file in src/main/resources/scalendar/ named messages_XX.properties where XX is the language code
2. Translate all the keys from messages.properties
3. The new locale will be automatically available via the --locale option

Example for German (messages_de.properties):

month.1=Januar
month.2=Februar
month.3=März
# ... etc
day.0=So
day.1=Mo
# ... etc
error.invalid.month=Ungültiger Monat: {0}. Der Monat muss zwischen 1 und 12 liegen.

Building and Running

Prerequisites

• Scala 3.7.3 or later (using modern significant indentation syntax)
• SBT (Scala Build Tool)

Build

sbt compile

Run

sbt run

Run Tests

sbt test

Create Executable

sbt stage

This creates an executable script in target/universal/stage/bin/scalendar-scala.

Project Structure

src/
├── main/
│   ├── scala/scalendar/
│   │   ├── Calendar.scala              # Core calendar logic
│   │   ├── ScalendarApp.scala         # Command-line interface
│   │   └── LocalizationManager.scala  # Internationalization support
│   └── resources/scalendar/
│       ├── messages.properties         # English (default)
│       ├── messages_es.properties      # Spanish
│       └── messages_fr.properties      # French
└── test/scala/scalendar/
    ├── CalendarTest.scala     # Unit tests for Calendar class
    ├── ScalendarAppTest.scala # Tests for command-line interface and i18n
    └── IntegrationTest.scala  # Integration tests

Features

Calendar Class

• displayMonth(year, month): Display a specific month
• displayCurrentMonth(): Display current month
• displayYear(year): Display entire year
• displayCurrentYear(): Display current year
• getDaysInMonth(year, month): Get number of days in a month
• isLeapYear(year): Check if a year is a leap year
• getDayOfWeek(year, month, day): Get day of week for a date

Calendar Factory Methods

• Calendar.withLocale(locale): Create calendar with specific Java Locale
• Calendar.withLanguage(languageTag): Create calendar with specific language

LocalizationManager Class

• getMonthName(month): Get localized month name
• getDayName(dayOfWeek): Get localized day name
• getInvalidMonthError(month): Get localized error message for invalid month
• getInvalidYearError(year): Get localized error message for invalid year
• LocalizationManager.forLanguage(tag): Create manager for specific language

Command Line Interface

• Argument parsing and validation
• Error handling for invalid dates
• Help system
• Support for various date formats

Testing

The project includes comprehensive tests:

• Unit Tests: Test individual methods and edge cases
• Integration Tests: Test complete workflows and real-world scenarios
• Application Tests: Test command-line argument parsing and validation

Run all tests with:

sbt test

Development

Adding New Features

1. Add functionality to the Calendar class
2. Update the ScalendarApp object for command-line interface changes
3. Add corresponding tests
4. Update this README

Code Style

The project follows modern Scala 3 conventions:

• Uses significant indentation (no curly braces)
• Use camelCase for methods and variables
• Use PascalCase for classes and objects
• Include comprehensive documentation
• Write tests for all new functionality

License

This project is open source. Feel free to use and modify as needed.