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Filtrera

Duration

The duration data type in Filtrera represents a timespan. It is a special type because it encompasses a class of types, each representing a different unit of time. This reference guide provides a detailed specification of the duration data type, its syntax, and usage for users already familiar with the concept.

Duration Types

The different duration types in Filtrera are:

  • years
  • months
  • days
  • weeks
  • hours
  • minutes
  • seconds
  • milliseconds (or ms)
  • ticks

The type notation duration (which can be used for parameters) is a union of all these duration types.

Syntax

Literal duration values are defined by <number> <type>. The unit is always plural, even for a single value.

Examples

from 1 years
from 2 months
from 10 days
from 1 weeks
from 5 hours
from 30 minutes
from 45 seconds
from 500 milliseconds
from 1000 ms
from 10000 ticks

In these examples:

  • 1 years represents a duration of one year.
  • 2 months represents a duration of two months.
  • 10 days represents a duration of ten days.
  • 1 weeks represents a duration of one week.
  • 5 hours represents a duration of five hours.
  • 30 minutes represents a duration of thirty minutes.
  • 45 seconds represents a duration of forty-five seconds.
  • 500 milliseconds and 500 ms both represent a duration of five hundred milliseconds.
  • 10000 ticks represents a duration of ten thousand ticks.

Type Notation for duration

When defining parameters or variables, you can use the type notation duration to represent any of the duration types.

Example

param timeout: duration
let message = $'The timeout duration is {timeout}.'
from message

In this example, timeout is defined as a duration type, and message incorporates timeout.

Arithmetic Operations with Durations

Durations can be added and subtracted if they are of the same unit. For more details on arithmetic operations, refer to the Arithmetic article.

Example

let duration1 = 5 days
let duration2 = 3 days
let totalDuration = duration1 + duration2
let remainingDuration = duration1 - duration2


from totalDuration
from remainingDuration

In this example, totalDuration is 8 days, and remainingDuration is 2 days.

Literal Types

As with all other primitive types, duration types can be literal:

param myParam: 4 days|5 days

Practical Usage

Example: Calculating Future Dates

let startDate = 2023-01-01
let duration = 10 days
let endDate = startDate + duration


from endDate

In this example, startDate is an instant, duration is 10 days, and endDate is calculated by adding duration to startDate.

Example: Using Different Duration Types

let projectDuration = 6 months
let meetingLength = 1 hours
let responseTime = 30 minutes


let message = $'The project duration is {projectDuration}, each meeting lasts {meetingLength}, and the expected response time is {responseTime}.'
from message

In this example, projectDuration, meetingLength, and responseTime are different duration types, and message incorporates all of them.

Summary

The duration data type in Filtrera allows you to work with timespans effectively. By understanding its syntax and usage, including the different duration types and their literals, you can accurately represent and manipulate durations. The type notation duration serves as a union of all duration types, providing flexibility in parameter and variable definitions. Additionally, durations of the same unit can be added and subtracted. For more details on arithmetic operations with durations, refer to the Arithmetic article. Leveraging these features enables you to create precise and reliable Filtrera programs that handle timespans with ease.