FLIP 251: Cadence Date and Time #245

darkdrag00nv2 · 2024-01-29T17:57:04Z

#251

Work towards onflow/cadence#843

darkdrag00nv2 · 2024-02-04T13:36:04Z

cc: @turbolent @SupunS @dsainati1

bluesign · 2024-02-19T14:17:56Z

It is assumed that there are 3600*24 seconds in every day and there are no leap years.

I think ignoring leap years is not a good idea.

turbolent · 2024-02-19T22:02:36Z

It is assumed that there are 3600*24 seconds in every day and there are no leap years.

I think ignoring leap years is not a good idea.

Agreed, we can probably at least support leap years, like e.g. Java's java.time.LocalDate does.

In general, we should not reinvent the wheel here and base the API and implementation of an established solution, like e.g. Java's JSR310

darkdrag00nv2 · 2024-02-20T07:42:23Z

In general, we should not reinvent the wheel here and base the API and implementation of an established solution, like e.g. Java's JSR310

Yep, the current proposal is more based on the python datetime module.

I wrongly made the assumption that they don't support leap years 🙁. I was just giving the wrong input with the year 2011 🤦

>>> datetime.datetime(2011, 2, 29)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: day is out of range for month

Trying with an actual leap year works fine.

>>> datetime.datetime(2024, 2, 29)

KshitijChaudhary666 · 2024-02-28T22:58:02Z

Hi @darkdrag00nv2 - this FLIP is not reflected on FLIP project tracker. Did you follow the process outlined in https://github.com/onflow/flips? Specifically please remember to do the following without which the FLIP won't get visibility on the project tracker-

Create an issue by using one of the FLIP issue templates based on the type of the FLIP - application, governance, cadence or protocol. The title of the issue should be the title of your FLIP, e.g., "Dynamic Inclusion fees". Submit the issue. Note the issue number that gets assigned.
Then, create your FLIP as a pull request to this repository (onflow/flips). Use the issue number generated in step 2 as the FLIP number. And mention the FLIP issue by copying the GitHub URL or the issue in the comment section.

Thank you!

cadence/20240115-cadence-date-time.md

turbolent

Looks good!

As we're finishing work on Cadence 1.0, we can finally come back to proposals like this. Thank you for your patience!

I left some comments and suggestions, and am happy to apply suggested edits and add remaining details. Does that sound good to you @darkdrag00nv2 ?

Once we addressed the outstanding issues, we can schedule to vote on it in the next WG call

turbolent · 2024-07-16T18:01:38Z

cadence/20240115-cadence-date-time.md

+
+- `LocalDateTime.fromTimestamp(timestamp : UFix64)`: Creates a `LocalDateTime` with value based on the passed timestamp argument.
+
+- `LocalDateTime.of(year: UInt64, month: Month, day: UInt8, hour: UInt8, minute: UInt8, second: UInt8)`: Creates a `LocalDateTime` with value based on the passed arguments assuming that there are 3600*24 seconds in every day.


This can maybe just be a constructor function. It might be good to improve the naming of day and make it explicit that it is the day of the month, e.g. dayOfMonth:

Suggested change

- `LocalDateTime.of(year: UInt64, month: Month, day: UInt8, hour: UInt8, minute: UInt8, second: UInt8)`: Creates a `LocalDateTime` with value based on the passed arguments assuming that there are 3600*24 seconds in every day.

- `LocalDateTime(year: UInt64, month: Month, dayOfMonth: UInt8, hour: UInt8, minute: UInt8, second: UInt8)`: Creates a `LocalDateTime` with value based on the passed arguments assuming that there are 3600*24 seconds in every day.

Examples below also need to be updated

turbolent · 2024-07-16T18:05:21Z

cadence/20240115-cadence-date-time.md

+
+1. `getYear(): UInt32`: Get the year of the date-time.
+2. `getMonth(): Month`: Get the month of the date-time.
+3. `getDate(): UInt8`: Get the date of the date-time.


Maybe improve the naming and clarify it is the day of the month, i.e.

Suggested change

3. `getDate(): UInt8`: Get the date of the date-time.

3. `getDayOfMonth(): UInt8`: Get the day-of-month of the date-time.

Examples below also need to be updated

turbolent · 2024-07-16T18:07:10Z

cadence/20240115-cadence-date-time.md

+The `LocalDateTime` type will be defined as follows:
+
+```cadence
+pub struct LocalDateTime {


The proposal needs to be updated to Cadence 1.0. For example:

pub -> access(all)

Add view function modifier to getter functions

turbolent · 2024-07-16T18:08:34Z

cadence/20240115-cadence-date-time.md

+
+## Design Proposal
+
+New types `LocalDateTime` & `Duration` will be added to Cadence. Both of these data types assume that there are 3600*24 seconds in every day and there are no leap years.


I wonder if we should add this functionality as a standard library contract, i.e. namespace it and not add them to the global namespace.

turbolent · 2024-07-16T18:10:32Z

cadence/20240115-cadence-date-time.md

+- `getDays(): Int32`: Get the days of the `Duration`.
+- `getSeconds(): UInt32`: Get the second of the `Duration`.
+- `getMicroseconds(): UInt32`: Get the microseconds of the `Duration`.
+- `addYears(years : UInt32): Duration`: Return a new `Duration` after adding the provided number of years to it.


Here and for the other functions below: The function name already clarifies what the parameter is, so the argument label can be removed:

Suggested change

- `addYears(years : UInt32): Duration`: Return a new `Duration` after adding the provided number of years to it.

- `addYears(_ years: UInt32): Duration`: Return a new `Duration` after adding the provided number of years to it.

turbolent · 2024-07-16T18:11:46Z

cadence/20240115-cadence-date-time.md

+- `getDays(): Int32`: Get the days of the `Duration`.
+- `getSeconds(): UInt32`: Get the second of the `Duration`.
+- `getMicroseconds(): UInt32`: Get the microseconds of the `Duration`.
+- `addYears(years : UInt32): Duration`: Return a new `Duration` after adding the provided number of years to it.


The add name sounds like it is mutating, but it seems like that isn't the case right?

Maybe we can use the plus and minus naming like in Java?

turbolent · 2024-07-16T18:12:55Z

cadence/20240115-cadence-date-time.md

+dateTimeFromTs.getSecond()    // 12
+dateTimeFromTs.getDayOfWeek() // wednesday
+
+let dateTimeFromComponents = LocalDateTime.of(2019, april, 29, 19, 49, 31)


Need to add argument labels, as required by the function declaration

turbolent · 2024-10-30T20:45:36Z

We had a working group call yesterday and discussed this FLIP, see the notes in https://github.com/onflow/Flow-Working-Groups/blob/main/cadence_language_and_execution_working_group/meetings/2024-10-29.md#flips.

Consensus is that the proposed library would be useful, but is low priority. Luckily it can be implemented purely in Cadence, and does not need any knowledge of or required any contributions to the Cadence implementation.

@onflow/flow-develop-experience-tools @gregsantos: @dete proposed this could be a good item for the community and could e.g. be implemented through a grant, at a hackathon, etc.

darkdrag00nv2 added 2 commits January 29, 2024 23:25

Add FLIP for Cadence Date and Time

6b8efbf

Update flip number to 245

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github-actions bot assigned darkdrag00nv2 Jan 29, 2024

darkdrag00nv2 changed the title ~~FLIP 245: Cadence Date and time~~ FLIP 245: Cadence Date and Time Jan 29, 2024

Fix Duration and add examples

6f79d09

darkdrag00nv2 marked this pull request as ready for review February 4, 2024 13:33

darkdrag00nv2 changed the title ~~FLIP 245: Cadence Date and Time~~ FLIP 251: Cadence Date and Time Mar 3, 2024

turbolent added the flip: cadence label Jul 9, 2024

turbolent reviewed Jul 16, 2024

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turbolent mentioned this pull request Oct 16, 2024

Cleanup all open FLIPs and plan next steps for them onflow/cadence#3615

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FLIP 251: Cadence Date and Time #245

FLIP 251: Cadence Date and Time #245

darkdrag00nv2 commented Jan 29, 2024 •

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bluesign commented Feb 19, 2024

turbolent commented Feb 19, 2024 •

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darkdrag00nv2 commented Feb 20, 2024

KshitijChaudhary666 commented Feb 28, 2024

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turbolent commented Oct 30, 2024


		- `LocalDateTime.fromTimestamp(timestamp : UFix64)`: Creates a `LocalDateTime` with value based on the passed timestamp argument.

		- `LocalDateTime.of(year: UInt64, month: Month, day: UInt8, hour: UInt8, minute: UInt8, second: UInt8)`: Creates a `LocalDateTime` with value based on the passed arguments assuming that there are 3600*24 seconds in every day.

	- `LocalDateTime.of(year: UInt64, month: Month, day: UInt8, hour: UInt8, minute: UInt8, second: UInt8)`: Creates a `LocalDateTime` with value based on the passed arguments assuming that there are 3600*24 seconds in every day.
	- `LocalDateTime(year: UInt64, month: Month, dayOfMonth: UInt8, hour: UInt8, minute: UInt8, second: UInt8)`: Creates a `LocalDateTime` with value based on the passed arguments assuming that there are 3600*24 seconds in every day.

	3. `getDate(): UInt8`: Get the date of the date-time.
	3. `getDayOfMonth(): UInt8`: Get the day-of-month of the date-time.


		## Design Proposal

		New types `LocalDateTime` & `Duration` will be added to Cadence. Both of these data types assume that there are 3600*24 seconds in every day and there are no leap years.

	- `addYears(years : UInt32): Duration`: Return a new `Duration` after adding the provided number of years to it.
	- `addYears(_ years: UInt32): Duration`: Return a new `Duration` after adding the provided number of years to it.

FLIP 251: Cadence Date and Time #245

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FLIP 251: Cadence Date and Time #245

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darkdrag00nv2 commented Jan 29, 2024 • edited Loading

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turbolent commented Feb 19, 2024 • edited Loading

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turbolent commented Oct 30, 2024

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