Advanced channel filters

[dnsge]

Description

Adds custom channel filters complete with their own mini-language. Filters can be created in settings, and applied by clicking the three dots to open the Split menu and selecting "Set filters".

I tried my hand at creating an icon for the filters tab in settings, but I'd like feedback on its design.

Example filters:

• message.content contains "hello"
• message.length <= 40 || author.subscribed
• (message.length <= 10 || message.content contains "look at this") && !(message.content contains "LULW")

Valid but useless filters:

• 2 + 3 == 5
• 10 / 2 == 3
• 20 % 3 == 2

Available per-message variables:

Variable	Type	Description
Author		User who sent the message
author.badges	List	List of author's badges
author.color	Color	Color code of author, or none
author.name	String	Display name of author
author.subbed	Bool	Whether author is subscribed
author.sub_length	Int	How long author has been subscribed (or zero)
Channel		The channel where the message was sent
channel.name	String	Channel name
channel.watching	Bool	Whether the channel is being watched (requires Chatterino extension)
Flags		Message-specific flags
flags.highlighted	Bool	Whether the message is highlighted
flags.points_redeemed	Bool	Whether the message was redeemed through channel points
flags.sub_message	Bool	Whether the message is a sub/resub/gift message
flags.system_message	Bool	Whether the message is a system message
flags.whisper	Bool	Whether the message is a whisper
Message		Actual message sent
message.content	String	Message content
message.length	Int	Message length

Available operators:

Operator	Description
&&	And
||	Or
==	Equals
!=	Not equals
%	Modulus
<	Less than
<=	Less than or equal to
>	Greater than
>=	Greater than or equal to
!	Not
contains	String, List, or Map contains
startswith	String or List starts with text or string, respectively
endswith	String or List ends with text or string, respectively
+	Add
-	Subtract
*	Multiply
/	Divide (integer)

Literals:

Name	Example
Int	123, 5
String	"Hello there", "Escaped \" quote"

Notes about the order of operations:

• Math operations are evaluated from left to right, not by MDAS. 2 + 3 * 4 yields 20, not 14.
• a && b || c && d is evaluated as (a && b) || (c && d)
• a || b && c || d is evaluated as a || (b && c) || d

Still working on:

• Persist assigned filters after relaunching Chatterino
• User feedback for parsing of filter
• Verifying that all types work correctly
• Fixing order of operations
• Documentation
• Properly filtering messages from splits
• Fixing edge cases

Closes #1643
Closes #1632
Closes #518

This PR should probably be squashed into one commit

[fourtf]

Why does this introduce a language for defining filters and not a GUI? Is this accessible to users that are not coders?

[ALazyMeme]

Quick question: Is it as simple as adding a filter with author.subbed and the author of the message would have to be subscribed? If so, it isn't working for me.

Secondly, using author.subscribed completely crashes chatterino for me.
Thirdly, please create a pr for the wiki to add the filters page: https://github.com/Chatterino/wiki

[dnsge]

@ALazyMeme
author.subbed is valid and works for me:

Filters are only applied to new messages, not messages that are already present in the channel. Perhaps that's what happened?

As for creating and applying a filter author.subscribed, my Chatterino doesn't crash. Maybe it's a platform-specific bug?

Nevermind, I found the issue (fixed in 1025894). I don't know why I wasn't able to replicate the crash earlier.

[pajlada]

Will be merging this in as is once #2081 has been merged into master. Thanks a lot for your contribution!

[gempir]

This is an amazing feature that makes Chatterino stand out from a lot of other chat clients. Thank you!