Welcome to the home page for the MessageFormat Working Group, a subgroup of the Unicode CLDR-TC.
The Message Format Working Group (MFWG) is tasked with developing an industry standard for the representation of localizable message strings to be a successor to ICU MessageFormat. MFWG will recommend how to remove redundancies, make the syntax more usable, and support more complex features, such as gender, inflections, and speech. MFWG will also consider the integration of the new standard with programming environments, including, but not limited to, ICU, DOM, and ECMAScript, and with localization platform interchange. The output of MFWG will be a specification for the new syntax.
The current draft syntax for defining messages can be found in spec/syntax.md. The syntax is formally described in ABNF.
Messages can be simple strings:
Hello, world!
Messages can interpolate arguments:
Hello {$user}!
Messages can transform those arguments using formatting functions. Functions can optionally take options:
Today is {$date :datetime}
Today is {$date :datetime weekday=long}.
Messages can use a selector to choose between different variants, which correspond to the grammatical (or other) requirements of the language:
.match {$count :integer}
0 {{You have no notifications.}}
one {{You have {$count} notification.}}
* {{You have {$count} notifications.}}
Messages can annotate arguments with formatting instructions or assign local values for use in the formatted message:
.input {$date :datetime weekday=long month=medium day=short}
.local $numPigs = {$pigs :integer}
{{On {$date} you had this many pigs: {$numPigs}}}
The message syntax supports using multiple selectors and other features to build complex messages. It is designed so that implementations can extend the set of functions or their options using the same syntax. Implementations may even support users creating their own functions.
See more examples and the formal definition of the grammar in spec/syntax.md.
- Java:
com.ibm.icu.message2, part of ICU 72 released in October 2022, is a tech preview implementation of the MessageFormat 2 syntax, together with a formatting API. See the ICU User Guide for examples and a quickstart guide. - JavaScript:
messageformat4.0 implements the MessageFormat 2 syntax, together with a polyfill of the runtime API proposed for ECMA-402.
We invite feedback about the current syntax draft, as well as the real-life use-cases, requirements, tooling, runtime APIs, localization workflows, and other topics.
- General questions and thoughts → post a discussion thread.
- Actionable feedback (bugs, feature requests) → file a new issue.
To join in:
- Review CONTRIBUTING.md
- Apply to join our mailing list
- Watch this repository (use the "Watch" button in the upper right corner)
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The project is released under LICENSE.
A CLA is required to contribute to this project - please refer to the CONTRIBUTING.md file (or start a Pull Request) for more information.