jj/docs/templates.md

Templates

Jujutsu supports a functional language to customize output of commands. The language consists of literals, keywords, operators, functions, and methods.

A couple of jj commands accept a template via -T/--template option.

Keywords

Keywords represent objects of different types; the types are described in a follow-up section.

Commit keywords

The following keywords can be used in jj log/jj obslog templates.

• description: String
• change_id: ChangeId
• commit_id: CommitId
• parents: List<Commit>
• author: Signature
• committer: Signature
• working_copies: String: For multi-workspace repository, indicate working-copy commit as <workspace name>@.
• current_working_copy: Boolean: True for the working-copy commit of the current workspace.
• branches: String
• tags: String
• git_refs: String
• git_head: String
• divergent: Boolean: True if the commit's change id corresponds to multiple visible commits.
• hidden: Boolean: True if the commit is not visible (a.k.a. abandoned).
• conflict: Boolean: True if the commit contains merge conflicts.
• empty: Boolean: True if the commit modifies no files.
• root: Boolean: True if the commit is the root commit.

Operation keywords

The following keywords can be used in jj op log templates.

• current_operation: Boolean
• description: String
• id: OperationId
• tags: String
• time: TimestampRange
• user: String

Operators

The following operators are supported.

• x.f(): Method call.
• x ++ y: Concatenate x and y templates.

Global functions

The following functions are defined.

• fill(width: Integer, content: Template) -> Template: Fill lines at the given width.
• indent(prefix: Template, content: Template) -> Template: Indent non-empty lines by the given prefix.
• label(label: Template, content: Template) -> Template: Apply label to the content. The label is evaluated as a space-separated string.
• if(condition: Boolean, then: Template[, else: Template]) -> Template: Conditionally evaluate then/else template content.
• concat(content: Template...) -> Template: Same as content_1 ++ ... ++ content_n.
• separate(separator: Template, content: Template...) -> Template: Insert separator between non-empty contents.

Types

Boolean type

No methods are defined. Can be constructed with false or true literal.

Commit type

This type cannot be printed. All commit keywords are accessible as 0-argument methods.

CommitId / ChangeId type

The following methods are defined.

• .short([len: Integer]) -> String
• .shortest([min_len: Integer]) -> ShortestIdPrefix: Shortest unique prefix.

Integer type

No methods are defined.

List type

The following methods are defined.

• .join(separator: Template) -> Template: Concatenate elements with the given separator.
• .map(|item| expression) -> ListTemplate: Apply template expression to each element. Example: parents.map(|c| c.commit_id().short())

ListTemplate type

The following methods are defined. See also the List type.

• .join(separator: Template) -> Template

OperationId type

The following methods are defined.

• .short([len: Integer]) -> String

ShortestIdPrefix type

The following methods are defined.

• .prefix() -> String
• .rest() -> String
• .upper() -> ShortestIdPrefix
• .lower() -> ShortestIdPrefix

Signature type

The following methods are defined.

• .name() -> String
• .email() -> String
• .username() -> String
• .timestamp() -> Timestamp

String type

A string can be implicitly converted to Boolean. The following methods are defined.

• .contains(needle: Template) -> Boolean
• .first_line() -> String
• .lines() -> List<String>: Split into lines excluding newline characters.
• .upper() -> String
• .lower() -> String
• .starts_with(needle: Template) -> Boolean
• .ends_with(needle: Template) -> Boolean
• .remove_prefix(needle: Template) -> String: Removes the passed prefix, if present
• .remove_suffix(needle: Template) -> String: Removes the passed suffix, if present
• .substr(start: Integer, end: Integer) -> String: Extract substring. Negative values count from the end.

String literals

String literals must be surrounded by double quotes ("). The following escape sequences starting with a backslash have their usual meaning: \", \\, \n, \r, \t, \0. Other escape sequences are not supported. Any UTF-8 characters are allowed inside a string literal, with two exceptions: unescaped "-s and uses of \ that don't form a valid escape sequence.

Template type

Most types can be implicitly converted to Template. No methods are defined.

Timestamp type

The following methods are defined.

• .ago() -> String: Format as relative timestamp.
• .format(format: String) -> String: Format with the specified strftime-like format string.
• .utc() -> Timestamp: Convert timestamp into UTC timezone.

TimestampRange type

The following methods are defined.

• .start() -> Timestamp
• .end() -> Timestamp
• .duration() -> String

Configuration

The default templates and aliases() are defined in the [templates] and [template-aliases] sections of the config respectively. The exact definitions can be seen in the cli/src/config/templates.toml file in jj's source tree.

New keywords and functions can be defined as aliases, by using any combination of the predefined keywords/functions and other aliases.

For example:

[template-aliases]
'commit_change_ids' = '''
concat(
  format_field("Commit ID", commit_id),
  format_field("Change ID", commit_id),
)
'''
'format_field(key, value)' = 'key ++ ": " ++ value ++ "\n"'