jj/docs/templates.md
Yuya Nishihara c52efd9df3 templater: add fill(width, content) function
The parameter order follows indent()/label() functions, but this might be
a bad idea because fill() is more likely to have optional parameters. We can
instead add template.fill(width) method as well as .indent(prefix). If we take
this approach, we'll probably need to add string.fill()/indent() methods,
and/or implicit cast at method resolution. The good thing about the method
syntax is that we can add string.refill(), etc. for free, without inventing
generic labeled template functions.

For #1043, I think it's better to add a config like ui.log-word-wrap = true.
We could add term_width/graph_width keywords to the templater, but the
implementation would be more complicated, and is difficult to use for the
basic use case. Unlike Mercurial, our templater doesn't have a context map
to override the graph_width stub.
2023-03-10 16:07:55 +09:00

168 lines
4.1 KiB
Markdown

# 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`
* `parent_commit_ids: List<CommitId>`
* `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 change id corresponds to multiple visible
commits.
* `conflict: Boolean`: True if the commit contains merge conflicts.
* `empty: Boolean`: True if the commit modifies no files.
### 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.
### 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`.
### 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`
### Template type
Any types can be implicitly converted to `Template`. No methods are defined.
### Timestamp type
The following methods are defined.
* `.ago() -> String`: Format as relative timestamp.
### TimestampRange type
The following methods are defined.
* `.start() -> Timestamp`
* `.end() -> Timestamp`
* `.duration() -> String`
## Configuration
[The default templates and aliases](../src/config/templates.toml) are defined
in the `[templates]` and `[template-aliases]` sections respectively.
New keywords and functions can be defined as aliases, by using any
combination of the predefined keywords/functions and other aliases.
For example:
```toml
[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"'
```