58 lines
1.6 KiB
Markdown
58 lines
1.6 KiB
Markdown
---
|
|
outline: deep
|
|
---
|
|
|
|
# Formatter Specification
|
|
|
|
In order to keep the design of `treefmt` simple, we only supports formatters that adhere to a certain standard. This
|
|
document outlines that standard.
|
|
|
|
If the formatter you would like to use doesn't comply with the rules, it's often possible to create a wrapper script
|
|
that transforms the usage to match the specification.
|
|
|
|
In this design, we rely on `treefmt` to do the tree traversal, and only invoke
|
|
the code formatter on the selected files.
|
|
|
|
## Rules
|
|
|
|
In order for the formatter to comply to this spec, it **MUST** comply with the following:
|
|
|
|
### 1. Files passed as arguments
|
|
|
|
In order to be integrated with `treefmt`'s workflow, the formatter's CLI must be of the form:
|
|
|
|
```
|
|
<command> [options] [...<files>]
|
|
```
|
|
|
|
Where:
|
|
|
|
- `<command>` is the name of the formatting tool.
|
|
- `[options]` is any number of flags and options that the formatter accepts.
|
|
- `[...<files>]` is one or more files given to the formatter for processing.
|
|
|
|
Example:
|
|
|
|
```
|
|
$ rustfmt --edition 2018 src/main.rs src/lib.rs
|
|
```
|
|
|
|
> [!IMPORTANT]
|
|
> It _SHOULD_ processes only the specified files. Files that are not passed _SHOULD_ never be formatted.
|
|
|
|
### 2. Write to changed files
|
|
|
|
Whenever there is a change to the code formatting, the code formatter **MUST** write to the changes back to the
|
|
original location.
|
|
|
|
If there is no changes to the original file, the formatter **MUST** NOT write to the original location.
|
|
|
|
### 3. Idempotent
|
|
|
|
The code formatter _SHOULD_ be indempotent. Meaning that it produces stable
|
|
outputs.
|
|
|
|
### 4. Reliable
|
|
|
|
We expect the formatter to be reliable and not break the semantics of the formatted files.
|