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Add/update a lot of documentation

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Michael Wolf
2023-09-30 20:38:00 -06:00
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CUSTOMIZATION.md Normal file
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There are two main areas of per-project customization: how `would-format`
determines a given file's type, and how a file is checked or reformatted
after its type has been determined.
# Conventions
`$YOUR_PROJECT_ROOT` is the root where your project is checked out.
# File type sniffing
To change a file's mapping, create a script at
`$YOUR_PROJECT_ROOT/.would-reformat/custom-sniffer`. It should take one
argument, the fully qualified path of the file whose type is to be sniffed.
It should emit the type of file it thinks its argument is.
Here's an example:
```shell-script
#!/usr/bin/env bash
file="$1"
if [[ $file == *.pl ]] ; then
# the default is that .pl corresponds to perl, but not here!
echo -n "prolog"
fi
if [[ $file == *.ts ]] ; then
# qt translations, who knew
echo -n "qt-translation"
fi
# We're fine with the defaults for other types of files so we don't
# print anything else.
exit 0
```
(This file, possibly with updates, is also available
[here](./examples/custom-sniffer).)
Now, if you run this script against a file that ends in `.pl` or `.ts`,
`would-reformat` will not treat the file as perl or typescript as usual, but
instead as prolog or a qt-translation file. But if you run this script
against a file that ends in `.py` then it'll continue to be treated as python
as usual.
You can perform arbitrarily sophisticated checks here. They're not limited to
file names or extensions. You can take paths into account. You can can even
take files' contents into account. But do keep in mind that this program
will be run often. If it's slow you'll be frustrated by it.
Don't forget that this program can be written in something other than shell,
in case that's easier for you or if performance is a serious concern. It
doesn't actually need to be a "script".
Finally, keep in mind that if `would-reformat`'s defaults work for you, there
is no need to have this file at all.
## Acceptable output
<!-- FIXME: I can't remember the syntax to include and escape ., _, and -.
But those would be OK too, although starting with . or - is usually
more trouble than it's worth. -->
In general, you would do well to limit it to `/[0-9a-z]+/`. It must not
include the `/` character. `would-reformat` doesn't care if you use
uppercase, but some case-preserving filesystems make things difficult.
It must not output `custom-sniffer`. If there is a hitherto unknown
programming language named "custom sniffer" you'll have to output something else.
## Return values
`would-reformat` expects `custom-sniffer` to return one of the following
values:
- 0: success
- 254: file can't be read due to permissions, etc ("etc" is as of
2023-Q3 broad in scope; it could include trying and failing to read a file
on a NFS mount)
- 255: some sort of internal error
# Custom reformatter wrappers
Your custom wrappers live in `$YOUR_PROJECT_ROOT/.would-reformat`. Its name
should be the file type as identified by the sniffer.
It takes one command line argument, the fully qualified path of the file to be
checked or reformatted. It also receives input via three environment
variables:
- `WOULD_REFORMAT` can be set to either `would_reformat` or `do_reformat`. If
the former, it should run in non-destructive mode. If the latter, it should
perform changes on file whose path was passed as the main argument.
- `PROJECT_ROOT` has the value of `$YOUR_PROJECT_ROOT`.
- `WF_ROOT` holds the path where `would-format` is checked out.
Often, these scripts won't need to check `$PROJECT_ROOT` or `$WF_ROOT`.
`$WOULD_REFORMAT` is indepensable.
Here is an example:
```shell-script
#!/usr/bin/env bash
set -euo pipefail
IFS=$'\n\t'
DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
## This usually isn't necessary, but if you need to use wrflog this
## is how you get it:
# source "$WF_ROOT/_reformat-common.bash"
if [[ "$WOULD_REFORMAT" = "would_reformat" ]] ; then
set +e
out=$(php $DIR/.././vendor/bin/pint --test "$1")
retval="$?"
set -e
# unfortunately, pint doesn't distinguish between files with
# syntax errors and files that are merely misformatted
echo "$out"
exit "$retval"
fi
if [[ "$WOULD_REFORMAT" = "do_reformat" ]] ; then
set +e
out=$(php $DIR/.././vendor/bin/pint "$1")
retval="$?"
set -e
echo "$out"
exit "$retval"
fi
exit 255
```
(This file, possibly with updates, is also available
[here](./examples/php).)
As with `custom-sniffer`, a reformatter doesn't have to be written as a shell
script. It just needs to be properly named and executable.
## Acceptable output
As output, this script should emit whatever the programs it calls emit.
## Return values
### In `would_format` mode
`would-format.sh` interprets return values to mean the following:
- 0: file wouldn't be reformatted
- 1: file would be reformatted
- 2: file has at least one syntax error
- 252: Unexpected return value from the tool; that is, the value of `$?` is
unexpected and thus unhandled
- 253: Unexpected output from the tool; that is, the output emitted by the
tool is unexpected and thus unhandled
- 254: file can't be read due to permissions, etc ("etc" is as of
2023-Q3 broad in scope; it could include trying and failing to read a file
on an NFS mount)
- 255: error internal to the script in question
(FIXME: Unsurprisingly, `gofmt` is the only tool I've tested so far that gets
this right. That a file should be reformatted isn't an exceptional condition,
so there's no good reason to signal failure here.
Even less unsurprisingly, Laravel pint gets it worse than all the others I
checked; it doesn't distinguish misformatted files from files with actual
syntax errors.
Anyway, `gofmt` is the obviously the model to follow. So we should
probably drop `1`.)
### in `do_format` mode
`do-reformat` expects a wrapper to return one of the following
values:
- 0: file was successfully reformatted
- 1: file was not successfully reformatted, presumably due to a syntax error
- 254: file can't be rewritten due to permissions, etc ("etc" is as of
2023-Q3 broad in scope; it could include trying and failing to read or write
a file on an NFS mount)
- 255: error internal to the script in question
# What goes into version control and what does not?
FIXME: Write this section
# What files can I modify?
You should not modify any of the files in `.would-reformat/bin` or the files
that they link to. Everything else in `.would-reformat` is fair game.
Of course, `would-reformat` is FOSS. Within the limitations set by its
license, you can do what you like with it. But if you want to make deeper
changes, you're probably better off forking and going from there.

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# Dependencies
In addition to a fairly recent version of bash, it's helpful to have the
following tools installed:
- [shunit2](https://github.com/kward/shunit2)
- [shellcheck](https://www.shellcheck.net/)
- [shfmt](https://github.com/mvdan/sh)
In general, code should pass shellcheck without warnings, be formatted with
shfmt (please use it with `-i 4`), and come with new tests and pass them when
relevant.
If any of this causes you trouble, don't worry. Please submit your pull
request anyway and we can work on getting it up to snuff.
# General goals and non-goals
## Goals
- Be as batteries-included as possible. Go out of our way to just work, even
if not entirely optimally, in as many situations as possible.
- Support "relatively isolated" projects.
- Be easy to configure.
- Be clearly documented. Remember that many programmers are working in
high-stress situations. Documentation that is incomplete, unclear, or cute
will make things even worse for them. Use English correctly and, to the
extent possible, unambiguously.
## Non-goals
# Wishlist
- Generalize this beyond emacs
- In emacs, provide a minor mode or something to use instead of
`.dir-locals.el`, which I've always found to be very fragile
- Add support for more programming languages and file formats
- Clean up shell script code
- Be better at "just working"
- Make it easy to add "private" and alternate formatters
- It should signal more clearly when the file has a syntax error, subject to
the limitations set by third party tools.
- Would global (per-user) customization be useful? My guess is that it'd
probably be more confusing than helpful but I'm not wedded to this
conclusion.
- Write a doctor command to identify potential issues (you'd probably run it
similarly to how you run the install script, but `s/install/doctor`).
# Problems
- It would probably be better if we wrote reformatted code to temp files and
atomically renamed them. This might mean that the tool-specific programs
should emit diffs rather than working silently as they currently do.
- It probably doesn't work on Windows as-is.
- There are probably some Linuxisms and maybe even some recentbashisms.
- It doesn't work with tramp.
- As long as it's written in shell, it's always going to be a little bit slow
and, of course, fairly difficult to hack on. If the bulk of it were
rewritten in, say, go, then some problems would go away and some new ones
would be created. On balance I'm not sure if it's a good idea or not, but
I'm tempted.
- Stop writing files to `$PROJECT_ROOT/bin`; use
`$PROJECT_ROOT/.would-reformat/bin` instead.
- `PROJECT_ROOT` and `WF_ROOT` are probably too generic. Consider prefixing
them, maybe with `WOULD_FORMAT_`.

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README.md
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@@ -38,16 +38,16 @@ saving a file and to run `do-reformat.sh` when you hit `<F1>`.
- typescript - typescript
- vue - vue
Python uses `black`; go uses `gofmt`; dart uses `dart format`. The rest use Out of the box, python uses `isort` and `black`, go uses `gofmt`, and dart
`prettier`. Adding new programming languages is easy, assuming they have a uses `dart format`. The rest use `prettier`. Adding new programming
formatter with a dry run mode. languages is easy, assuming they have a formatter with a dry run mode.
# Installation # Installation
- Change to the directory where you want to use **would-reformat**: - Change to the directory where you want to use `would-reformat`:
`you@host:~ $ cd ~/devel/my-project` `you@host:~ $ cd ~/devel/my-project`
- From that directory, call the script `install.sh` in the directory where - From that directory, call the script `install.sh` in the directory where
you have **would-reformat** checked out: you have `would-reformat` checked out:
`you@host:~/devel/my-project $ ~/src/would-reformat/install.sh` `you@host:~/devel/my-project $ ~/src/would-reformat/install.sh`
Be sure to run the installation script from the root of your project's Be sure to run the installation script from the root of your project's
@@ -65,7 +65,8 @@ This will do the following:
This should work from a checkout wherever you happen to have it. It doesn't This should work from a checkout wherever you happen to have it. It doesn't
need to be in `~/src`. However, if you remove the checkout, then the symlinks need to be in `~/src`. However, if you remove the checkout, then the symlinks
will break, so don't do that. If you rename the checkout, the symlinks will break. will break, so don't do that. If you rename the checkout, the symlinks will
break.
The directory `bin` with respect to `my-project` however is hardcoded The directory `bin` with respect to `my-project` however is hardcoded
(enhancements here are welcome). (enhancements here are welcome).
@@ -76,6 +77,20 @@ checks whether it is a symlink to `~/src/would-reformat/do-reformat.sh`.
If it is not, then it just prints a warning rather than attempting to correct If it is not, then it just prints a warning rather than attempting to correct
the situation. the situation.
FIXME: Document how to reinstall if the checkout was moved, incompatible
changes were made, etc.
# Customization
For information on changing how `would-format` handles different files, see
[CUSTOMIZATION.md](CUSTOMIZATION.md).
# Development
If you want to hack on `would-format`, see [DEVELOPMENT.md](DEVELOPMENT.md)
for more info.
# Troubleshooting # Troubleshooting
## nothing works from emacs ## nothing works from emacs
@@ -106,21 +121,31 @@ cargoculty. There should be a more solid basis for this answer.)
The solution seems to be to run `pip install black pipx` somewhere. The solution seems to be to run `pip install black pipx` somewhere.
# Development ## I need to use one version of `would-reformat` with one of my projects and another with another
# Wishlist With the per-project configuration [see below] this should rarely be
necessary, but in case it is, one thing you can try is creating different
`would-reformat` checkouts for different projects. For example, something
like this might work:
- Generalize this beyond emacs ```
- In emacs, provide a minor mode or something to use instead of $ ls ~/devel
`.dir-locals.el`, which I've always found to be very fragile new-project1 new-project2 old-and-weird-project1
- Add support for more programming languages and file formats $ git clone https://github.com/maw/would-reformat
- Clean up shell script code $ cd new-project1; ../would-reformat/install.sh
- Be better at "just working" $ cd ../new-project2; ../would-reformat/install.sh
- Make it easy to add "private" and alternate formatters $ cd ..
$ git clone https://github.com/maw/would-reformat would-reformat-for-old-and-weird-project1
$ cd would-reformat-for-old-and-weird-project1; git checkout vSome-old-tag
$ cd ../old-and-weird-project1; ../would-reformat-for-old-and-weird-project1/install.sh
```
# Problems
- It would probably be better if we wrote reformatted code to temp files and # Similar projects
atomically renamed them
- This probably doesn't work on Windows as-is. If you don't like `would-reformat`'s approach, maybe one or more of these
- It doesn't work with tramp. would be more suitable.
- https://github.com/purcell/emacs-shfmt/
- https://github.com/pythonic-emacs/blacken
- https://github.com/dominikh/go-mode.el

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#!/usr/bin/env bash
set -euo pipefail
IFS=$'\n\t'
DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
## This usually isn't necessary, but if you need to use wrflog this
## is how you get it:
# source "$WF_ROOT/_reformat-common.bash"
if [[ "$WOULD_REFORMAT" = "would_reformat" ]] ; then
set +e
out=$(php $DIR/.././vendor/bin/pint --test "$1")
retval="$?"
set -e
# unfortunately, pint doesn't distinguish between files with
# syntax errors and files that are merely misformatted
echo "$out"
exit "$retval"
fi
if [[ "$WOULD_REFORMAT" = "do_reformat" ]] ; then
set +e
out=$(php $DIR/.././vendor/bin/pint "$1")
retval="$?"
set -e
echo "$out"
exit "$retval"
fi
exit 255