SPEC: add some thoughts about a config file and sensible (?) defaults (…

…#6)

* add some thoughts about a config file and sensible (?) defaults

* add a warning for paths on windows

* fix the NOTE in the "defaults" section

* add a newline in the Note and in the Warning

docs/specification.md

@@ -20,6 +20,106 @@ There should be a `--limit` parameter to limit to the number of characters per l
 
 There should be a `--lines-before` and `--lines-after` parameter to set the number of empty lines before and after a custom command.
 
+## Config file
+
+As `rustfmt` does it with a `TOML` file, `nufmt` could have a config file, alongside the command line flags above to set options in stone.
+We have identified the NUON format as a suitable data format for this project: after it's THE data format for `nushell`!
+
+With the values above, it could look something like:
+```nuon
+{
+ CRLF: false,
+ indent: 4,
+ limit: 100,
+ lines: {
+ after: 1,
+ before: 1
+ }
+}
+```
+
+## Sensible (?) default and features
+
+- :one: do not always add newlines when it can help understand the central point of a command call
+```nushell
+http get ({
+ scheme: https,
+ host: api.github.com,
+ path: /users/nushell/repos,
+ params: {
+ sort: updated,
+ per_page: 100
+ page: 1
+ }
+} | url join)
+```
+to put the emphasis on the url structure
+> **Note** 
+> the `({ ... } | url join)`
+
+- :two: put `|` at the start of the lines for readability, creating a "wall of pipes"
+```nushell
+def "apply to" [
+ file: path
+ modification: closure
+] {
+ $file
+ | path expand
+ | open --raw
+ | from toml
+ | do $modification
+ | save --force $file
+}
+```
+
+- :three: ternary-like conditions when conditions and the two branches are short
+```nushell
+let sign = if $value < 0 { -1 } else { 1 }
+```
+instead of
+```nushell
+let sign = (
+ if $value < 0 {
+ -1
+ } else {
+ 1
+ }
+)
+```
+
+- :four: a newline before a block of comments
+```nushell
+some command
+
+# a comment to explain
+another comment
+
+# a block
+# of comment
+# for this
+last command
+```
+
+:five: two spaces before and one space after a comment on the same line as a command
+```nushell
+my-command # and some explaination
+```
+or in command arguments as well
+```nushell
+def foo [
+ a: int # my integer argument
+ b: string # my string integer
+] {}
+```
+
+- :six: 4 spaces as the default indentation
+
+- :seven: remove trailing whitespaces
+
+- :eight: single quotes for single characters and double quotes for strings => that behaviour might change with string interpolation and paths.
+> **Warning** 
+> one should use single quotes (') or backticks (\`) to quote paths on Windows
+
 ## Supported Commands
 
 This is the list of the supported commands and their idiomatic formatting. Indentation will be covered by the `--indent` flag but for these examples, 2 spaces will be used.
@@ -42,4 +142,4 @@ if condition {
 for var in 0..100 {
  # do something here
 }
-```
+```