mfmt/
document.rs

1// https://homepages.inf.ed.ac.uk/wadler/papers/prettier/prettier.pdf
2//
3// Unlike the Wadler's algorithm or some other formatters like prettier, we do
4// not need to search the best format given source codes. For example, we do
5// not have any "group" combinator.
6//
7// However, we are rather given the "best" format by all information available
8// in the source codes like Go.
9//
10// We need soft-line and if-break nodes to make nodes totally agnostic about if
11// parent nodes are broken or not. But that also makes IR more complex.
12// (e.g. handling trailing commas in function calls)
13
14/// A document.
15#[derive(Clone, Debug, PartialEq)]
16pub enum Document<'a> {
17    /// A document broken into multiple lines.
18    Break {
19        broken: bool,
20        document: &'a Document<'a>,
21    },
22    /// An indented document.
23    Indent(&'a Document<'a>),
24    /// A line.
25    ///
26    /// A formatter considers it as a space if a document is not broken by
27    /// [`Break`](Document::Break).
28    Line,
29    /// A line suffix.
30    LineSuffix(&'a str),
31    /// A document indented to a current column.
32    ///
33    /// If it is `soft`, an indent becomes equal to or more than a current
34    /// indent.
35    Offside {
36        document: &'a Document<'a>,
37        soft: bool,
38    },
39    /// A sequence of documents.
40    Sequence(&'a [Document<'a>]),
41    /// A string.
42    String(&'a str),
43}
44
45impl<'a> From<&'a str> for Document<'a> {
46    fn from(string: &'a str) -> Self {
47        Self::String(string)
48    }
49}
50
51impl<'a> From<&'a [Self]> for Document<'a> {
52    fn from(documents: &'a [Self]) -> Self {
53        Self::Sequence(documents)
54    }
55}
mfmt/document.rs

mfmt/
document.rs
