sise 0.8.0

SISE (Simple S-expression) parser, serializer and utilities library.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152

use alloc::vec::Vec;

use crate::{Serializer, TreeNode};

/// Serializes a tree of nodes into `serializer`.
///
/// # Example
///
/// ```
/// use sise::sise_tree;
///
/// let tree = sise_tree!(["example", ["1", "2", "3"], ["a", "b", "c"]]);
///
/// let style = sise::SerializerStyle {
///     line_break: "\n",
///     indentation: " ",
/// };
///
/// let mut result = String::new();
/// let mut serializer = sise::Serializer::new(style, &mut result);
///
/// sise::serialize_tree(&mut serializer, &tree, usize::MAX);
/// // Don't forget to finish the serializer
/// serializer.finish(false);
///
/// let expected_result = "(example (1 2 3) (a b c))";
/// assert_eq!(result, expected_result);
/// ```
///
/// If you use multi-line style, atoms at the beginning of a list
/// will be placed in the same line as the openning `(`:
///
/// ```
/// use sise::sise_tree;
///
/// let tree = sise_tree!(["example", ["1", "2", "3"], ["a", "b", "c"]]);
///
/// let style = sise::SerializerStyle {
///     line_break: "\n",
///     indentation: " ",
/// };
///
/// let mut result = String::new();
/// let mut serializer = sise::Serializer::new(style, &mut result);
///
/// sise::serialize_tree(&mut serializer, &tree, 0);
/// // Don't forget to finish the serializer
/// serializer.finish(true);
///
/// let expected_result = "(example\n (1\n  2\n  3\n )\n (a\n  b\n  c\n )\n)\n";
/// assert_eq!(result, expected_result);
/// ```
///
/// It does not consume the serializer, so it can also be used to serialize
/// a sub-tree:
///
/// ```
/// use sise::sise_tree;
///
/// let tree = sise_tree!(["1", "2", "3"]);
///
/// let style = sise::SerializerStyle {
///     line_break: "\n",
///     indentation: " ",
/// };
///
/// let mut result = String::new();
/// let mut serializer = sise::Serializer::new(style, &mut result);
///
/// // Serialize the head
/// serializer.begin_list(usize::MAX);
/// serializer.put_atom("head", usize::MAX);
///
/// // Serialize the subtree
/// sise::serialize_tree(&mut serializer, &tree, usize::MAX);
///
/// // Serialize the tail
/// serializer.put_atom("tail", usize::MAX);
/// serializer.end_list();
/// serializer.finish(false);
///
/// let expected_result = "(head (1 2 3) tail)";
/// assert_eq!(result, expected_result);
/// ```
pub fn serialize_tree(
    serializer: &mut Serializer<'_, '_>,
    root_node: &TreeNode,
    break_line_at: usize,
) {
    enum State<'a> {
        Beginning(&'a TreeNode),
        Writing {
            stack: Vec<core::slice::Iter<'a, TreeNode>>,
            current_list: core::slice::Iter<'a, TreeNode>,
            list_beginning: bool,
        },
        Finished,
    }

    let mut state = State::Beginning(root_node);

    loop {
        match state {
            State::Beginning(node) => match node {
                TreeNode::Atom(atom) => {
                    serializer.put_atom(atom, break_line_at);
                    state = State::Finished;
                }
                TreeNode::List(list) => {
                    serializer.begin_list(break_line_at);
                    state = State::Writing {
                        stack: Vec::new(),
                        current_list: list.iter(),
                        list_beginning: true,
                    };
                }
            },
            State::Writing {
                ref mut stack,
                ref mut current_list,
                ref mut list_beginning,
            } => {
                if let Some(node) = current_list.next() {
                    match node {
                        TreeNode::Atom(atom) => {
                            if *list_beginning {
                                serializer.put_atom(atom, usize::MAX);
                            } else {
                                serializer.put_atom(atom, break_line_at);
                            }
                            *list_beginning = false;
                        }
                        TreeNode::List(list) => {
                            serializer.begin_list(break_line_at);
                            stack.push(core::mem::replace(current_list, list.iter()));
                            *list_beginning = true;
                        }
                    }
                } else {
                    serializer.end_list();
                    if let Some(parent_list) = stack.pop() {
                        *current_list = parent_list;
                        *list_beginning = false;
                    } else {
                        state = State::Finished;
                    }
                }
            }
            State::Finished => return,
        }
    }
}