menugen 0.1.1

Hierarchical menu generation 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

use crate::menu::Menu;
use crate::menuitem::MenuItem;

pub enum Event<'a, C>
where
  C: Clone + Default
{
  EnterScope,
  LeaveScope,
  MenuItem(&'a MenuItem<C>)
}

struct IterNode<'a, C>
where
  C: Clone + Default
{
  lst: &'a Vec<MenuItem<C>>,
  idx: usize,
  did_enter_scope: bool,
  did_leave_scope: bool
}

pub struct MenuIter<'a, C, F>
where
  C: Clone + Default,
  F: Fn(&MenuItem<C>) -> bool
{
  stack: Vec<IterNode<'a, C>>,
  myfilter: F
}

impl<'a, C, F> MenuIter<'a, C, F>
where
  C: Clone + Default,
  F: Fn(&MenuItem<C>) -> bool
{
  pub fn new(menu: &'a Menu<C>, p: F) -> Self {
    let mut iterstack = Vec::new();

    // Default to not scoping the root nodes
    iterstack.push(IterNode {
      lst: &menu.rootlst,
      idx: 0,
      did_enter_scope: true,
      did_leave_scope: true
    });

    MenuIter {
      stack: iterstack,
      myfilter: p
    }
  }

  /// Tell the iterator to scope the root items.  By default the iterator will
  /// not generate scope events for the root elements.
  ///
  /// # Constraints
  /// This setting must only be changed before iteration has started.
  pub fn root_scope(&mut self) -> &mut Self {
    if let Some(root) = self.stack.first_mut() {
      root.did_enter_scope = false;
      root.did_leave_scope = false;
    }
    self
  }
}


impl<'a, C, F> Iterator for MenuIter<'a, C, F>
where
  C: Clone + Default,
  F: Fn(&MenuItem<C>) -> bool
{
  type Item = Event<'a, C>;

  fn next(&mut self) -> Option<Self::Item> {
    while !self.stack.is_empty() {
      // last_mut()
      let mut it = self.stack.pop().unwrap();

      // If there's a filter defined then call it
      if it.idx < it.lst.len() {
        let mi = &it.lst[it.idx];

        // If the filter returns false then skip this entry
        if (self.myfilter)(mi) == false {
          it.idx += 1;
          self.stack.push(it);
          continue;
        }
      }

      // Let application know that iterator entered a new scope
      if it.did_enter_scope == false {
        it.did_enter_scope = true;
        self.stack.push(it);
        return Some(Event::EnterScope);
      }

      // Reached end of iterator
      if it.idx == it.lst.len() {
        // Before backing out make sure the application knows that a scope has
        // been left

        if it.did_enter_scope == true && it.did_leave_scope == false {
          it.did_leave_scope = true;
          self.stack.push(it);
          return Some(Event::LeaveScope);
        }

        continue;
      }


      if it.lst[it.idx].children.is_empty() {
        // Don't step into -- return next child in list
        let ret = Event::MenuItem(&it.lst[it.idx]);
        it.idx += 1;
        self.stack.push(it);
        return Some(ret);
      } else {
        let ret = Event::MenuItem(&it.lst[it.idx]);

        self.stack.push(IterNode {
          lst: &it.lst,
          idx: it.idx + 1,
          did_enter_scope: it.did_enter_scope,
          did_leave_scope: it.did_leave_scope
        });

        // Step into
        self.stack.push(IterNode {
          lst: &it.lst[it.idx].children,
          idx: 0,
          did_enter_scope: false,
          did_leave_scope: false
        });

        return Some(ret);
      }
    }
    None
  }
}

// vim: set ft=rust et sw=2 ts=2 sts=2 cinoptions=2 tw=79 :