]>
Commit | Line | Data |
---|---|---|
abe05a73 XL |
1 | use std::fmt; |
2 | use std::cell::RefCell; | |
3 | ||
4 | /// Format all iterator elements lazily, separated by `sep`. | |
5 | /// | |
6 | /// The format value can only be formatted once, after that the iterator is | |
7 | /// exhausted. | |
8 | /// | |
9 | /// See [`.format_with()`](../trait.Itertools.html#method.format_with) for more information. | |
10 | pub struct FormatWith<'a, I, F> { | |
11 | sep: &'a str, | |
12 | /// FormatWith uses interior mutability because Display::fmt takes &self. | |
13 | inner: RefCell<Option<(I, F)>>, | |
14 | } | |
15 | ||
16 | /// Format all iterator elements lazily, separated by `sep`. | |
17 | /// | |
18 | /// The format value can only be formatted once, after that the iterator is | |
19 | /// exhausted. | |
20 | /// | |
21 | /// See [`.format()`](../trait.Itertools.html#method.format) | |
22 | /// for more information. | |
23 | #[derive(Clone)] | |
24 | pub struct Format<'a, I> { | |
25 | sep: &'a str, | |
26 | /// Format uses interior mutability because Display::fmt takes &self. | |
27 | inner: RefCell<Option<I>>, | |
28 | } | |
29 | ||
30 | pub fn new_format<'a, I, F>(iter: I, separator: &'a str, f: F) -> FormatWith<'a, I, F> | |
31 | where I: Iterator, | |
32 | F: FnMut(I::Item, &mut FnMut(&fmt::Display) -> fmt::Result) -> fmt::Result | |
33 | { | |
34 | FormatWith { | |
35 | sep: separator, | |
36 | inner: RefCell::new(Some((iter, f))), | |
37 | } | |
38 | } | |
39 | ||
40 | pub fn new_format_default<'a, I>(iter: I, separator: &'a str) -> Format<'a, I> | |
41 | where I: Iterator, | |
42 | { | |
43 | Format { | |
44 | sep: separator, | |
45 | inner: RefCell::new(Some(iter)), | |
46 | } | |
47 | } | |
48 | ||
49 | impl<'a, I, F> fmt::Display for FormatWith<'a, I, F> | |
50 | where I: Iterator, | |
51 | F: FnMut(I::Item, &mut FnMut(&fmt::Display) -> fmt::Result) -> fmt::Result | |
52 | { | |
53 | fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
54 | let (mut iter, mut format) = match self.inner.borrow_mut().take() { | |
55 | Some(t) => t, | |
56 | None => panic!("FormatWith: was already formatted once"), | |
57 | }; | |
58 | ||
59 | if let Some(fst) = iter.next() { | |
60 | try!(format(fst, &mut |disp: &fmt::Display| disp.fmt(f))); | |
61 | for elt in iter { | |
62 | if self.sep.len() > 0 { | |
63 | ||
64 | try!(f.write_str(self.sep)); | |
65 | } | |
66 | try!(format(elt, &mut |disp: &fmt::Display| disp.fmt(f))); | |
67 | } | |
68 | } | |
69 | Ok(()) | |
70 | } | |
71 | } | |
72 | ||
73 | impl<'a, I> Format<'a, I> | |
74 | where I: Iterator, | |
75 | { | |
76 | fn format<F>(&self, f: &mut fmt::Formatter, mut cb: F) -> fmt::Result | |
77 | where F: FnMut(&I::Item, &mut fmt::Formatter) -> fmt::Result, | |
78 | { | |
79 | let mut iter = match self.inner.borrow_mut().take() { | |
80 | Some(t) => t, | |
81 | None => panic!("Format: was already formatted once"), | |
82 | }; | |
83 | ||
84 | if let Some(fst) = iter.next() { | |
85 | try!(cb(&fst, f)); | |
86 | for elt in iter { | |
87 | if self.sep.len() > 0 { | |
88 | try!(f.write_str(self.sep)); | |
89 | } | |
90 | try!(cb(&elt, f)); | |
91 | } | |
92 | } | |
93 | Ok(()) | |
94 | } | |
95 | } | |
96 | ||
97 | macro_rules! impl_format { | |
98 | ($($fmt_trait:ident)*) => { | |
99 | $( | |
100 | impl<'a, I> fmt::$fmt_trait for Format<'a, I> | |
101 | where I: Iterator, | |
102 | I::Item: fmt::$fmt_trait, | |
103 | { | |
104 | fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
105 | self.format(f, fmt::$fmt_trait::fmt) | |
106 | } | |
107 | } | |
108 | )* | |
109 | } | |
110 | } | |
111 | ||
112 | impl_format!{Display Debug | |
113 | UpperExp LowerExp UpperHex LowerHex Octal Binary Pointer} |