chinese_format/
placeholders.rs

1/// Defines a new **placeholder** type.
2///
3/// Every *placeholder* wraps a [ChineseFormat](crate::ChineseFormat) instance and implements [ChineseFormat](crate::ChineseFormat) as follows:
4///
5///   * first, convert the wrapped [ChineseFormat](crate::ChineseFormat) instance to [Chinese](crate::Chinese)
6///
7///   * if the result is not [omissible](crate::Chinese::omissible), return it unchanged
8///
9///     * otherwise, return a [Chinese](crate::Chinese) that is still [omissible](crate::Chinese::omissible),
10///       but whose [logograms](crate::Chinese::logograms) are the obtained by calling `$replacement_logograms.to_string()`.
11///
12/// Anyway, the `omissible` property of any placeholder always reflects the [Chinese](crate::Chinese) produced by the wrapped [ChineseFormat](crate::ChineseFormat) instance.
13///
14/// Last but not least, every placeholder can be built via its `new()` constructor.
15///
16/// # Ready-made placeholders
17///
18/// ## [LingPlaceholder]
19///
20/// Uses `零` in lieu of [omissible](crate::Chinese::omissible) logograms:
21///
22/// ```
23/// use chinese_format::*;
24///
25/// let placeholder_with_non_omissible = LingPlaceholder::new(&"二九零四");
26///
27/// assert_eq!(placeholder_with_non_omissible.to_chinese(Variant::Simplified), Chinese {
28///     logograms: "二九零四".to_string(),
29///     omissible: false
30/// });
31///
32/// assert_eq!(placeholder_with_non_omissible.to_chinese(Variant::Traditional), "二九零四");
33///
34///
35/// let placeholder_with_omissible = LingPlaceholder::new(&"");
36///
37/// assert_eq!(placeholder_with_omissible.to_chinese(Variant::Simplified), Chinese {
38///     logograms: "零".to_string(),
39///     omissible: true
40/// });
41///
42/// assert_eq!(placeholder_with_omissible.to_chinese(Variant::Traditional), "零");
43/// ```
44///
45/// ## [EmptyPlaceholder]
46///
47/// Uses an *empty string* in lieu of [omissible](crate::Chinese::omissible) logograms:
48///
49/// ```
50/// use chinese_format::*;
51///
52/// let placeholder_with_non_omissible = EmptyPlaceholder::new(&"二九零四");
53///
54/// assert_eq!(placeholder_with_non_omissible.to_chinese(Variant::Simplified), Chinese {
55///     logograms: "二九零四".to_string(),
56///     omissible: false
57/// });
58///
59/// assert_eq!(placeholder_with_non_omissible.to_chinese(Variant::Traditional), "二九零四");
60///
61///
62/// let placeholder_with_omissible = EmptyPlaceholder::new(&"");
63///
64/// assert_eq!(placeholder_with_omissible.to_chinese(Variant::Simplified), Chinese {
65///     logograms: "".to_string(),
66///     omissible: true
67/// });
68///
69/// assert_eq!(placeholder_with_omissible.to_chinese(Variant::Traditional), "");
70/// ```
71#[macro_export]
72macro_rules! define_string_placeholder {
73    (
74        //The visibility of the type to create.
75        $type_visibility: vis,
76
77        //The name of the type to create.
78        $type: ident,
79
80        //String of logograms in lieu of wrapped omissible ones.
81        $replacement_logograms: expr,
82
83        //The RustDoc string for the type to create.
84        $doc_string: literal
85    ) => {
86        #[doc = $doc_string]
87        $type_visibility struct $type<'a>(&'a dyn $crate::ChineseFormat);
88
89        impl <'a> $type<'a> {
90            pub fn new<T: $crate::ChineseFormat>(value: &'a T) -> Self {
91                Self(value)
92            }
93        }
94
95        impl <'a> $crate::ChineseFormat for $type<'a>{
96            fn to_chinese(&self, variant: $crate::Variant) -> $crate::Chinese {
97                let wrapped_chinese = self.0.to_chinese(variant);
98
99                let result_logograms = if wrapped_chinese.omissible {
100                    $replacement_logograms.to_string()
101                } else {
102                    wrapped_chinese.logograms
103                };
104
105                $crate::Chinese {
106                    logograms:  result_logograms,
107                    omissible: wrapped_chinese.omissible
108                }
109            }
110        }
111    };
112}
113
114define_string_placeholder!(
115    pub,
116    LingPlaceholder,
117    "零",
118    "[Placeholder](crate::define_string_placeholder) replacing an *omissible* value with `零`."
119);
120
121define_string_placeholder!(
122    pub,
123    EmptyPlaceholder,
124    "",
125    "[Placeholder](crate::define_string_placeholder) replacing an *omissible* value with an empty string."
126);
chinese_format/placeholders.rs

chinese_format/
placeholders.rs
