anathema_value_resolver/functions/
mod.rs

1use std::collections::HashMap;
2use std::fmt::{Debug, Display};
3
4use crate::ValueKind;
5
6mod list;
7mod number;
8mod string;
9
10#[derive(Debug)]
11pub enum Error {
12    FunctionAlreadyRegistered(String),
13}
14
15impl Display for Error {
16    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
17        match self {
18            Error::FunctionAlreadyRegistered(name) => write!(f, "function `{name}` is already registered"),
19        }
20    }
21}
22
23impl std::error::Error for Error {}
24
25pub struct Function {
26    inner: Box<dyn for<'bp> Fn(&[ValueKind<'bp>]) -> ValueKind<'bp>>,
27}
28
29impl Function {
30    pub(crate) fn invoke<'bp>(&self, args: &[ValueKind<'bp>]) -> ValueKind<'bp> {
31        (self.inner)(args)
32    }
33}
34
35impl Debug for Function {
36    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
37        write!(f, "<fun>")
38    }
39}
40
41impl<T> From<T> for Function
42where
43    T: 'static,
44    T: for<'bp> Fn(&[ValueKind<'bp>]) -> ValueKind<'bp>,
45{
46    fn from(value: T) -> Self {
47        Self { inner: Box::new(value) }
48    }
49}
50
51pub struct FunctionTable {
52    inner: HashMap<String, Function>,
53}
54
55impl FunctionTable {
56    pub fn new() -> Self {
57        let mut inner = HashMap::new();
58        inner.insert("to_upper".into(), Function::from(string::to_upper));
59        inner.insert("to_lower".into(), Function::from(string::to_lower));
60        inner.insert("to_str".into(), Function::from(string::to_str));
61        inner.insert("to_int".into(), Function::from(number::to_int));
62        inner.insert("round".into(), Function::from(number::round));
63        inner.insert("contains".into(), Function::from(list::contains));
64        Self { inner }
65    }
66
67    pub fn insert(&mut self, ident: impl Into<String>, f: impl Into<Function>) -> Result<(), Error> {
68        let key = ident.into();
69        if self.inner.contains_key(&key) {
70            return Err(Error::FunctionAlreadyRegistered(key));
71        }
72        self.inner.insert(key, f.into());
73        Ok(())
74    }
75
76    pub fn lookup(&self, ident: &str) -> Option<&Function> {
77        self.inner.get(ident)
78    }
79}
80
81#[cfg(test)]
82mod test {
83    use crate::ValueKind;
84
85    pub(crate) fn list<T, U>(items: T) -> ValueKind<'static>
86    where
87        U: Into<ValueKind<'static>>,
88        T: IntoIterator<Item = U>,
89    {
90        let inner = items.into_iter().map(Into::into).collect::<Box<[ValueKind<'_>]>>();
91
92        ValueKind::List(inner)
93    }
94
95    pub(crate) fn value<T>(val: T) -> ValueKind<'static>
96    where
97        T: Into<ValueKind<'static>>,
98    {
99        val.into()
100    }
101}
anathema_value_resolver/functions/mod.rs

anathema_value_resolver/functions/
mod.rs
