openpql_pql_parser/ast/
selector.rs

1use super::{Error, Expr, Ident, ResultE, SelectorKind, String};
2
3/// Aggregate selector such as `avg(expr) as alias`.
4#[derive(Clone, PartialEq, derive_more::Debug)]
5#[debug("{:?}({:?}){}", self.kind, self.expr, _alias_to_str(self.alias.as_ref()))]
6pub struct Selector<'i> {
7    /// Aggregate kind.
8    pub kind: SelectorKind,
9    /// Inner expression the aggregate applies to.
10    pub expr: Expr<'i>,
11    /// Optional `as` alias.
12    pub alias: Option<Ident<'i>>,
13}
14
15fn _alias_to_str(alias: Option<&Ident>) -> String {
16    alias.map_or_else(String::default, |id| format!(" as {id:?}"))
17}
18
19impl<'i> Selector<'i> {
20    /// Builds a selector, resolving `kind` against the supported aggregates.
21    pub fn new(kind: &Ident<'i>, expr: Expr<'i>, alias: Option<Ident<'i>>) -> ResultE<'i, Self> {
22        let kind = match kind.inner.to_ascii_lowercase().as_str() {
23            "avg" => SelectorKind::Avg,
24            "count" => SelectorKind::Count,
25            "max" => SelectorKind::Max,
26            "min" => SelectorKind::Min,
27            _ => return Err(Error::UnrecognizedSelector(kind.loc).into()),
28        };
29
30        Ok(Self { kind, expr, alias })
31    }
32}
33
34#[cfg(test)]
35#[cfg_attr(coverage_nightly, coverage(off))]
36mod tests {
37    use crate::*;
38
39    fn assert_selector(src: &str, expected: &str) {
40        assert_eq!(format!("{:?}", parse_selector(src).unwrap()), expected);
41    }
42
43    #[test]
44    fn test_selector() {
45        assert_selector("avg(equity(hero, river))", "avg(equity(hero,river))");
46        assert_selector(
47            "avg(equity(hero, river)) as s1",
48            "avg(equity(hero,river)) as s1",
49        );
50
51        assert_selector("count(_)", "count(_)");
52        assert_selector("max(_)", "max(_)");
53        assert_selector("min(_)", "min(_)");
54    }
55
56    fn assert_err(src: &str, expected: Error) {
57        assert_eq!(parse_selector(src).unwrap_err(), expected);
58    }
59
60    #[test]
61    fn test_selector_err() {
62        let src = "invalid(_)";
63        assert_err(src, Error::UnrecognizedSelector(loc(src, "invalid")));
64    }
65}
openpql_pql_parser/ast/selector.rs

openpql_pql_parser/ast/
selector.rs
