squawk_syntax/
quote.rs

1use crate::SyntaxNode;
2use crate::generated::keywords::RESERVED_KEYWORDS;
3
4pub fn quote_column_alias(text: &str) -> String {
5    if needs_quoting(text) {
6        format!(r#""{}""#, text.replace('"', r#""""#))
7    } else {
8        text.to_string()
9    }
10}
11
12pub fn unquote_ident(node: &SyntaxNode) -> Option<String> {
13    let text = node.text().to_string();
14
15    if !text.starts_with('"') || !text.ends_with('"') {
16        return None;
17    }
18
19    let text = &text[1..text.len() - 1];
20
21    if is_reserved_word(text) {
22        return None;
23    }
24
25    if text.is_empty() {
26        return None;
27    }
28
29    let mut chars = text.chars();
30
31    // see: https://www.postgresql.org/docs/18/sql-syntax-lexical.html#SQL-SYNTAX-IDENTIFIERS
32    match chars.next() {
33        Some(c) if c.is_lowercase() || c == '_' => {}
34        _ => return None,
35    }
36
37    for c in chars {
38        if c.is_lowercase() || c.is_ascii_digit() || c == '_' || c == '$' {
39            continue;
40        }
41        return None;
42    }
43
44    Some(text.to_string())
45}
46
47fn needs_quoting(text: &str) -> bool {
48    if text.is_empty() {
49        return true;
50    }
51
52    // Column labels in AS clauses allow all keywords, so we don't need to check
53    // for reserved words. See PostgreSQL grammar:
54    // ColLabel: IDENT | unreserved_keyword | col_name_keyword | type_func_name_keyword | reserved_keyword
55
56    let mut chars = text.chars();
57
58    match chars.next() {
59        Some(c) if c.is_lowercase() || c == '_' => {}
60        _ => return true,
61    }
62
63    for c in chars {
64        if c.is_lowercase() || c.is_ascii_digit() || c == '_' || c == '$' {
65            continue;
66        }
67        return true;
68    }
69
70    false
71}
72
73pub fn is_reserved_word(text: &str) -> bool {
74    RESERVED_KEYWORDS
75        .binary_search(&text.to_lowercase().as_str())
76        .is_ok()
77}
78
79pub fn normalize_identifier(text: &str) -> String {
80    // TODO: Cow/SmolStr/Salsa Interned?
81    text.strip_prefix('"')
82        .and_then(|t| t.strip_suffix('"'))
83        .map(|x| x.replace(r#""""#, "\""))
84        .unwrap_or_else(|| text.to_ascii_lowercase())
85}
86
87#[cfg(test)]
88mod tests {
89    use insta::assert_snapshot;
90
91    use super::*;
92
93    #[test]
94    fn quote_column_alias_handles_embedded_quotes() {
95        assert_snapshot!(quote_column_alias(r#"foo"bar"#), @r#""foo""bar""#);
96    }
97
98    #[test]
99    fn quote_column_alias_doesnt_quote_reserved_words() {
100        // Keywords are allowed as column labels in AS clauses
101        assert_snapshot!(quote_column_alias("case"), @"case");
102        assert_snapshot!(quote_column_alias("array"), @"array");
103    }
104
105    #[test]
106    fn quote_column_alias_doesnt_quote_simple_identifiers() {
107        assert_snapshot!(quote_column_alias("col_name"), @"col_name");
108    }
109
110    #[test]
111    fn quote_column_alias_handles_special_column_name() {
112        assert_snapshot!(quote_column_alias("?column?"), @r#""?column?""#);
113    }
114}
squawk_syntax/quote.rs

squawk_syntax/
quote.rs
