AST doesn't include the original casing of the NULL and CURRENT_* literals

[merceyz]

The AST doesn't provide the original casing used for the literals NULL, CURRENT_DATE, CURRENT_TIME, and CURRENT_TIMESTAMP making it impossible to detect what the column name would be from just the AST.

use fallible_iterator::FallibleIterator;
use sqlite3_parser::lexer::sql::Parser;

pub fn main() {
    let mut parser = Parser::new(b"SELECT nuLL, current_TIME");

    let ast = parser.next().unwrap().unwrap();

    println!("{}", ast);
    // SELECT NULL, CURRENT_TIME;

    println!("{:?}", ast);
    // Stmt(Select(Select { with: None, body: SelectBody { select: Select { distinctness: None, columns: [Expr(Literal(Null), None), Expr(Literal(CurrentTime), None)], from: None, where_clause: None, group_by: None, window_clause: None }, compounds: None }, order_by: None, limit: None }))
}

SQLite itself preserves the casing in the column name:

$ sqlite3 --table
SQLite version 3.46.0 2024-05-23 13:25:27
Enter ".help" for usage hints.
sqlite> SELECT nuLL, current_TIME;
+------+--------------+
| nuLL | current_TIME |
+------+--------------+
|      | 00:00:00     |
+------+--------------+

[gwenn]

This is expected because all keywords are normalized.

lemon-rs/src/parser/ast/fmt.rs

Line 766 in d98b3f2

Self::CurrentTimestamp => s.append(TK_CTIME_KW, Some("CURRENT_TIMESTAMP")),

You might be able to preserve the original case if we implement #33
But for now I would prefer to keep the memory footprint of the AST as low as possible.

Also the SQLite syntax is case-insensitive.
So your sentence:

making it impossible to detect what the column name would be from just the AST.

seems wrong to me.

sqlite> .headers on
sqlite> CREATE TABLE x(A);
sqlite> INSERT INTO x VALUES ('...');
sqlite> SELECT a FROM x;
A
...```

[merceyz]

Literals are treated differently, their casing is preserved in the resulting column name.

[gwenn]

I agree but not keywords.
And lemon-rs cannot preserve original column name like SQLite3 because there is no schema access...