Function parse_date 

pub fn parse_date(s: &str) -> Result<Date, String>

Strictly parse a calendar date in YYYY-MM-DD format.

Behavior

• Trims surrounding whitespace.
• Requires zero-padded year-month-day (e.g., 2025-09-02).
• Rejects datetime strings (e.g., 2025-09-02 12:34:56) and other formats.
• Validates real calendar dates (e.g., leap years).

Arguments

• s: The input string (typically from CLI).

Returns

• Ok(Date) on success.
• Err(String) with a short, user-friendly message otherwise (good for CLI).

Examples

use linkleaf_core::validation::parse_date;
let d = parse_date("2025-01-03").unwrap();
assert_eq!(d.to_string(), "2025-01-03");

use linkleaf_core::validation::parse_date;
assert!(parse_date("2025/01/03").is_err());
assert!(parse_date("2025-1-3").is_err()); // not zero-padded