Constant E0001_UNCLOSED_DELIMITER 

pub const E0001_UNCLOSED_DELIMITER: ErrorCode;

E0001: Unclosed delimiter

This error occurs when the parser encounters an opening delimiter like (, {, or [ that isn’t properly closed. Compose requires all delimiters to be balanced and properly nested.

Unclosed delimiters can happen in several ways: forgetting a closing character, accidentally mismatching different kinds of delimiters, or reaching the end of the file before closing.

---

Example 1: Missing closing parenthesis

# let unclosed_paren = 2;
{unclosed_paren == 2;
let other_statement;

// autogenerated

The opening ( is never closed before the next statement begins.

✅ Fix:

# let unclosed_paren = 2;
(unclosed_paren == 2);
let other_statement;

---

Example 2: Unexpected closing delimiter

{
    let f = { a, b => a == b };
)

// autogenerated

A block opened with { was never closed with }. Instead, an unrelated ) was found.

✅ Fix:

{
    let f = { a, b => a == b };
}

---

Example 3: Reaching the end of the file without closing

{ unclosed_to_eof

The block was never closed, and the file ended before the parser could find the matching }.

✅ Fix:

# let unclosed_to_eof = 2;
{ unclosed_to_eof; }

---

Summary

Unclosed delimiters are a syntax error. To fix them:

• Make sure every ( has a matching ), every { has a matching }, and every [ has a matching ].
• Watch for mismatched pairs, such as opening with { and closing with ).
• Check for missing closings especially near the end of files or after nested code.

💡 Tip: If you see many unclosed delimiter errors, start by fixing the first one. Later ones are often caused by it.