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Seeking Guidance: Dict Iterator Pattern for Building Nested Structures

Hi Mojo community! I’m relatively new to Mojo and building a native TOML parser as a learning project (GitHub). I’ve hit what seems like a Dict iteration limitation and would love guidance on the right pattern to use.

What I’m Trying To Do: Parse TOML files with table headers and build nested Dict structures:

[database]
host = "localhost"

→ Should create {"database": {"host": "localhost"}}

The Problem: I need to iterate Dict entries to copy/build nested structures, but can’t access the entries:

for entry in dict.items():
    var key = entry[].key     // ❌ Error: DictEntry is not subscriptable
    var val = entry[].value   // ❌ Error: not subscriptable

What I’ve Tried: - Using .keys() iterator → same subscripting issue - Get-modify-put pattern → requires iteration to copy - Multiple architectural approaches → all hit the same wall

Current Status: ✅ Arrays and inline tables work great (71 tests passing) ❌ Blocked on table headers due to this iteration issue

Question: Is there a recommended pattern for iterating Dict entries to build new structures? Or am I approaching this wrong for Mojo’s ownership model?

Full technical details and attempted approaches: TABLE_HEADERS_BLOCKER.md

Any guidance appreciated! Still learning Mojo’s patterns. 🔥

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