[RFC] array_search_range — Concrete Use Cases

Hi everyone,

After the feedback from Larry and mickmackusa, I thought it would be more
helpful to lay out the concrete, real-world use cases for this function in
one place, rather than discussing it in abstract terms.

The Core Problem

array_slice() always creates a new array. For large arrays, this means
significant memory overhead and slowdown, just to find the position of an
element or a range of elements.

array_search_range() is designed to return only the indices, without making
any copy.

Real-World Use Cases

1. Pagination on large arrays

When you have an array with a hundred thousand elements and you only want
to process a specific range, you currently have to copy the whole slice or
loop over everything. This function gives you just the indices of that
range.

2. Processing large log files

You read a big log file into an array and you want to find only the lines
within a specific time range. Instead of a full scan or a copy, you get
just the relevant positions.

3. Queues

When you want to find items between two positions without modifying or
copying the queue. The function returns only the indices, leaving the queue
untouched.

4. Database cache

When you cache a query result in an array and want to find a specific range
of results without re-running the query. Instead of copying records, you
just get the indices.

Why This Small Function Is Worth It

• ✅ Memory: no copy means memory usage stays constant
• ✅ Speed: a bounded search instead of a full scan
• ✅ Simplicity: a small function, with no dependency on a large lazy
  slice project
• ✅ Available now: usable today, not after a multi-month RFC

Thanks for your time. I’d love to hear your thoughts, especially if any
other use cases come to mind that could be added to the RFC.

Best regards,

Sepehr