# `Milvex.ExprParams`

Converts Elixir values to Milvus `TemplateValue` protobuf structs for filter expression templating.

Filter templates allow parameterized filter expressions using `{placeholder}` syntax,
where values are substituted at query time by Milvus. This improves performance by
reducing expression parsing overhead, especially with large arrays or complex expressions.

## Supported types

  - `boolean` -> `bool_val`
  - `integer` -> `int64_val`
  - `float` -> `float_val`
  - `string` -> `string_val`
  - `[boolean]` -> `BoolArray`
  - `[integer]` -> `LongArray`
  - `[float]` -> `DoubleArray`
  - `[string]` -> `StringArray`

# `to_proto`

```elixir
@spec to_proto(map() | nil) :: %{
  required(String.t()) => Milvex.Milvus.Proto.Schema.TemplateValue.t()
}
```

Converts a map of parameter names to Elixir values into a map of `TemplateValue` protobuf structs.

Returns an empty map when given `nil` or an empty map.

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*Consult [api-reference.md](api-reference.md) for complete listing*