Trait ColumnSource 

#[doc(hidden)]
pub trait ColumnSource {
    // Required method
    fn into_column_list(self) -> List;

    // Provided methods
    fn into_named_columns(self) -> Vec<(String, SEXP)>
       where Self: Sized { ... }
    fn into_dataframe(self) -> Result<DataFrame, DataFrameError>
       where Self: Sized { ... }
}

Internal engine that turns a value into a data.frame-shaped List.

This was the historical public convert::IntoDataFrame (-> List). It is now an internal engine: the public IntoDataFrame (-> Result<DataFrame, _>) and the enum-flatten codegen both delegate to it. Not part of the public verb surface.

Required Methods

fn into_column_list(self) -> List

Convert into a data.frame-shaped List (named columns, data.frame class, row.names).

Provided Methods

fn into_named_columns(self) -> Vec<(String, SEXP)>

where Self: Sized,

Extract named column SEXPs from this value.

Returns (name, raw SEXP) per column. The SEXPs are owned by the produced data-frame SEXP and must be protected by the caller before it is released.

Safety

Calls R API functions; must run on the R main thread.

fn into_dataframe(self) -> Result<DataFrame, DataFrameError>

where Self: Sized,

Assemble this source into a validated DataFrame.

The column engine always sets the data.frame class (even for an empty frame); the one exception is the unnamed-row degradation, which returns a bare unclassed empty list — the old panic!("unnamed list elements") case, now a clean Err(UnnamedColumns).

This is the bridge from the internal column-assembly engine to the public DataFrame. We deliberately do not offer a blanket impl<T: ColumnSource> IntoDataFrame for T: #[derive(DataFrameRow)] emits a concrete impl IntoDataFrame for Vec<Row> per row type (and serde uses the SerdeRows<T> newtype), so a generic for T blanket would coherence-conflict with every one of those (the compiler treats Vec<Row>: ColumnSource as possibly-true). The derive’s into_dataframe glue calls this method instead.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors