Function builtin_append 

fn builtin_append(
    args: &[RValue],
    named: &[(String, RValue)],
) -> Result<RValue, RError>

Append elements to a vector.

Concatenates values into x at position after. Type coercion follows R’s hierarchy: raw < logical < integer < double < complex < character.

@param x a vector @param values values to append @param after index after which to insert (default: end of x) @return concatenated vector preserving the highest type