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use crate::physical_plan::executors::evaluate_physical_expressions;
use crate::physical_plan::state::ExecutionState;
use crate::prelude::*;
use polars_core::prelude::*;

/// Take an input Executor (creates the input DataFrame)
/// and a multiple PhysicalExpressions (create the output Series)
pub struct ProjectionExec {
    input: Box<dyn Executor>,
    expr: Vec<Arc<dyn PhysicalExpr>>,
}

impl ProjectionExec {
    pub(crate) fn new(input: Box<dyn Executor>, expr: Vec<Arc<dyn PhysicalExpr>>) -> Self {
        Self { input, expr }
    }
}

impl Executor for ProjectionExec {
    fn execute(&mut self, state: &ExecutionState) -> Result<DataFrame> {
        let df = self.input.execute(state)?;

        let df = evaluate_physical_expressions(&df, &self.expr, state);
        state.clear_expr_cache();
        df
    }
}