udf.rs

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//
//   http://www.apache.org/licenses/LICENSE-2.0
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//! UDF support

use super::type_coercion::coerce;
use crate::error::Result;
use crate::physical_plan::functions::ScalarFunctionExpr;
use crate::physical_plan::PhysicalExpr;
use arrow::datatypes::Schema;

pub use datafusion_expr::ScalarUDF;

use std::sync::Arc;

/// Create a physical expression of the UDF.
/// This function errors when `args`' can't be coerced to a valid argument type of the UDF.
pub fn create_physical_expr(
    fun: &ScalarUDF,
    input_phy_exprs: &[Arc<dyn PhysicalExpr>],
    input_schema: &Schema,
) -> Result<Arc<dyn PhysicalExpr>> {
    // coerce
    let coerced_phy_exprs = coerce(input_phy_exprs, input_schema, &fun.signature)?;

    let coerced_exprs_types = coerced_phy_exprs
        .iter()
        .map(|e| e.data_type(input_schema))
        .collect::<Result<Vec<_>>>()?;

    Ok(Arc::new(ScalarFunctionExpr::new(
        &fun.name,
        fun.fun.clone(),
        coerced_phy_exprs,
        (fun.return_type)(&coerced_exprs_types)?.as_ref(),
    )))
}