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Merged
ayushdg merged 5 commits into from
May 9, 2022
Merged

Improve code for getting column name from expression #509

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7c44afa
helper code for getting column name from expression
andygrove May 6, 2022
d4b6380
Update dask_planner/src/expression.rs
andygrove May 9, 2022
290b68b
Update dask_planner/src/expression.rs
andygrove May 9, 2022
62a2969
fix build
andygrove May 9, 2022
b99bec0
Improve error handling
andygrove May 9, 2022
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94 changes: 14 additions & 80 deletions dask_planner/src/expression.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@ use crate::sql::types::RexType;
use pyo3::prelude::*;
use std::convert::{From, Into};

use datafusion::error::DataFusionError;
use datafusion::error::{DataFusionError, Result};

use datafusion::arrow::datatypes::DataType;
use datafusion_expr::{lit, BuiltinScalarFunction, Expr};
Expand All @@ -15,6 +15,8 @@ pub use datafusion_expr::LogicalPlan;

use datafusion::prelude::Column;

use datafusion::common::DFField;
use datafusion::logical_plan::exprlist_to_fields;
use std::sync::Arc;

/// An PyExpr that can be used on a DataFrame
Expand Down Expand Up @@ -62,84 +64,8 @@ impl PyExpr {
}

fn _column_name(&self, plan: LogicalPlan) -> String {
match &self.expr {
Expr::Alias(expr, name) => {
// Only certain LogicalPlan variants are valid in this nested Alias scenario so we
// extract the valid ones and error on the invalid ones
match expr.as_ref() {
Expr::Column(col) => {
// First we must iterate the current node before getting its input
match plan {
LogicalPlan::Projection(proj) => {
match proj.input.as_ref() {
LogicalPlan::Aggregate(agg) => {
let mut exprs = agg.group_expr.clone();
exprs.extend_from_slice(&agg.aggr_expr);
let col_index: usize =
proj.input.schema().index_of_column(col).unwrap();
// match &exprs[plan.get_index(col)] {
match &exprs[col_index] {
Expr::AggregateFunction { args, .. } => {
match &args[0] {
Expr::Column(col) => {
println!(
"AGGREGATE COLUMN IS {}",
col.name
);
col.name.clone()
}
_ => name.clone(),
}
}
_ => name.clone(),
}
}
_ => {
println!("Encountered a non-Aggregate type");

name.clone()
}
}
}
_ => name.clone(),
}
}
_ => {
println!("Encountered a non Expr::Column instance");
name.clone()
}
}
}
Expr::Column(column) => column.name.clone(),
Expr::ScalarVariable(..) => unimplemented!("ScalarVariable!!!"),
Expr::Literal(..) => unimplemented!("Literal!!!"),
Expr::BinaryExpr {
left: _,
op: _,
right: _,
} => {
// /// TODO: Examine this more deeply about whether name comes from the left or right
// self.column_name(left)
unimplemented!("BinaryExpr HERE!!!")
}
Expr::Not(..) => unimplemented!("Not!!!"),
Expr::IsNotNull(..) => unimplemented!("IsNotNull!!!"),
Expr::Negative(..) => unimplemented!("Negative!!!"),
Expr::GetIndexedField { .. } => unimplemented!("GetIndexedField!!!"),
Expr::IsNull(..) => unimplemented!("IsNull!!!"),
Expr::Between { .. } => unimplemented!("Between!!!"),
Expr::Case { .. } => unimplemented!("Case!!!"),
Expr::Cast { .. } => unimplemented!("Cast!!!"),
Expr::TryCast { .. } => unimplemented!("TryCast!!!"),
Expr::Sort { .. } => unimplemented!("Sort!!!"),
Expr::ScalarFunction { .. } => unimplemented!("ScalarFunction!!!"),
Expr::AggregateFunction { .. } => unimplemented!("AggregateFunction!!!"),
Expr::WindowFunction { .. } => unimplemented!("WindowFunction!!!"),
Expr::AggregateUDF { .. } => unimplemented!("AggregateUDF!!!"),
Expr::InList { .. } => unimplemented!("InList!!!"),
Expr::Wildcard => unimplemented!("Wildcard!!!"),
_ => panic!("Nothing found!!!"),
}
let field = expr_to_field(&self.expr, &plan).unwrap();
field.unqualified_column().name.clone()
}
}

Expand Down Expand Up @@ -171,7 +97,7 @@ impl PyExpr {
let input: &Option<Arc<LogicalPlan>> = &self.input_plan;
match input {
Some(plan) => {
let name: Result<String, DataFusionError> = self.expr.name(plan.schema());
let name: Result<String> = self.expr.name(plan.schema());
match name {
Ok(fq_name) => Ok(plan
.schema()
Expand Down Expand Up @@ -540,3 +466,11 @@ impl PyExpr {
}
}
}

/// Create a [DFField] representing an [Expr], given an input [LogicalPlan] to resolve against
pub fn expr_to_field(expr: &Expr, input_plan: &LogicalPlan) -> Result<DFField> {
// TODO this is not the implementation that we really want and will be improved
// once some changes are made in DataFusion
let fields = exprlist_to_fields(&[expr.clone()], &input_plan.schema())?;
Ok(fields[0].clone())
}