feat: add Visitor & VisitorMut to simply ScalarExpression visit (#270)

* feat: add `Visitor` & 'VisitorMut' to simply `ScalarExpression` visit

* chore: codefmt

Author: KKould

Cargo.lock

@@ -49,6 +49,7 @@ ordered-float         = { version = "4", features = ["serde"] }
 paste                 = { version = "1" }
 parking_lot           = { version = "0.12", features = ["arc_lock"] }
 petgraph              = { version = "0.6" }
+recursive             = { version = "0.1" }
 regex                 = { version = "1" }
 rocksdb               = { version = "0.22" }
 rust_decimal          = { version = "1" }

Cargo.toml

@@ -1,5 +1,7 @@
 use crate::binder::{lower_case_name, Binder};
 use crate::errors::DatabaseError;
+use crate::expression::simplify::ConstantCalculator;
+use crate::expression::visitor_mut::VisitorMut;
 use crate::expression::ScalarExpression;
 use crate::planner::operator::insert::InsertOperator;
 use crate::planner::operator::values::ValuesOperator;
@@ -70,7 +72,7 @@ impl<T: Transaction, A: AsRef<[(&'static str, DataValue)]>> Binder<'_, '_, T, A>
             for (i, expr) in expr_row.iter().enumerate() {
                 let mut expression = self.bind_expr(expr)?;
 
-                expression.constant_calculation()?;
+                ConstantCalculator.visit(&mut expression)?;
                 match expression {
                     ScalarExpression::Constant(value) => {
                         let ty = schema_ref[i].datatype();

src/binder/insert.rs

@@ -33,7 +33,6 @@ use crate::planner::{Childrens, LogicalPlan, SchemaOutput};
 use crate::storage::Transaction;
 use crate::types::tuple::{Schema, SchemaRef};
 use crate::types::value::Utf8Type;
-use crate::types::LogicalType::Char;
 use crate::types::{ColumnId, LogicalType};
 use itertools::Itertools;
 use sqlparser::ast::{