pandrs 0.4.1

A high-performance DataFrame library for Rust, providing pandas-like API with advanced features including SIMD optimization, parallel processing, and distributed computing capabilities
Documentation 
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//! # Expression Support for Distributed Processing
//!
//! This module provides support for complex expressions and user-defined functions
//! for distributed DataFrames, enabling more complex transformations and calculations.

use serde::{Deserialize, Serialize};
use std::fmt;

pub mod core;
pub mod projection;
pub mod schema;
pub mod validator;

// NOTE: a `backward_compat` module used to live here and was glob re-exported
// (`pub use backward_compat::*`). It defined a SECOND `Expr`, `Literal`,
// `BinaryOperator`, `UnaryOperator`, `ProjectionExt`, `ColumnProjection`, and
// `UdfDefinition`, which collided with the canonical types re-exported below
// and made `df.select_expr(..)` / `df.filter_expr(..)` ambiguous whenever both
// `ProjectionExt` traits were in scope. Only the canonical set (from `core`,
// `projection`, `schema`, `validator`) is exported now.

/// Data types for expressions
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum ExprDataType {
    /// Boolean type
    Boolean,
    /// Integer type
    Integer,
    /// Float type
    Float,
    /// String type
    String,
    /// Date type
    Date,
    /// Timestamp type
    Timestamp,
}

impl fmt::Display for ExprDataType {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Self::Boolean => write!(f, "BOOLEAN"),
            Self::Integer => write!(f, "BIGINT"),
            Self::Float => write!(f, "DOUBLE"),
            Self::String => write!(f, "VARCHAR"),
            Self::Date => write!(f, "DATE"),
            Self::Timestamp => write!(f, "TIMESTAMP"),
        }
    }
}

// Re-exports for backward compatibility
pub use self::core::{BinaryOperator, Expr, Literal, UnaryOperator};
pub use self::projection::{ColumnProjection, ProjectionExt, UdfDefinition};
pub use self::schema::{ColumnMeta, ExprSchema};
pub use self::validator::{ExprValidator, InferredType};