Enum DExpr 

pub enum DExpr {
    Col(String),
    LitInt(i64),
    LitFloat(f64),
    LitBool(bool),
    LitStr(String),
    BinOp {
        op: DBinOp,
        left: Box<DExpr>,
        right: Box<DExpr>,
    },
    Agg(AggFunc, Box<DExpr>),
    Count,
    FnCall(String, Vec<DExpr>),
    CumSum(Box<DExpr>),
    CumProd(Box<DExpr>),
    CumMax(Box<DExpr>),
    CumMin(Box<DExpr>),
    Lag(Box<DExpr>, usize),
    Lead(Box<DExpr>, usize),
    Rank(Box<DExpr>),
    DenseRank(Box<DExpr>),
    RowNumber,
    RollingSum(String, usize),
    RollingMean(String, usize),
    RollingMin(String, usize),
    RollingMax(String, usize),
    RollingVar(String, usize),
    RollingSd(String, usize),
}

An expression in the Data DSL.

Variants

Col(String)

Column reference: col(“name”)

LitInt(i64)

Literal integer

LitFloat(f64)

Literal float

LitBool(bool)

Literal bool

LitStr(String)

Literal string

BinOp

Binary operation

Fields

op: DBinOp

left: Box<DExpr>

right: Box<DExpr>

Agg(AggFunc, Box<DExpr>)

Aggregation function

Count

Count (no argument)

FnCall(String, Vec<DExpr>)

Named function call: FnCall(“log”, vec![Col(“x”)])

CumSum(Box<DExpr>)

Cumulative sum (window)

CumProd(Box<DExpr>)

Cumulative product (window)

CumMax(Box<DExpr>)

Cumulative max (window)

CumMin(Box<DExpr>)

Cumulative min (window)

Lag(Box<DExpr>, usize)

Lag(expr, k): value at row i-k, or NaN if i < k

Lead(Box<DExpr>, usize)

Lead(expr, k): value at row i+k, or NaN if i+k >= n

Rank(Box<DExpr>)

Rank of values (1-based, average ties)

DenseRank(Box<DExpr>)

Dense rank (1-based, no gaps)

RowNumber

Row number (1-indexed sequential)

RollingSum(String, usize)

Rolling sum over a fixed-size window (Kahan-compensated removable accumulation)

RollingMean(String, usize)

Rolling mean over a fixed-size window

RollingMin(String, usize)

Rolling minimum over a fixed-size window (monotonic deque, O(n) amortized)

RollingMax(String, usize)

Rolling maximum over a fixed-size window (monotonic deque, O(n) amortized)

RollingVar(String, usize)

Rolling variance over a fixed-size window (Welford’s online with removal)

RollingSd(String, usize)

Rolling standard deviation over a fixed-size window

Trait Implementations

impl Clone for DExpr

fn clone(&self) -> DExpr

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for DExpr

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for DExpr

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.