Struct HistogramConstraint 

pub struct HistogramConstraint { /* private fields */ }

A constraint that analyzes value distribution in a column and applies custom assertions.

This constraint computes a histogram of value frequencies and allows custom assertion functions to validate the distribution characteristics.

Examples

use term_guard::constraints::{HistogramConstraint, Histogram};
use term_guard::core::Constraint;
use std::sync::Arc;

// Check that no single value dominates
let constraint = HistogramConstraint::new("status", Arc::new(|hist: &Histogram| {
    hist.most_common_ratio() < 0.5
}));

// Verify distribution has expected number of categories
let constraint = HistogramConstraint::new("category", Arc::new(|hist| {
    hist.bucket_count() >= 5 && hist.bucket_count() <= 10
}));

Implementations

impl HistogramConstraint

pub fn new(column: impl Into<String>, assertion: HistogramAssertion) -> Self

Creates a new histogram constraint.

Arguments

• column - The column to analyze
• assertion - The assertion function to apply to the histogram

pub fn new_with_description( column: impl Into<String>, assertion: HistogramAssertion, description: impl Into<String>, ) -> Self

Creates a new histogram constraint with a description.

Arguments

• column - The column to analyze
• assertion - The assertion function to apply to the histogram
• description - A description of what the assertion checks

Trait Implementations

impl Clone for HistogramConstraint

fn clone(&self) -> HistogramConstraint

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Constraint for HistogramConstraint

fn evaluate<'life0, 'life1, 'async_trait>( &'life0 self, ctx: &'life1 SessionContext, ) -> Pin<Box<dyn Future<Output = Result<ConstraintResult>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Evaluates the constraint against the data in the session context.

fn name(&self) -> &str

Returns the name of the constraint.

fn column(&self) -> Option<&str>

Returns the column this constraint operates on (if single-column).

fn metadata(&self) -> ConstraintMetadata

Returns the metadata associated with this constraint.

fn description(&self) -> Option<&str>

Returns a description of what this constraint validates.

impl Debug for HistogramConstraint

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

Formats the value using the given formatter.