Struct RuleContext 

pub struct RuleContext {
    pub field_name: Option<Arc<str>>,
    pub parent_path: Path,
    pub value_debug: Option<String>,
}

Context information available to validation rules.

RuleContext provides rules with information about the field being validated, enabling more helpful, context-aware error messages.

Examples

use domainstack::{Rule, RuleContext, ValidationError, Path};

fn min_len_with_context(min: usize) -> Rule<str> {
    Rule::new(move |value: &str, ctx: &RuleContext| {
        if value.len() < min {
            ValidationError::single(
                ctx.parent_path.clone(),
                "min_length",
                format!(
                    "Field '{}' must be at least {} characters (got {})",
                    ctx.field_name.as_ref().map(|s| s.as_ref()).unwrap_or("unknown"),
                    min,
                    value.len()
                )
            )
        } else {
            ValidationError::default()
        }
    })
}

Fields

field_name: Option<Arc<str>>

The name of the field being validated, if known.

This is typically provided by the derive macro or when using the validate() helper. For ad-hoc validation, this may be None.

parent_path: Path

The path from the root to the parent of the current field.

For example, when validating user.email, the parent_path would be "user". Rules should typically append their field_name to this path when creating errors.

value_debug: Option<String>

Optional string representation of the current value for debugging.

This can be included in error messages to help users understand what value failed validation. For sensitive fields (passwords, tokens), this should be None.

Implementations

impl RuleContext

pub fn root(field_name: impl Into<Arc<str>>) -> Self

Creates a new RuleContext for a root-level field.

Examples

use domainstack::RuleContext;

let ctx = RuleContext::root("email");
assert_eq!(ctx.field_name, Some("email".into()));
assert_eq!(ctx.parent_path.to_string(), "");

pub fn anonymous() -> Self

Creates a new RuleContext without a field name.

Useful for ad-hoc validation where field information isn’t available.

Examples

use domainstack::RuleContext;

let ctx = RuleContext::anonymous();
assert_eq!(ctx.field_name, None);

pub fn child(&self, field_name: impl Into<Arc<str>>) -> Self

Creates a child context for a nested field.

Examples

use domainstack::RuleContext;

let parent = RuleContext::root("user");
let child = parent.child("email");

assert_eq!(child.field_name, Some("email".into()));
assert_eq!(child.parent_path.to_string(), "user");

pub fn with_value_debug(self, value: impl Into<String>) -> Self

Sets the debug representation of the value being validated.

Examples

use domainstack::RuleContext;

let ctx = RuleContext::root("age")
    .with_value_debug("42");

assert_eq!(ctx.value_debug, Some("42".to_string()));

pub fn full_path(&self) -> Path

Gets the full path to the current field.

Combines parent_path with field_name to produce the complete path.

Examples

use domainstack::{RuleContext, Path};

let ctx = RuleContext::root("email");
assert_eq!(ctx.full_path(), Path::root().field("email"));

let parent = RuleContext::root("user");
let child = parent.child("email");
assert_eq!(child.full_path().to_string(), "user.email");

Trait Implementations

impl Clone for RuleContext

fn clone(&self) -> RuleContext

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for RuleContext

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

Formats the value using the given formatter.

impl Default for RuleContext

fn default() -> Self

Returns the “default value” for a type.