Module conditions 

Condition objects

In R, a condition is an S3 list with:

• message: a character vector describing the condition
• call: the call that triggered the condition, or NULL
• a class attribute including "condition" and optionally "error", "warning", or "message"

rlang conditions may include trace and parent fields, which are represented as Option<List> and Option<RCondition> respectively.

Types

This module provides four types:

• ConditionKind: an enum discriminating the base R condition type (condition, message, warning, error).

• Condition: a Rust-native representation. Construct one with ConditionBuilder::default(). This is the primary type we encourage you to work with for its ergonomics due to its use of std types.

• RCondition: a thin wrapper around a List that already exists in R memory as a proper condition object. Use this when receiving or returning condition objects at the R boundary.

• ConditionBuilder: a builder for Condition. Create a builder with ConditionBuilder::default() to start, chain setters, and call .build() to produce a Condition.

Conversions

From \ To	List	RCondition	Robj	Condition
Condition	From	From	From	—
List	—	TryFrom	blanket	TryFrom
&List	—	TryFrom	—	TryFrom
RCondition	From	—	From	TryFrom
Robj	—	TryFrom	—	TryFrom
&Robj	—	TryFrom	—	TryFrom

Structs

Condition

Rust-native representation of an R condition.

ConditionBuilder

Builder for constructing a Condition.

RCondition

A validated R condition object held as a List.

Enums

ConditionKind

Discriminates the kind of R condition being constructed.

Functions

format_cnd_message

Format an error message with rlang-style bullets.

format_warn_message

Format a warning message with rlang-style bullets.