Module expr 

Expressions in RisingWave.

All expressions are implemented under the SyncExpression or AsyncExpression trait.

Construction

Expressions can be constructed by build_func() function, which returns a BoxedExpression.

They can also be transformed from the prost ExprNode using the build_from_prost() function.

Evaluation

Expressions can be evaluated using the eval function.

Re-exports

pub use super::ExprError;

pub use super::Result;

Modules

and_or 🔒

For expression that only accept two nullable arguments as input.

build 🔒

expr_input_ref 🔒

expr_literal 🔒

expr_some_all 🔒

expr_udf 🔒

test_utils

Helper functions to construct prost ExprNode for test.

value 🔒

wrapper 🔒

Structs

Context

An optional context that can be used in a function.

InputRefExpression

A reference to a column in input relation.

LiteralExpression

A literal expression.

LogReport

Log the error to report an error during evaluation.

Enums

BoxedExpression

An owned dynamically typed expression.

NonStrictExpression

An type-safe wrapper that indicates the inner expression can be evaluated in a non-strict manner, i.e., developers can directly call eval_infallible and eval_row_infallible without checking the result.

ValueImpl

The type-erased return value of an expression.

ValueRef

The generic reference type of ValueImpl. Used as the arguments of expressions.

Traits

AsyncDynExpression

Object-safe adapter for asynchronous expressions.

AsyncExpression

Interface of an asynchronous expression.

AsyncExpressionBoxExt

Extension trait for boxing async expressions.

EvalErrorReport

Report an error during evaluation.

ExpressionInfo

Common metadata of an expression.

SyncExpression

Interface of a synchronous expression.

SyncExpressionBoxExt

Extension trait for boxing expressions.

Functions

build_batch_expr_from_prost

Build a strict or non-strict expression according to expr context.

build_from_pretty

Build an expression from a string.

build_from_prost

Build an expression from protobuf.

build_func

Build an expression in FuncCall variant.

build_func_non_strict

Build an expression in FuncCall variant in non-strict mode.

build_non_strict_from_prost

Build an expression from protobuf in non-strict mode.

try_convert_all

Try to convert all items in a vector, or return the original vector if any conversion fails.

try_into_sync_exprs

Try to unwrap boxed expressions into sync expressions.