Module qrlew::expr

Expr definition and manipulation

Expr combine values and columns with functions and aggregations.

Expr propagate data types and ranges.

Re-exports

• pub use identifier::Identifier;
• pub use split::Map;
• pub use split::Reduce;
• pub use split::Split;

Modules

• aggregate
• bijection
• dot
  Plot the dot graph of an expression to debug
• dsl
  A simple DSL to write expressions
• function
• identifier
• implementation
• rewriting
• split
  The splits with some improvements Each split has named Expr and anonymous exprs
• sql
  Convert Expr into ast::Expr

Structs

• Aggregate
  An aggregate function expression
• AggregateColumn
  An aggregate column expr
• ColumnsVisitor
  A visitor to collect column
• DisplayVisitor
  Visit the expression to display it
• DomainVisitor
  A visitor to compute the domain
• Function
  A function expression
• HasColumnVisitor
  A visitor to test the presence of column
• RenameVisitor
  Rename the columns with the namer
• ReplaceVisitor
  A visitor to replace sub-expressions with expressions
• Struct
  An aggregate function expression
• SuperImageVisitor
  A visitor to compute the super_image
• ValueVisitor
  A visitor to compute the value

Enums

• Error
• Expr
  A Expr enum inspired by: https://docs.rs/sqlparser/latest/sqlparser/ast/enum.Expr.html and mostly: https://docs.rs/polars/latest/polars/prelude/enum.Expr.html or https://docs.rs/polars-lazy/latest/polars_lazy/dsl/enum.Expr.html

Traits

• Variant
  Each expression variant must comply with this trait
• Visitor
  A Visitor for the type Expr

Type Aliases

• Column
  A column expression
• Result
• Value
  A value expression