Compiler (Apache Calcite API)

All Known Implementing Classes:

Interpreter.CompilerImpl, Nodes.CoreCompiler
```
public interface Compiler
```
Context while converting a tree of RelNode to a program that can be run by an Interpreter.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`RelDataType`	`combinedRowType(java.util.List<RelNode> inputs)`
`Scalar`	`compile(java.util.List<RexNode> nodes, RelDataType inputRowType)`	Compiles an expression to an executable form.
`Context`	`createContext()`
`void`	`enumerable(RelNode rel, Enumerable<Row> rowEnumerable)`	Tells the interpreter that a given relational expression wishes to give its output as an enumerable.
`DataContext`	`getDataContext()`
`Sink`	`sink(RelNode rel)`	Creates a Sink for a relational expression to write into.
`Source`	`source(RelNode rel, int ordinal)`

- Method Detail
  - compile
```
Scalar compile(java.util.List<RexNode> nodes,
               RelDataType inputRowType)
```
    Compiles an expression to an executable form.
  - combinedRowType
```
RelDataType combinedRowType(java.util.List<RelNode> inputs)
```
  - source
```
Source source(RelNode rel,
              int ordinal)
```
  - sink
```
Sink sink(RelNode rel)
```
    Creates a Sink for a relational expression to write into.
    This method is generally called from the constructor of a Node. But a constructor could instead call enumerable(RelNode, Enumerable).
    
    Parameters:
    
    rel - Relational expression
    
    Returns:
    
    Sink
  - enumerable
```
void enumerable(RelNode rel,
                Enumerable<Row> rowEnumerable)
```
    Tells the interpreter that a given relational expression wishes to give its output as an enumerable.
    This is as opposed to the norm, where a relational expression calls sink(RelNode), then its Node.run() method writes into that sink.
    
    Parameters:
    
    rel - Relational expression
    
    rowEnumerable - Contents of relational expression
  - getDataContext
```
DataContext getDataContext()
```
  - createContext
```
Context createContext()
```