| Package | Description | 
|---|---|
| org.springframework.expression.spel.ast | SpEL's abstract syntax tree. | 
| org.springframework.expression.spel.standard | SpEL's standard parser implementation. | 
| Class and Description | 
|---|
| Literal Common superclass for nodes representing literals (boolean, string, number, etc). | 
| Operator Common supertype for operators that operate on either one or two operands. | 
| Operator.DescriptorComparison A descriptor comparison encapsulates the result of comparing descriptor
 for two operands and describes at what level they are compatible. | 
| SpelNodeImpl The common supertype of all AST nodes in a parsed Spring Expression Language
 format expression. | 
| TypeCode Captures primitive types and their corresponding class objects, plus one special entry
 that represents all reference (non-primitive) types. | 
| ValueRef Represents a reference to a value. | 
| Class and Description | 
|---|
| SpelNodeImpl The common supertype of all AST nodes in a parsed Spring Expression Language
 format expression. |