Data Structures

Data processed by Refal Plus Programs can be tree-like structures or directed graphs.

• Objects vs. Values
  All data in Refal Plus are represented by ground expressions and objects.
• Ground Expressions
  All values processed by Refal Plus programs are so-called ground expressions.
• Representing Tree Structures
  Ground expressions are especially convenient for representing symbolic (i.e. not purely numeric) data, organized in a linear or tree fashion.
• Types of Objects
  Refal Plus programs deal with objects of several types: function objects, box objects, table objects, channel objects, vector objects and string objects.
• Garbage Collection
  The memory used by objects and ground expressions that cannot be accessed any more is considered as garbage, and is reclaimed automatically.