DartBlockProgramTreeNode class sealed

The tree-based representation of a DartBlock component (Statement, Function) as a node.

A node can have an optional parent node, as well as a list of child nodes.

The purpose of this tree representation is to primarily keep track of the variable scopes. As such, by traversing upward from a given node, we can determine the variables which have already been declared and which are usable in the current scope.

A second usage of this tree representation is to enable the evaluation schema DartBlockVariableCountEvaluationSchema.

Technical details:

• The root node, defined by the concrete DartBlockProgramTreeRootNode, has no parent. The root node is created by DartBlockProgram.buildTree.
• The child nodes of DartBlockProgramTreeRootNode are the main DartBlockFunction and any additional custom DartBlockFunction. The concrete implementation is given by DartBlockProgramTreeCustomFunctionNode.
• Each DartBlockProgramTreeCustomFunctionNode has as a singular child the first Statement in its body. The concrete implementation is given by DartBlockProgramTreeStatementNode.
• Compound Statements, such as WhileLoopStatement, again have the first Statement in their body as a singular child.
• Special cases include IfElseStatement and ForLoopStatement:
  • IfElseStatement: it has a child for its if-body, another for its else-body and one for each additional else-if clause's body.
  • ForLoopStatement: if its ForLoopStatement.initStatement is not null, it is its singular chilld. Otherwise, the starting child is the first statement of its body.