ast-visitor

AST Visitor Example

This example demonstrates how to use the visitor pattern to traverse and analyze the Abstract Syntax Tree (AST).

What it does

• Shows how to implement custom visitors to collect specific information from the AST
• Demonstrates the use of built-in visitor functions for common tasks
• Provides examples of different analysis patterns:
  • Variable collection with duplicate removal
  • Function declaration analysis
  • AST depth calculation
  • Node type statistics

Key concepts

Custom Visitors

• VariableCollector: Finds all variable usage in the code
• FunctionCollector: Collects function declarations with parameter counts
• DepthCounter: Calculates the maximum depth of the AST

Built-in Visitor Functions

• ast.FindAllFunc(): Find all nodes matching a condition
• ast.CountFunc(): Count nodes matching a condition
• ast.WalkFunc(): Simple traversal with a function

Running the example

cd examples/ast-visitor
go run main.go

Expected output

The program will display:

• List of all unique variables found in the code
• Information about each function declaration
• Maximum depth of the AST
• Statistics about different node types
• Count of various expression types

This pattern is useful for building code analysis tools, linters, and documentation generators.