Saturday, December 23, 2023


Go lang compiler is written in Go, so parsing source code and AST are available as packages.
Getting AST is "one line of code"
But the AST is using recursive pointers, and serializing to JSON requires some extra effort.

Here is a useful tool for that:

asty-org/asty: Converts golang AST to JSON and JSON to AST @GitHub


Marshals golang AST into JSON and unmarshals it back from JSON.

It allows building pattern matching, statistical analysis, language transformation, search/data-mine/anything algorithms for golang with any other language (I like to do it with python. Check out asty-python)


Go-to-AST-JSON: Convert Go to AST-JSON instantly

how it works

Analyzing AST in Go with JSON tools - DEV Community

Basic AST Traversal in Go - zupzup

Here is a minimalistic example of using Go AST

package main

import (

func main() {
    if len(os.Args) < 2 {
        fmt.Println("Please provide a filename as a command line argument.")
    filename := os.Args[1]

    // read source from text file
    data, err := os.ReadFile(filename)
    if err != nil {
        fmt.Println("Error reading file:", err)
    src := string(data)

    // Initialize a new token file set
    fset := token.NewFileSet()
    // Parse the source code
    f, err := parser.ParseFile(fset, "", src, parser.ParseComments)
    if err != nil {
    // Print the AST
    ast.Print(fset, f)

Abstract syntax tree - Wikipedia

An abstract syntax tree (AST) is a data structure used in computer science to represent the structure of a program or code snippet. It is a tree representation of the abstract syntactic structure of text (often source code) written in a formal language. Each node of the tree denotes a construct occurring in the text. It is sometimes called just a syntax tree.

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