Input
Output

Online ast dump of golang code

Go ast is very useful mechanism which is provide how to read your text code into valid go code without checking scope and undefined variables.

But normal AST in go language are not provide all information. Such as data type of binary expression, calling method return type and package of calling method etc.

Here provides basic example which is mention some missing information.

// Go Code
package main

import (
  "fmt"
  "math"
  "math/rand"
)

func main() {
  fmt.Println(math.Abs(-3))
  fmt.Println(rand.Intn(3))
}
AST Output 
{
  "source": [
    {
      "0": "ast.File",
      "Package": "1:1",
      "Name": {
        "0": "ast.Ident",
        "NamePos": "1:9",
        "Name": "main"
      },
      "Decls": [
        {
          "0": "ast.GenDecl",
          "TokPos": "3:1",
          "Tok": "import",
          "Lparen": "3:8",
          "Specs": [
            {
              "0": "ast.ImportSpec",
              "Path": {
                "0": "ast.BasicLit",
                "ValuePos": "4:2",
                "Kind": "STRING",
                "Value": "\"fmt\""
              },
              "EndPos": "-"
            },
            {
              "0": "ast.ImportSpec",
              "Path": {
                "0": "ast.BasicLit",
                "ValuePos": "5:2",
                "Kind": "STRING",
                "Value": "\"math\""
              },
              "EndPos": "-"
            },
            {
              "0": "ast.ImportSpec",
              "Path": {
                "0": "ast.BasicLit",
                "ValuePos": "6:2",
                "Kind": "STRING",
                "Value": "\"math/rand\""
              },
              "EndPos": "-"
            }
          ],
          "Rparen": "7:1"
        },
        {
          "0": "ast.FuncDecl",
          "Name": {
            "0": "ast.Ident",
            "NamePos": "9:6",
            "is": "Func",
            "is_signature": "func main()",
            "is_pkg": "main",
            "is_path": "",
            "Name": "main",
            "Obj": {
              "0": "ast.Object",
              "Kind": "func",
              "Name": "main",
              "Decl": "39"
            }
          },
          "Type": {
            "0": "ast.FuncType",
            "Func": "9:1",
            "Params": {
              "0": "ast.FieldList",
              "Opening": "9:10",
              "Closing": "9:11"
            }
          },
          "Body": {
            "0": "ast.BlockStmt",
            "Lbrace": "9:13",
            "List": [
              {
                "0": "ast.ExprStmt",
                "X": {
                  "0": "ast.CallExpr",
                  "Fun": {
                    "0": "ast.SelectorExpr",
                    "X": {
                      "0": "ast.Ident",
                      "NamePos": "10:2",
                      "is": "PkgName",
                      "is_pakage": "main",
                      "is_imported": "fmt",
                      "Name": "fmt"
                    },
                    "Sel": {
                      "0": "ast.Ident",
                      "NamePos": "10:6",
                      "is_path": "fmt",
                      "is": "Func",
                      "is_signature": "func fmt.Println(a ...any) (n int, err error)",
                      "is_pkg": "fmt",
                      "Name": "Println"
                    }
                  },
                  "Lparen": "10:13",
                  "return": "(n int, err error)",
                  "Args": [
                    {
                      "0": "ast.CallExpr",
                      "Fun": {
                        "0": "ast.SelectorExpr",
                        "X": {
                          "0": "ast.Ident",
                          "NamePos": "10:14",
                          "is": "PkgName",
                          "is_pakage": "main",
                          "is_imported": "math",
                          "Name": "math"
                        },
                        "Sel": {
                          "0": "ast.Ident",
                          "NamePos": "10:19",
                          "is": "Func",
                          "is_signature": "func math.Abs(x float64) float64",
                          "is_pkg": "math",
                          "is_path": "math",
                          "Name": "Abs"
                        }
                      },
                      "Lparen": "10:22",
                      "return": "float64",
                      "Args": [
                        {
                          "0": "ast.UnaryExpr",
                          "OpPos": "10:23",
                          "Op": "-",
                          "X": {
                            "0": "ast.BasicLit",
                            "ValuePos": "10:24",
                            "Kind": "INT",
                            "Value": "3"
                          }
                        }
                      ],
                      "Ellipsis": "-",
                      "Rparen": "10:25"
                    }
                  ],
                  "Ellipsis": "-",
                  "Rparen": "10:26"
                }
              },
              {
                "0": "ast.ExprStmt",
                "X": {
                  "0": "ast.CallExpr",
                  "Fun": {
                    "0": "ast.SelectorExpr",
                    "X": {
                      "0": "ast.Ident",
                      "NamePos": "11:2",
                      "is_imported": "fmt",
                      "is": "PkgName",
                      "is_pakage": "main",
                      "Name": "fmt"
                    },
                    "Sel": {
                      "0": "ast.Ident",
                      "NamePos": "11:6",
                      "is_signature": "func fmt.Println(a ...any) (n int, err error)",
                      "is_pkg": "fmt",
                      "is_path": "fmt",
                      "is": "Func",
                      "Name": "Println"
                    }
                  },
                  "Lparen": "11:13",
                  "return": "(n int, err error)",
                  "Args": [
                    {
                      "0": "ast.CallExpr",
                      "Fun": {
                        "0": "ast.SelectorExpr",
                        "X": {
                          "0": "ast.Ident",
                          "NamePos": "11:14",
                          "is": "PkgName",
                          "is_pakage": "main",
                          "is_imported": "rand",
                          "Name": "rand"
                        },
                        "Sel": {
                          "0": "ast.Ident",
                          "NamePos": "11:19",
                          "is_pkg": "rand",
                          "is_path": "math/rand",
                          "is": "Func",
                          "is_signature": "func math/rand.Intn(n int) int",
                          "Name": "Intn"
                        }
                      },
                      "Lparen": "11:23",
                      "return": "int",
                      "Args": [
                        {
                          "0": "ast.BasicLit",
                          "ValuePos": "11:24",
                          "Kind": "INT",
                          "Value": "3"
                        }
                      ],
                      "Ellipsis": "-",
                      "Rparen": "11:25"
                    }
                  ],
                  "Ellipsis": "-",
                  "Rparen": "11:26"
                }
              }
            ],
            "Rbrace": "12:1"
          }
        }
      ],
      "Scope": {
        "0": "ast.Scope",
        "Objects": {
          "0": "map[string]*ast.Object",
          "main": "47"
        }
      },
      "Imports": [
        "12",
        "20",
        "28"
      ],
      "Unresolved": [
        "66",
        "87",
        "127",
        "148"
      ]
    }
  ]
}

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