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Example for Basic AST Traversal in Go
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| package main | |
| import ( | |
| "fmt" | |
| "go/ast" | |
| "go/parser" | |
| "go/printer" | |
| "go/token" | |
| "log" | |
| "os" | |
| ) | |
| func main() { | |
| fset := token.NewFileSet() | |
| node, err := parser.ParseFile(fset, "test.go", nil, parser.ParseComments) | |
| if err != nil { | |
| log.Fatal(err) | |
| } | |
| fmt.Println("########### Manual Iteration ###########") | |
| fmt.Println("Imports:") | |
| for _, i := range node.Imports { | |
| fmt.Println(i.Path.Value) | |
| } | |
| fmt.Println("Comments:") | |
| for _, c := range node.Comments { | |
| fmt.Print(c.Text()) | |
| } | |
| fmt.Println("Functions:") | |
| for _, f := range node.Decls { | |
| fn, ok := f.(*ast.FuncDecl) | |
| if !ok { | |
| continue | |
| } | |
| fmt.Println(fn.Name.Name) | |
| } | |
| fmt.Println("########### Inspect ###########") | |
| ast.Inspect(node, func(n ast.Node) bool { | |
| // Find Return Statements | |
| ret, ok := n.(*ast.ReturnStmt) | |
| if ok { | |
| fmt.Printf("return statement found on line %d:\n\t", fset.Position(ret.Pos()).Line) | |
| printer.Fprint(os.Stdout, fset, ret) | |
| return true | |
| } | |
| // Find Functions | |
| fn, ok := n.(*ast.FuncDecl) | |
| if ok { | |
| var exported string | |
| if fn.Name.IsExported() { | |
| exported = "exported " | |
| } | |
| fmt.Printf("%sfunction declaration found on line %d: \n\t%s\n", exported, fset.Position(fn.Pos()).Line, fn.Name.Name) | |
| return true | |
| } | |
| return true | |
| }) | |
| fmt.Println() | |
| } |
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| package main | |
| import "fmt" | |
| import "strings" | |
| func main() { | |
| hello := "Hello" | |
| world := "World" | |
| words := []string{hello, world} | |
| SayHello(words) | |
| } | |
| // SayHello says Hello | |
| func SayHello(words []string) { | |
| fmt.Println(joinStrings(words)) | |
| } | |
| // joinStrings joins strings | |
| func joinStrings(words []string) string { | |
| return strings.Join(words, ", ") | |
| } |
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