ast

main.go

package main

import (
        "bytes"
        "fmt"
        "go/ast"
        "go/parser"
        "go/token"
        "io"
        "log"
        "os"
        "strings"
)

func parse(src io.Reader) error {
        var (
                node *ast.File
                err  error
        )
        fset := token.NewFileSet()
        if file, ok := src.(*os.File); ok {
                node, err = parser.ParseFile(fset, file.Name(), nil, parser.Mode(0))
                if err != nil {
                        return err
                }
        } else {
                dst := new(bytes.Buffer)
                io.Copy(dst, src)
                node, err = parser.ParseFile(fset, "file.go", dst, parser.Mode(0))
                if err != nil {
                        return err
                }
        }

        ast.Inspect(node, func(n ast.Node) bool {
                switch x := n.(type) {
                case *ast.BasicLit:
                        if strings.HasPrefix(strings.TrimSpace(x.Value), "") {
                                fmt.Println("====================================")
                                fmt.Printf("%+v\n", strings.TrimSpace(x.Value))
                        }
                }
                return true
        })
        return nil
}

func main() {
        if len(os.Args) < 2 {
                os.Exit(1)
        }
        for i := 1; i < len(os.Args); i++ {
                f, err := os.Open(os.Args[i])
                if err != nil {
                        log.Fatal(err)
                }
                defer f.Close()
                parse(f)
        }
}

main_test.go

package main

import (
        "strings"
        "testing"
)

func TestParse(t *testing.T) {
        r := strings.NewReader(dummyGoFile)
        err := parse(r)
        if err != nil {
                t.Fatal(err)
        }
}

var dummyGoFile = `
package main

import (
        "database/sql"
        "fmt"
)

func sendSQL() (int64, error) {
        var id int
        err := sql.DB.QueryRow("select * from table_name").Scan(&id)
        if err != nil {
                return 0, err
        }
        return id, nil
}

func main() {
        fmt.Println("abcdefgh")
}
`