Hi, the `watch err` could also work in "APIs" that already return "error".
For instance:
package myapi
func First() (err error) {
watch err
err = internalFunction(1,2,3)
err = internalFunction(3,2,1)
err = internalFunction(1,3,2)
}
On Tuesday, September 5, 2017 at 4:27:20 AM UTC+10,
marti...@programmfabrik.de wrote:
>
> Hi guys,
>
> at first I though I really like the idea of how Go deals with error
> management and handling, but the more Go code I look at or try to program,
> the more I get scared about checking errors every second line in every
> given block of code.
>
> Take a look at this example here from "Build Web Application with Golang":
>
> // insert
> stmt, err := db.Prepare("INSERT INTO userinfo(username, departname, created)
> values(?,?,?)")
> if err != nil {
> // handle error
> }
> res, err := stmt.Exec("astaxie", "研发部门", "2012-12-09")
> if err != nil {
> // handle error
> }
> id, err := res.LastInsertId()
> if err != nil {
> // handle error
> }
> fmt.Println(id)
> // update
> stmt, err = db.Prepare("update userinfo set username=? where uid=?")
> if err != nil {
> // handle error
> }
> res, err = stmt.Exec("astaxieupdate", id)
> if err != nil {
> // handle error
> }
> affect, err := res.RowsAffected()
> if err != nil {
> // handle error
> }
>
>
> Seriously? And yes, I have read https://blog.golang.org/errors-are-values.
> ..
>
> The best case reduction I found is:
>
> ...
> res, err = stmt.Exec("astaxieupdate", id)
> checkError(err)
> ...
>
> Still, I need this after each line of calling a function which may return
> an error.
>
> I bet this is not pleasant to do in larger code bases and it also takes
> away focus from what is actually happening.
>
> 50-80% of all lines of code in my example deal with error handling?
>
> This is not good. Seriously.
>
> And don't get me wrong, there is a lot of things I really like, love and
> adore about Go, but catching errors needs an improved syntax!
>
> And I am not proposing try...catch here.
>
> How about introducing a new piece of syntax
>
> "watch if .... "
>
> which tells the compiler to watch out for changes in a given SimpleStmt
>
> The same code as above would look like this:
>
> var err Error
>
> watch if err != nil {
> // handle error(s)
> }
>
> // insert
> stmt, err := db.Prepare("INSERT INTO userinfo(username, departname,
> created) values(?,?,?)")
> res, err := stmt.Exec("astaxie", "研发部门", "2012-12-09")
> id, err := res.LastInsertId()
> fmt.Println(id)
>
> // update
> stmt, err = db.Prepare("update userinfo set username=? where uid=?")
> res, err = stmt.Exec("astaxieupdate", id)
> affect, err := res.RowsAffected()
>
>
> - The "watch if" would be executed after each assignment of any of the
> variables used in SimpleStmt of the statement.
> - Multiple "watch if" would be executed in order or appearance
> - The "watch if" could be used like "defer..." inside functions
> - The "watch if" would work in its full scope of the watched variables
>
> I am not a language expert, so may be there is a saner way of expression
> what I want to achieve.
>
> But bottom line is, there should by an easier to read and write way to
> deal with errors in Go.
>
>
> Martin
>
>
>
>
>
>
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