unexpected semicolon or newline before else even though there is neither before else if

Question

I'm trying to fix these errors in my golang code and if someone could help me with that, I'd appreciate it.

Here is my code: http://play.golang.org/p/yELWfIdWz5

Although, the one that is troubling me the most is the first one on line 21 where the error says: syntax error: unexpected semicolon or newline before else. I can't find a semicolon or new line on or just before line 21 at all.

Also, what do the errors on line 28 and 32 mean ( non-declaration statement outside function body )-- those statements are in the main() function and the last closing brace closes that function so why is there an error there.

I have a feeling that all of these errors are due to the first one.

I'd greatly appreciate any and all help in resolving these or at least learning more about them.

Here is the code:

package main

import "fmt"

func main() {
    var current_mid = ""
    current_topic := make(map[string][]string)
    f, err := os.Open(*inputFile)
    if err != nil {
       fmt.Println(err)
        return
    }
    r := bufio.NewReader(f)
    xmlFile, _ := os.Create("freebase.xml")
    line, err := r.ReadString('\n')
    for err == nil{
        subject, predicate, object := parseTriple(line)
        if subject == current_mid{
            current_topic[predicate] = append(current_topic[predicate], object)
        }
        else if len(current_mid) > 0{
            processTopic(current_mid, current_topic, xmlFile)
            current_topic = make(map[string][]string)
        }
        current_mid = subject
        line, err = r.ReadString('\n')
    }
    processTopic(current_mid, current_topic, xmlFile)
    if err != io.EOF {
        fmt.Println(err)
        return
    }
 }

Answer 1

You need to put the 'else' on the line with the close brace in Go.

Go inserts a ; at the end of lines ending in certain tokens including }; see the spec. That means that, fortunately, it can insert the ending semicolon on x := func(){...} or x := []int{1,2,3}, but it also means it inserts one after the } closing your if block. Since if {...} else {...} is a single compound statement, you can't stick a semicolon in the middle of it after the first }, hence the requirement to put } else { on one line

It's unusual, but it keeps the semicolon-insertion behavior simple. Having been hit with unexpected program behavior because of the cleverer semicolon insertion rules in another semicolon-optional language, this seems alright in the scheme of things.

And I can see how the error message was confusing, but 'newline before else' just refers to the newline after the } on the previous line.