<p>Either I forgot how to do this or I'm confused. I want to parse all my template files in one file but make that available in the others, all inside the same package. So I tried this outside any function:</p>
<pre><code>var Thing, err = template.ParseFiles(baseTemplate...)
</code></pre>
<p>Which works when I do </p>
<pre><code>t := Thing
</code></pre>
<p>in another module inside the same package but if I try to follow that with some error handling like:</p>
<pre><code>if err != nil { ... }
</code></pre>
<p>It fails with </p>
<blockquote>
<p>non-declaration statement outside function body</p>
</blockquote>
<p>but if I put all that inside a function, one of the other go modules can't see Thing. It's "undefined". </p>
<p>How can I get the other go files inside the same package to use Thing?</p>
<p>EDIT: Perhaps my real question is, how do I handle err in the code above that works?</p>
<hr/>**评论：**<br/><br/>FUZxxl: <pre><p>Use an <code>init</code> function to initialize these variables.</p></pre>dhdfdh: <pre><p>Example please. I've tried so many variations.</p>
<p>Here's mine:</p>
<pre><code>var Thing *template.Template
func SetupHandlers() {
Thing, err = template.ParseFiles(baseTemplates...)
}
</code></pre>
<p>This gives the error:</p>
<blockquote>
<p>undefined: err</p>
</blockquote></pre>FUZxxl: <pre><p>Your variable <code>err</code> is undeclared. Try this:</p>
<pre><code>func SetupHandlers() {
var err error
Thing, err = template.ParseFiles(baseTemplates...)
}
</code></pre></pre>argandas: <pre><p><a href="https://golang.org/doc/effective_go.html#init" rel="nofollow">https://golang.org/doc/effective_go.html#init</a></p>
<pre><code>var Thing *template.Template
func init() {
var err error
Thing, err = template.ParseFiles(baseTemplates...)
if err != nil {
panic(err)
}
}
</code></pre></pre>dhdfdh: <pre><p>Apparently my only error is thinking err is already defined by template/Template. The examples I've been following all use 'err' so I made that assumption.</p>
<p>Anyway, just adding 'var err error' solved all my issues. Thanks.</p></pre>TheMerovius: <pre><p>Use <a href="http://golang.org/pkg/text/template/#Must" rel="nofollow">template.Must</a></p></pre>dhdfdh: <pre><p>That doesn't answer the question but, at the same time, it solves the problem. However, I didn't understand why I couldn't figure out what was going on with 'err', which was the real objective.</p>
<p>EDIT: For that matter, I still don't understand why I have to define 'err' when it's the return value for template.ParseFiles</p></pre>FUZxxl: <pre><p>In Go, you need to declare variables before you use them. In <a href="https://www.reddit.com/r/golang/comments/3hgwmd/-/cu78woy" rel="nofollow">your comment</a> you don't do so, which is why you get an error.</p></pre>dhdfdh: <pre><p>I know but the examples I've been using don't declare it either, and they worked, which led to my confusion as to why it doesn't work now. </p></pre>trinchan: <pre><pre><code>var Thing *template.Template
func SetupHandlers() {
Thing, err := template.ParseFiles(baseTemplates...)
if err != nil {
panic(err)
}
}
</code></pre>
<p>In this case, the code will compile, but when you assign a variable using :=, like</p>
<pre><code>Thing, err := template.ParseFiles(baseTemplates...)
</code></pre>
<p><em>both</em> Thing and err are assigned to new local variables. The package global Thing is not assigned. This is <a href="https://en.wikipedia.org/wiki/Variable_shadowing" rel="nofollow">variable shadowing</a>.</p>
<p>On the other hand, assigning with the = operator, like</p>
<pre><code>Thing, err = template.ParseFiles(baseTemplates...)
</code></pre>
<p>tries to assign to already declared variables. Thing is defined at the package level. However, err is not defined yet, so you will get a compilation error. This is why we first define err, then use the = operator to assign to the local err variable and the package level Thing,</p>
<pre><code>var err error
Thing, err = template.ParseFiles(baseTemplates...)
</code></pre>
<p>A playground exemplifying this effect is <a href="http://play.golang.org/p/wtWyBKVCjf" rel="nofollow">here</a>.</p>
<p>Hopefully this clears things up!</p></pre>dhdfdh: <pre><p>Aha! <strong>That</strong> is where my mistake lies. I should have caught that myself but thanks cause I moved on and wouldn't have run into it again for who knows how long.</p></pre>
