Add concat template function

Signed-off-by: Knut Ahlers <knut@ahlers.me>

functions.go

@@ -61,4 +61,5 @@ func init() {
 	tplFuncs.Register("toLower", genericTemplateFunctionGetter(strings.ToLower))
 	tplFuncs.Register("toUpper", genericTemplateFunctionGetter(strings.ToUpper))
 	tplFuncs.Register("followDate", genericTemplateFunctionGetter(twitch.GetFollowDate))
+	tplFuncs.Register("concat", genericTemplateFunctionGetter(func(delim string, parts ...string) string { return strings.Join(parts, delim) }))
 }

wiki/Home.md

@@ -144,6 +144,7 @@ Additionally there are some functions available in the templates:
 
 - `arg <idx>` - Takes the message sent to the channel, splits by space and returns the Nth element
 - `channelCounter <counter name>` - Wraps the counter name into a channel specific counter name including the channel name
+- `concat <delimiter> <...parts>` - Join the given string parts with delimiter
 - `counterValue <counter name>` - Returns the current value of the counter which identifier was supplied
 - `displayName <username> [fallback]` - Returns the display name the specified user set for themselves
 - `fixUsername <username>` - Ensures the username no longer contains the `@` or `#` prefix