// associate installs the new template into the group of templates associated
// with t. It is an error to reuse a name except to overwrite an empty
// template. The two are already known to share the common structure.
// The boolean return value reports wither to store this tree as t.Tree.
func (t *Template) associate(new *Template, tree *parse.Tree) (bool, error) {
if new.common != t.common {
panic("internal error: associate not common")
}
name := new.name
if old := t.tmpl[name]; old != nil {
oldIsEmpty := parse.IsEmptyTree(old.Root)
newIsEmpty := parse.IsEmptyTree(tree.Root)
if newIsEmpty {
// Whether old is empty or not, new is empty; no reason to replace old.
return false, nil
}
if !oldIsEmpty {
return false, fmt.Errorf("template: redefinition of template %q", name)
}
}
t.tmpl[name] = new
return true, nil
}
// associate installs the new template into the group of templates associated
// with t. The two are already known to share the common structure.
// The boolean return value reports whether to store this tree as t.Tree.
func (t *Template) associate(new *Template, tree *parse.Tree) (bool, error) {
if new.common != t.common {
panic("internal error: associate not common")
}
if t.tmpl[new.name] != nil && parse.IsEmptyTree(tree.Root) {
// If a template by that name exists,
// don't replace it with an empty template.
return false, nil
}
t.tmpl[new.name] = new
return true, nil
}