// Parse parses a string into a template. Nested template definitions will be
// associated with the top-level template t. Parse may be called multiple times
// to parse definitions of templates to associate with t. It is an error if a
// resulting template is non-empty (contains content other than template
// definitions) and would replace a non-empty template with the same name.
// (In multiple calls to Parse with the same receiver template, only one call
// can contain text other than space, comments, and template definitions.)
func (t *Template) Parse(text string) (*Template, error) {
t.init()
trees, err := parse.Parse(t.name, text, t.leftDelim, t.rightDelim, t.parseFuncs, builtins)
if err != nil {
return nil, err
}
// Add the newly parsed trees, including the one for t, into our common structure.
for name, tree := range trees {
// If the name we parsed is the name of this template, overwrite this template.
// The associate method checks it's not a redefinition.
tmpl := t
if name != t.name {
tmpl = t.New(name)
}
// Even if t == tmpl, we need to install it in the common.tmpl map.
if replace, err := t.associate(tmpl, tree); err != nil {
return nil, err
} else if replace {
tmpl.Tree = tree
}
tmpl.leftDelim = t.leftDelim
tmpl.rightDelim = t.rightDelim
}
return t, nil
}
func TestAddParseTree(t *testing.T) {
// Create some templates.
root, err := New("root").Parse(cloneText1)
if err != nil {
t.Fatal(err)
}
_, err = root.Parse(cloneText2)
if err != nil {
t.Fatal(err)
}
// Add a new parse tree.
tree, err := parse.Parse("cloneText3", cloneText3, "", "", nil, builtins)
if err != nil {
t.Fatal(err)
}
added, err := root.AddParseTree("c", tree["c"])
// Execute.
var b bytes.Buffer
err = added.ExecuteTemplate(&b, "a", 0)
if err != nil {
t.Fatal(err)
}
if b.String() != "broot" {
t.Errorf("expected %q got %q", "broot", b.String())
}
}
// Issue 7032
func TestAddParseTreeToUnparsedTemplate(t *testing.T) {
master := "{{define \"master\"}}{{end}}"
tmpl := New("master")
tree, err := parse.Parse("master", master, "", "", nil)
if err != nil {
t.Fatalf("unexpected parse err: %v", err)
}
masterTree := tree["master"]
tmpl.AddParseTree("master", masterTree) // used to panic
}