package go/printer
A CommentedNode bundles an AST node and corresponding comments. It may be provided as argument to any of the Fprint functions.
Golang go/printer.CommentedNode type usage example
func (lp *linePrinter) printWithComments(n ast.Node) {
nfirst := lp.fset.Position(n.Pos()).Line
nlast := lp.fset.Position(n.End()).Line
for _, g := range lp.fnode.Comments {
cfirst := lp.fset.Position(g.Pos()).Line
clast := lp.fset.Position(g.End()).Line
if clast == nfirst-1 && lp.fset.Position(n.Pos()).Column == lp.fset.Position(g.Pos()).Column {
for _, c := range g.List {
lp.output.WriteString(c.Text)
lp.output.WriteByte('\n')
}
}
if cfirst >= nfirst && cfirst <= nlast && n.End() <= g.List[0].Slash {
// The printer will not include the comment if it starts past
// the node itself. Trick it into printing by overlapping the
// slash with the end of the statement.
g.List[0].Slash = n.End() - 1
}
}
node := &printer.CommentedNode{n, lp.fnode.Comments} // <-- here
lp.config.Fprint(&lp.output, lp.fset, node)
}
References :
https://github.com/adjust/gocheck/blob/master/printer.go
http://golang.org/pkg/go/printer/#CommentedNode
