ast.go
func (ps *printState) writeString(s string) {
	if len(s) > 0 {
		ps.last = s[len(s)-1]
	}
	ps.buf.WriteString(s)
}
func (ps *printState) writeString(s string) {
	if len(s) > 0 {
		ps.last = s[len(s)-1]
	}
	ps.buf.WriteString(s)
}
func ( ps * printState ) writeString ( s string ) { if len ( s ) > 0 { ps . last = s [ len ( s ) - 1 ] } ps . buf . WriteString ( s ) }
// writeString adds a string to the string being printed.
writeString adds a string to the string being printed .