let string_of_pcdata (s : string): string =
let s_amp = Str.global_replace (Str.regexp "&") "&" s in
let s_lt = Str.global_replace (Str.regexp "<") "<" s_amp in
let s_gt = Str.global_replace (Str.regexp ">") ">" s_lt in
let s_apos = Str.global_replace (Str.regexp "'") "\'" s_gt in
let s_quot = Str.global_replace (Str.regexp """) "\"" s_apos in
s_quot