[DOC] Clarification of Stream methods' availability in objects from derived libraries

[q2dg]

Hello. I read in https://www.arduino.cc/reference/en/language/functions/communication/stream/ that Stream object is the base of several other objects (namely, five: Serial, SD, Wire, EthernetServer and EthernetClient) and it has several methods (find(), findUntil(), readBytes(), readBytesUntil(), readString(), readStringUntil(), peek(), parseInt(), parseFloat(), setTimeout()...) which are only mentioned there and in Serial's page (https://www.arduino.cc/reference/en/language/functions/communication/serial/) but not in the other four ones (SD, Wire, EthernetServer, EthernetClient). So, it isn't clear if it is possible to use all Stream methods as SD/EthernetServer/etc methods. I mean, for instance,could I write this?

#include <SPI.h>
#include <Ethernet.h>
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
byte ip[] = { 192, 168, 1, 177 };
EthernetServer myserver(23);
EthernetClient myclient;
boolean found;
void setup() {
Ethernet.begin(mac, ip);
myserver.begin();
Serial.begin(9600);
}
void loop() {
myclient = myserver.available();
if (myclient > 0) {
found=myclient.find("astring");
Serial.println(found);
}
}

It compiles but I have'nt right now a Ethernet Shield to check if this sketch works as it should: it isn't clear from documentation.

In conclusion: I think Stream and derived/related pages need a big rewrite to clarify/arrange this.

Thanks.

[q2dg]

Well, it seems WiFi library also derives from Stream because it has several familiar methods: available(), read(), flush()...but this suspiction is not asserted anywhere.

[per1234]

@q2dg had a good comment on #2919 that might otherwise be missed since that issue was closed as a duplicate of this one:

I think documentation should be refactored to list in one point common methods (Stream page) and then, in library reference pages a link to these (cleaning some redundancies).

I think this would make the reference pages easier to maintain since it would avoid a lot of duplicate content.