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## Zero of One - PROTOCOL VERSION 1 ############################################
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Communications are done through bi-directional sockets.

All communications are text based. Messages are separated by the '\n'
character.

#### SUPPORTED MESSAGES ########################################################
Messages use the "<TAG>[ <CONTENT>]\n" format. Neither <TAG> nor <CONTENT> are
allowed to contain the character '\n'.

###### Requests ################################################################
######## Request Protocol Version ##############################################
########## Syntax
"<TAG>": "?RPV"
"<CONTENT>": list of comma separated unsigned integers, in a ascending order.

########## Semantic
Upon reception of one such message, one should start using the latest
Zero of One protocol version listed in <CONTENT> that one can. If none are
supported, a Negative reply is sent. Otherwise, a Confirm Protocol Version
message should be sent.

######## Request Learn #########################################################
########## Syntax
"<TAG>": "?RL"
"<CONTENT>": Any character string (does not expect null termination).

########## Semantic
Requests the learning of <CONTENT>. Response should be either a Positive
message, or a Negative message.

######## Request Learn & Store #################################################
########## Syntax
"<TAG>": "?RLS"
"<CONTENT>": Any character string (does not expect null termination).

########## Semantic
Requests the learning of <CONTENT>, followed by the storing of <CONTENT> in
the storage file. Response should be either a Positive message, or a Negative
message.

######## Request Learn & Store & Reply #########################################
########## Syntax
"<TAG>": "?RLSR"
"<CONTENT>": Any character string (does not expect null termination).

########## Semantic
Requests the learning of <CONTENT>, followed by the storing of <CONTENT> in
the storage file, as well as the generation of a reply.
Response should be either a Positive message preceded by a Generated Reply
message, or a Negative message.

######## Request Reply #########################################################
########## Syntax
"<TAG>": "?RR"
"<CONTENT>": Any character string (does not expect null termination).

########## Semantic
Requests the generation of a reply to <CONTENT>.
Response should be either a Positive message preceded by a Generated Reply
message, or a Negative message.

###### Replies #################################################################
######## Confirm Protocol Version ##############################################
########## Syntax
"<TAG>": "!CPV"
"<CONTENT>": unsigned integer.

########## Semantic
Indicates the Zero of One protocol version that will henceforth be used.

######## Positive ##############################################################
########## Syntax
"<TAG>": "!P"
"<CONTENT>": None.

########## Semantic
Previous request should be considered as being completed (no more messages
related to it will be sent).

######## Negative ##############################################################
########## Syntax
"<TAG>": "!N"
"<CONTENT>": None.

########## Semantic
Previous request should be considered as having failed (no more messages related
to it will be sent).

######## Generated Reply #######################################################
########## Syntax
"<TAG>": "!GR"
"<CONTENT>": Any character string (without null termination).

########## Semantic
This is a string that has been generated following a request.

###### Errors ##################################################################
######## Debug Message #########################################################
########## Syntax
"<TAG>": "[D]"
"<CONTENT>": Any character string (without null termination).

########## Semantic
Debug message that has been generated during the handling of the previous
request.

######## Warning Message #######################################################
########## Syntax
"<TAG>": "[W]"
"<CONTENT>": Any character string (without null termination).

########## Semantic
Warning message that has been generated during the handling of the previous
request.

######## Error Message #########################################################
########## Syntax
"<TAG>": "[E]"
"<CONTENT>": Any character string (without null termination).

########## Semantic
Error message that has been generated during the handling of the previous
request.

######## Programming fault Message #############################################
########## Syntax
"<TAG>": "[P]"
"<CONTENT>": Any character string (without null termination).

########## Semantic
A serious programming fault occurred during the handling of the previous
request.

######## Fatal error Message #############################################
########## Syntax
"<TAG>": "[F]"
"<CONTENT>": Any character string (without null termination).

########## Semantic
A fatal error occurred during the handling of the previous request.