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diff --git a/doc/README.mrl b/doc/README.mrl new file mode 100644 index 000000000..f2d343e28 --- /dev/null +++ b/doc/README.mrl @@ -0,0 +1,76 @@ +proposition of generic syntax of MRLs +===================================== + +This document defines a draft for a syntactic specification of MRLs as +used by xine-lib. The language of MRLs is designed to be a true subset +of the language of URIs as given in RFC2396. A type 2 grammar for the +language of MRLs is given in EBNF below. + +Semantically, MRLs consist of two distinct parts that are evaluated by +different components of the xine architecture. The first part, +derivable from the symbol <input_source> in the given grammar, is +completely handed to the input plugins, with input plugins signaling +if they can handle the MRL. +The second part, derivable from <stream_setup> and delimited from the +first by a crosshatch ('#') contains parameters that modify the +initialization and playback behaviour of the stream to which the MRL +is passed. The possible parameters are mentioned in the manpage to +xine-ui. + +The following definition should be regarded as a guideline only. +Of course any given input plugin only understands a subset of all +possible MRLs. On the other hand, invalid MRLs according to this +definition might be understood for convenience reasons. +Some user awareness is required at this point. + +EBNF grammar for MRLs: + +<mrl> ::= <input_source>[#<stream_setup>] +<input_source> ::= (<absolute_mrl>|<relative_mrl>) +<absolute_mrl> ::= <input>:(<net_path>|<abs_path>)[?<query>] +<relative_mrl> ::= (<abs_path>|<rel_path>) +<net_path> ::= //<authority>[<abs_path>] +<abs_path> ::= /<path_segments> +<rel_path> ::= <rel_segment>[<abs_path>] +<rel_segment> ::= <rel_char>{<rel_char>} +<rel_char> ::= (<unreserved>|<escaped>|;|@|&|=|+|$|,) +<input> ::= <alpha>{(<alpha>|<digit>|+|-|.)} +<authority> ::= (<server>|<reg_name>) +<server> ::= [[<userinfo>@]<host>[:<port>]] +<userinfo> ::= {(<unreserved>|<escaped>|;|:|&|=|+|$|,)} +<host> ::= (<hostname>|<ipv4_address>) +<hostname> ::= {<domainlabel>.}<toplabel>[.] +<domainlabel> ::= (<alphanum>|<alphanum>{(<alphanum>|-)}<alphanum>) +<toplabel> ::= (<alpha>|<alpha>{(<alphanum>|-)}<alphanum>) +<ipv4_address> ::= <digit>{<digit>}.<digit>{<digit>}.<digit>{<digit>}.<digit>{<digit>} +<port> ::= {<digit>} +<reg_name> ::= <reg_char>{<reg_char>} +<reg_char> ::= (<unreserved>|<escaped>|;|:|@|&|=|+|$|,) +<path_segments> ::= <segment>{/<segment>} +<segment> ::= {<path_char>}{;<param>} +<param> ::= {<path_char>} +<path_char> ::= (<unreserved>|<escaped>|:|@|&|=|+|$|,) +<query> ::= {<mrl_char>} +<stream_setup> ::= <stream_option>;{<stream_option>} +<stream_option> ::= (<configoption>|<engine_option>|novideo|noaudio|nospu) +<configoption> ::= <configentry>:<configvalue> +<configentry> ::= <unreserved>{<unreserved>} +<configvalue> ::= <conf_char>{<conf_char>} +<engine_option> ::= <unreserved>{<unreserved>}:<stream_char>{<stream_char>} +<stream_char> ::= (<unreserved>|<escaped>|:|@|&|=|+|$|,) +<mrl_char> ::= (<reserved>|<unreserved>|<escaped>) +<reserved> ::= (;|/|?|:|@|&|=|+|$|,) +<unreserved> ::= (<alphanum>|<mark>) +<mark> ::= (-|_|.|!|~|*|'|(|)) +<escaped> ::= %<hex><hex> +<hex> ::= (<digit>|A|B|C|D|E|F|a|b|c|d|e|f) +<alphanum> ::= (<alpha>|<digit>) +<alpha> ::= (<lowalpha>|<upalpha>) +<lowalpha> ::= (a|b|c|d|e|f|g|h|i|j|k|l|m|n|o|p|q|r|s|t|u|v|w|x|y|z) +<upalpha> ::= (A|B|C|D|E|F|G|H|I|J|K|L|M|N|O|P|Q|R|S|T|U|V|W|X|Y|Z) +<digit> ::= (0|1|2|3|4|5|6|7|8|9) + + +--- +version of this file: + $Id: README.mrl,v 1.1 2003/01/05 13:11:53 guenter Exp $ |