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hectorj/esi.ebnf

Created May 17, 2015 04:15
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Attempt at defining the ESI expressions' grammar
Raw
esi.ebnf
Expression = Value {{" "} Operator {" "} Value}.
Operator = Comparison_operator | Logical_operator .
Comparison_operator = "==" | "!=" | "<" | ">" | "<=" | ">=".
Logical_operator = "!" | "&" | "|".
Variable = "$(" (Simple_variable | Substructure) ")".
Simple_variable = "HTTP_HOST" | "HTTP_REFERER".
Substructure = ("HTTP_ACCEPT_LANGUAGE" | "HTTP_COOKIE" | "HTTP_USER_AGENT" | "QUERY_STRING") "{" word "}".
word = .
Value = (Expression | Variable | string | int | float).
string = .
int = .
float = .
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