extract an ebnf for railroad diagram generation in one file, the railroad generator uses "::=" as rule separator, no semicolon at the end of a rule, and "?+*" for repetiton instead of "[]{}" and uses C comments instead of pascal comments

//
// EBNF to be viewd at
//    (IPV6) https://www.bottlecaps.de/rr/ui
//    (IPV4) https://rr.red-dove.com/ui
//
// Copy and paste this at one of the urls shown above in the 'Edit Grammar' tab
// then click the 'View Diagram' tab.
//

/* ChaiScript EBNF for railroad diagrams */

statements           ::= (def | try | if | while | class | for | switch | return | break | continue | equation | block | eol)+

def                  ::= "def" id ("::" id)? "(" decl_arg_list ")" eos* (":" operator)? eol* block
lambda               ::= "fun" ("[" id_arg_list "]" |) "(" decl_arg_list ")" eol* block
try                  ::= "try" eol* block (catch+)? (finally)?
catch                ::= "catch" ("(" arg ")")? eol* block
finally              ::= "finally" eol* block

if                   ::= "if" "(" equation (eol equation)? ")" eol* block (("else" (if | eol* block))*)
while                ::= "while" "(" operator ")" eol* block

for                  ::= "for" "(" (for_guards ")" | (equation ":" equation ")")) eol* block
for_guards           ::= (equation eol)+ (equation eol)? equation

class                ::= "class" id eol* class_block
class_block          ::= "{" class_statements* "}"
class_statements     ::= (def | var_decl) | eol

switch               ::= "switch" "(" operator ")" eol* "{" (case | default)+ "}"
case                 ::= "case" "(" operator ")" eol* block
default              ::= "default" eol* block

block                ::= "{" statements* "}"
return               ::= "return" operator?
break                ::= "break"
continue             ::= "continue"
eol                  ::= "\n" | "\r\n" | ";"

equation             ::= operator (("=" | ":=" | "+=" | "-=" | "*=" | "/=" | "%=" | "<<=" | ">>=" | "&=" | "^=" | "|=") equation)?
operator             ::= prefix | value | (operator binary_operator operator)+
prefix               ::= ("++" | "--" | "-" | "+" | "!" | "~") operator
binary_operator      ::= "?" | "||" | "&&" | "|" | "^" | "&" | "==" | "!=" | "<" | "<=" | ">" | ">=" | "<<" | ">>" | "+" | "-" | "*" | "/" | "%"

value                ::= var_decl | dot_fun_array | prefix
dot_fun_array        ::= (lambda | num | quoted_string | single_quoted_string | paren_expression | inline_container | id) (fun_call | array_call | dot_access)*
fun_call             ::= "(" arg_list ")"
array_call           ::= "[" operator "]"
dot_access           ::= "." id

var_decl             ::= ("auto" | "var") (reference | id) | "global" (reference | id) | "attr" id ("::" id)?
reference            ::= "&" id

paren_expression     ::= "(" operator ")"
inline_container     ::= "[" container_arg_list "]"
container_arg_list   ::= value_range | map_pair ("," map_pair)* | operator ("," operator)*

quoted_string        ::= '"' (char | escape | interpolation)* '"'
single_quoted_string ::= "'" (char | escape)* "'"

id_arg_list          ::= arg ("," arg)*
decl_arg_list        ::= arg ("," arg)*
arg_list             ::= equation ("," equation)*
arg                  ::= id id?    /* type allowed */

id                   ::= [a-zA-Z_] [a-zA-Z0-9_]* | "`" char+ "`"
num                  ::= hex | binary | float | int
hex                  ::= "0" ("x" | "X") [0-9a-fA-F]+ int_suffix*
binary               ::= "0" ("b" | "B") [01]+
float                ::= [0-9]+ "." [0-9]+ (("e"|"E") ("+"|"-")? [0-9]+)? float_suffix*
int                  ::= [0-9]+ int_suffix*

int_suffix           ::= "l" | "L" | "u" | "U"
float_suffix         ::= "l" | "L" | "f" | "F"

quoted_string        ::= '"' (char | escape | interpolation)* '"'
single_quoted_string ::= "'" (char | escape)* "'"

escape               ::= "\" ("'" | '"' | "?" | "\" | "a" | "b" | "f" | "n" | "r" | "t" | "v" | "$" | "x" hex_digit+ | "u" hex_digit hex_digit hex_digit hex_digit | "U" hex_digit hex_digit hex_digit hex_digit hex_digit hex_digit hex_digit hex_digit | octal_digit+)
octal_digit          ::= [0-7]
hex_digit            ::= [0-9a-fA-F]
interpolation        ::= "$" "{" equation "}"

value_range          ::= operator ".." operator
map_pair             ::= operator ":" operator

/* Utility */
eos                  ::= eol | ";"