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<chapter title="Pike BNF">
<contents><pre>
program ::= definition+
definition ::= import | inheritance | function_declaration | function_definition | variables | constant | class_def
import ::= modifiers+ "import" ( constant_identifier | string ) ";"
inheritance ::= modifiers+ "inherit" program_specifier ( ":" identifier )? ";"
function_declaration ::= modifiers+ type identifier "(" ( arguments | prot_arguments )? ")" ";"
function_definition ::= modifiers+ type identifier "(" arguments? ")" block
variables ::= modifiers+ type variable_names ";"
variable_names ::= variable_name ( "," variable_name )*
variable_name ::= identifier ( "=" expression2 )?
constant ::= modifiers+ "constant" constant_names ";"
constant_names ::= constant_name ( "," constant_name )*
constant_name ::= identifier "=" expression2
class_def ::= modifiers+ class ";"?
<!-- Is it arguments or arguments? in class? -->
class ::= "class" identifier? ( "(" arguments ")" )? "{" program "}"
modifiers ::= ( "extern" | "final" | "inline" | "local" | "nomask" | "optional" | "private" |
"protected" | "public" | "static" | "variant" )
block ::= "{" statement* "}"
statement ::= expression ";" | cond | while | do_while | for | switch | return | block | foreach | ";"
cond ::= "if" statement ( "else" statement )?
while ::= "while" "(" expression ")" statement
do_while ::= "do" statement "while" "(" expression ")" ";"
for ::= "for" "(" expression? ";" expression? ";" expression? ")" statement
switch ::= "switch" "(" expression ")" block
case_block ::= "{" ( case | default | statement | break | continue )* "}"
case ::= "case" expression [ ".." expression ] ":"
default ::= "default" ":"
<!-- It can't be expression6 here, since that would make foreach(x, "hello") valid -->
foreach ::= "foreach" "(" expression "," expression6 ")" statement
<!-- Labelled breaks -->
break ::= "break" ";"
continue ::= "continue" ";"
expression ::= expression2 ( "," expression2 )*
expression2 ::= ( lvalue ( "=" | "+=" | "*=" | "/=" | "&=" | "|=" | "^=" | "<<=" | ">>=" | "%=" ) )* expression3
expression3 ::= expression4 '?' expression3 ":" expression3
expression4 ::= ( expression5 ( "||" | "&&" | "|" | "^" | "&" | "==" | "!=" | ">" | "<" | ">=" | "<=" | "<<" |
">>" | "+" | "*" | "/" | "%" ) )* expression5
expression5 ::= expression6 | "(" type ")" expression5 | "--" expression6 | "++" expression6 | expression6 "--" |
expression6 "++" | "~" expression5 | "-" expression5
expression6 ::= string | int | float | catch | gauge | typeof | sscanf | lambda | class | constant_identifier | call |
index | mapping | multiset | array | parenthesis | arrow
int ::= "-"? ( ["1" - "9"] digit* | hex_int | bin_int | oct_int | "'" character "'" )
hex_int ::= "0" ( "x" | "X" ) hex_number
hex_number ::= hex_digit+
hex_digit ::= ( digit | ["a" - "f"] | ["A" - "F"] )
bin_int ::= "0" ( "b" | "B" ) bin_number
bin_number ::= bin_digit+
bin_digit ::= ( "1" | "0" )
oct_int ::= "0" oct_number
oct_number ::= oct_digit+
oct_digit ::= ["0" - "7"]
float ::= "-"? digit* "." digit+ ( ( "e" | "E" ) "-"? digit+ )?
catch ::= "catch" ( "(" expression ")" | block )
gauge ::= "gauge" ( "(" expression ")" | block )
sscanf ::= "sscanf" "(" expression2 "," expression2 ( "," lvalue )* ")"
lvalue ::= expression6 | type identifier | "[" ( lvalue ( "," lvalue )* ","? )? "]"
lambda ::= "lambda" "(" arguments? ")" block
constant_identifier ::= "."? identifier ( "." identifier )*
call ::= expression6 "(" expression_list ")"
index_expression ::= "<"? expression
index ::= expression6 "[" ( index_expression | ".." index_expression | index_expression ".." | index_expresion ".." index_expresion ) "]"
array ::= "({" expression_list "})"
multiset ::= "(<" expression_list ">)"
mapping ::= "([" ( expression ":" expression ( "," expression ":" expression )* ","? )? "])"
arrow ::= expression6 "->" identifier
parenthesis ::= "(" expression ")"
expression_list ::= ( splice_expression ( "," splice_expression )* ","? )?
splice_expression ::= "@"? expression2
type ::= int_type | "string" | "float" | "program" | object_type | program_specifier |
mapping_type | array_type | multiset_type | function [ function_type ]
int_type ::= "int" ( "(" ( digit+ | ".." digit+ | digit+ ".." | digit+ ".." digit+ ) ")" )?
object_type ::= "object" ( "(" program_specifier ")" )?
mapping_type ::= "mapping" ( "(" type ":" type ")" )?
array_type ::= "array" ( "(" type ")" )?
multiset_type ::= "multiset" ( "(" type ")" )?
function_type ::= "function" ( "(" type ( "," type )* "..."? ":" type ")" )?
arguments ::= ( argument ( "," argument )* varargs? | varargs ) ","?
argument ::= type identifier
varargs ::= type "..." identifier
prot_arguments ::= ( type ( "," type )* ( type "..." )? | ( type "..." ) ) ","?
program_specifier ::= string_constant | constant_identifier
string ::= ( 0x22 character* 0x22 )+
hex4 ::= hex_digit hex_digit hex_digit hex_digit
character ::= [0x0000 - 0xffff] | "\" oct_number | "\x" hex_number | "\d" digit* | "\u" hex4 | "\U" hex4 hex4 | "\a" | "\b" | "\t" | "\n" | "\v" | "\f" | "\r" | "\" 0x22 | "\\"
identifier ::= letter { letter | digit } | "`+" | "`/" | "`%" | "`*" | "`&" | "`|" | "`^" | "`~" |
"`<" | "`<<" | "`<=" | "`>" | "`>>" | "`>=" | "`==" | "`!=" | "`!" | "`()" | "`-" |
"`->" | "`->=" | "`[]" | "`[]="
letter ::= ["a"-"z"] | ["A"-"Z"] | "_"
digit ::= ["0"-"9"]
</pre></contents>
</chapter>
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