mojom/mojom.ebnf

(* Copyright 2015 The Chromium Authors. All rights reserved.
   Use of this source code is governed by a BSD-style license that can be
   found in the LICENSE file. *)

(* mojom_file is the root production rule. *)
mojom_file                 = [ module_decl ] , { import_stmt } , { primary_object_decl } ;
module_decl                = attribute_section , "module" , identifier , ";" ;
import_stmt                = "import" , STRING_LITERAL , ";" ;
primary_object_decl        = interface_decl | struct_decl | union_decl | enum_decl | const_decl ;
attribute_section          = [ "[" , attribute_list , "]" ] ;
attribute_list             = [ attribute_assignment , { "," , attribute_assignment } ] ;
attribute_assignment       = NAME , "=" , ( NAME | literal ) ;
interface_decl             = attribute_section , "interface" , NAME , "{" , interface_body , "}" , ";" ;
interface_body             = { method_decl | enum_decl | const_decl } ;
method_decl                = attribute_section , NAME , [ ORDINAL ] , "(" , parameter_list , ")" , response_decl , ";" ;
response_decl              = [ "=>" , "(" , parameter_list , ")" ] ;
parameter_list             = [ parameter_decl { "," , parameter_decl } ] ;
parameter_decl             = attribute_section , typespec , NAME , [ ORDINAL ] ;
struct_decl                = attribute_section , "struct" , NAME , "{" , struct_body , "}" , ";" ;
struct_body                = { struct_field_decl | enum_decl | const_decl } ;
struct_field_decl          = attribute_section , typespec , NAME , [ ORDINAL ] , default_value_assignment , ";" ;
union_decl                 = attribute_section , "union" , NAME , "{" , union_body , "}" , ";" ;
union_body                 = { union_field_decl  } ;
union_field_decl           = attribute_section , typespec , NAME , [ ORDINAL ] , ";" ;
default_value_assignment   = [ "=" , constant ] ;
enum_decl                  = attribute_section , "enum" , NAME , "{" , enum_value_list , [ "," ] , "}" , ";" ;
enum_value_list            = enum_value , { "," , enum_value } ;
enum_value                 = attribute_section , NAME , [ "=" , ( identifier | int_literal ) ] ;
const_decl                 = "const" , typespec , NAME , "=" , constant , ";" ;
typespec                   = nonnullable_typespec , [ "?" ] ;
nonnullable_typespec       = basictypespec | map_typespec | array_typespec
                           | fixed_array_typespec | interface_request_typespec ;
basictypespec              = handle_typespec | identifier ;
handle_typespec            = "handle" , [ "<" , NAME , ">" ] ;
array_typespec             = "array" , "<" , typespec , ">" ;
fixed_array_typespec       = "array" , "<" , typespec , "," , INT_CONST_DEC , ">" ;
map_typespec               = "map" , "<" , identifier , "," , typespec , ">" ;
interface_request_typespec = identifier , "&" ;
constant                   = identifier | literal ;
identifier                 = NAME , [ "." , identifier ] ;
literal                    = "default" | "true" | "false" | int_literal
                           | float_literal | STRING_LITERAL ;
float_literal              = [ "-" | "+" ] , FLOAT_CONST ;
int_literal                = [ "-" | "+" ] , int_const ;
int_const                  = INT_CONST_DEC | INT_CONST_HEX ;

(* Capitalized names are terminals expressed as regular expressions. *)
ORDINAL                    = @[0-9]+

(* character constants (K&R2: A.2.5.2) *)
STRING_LITERAL             = "([^"\\\n]|(\\(([a-zA-Z._~!=&\^\-\\?'"])|(\d+)|(x[0-9a-fA-F]+))))*"

(* integer constants (K&R2: A.2.5.1) *)
INT_CONST_HEX              = 0[xX][0-9a-fA-F]+
INT_CONST_DEC              = 0|([1-9][0-9]*)

(* floating constants (K&R2: A.2.5.3) *)
FLOAT_CONST                = ((((([0-9]*\.[0-9]+)|([0-9]+\.))([eE][-+]?[0-9]+)?)|([0-9]+([eE][-+]?[0-9]+))))

(* valid C identifiers (K&R2: A.2.3)
 Some names are reserved. That is indicated by their literal use in the grammar
 above. *)
NAME                       = [a-zA-Z_][0-9a-zA-Z_]*