# A grammar file for reading BNF notation
# FIXME: Too many errors!

[space]: %x20\t

[id]: a-zA-Z\-_+*@

[rule_name_char]: ^[]:%x20\n

[notnewline]: ^\n\r

[class_range_char]: ^\n\r\^\\

[class_single_char]: ^\n\r\^\\\-

[any]:

[double_string_char]: ^"\n

[single_string_char]: ^'\n

--

BNF: "#" notnewlines empty BNF
BNF: predicate_section "--\n" empty rules_section
BNF: rules_section
BNF:

spaces: [space] spaces
spaces: [space]

optional_spaces: [space] optional_spaces
optional_spaces:

empty: [space] empty
empty: "\n" empty
empty: "\r" empty
empty: "\n#" notnewlines
empty:

notnewlines: [notnewline] notnewlines
notnewlines:

predicate_section: predicate empty "\n" predicate_section
predicate_section:

predicate: "[" ids "]:" optional_spaces class

ids: [id] ids
ids: [id]

# Yes, a class specification can be empty, in which case the predicate
# matches everything.

class: positive_class
class: "^" positive_class

positive_class: positive_specification positive_class
positive_class:

positive_specification: class_single_chars
positive_specification: class_range_chars "-" class_range_chars

class_single_chars: [class_single_char]
class_single_chars: "\\" [any]

class_range_chars: [class_range_char]
class_range_chars: "\\" [any]

rules_section: rule empty "\n" rules_section
rules_section:

rule: rule_name optional_spaces ":" optional_spaces rule_rhs

rule_name: [rule_name_char] rule_name
rule_name:

spaces_or_escaped_newline: optional_spaces
spaces_or_escaped_newline: "\\\n"

rule_rhs: ids spaces_or_escaped_newline rule_rhs
rule_rhs: '[' ids ']' spaces_or_escaped_newline rule_rhs
rule_rhs: '"' double_string_chars '"' spaces_or_escaped_newline rule_rhs
rule_rhs: "'" single_string_chars "'" spaces_or_escaped_newline rule_rhs
rule_rhs: 

double_string_chars: [double_string_char]
double_string_chars: "\\" [any]
double_string_chars: [double_string_char] double_string_char
double_string_chars: "\\" [any] double_string_chars

single_string_chars: [single_string_char]
single_string_chars: "\\" [any]
single_string_chars: [single_string_char] single_string_char
single_string_chars: "\\" [any] single_string_chars