aosp12/external/antlr/runtime/Python/tests/t033backtracking.g

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grammar t033backtracking;
options {
language=Python;
backtrack=true;
memoize=true;
k=2;
}
scope Symbols {
types;
}
@header {
# compatibility stuff
try:
set = set
frozenset = frozenset
except NameError:
from sets import Set as set, ImmutableSet as frozenset
try:
reversed = reversed
except NameError:
def reversed(l):
l = l[:]
l.reverse()
return l
}
@members {
def isTypeName(self, name):
for scope in reversed(self.Symbols_stack):
if name in scope.types:
return True
return False
}
translation_unit
scope Symbols; // entire file is a scope
@init {
$Symbols::types = set()
}
: external_declaration+
;
/** Either a function definition or any other kind of C decl/def.
* The LL(*) analysis algorithm fails to deal with this due to
* recursion in the declarator rules. I'm putting in a
* manual predicate here so that we don't backtrack over
* the entire function. Further, you get a better error
* as errors within the function itself don't make it fail
* to predict that it's a function. Weird errors previously.
* Remember: the goal is to avoid backtrack like the plague
* because it makes debugging, actions, and errors harder.
*
* Note that k=1 results in a much smaller predictor for the
* fixed lookahead; k=2 made a few extra thousand lines. ;)
* I'll have to optimize that in the future.
*/
external_declaration
options {k=1;}
: ( declaration_specifiers? declarator declaration* '{' )=> function_definition
| declaration
;
function_definition
scope Symbols; // put parameters and locals into same scope for now
@init {
$Symbols::types = set()
}
: declaration_specifiers? declarator
// ( declaration+ compound_statement // K&R style
// | compound_statement // ANSI style
// )
;
declaration
scope {
isTypedef;
}
@init {
$declaration::isTypedef = False
}
: 'typedef' declaration_specifiers? {$declaration::isTypedef = True}
init_declarator_list ';' // special case, looking for typedef
| declaration_specifiers init_declarator_list? ';'
;
declaration_specifiers
: ( storage_class_specifier
| type_specifier
| type_qualifier
)+
;
init_declarator_list
: init_declarator (',' init_declarator)*
;
init_declarator
: declarator //('=' initializer)?
;
storage_class_specifier
: 'extern'
| 'static'
| 'auto'
| 'register'
;
type_specifier
: 'void'
| 'char'
| 'short'
| 'int'
| 'long'
| 'float'
| 'double'
| 'signed'
| 'unsigned'
// | struct_or_union_specifier
// | enum_specifier
| type_id
;
type_id
: {self.isTypeName(self.input.LT(1).getText())}? IDENTIFIER
// {System.out.println($IDENTIFIER.text+" is a type");}
;
// struct_or_union_specifier
// options {k=3;}
// scope Symbols; // structs are scopes
// @init {
// $Symbols::types = set()
// }
// : struct_or_union IDENTIFIER? '{' struct_declaration_list '}'
// | struct_or_union IDENTIFIER
// ;
// struct_or_union
// : 'struct'
// | 'union'
// ;
// struct_declaration_list
// : struct_declaration+
// ;
// struct_declaration
// : specifier_qualifier_list struct_declarator_list ';'
// ;
// specifier_qualifier_list
// : ( type_qualifier | type_specifier )+
// ;
// struct_declarator_list
// : struct_declarator (',' struct_declarator)*
// ;
// struct_declarator
// : declarator (':' constant_expression)?
// | ':' constant_expression
// ;
// enum_specifier
// options {k=3;}
// : 'enum' '{' enumerator_list '}'
// | 'enum' IDENTIFIER '{' enumerator_list '}'
// | 'enum' IDENTIFIER
// ;
// enumerator_list
// : enumerator (',' enumerator)*
// ;
// enumerator
// : IDENTIFIER ('=' constant_expression)?
// ;
type_qualifier
: 'const'
| 'volatile'
;
declarator
: pointer? direct_declarator
| pointer
;
direct_declarator
: ( IDENTIFIER
{
if len($declaration)>0 and $declaration::isTypedef:
$Symbols::types.add($IDENTIFIER.text)
print "define type "+$IDENTIFIER.text
}
| '(' declarator ')'
)
declarator_suffix*
;
declarator_suffix
: /*'[' constant_expression ']'
|*/ '[' ']'
// | '(' parameter_type_list ')'
// | '(' identifier_list ')'
| '(' ')'
;
pointer
: '*' type_qualifier+ pointer?
| '*' pointer
| '*'
;
// parameter_type_list
// : parameter_list (',' '...')?
// ;
// parameter_list
// : parameter_declaration (',' parameter_declaration)*
// ;
// parameter_declaration
// : declaration_specifiers (declarator|abstract_declarator)*
// ;
// identifier_list
// : IDENTIFIER (',' IDENTIFIER)*
// ;
// type_name
// : specifier_qualifier_list abstract_declarator?
// ;
// abstract_declarator
// : pointer direct_abstract_declarator?
// | direct_abstract_declarator
// ;
// direct_abstract_declarator
// : ( '(' abstract_declarator ')' | abstract_declarator_suffix ) abstract_declarator_suffix*
// ;
// abstract_declarator_suffix
// : '[' ']'
// | '[' constant_expression ']'
// | '(' ')'
// | '(' parameter_type_list ')'
// ;
// initializer
// : assignment_expression
// | '{' initializer_list ','? '}'
// ;
// initializer_list
// : initializer (',' initializer)*
// ;
// // E x p r e s s i o n s
// argument_expression_list
// : assignment_expression (',' assignment_expression)*
// ;
// additive_expression
// : (multiplicative_expression) ('+' multiplicative_expression | '-' multiplicative_expression)*
// ;
// multiplicative_expression
// : (cast_expression) ('*' cast_expression | '/' cast_expression | '%' cast_expression)*
// ;
// cast_expression
// : '(' type_name ')' cast_expression
// | unary_expression
// ;
// unary_expression
// : postfix_expression
// | '++' unary_expression
// | '--' unary_expression
// | unary_operator cast_expression
// | 'sizeof' unary_expression
// | 'sizeof' '(' type_name ')'
// ;
// postfix_expression
// : primary_expression
// ( '[' expression ']'
// | '(' ')'
// | '(' argument_expression_list ')'
// | '.' IDENTIFIER
// | '*' IDENTIFIER
// | '->' IDENTIFIER
// | '++'
// | '--'
// )*
// ;
// unary_operator
// : '&'
// | '*'
// | '+'
// | '-'
// | '~'
// | '!'
// ;
// primary_expression
// : IDENTIFIER
// | constant
// | '(' expression ')'
// ;
// constant
// : HEX_LITERAL
// | OCTAL_LITERAL
// | DECIMAL_LITERAL
// | CHARACTER_LITERAL
// | STRING_LITERAL
// | FLOATING_POINT_LITERAL
// ;
// /////
// expression
// : assignment_expression (',' assignment_expression)*
// ;
// constant_expression
// : conditional_expression
// ;
// assignment_expression
// : lvalue assignment_operator assignment_expression
// | conditional_expression
// ;
// lvalue
// : unary_expression
// ;
// assignment_operator
// : '='
// | '*='
// | '/='
// | '%='
// | '+='
// | '-='
// | '<<='
// | '>>='
// | '&='
// | '^='
// | '|='
// ;
// conditional_expression
// : logical_or_expression ('?' expression ':' conditional_expression)?
// ;
// logical_or_expression
// : logical_and_expression ('||' logical_and_expression)*
// ;
// logical_and_expression
// : inclusive_or_expression ('&&' inclusive_or_expression)*
// ;
// inclusive_or_expression
// : exclusive_or_expression ('|' exclusive_or_expression)*
// ;
// exclusive_or_expression
// : and_expression ('^' and_expression)*
// ;
// and_expression
// : equality_expression ('&' equality_expression)*
// ;
// equality_expression
// : relational_expression (('=='|'!=') relational_expression)*
// ;
// relational_expression
// : shift_expression (('<'|'>'|'<='|'>=') shift_expression)*
// ;
// shift_expression
// : additive_expression (('<<'|'>>') additive_expression)*
// ;
// // S t a t e m e n t s
// statement
// : labeled_statement
// | compound_statement
// | expression_statement
// | selection_statement
// | iteration_statement
// | jump_statement
// ;
// labeled_statement
// : IDENTIFIER ':' statement
// | 'case' constant_expression ':' statement
// | 'default' ':' statement
// ;
// compound_statement
// scope Symbols; // blocks have a scope of symbols
// @init {
// $Symbols::types = {}
// }
// : '{' declaration* statement_list? '}'
// ;
// statement_list
// : statement+
// ;
// expression_statement
// : ';'
// | expression ';'
// ;
// selection_statement
// : 'if' '(' expression ')' statement (options {k=1; backtrack=false;}:'else' statement)?
// | 'switch' '(' expression ')' statement
// ;
// iteration_statement
// : 'while' '(' expression ')' statement
// | 'do' statement 'while' '(' expression ')' ';'
// | 'for' '(' expression_statement expression_statement expression? ')' statement
// ;
// jump_statement
// : 'goto' IDENTIFIER ';'
// | 'continue' ';'
// | 'break' ';'
// | 'return' ';'
// | 'return' expression ';'
// ;
IDENTIFIER
: LETTER (LETTER|'0'..'9')*
;
fragment
LETTER
: '$'
| 'A'..'Z'
| 'a'..'z'
| '_'
;
CHARACTER_LITERAL
: '\'' ( EscapeSequence | ~('\''|'\\') ) '\''
;
STRING_LITERAL
: '"' ( EscapeSequence | ~('\\'|'"') )* '"'
;
HEX_LITERAL : '0' ('x'|'X') HexDigit+ IntegerTypeSuffix? ;
DECIMAL_LITERAL : ('0' | '1'..'9' '0'..'9'*) IntegerTypeSuffix? ;
OCTAL_LITERAL : '0' ('0'..'7')+ IntegerTypeSuffix? ;
fragment
HexDigit : ('0'..'9'|'a'..'f'|'A'..'F') ;
fragment
IntegerTypeSuffix
: ('u'|'U')? ('l'|'L')
| ('u'|'U') ('l'|'L')?
;
FLOATING_POINT_LITERAL
: ('0'..'9')+ '.' ('0'..'9')* Exponent? FloatTypeSuffix?
| '.' ('0'..'9')+ Exponent? FloatTypeSuffix?
| ('0'..'9')+ Exponent FloatTypeSuffix?
| ('0'..'9')+ Exponent? FloatTypeSuffix
;
fragment
Exponent : ('e'|'E') ('+'|'-')? ('0'..'9')+ ;
fragment
FloatTypeSuffix : ('f'|'F'|'d'|'D') ;
fragment
EscapeSequence
: '\\' ('b'|'t'|'n'|'f'|'r'|'\"'|'\''|'\\')
| OctalEscape
;
fragment
OctalEscape
: '\\' ('0'..'3') ('0'..'7') ('0'..'7')
| '\\' ('0'..'7') ('0'..'7')
| '\\' ('0'..'7')
;
fragment
UnicodeEscape
: '\\' 'u' HexDigit HexDigit HexDigit HexDigit
;
WS : (' '|'\r'|'\t'|'\u000C'|'\n') {$channel=HIDDEN;}
;
COMMENT
: '/*' ( options {greedy=false;} : . )* '*/' {$channel=HIDDEN;}
;
LINE_COMMENT
: '//' ~('\n'|'\r')* '\r'? '\n' {$channel=HIDDEN;}
;
// ignore #line info for now
LINE_COMMAND
: '#' ~('\n'|'\r')* '\r'? '\n' {$channel=HIDDEN;}
;