grammar Hello;

s : title declaration? body;
numbers : Unary_minus?UnsignedInt ;
operators : Unary_minus|Multiplicative|Additive|Relational|Logical|StringConcatenation|Assignment;
separators : LPAREN |RPAREN|LBRACK|RBRACK|SEMICOLON|COLON|COMMA;
title : PROGRAM  Identifiers;
array: ARRAY  LBRACK numbers RBRACK OF VAR_TYPES;
var_declaration : Identifiers (COMMA Identifiers)* COLON (VAR_TYPES|array);
declaration : VAR var_declaration (SEMICOLON var_declaration)*;
body : BODY (statemen| block);
simple_block : BEGIN (statemen|block) END;
complex_block: BEGIN (simple_block|statemen) (SEMICOLON block|SEMICOLON statemen)* END;
block: simple_block | complex_block;
expr_numb : (Identifiers | numbers)  ne;
ne: (expr_numb Additive expr_numb |  expr_numb Multiplicative expr_numb| Whitespace );
expr_bool : (Logic | Identifiers) be;
be : (expr_bool Logical expr_bool | expr_numb Relational expr_numb| Whitespace );
expr_string: (Constans Identifiers) se;
se: (expr_string StringConcatenation expr_string| Whitespace );
expr : (expr_numb |  expr_string | expr_bool ) r;
r: expr expr;
array_pointer: LPAREN (Identifiers|UnsignedInt) RPAREN;
assignments : Identifiers (array_pointer)? Assignment  expr;
read : READ LPAREN Identifiers (COMMA Identifiers)* RPAREN;
write: WRITE LPAREN expr (COMMA expr)* RPAREN;
simple_if : IF expr_bool THEN (statemen | block );
complex_if: simple_if ELSE (statemen | block );
if_statemen : simple_if |complex_if;
while_statemen : WHILE expr_bool DO (statemen | block );
exit_statemnet : EXIT;
statemen:  read|write| if_statemen | while_statemen | exit_statemnet | assignments;
//Termatika
PROGRAM = 'PROGRAM ';
ARRAY = 'ARRAY' ;
OF= 'OF';
VAR='VAR';
BODY='BODY';
BEGIN='BEGIN';
END='END';
WHILE='WHILE';
DO='DO';
EXIT='EXIT';
READ='READ';
WRITE='WRITE';
IF='IF';
THEN='THEN' ;
ELSE='ELSE' ;
Character_Set : [.~];
Whitespace :   [ \t\r\n]+ -> skip ;
Comments : '{'.*?'}' -> skip ;
Identifiers : [_a-zA-Z]+[_a-zA-Z0-9]*;
Logic : 'TRUE'|'FALSE';
Constans : '"'.*?'"' | '"'numbers'"' | '"'Logic'"';
Unary_minus : '-';
UnsignedInt: [1-9][0-9]*|[0];
Multiplicative : [*%/];
Additive : [+-];
Relational : '=' | '<>' | '<' | '>' | '<=' | '>=' ;
Logical : 'AND' | 'OR' | 'NOT';
StringConcatenation : '|';
Assignment : ':=';
LPAREN : '(';
RPAREN : ')';
LBRACK : '[';
RBRACK : ']';
SEMICOLON : ';';
COLON : ':';
COMMA : ',';
VAR_TYPES: 'INTEGER'|'STRING'|'BOOLEAN';