%{
// * Java declarations
//   This code is copied in the beginning of the generated Java file
import scanner.Scanner;
%}

// * Yacc declarations
//   Token definition
%token INT_CONSTANT CHAR_CONSTANT REAL_CONSTANT
%token INT DOUBLE CHAR VOID STRUCT
%token ID IF ELSE
%token MAIN RETURN WHILE READ WRITE
%token AND OR
%token EQUALS GREATEREQUAL LOWEREQUAL DISTINCT INCREMENT

//lower precedence

%right '='
%left AND OR '!'
%left '>' '<' EQUALS DISTINCT GREATEREQUAL LOWEREQUAL
%left '+' '-'
%left '*' '/' '%'
%right UNARY_MINUS
%nonassoc '(' ')'
%nonassoc '[' ']'
%nonassoc '.'
%right THEN ELSE

%%
// * Actions

program: varDef program
	| functionDef program
	| VOID MAIN '('')' '{' varDefs statements '}'
	;

functionDef:  type ID '(' params ')' '{' varDefs statements '}'
		  |  VOID ID '(' params ')' '{' varDefs statements '}'
		  ;

varDefs: varDef varDefs
	   | /* empty */
	   ;

varDef: type listIDs ';'
	  ;

type: INT
	| DOUBLE
	| CHAR
	| structConstructor
	| type '[' INT_CONSTANT ']'
	;

structConstructor: STRUCT '{' varDefs '}' ;

listIDs: listIDs ',' ID
	| ID
	;

params:
	  | listOfParams
	  ;

listOfParams: listOfParams ',' type ID
			| type ID
			;

statements: statements statement
		  | /* empty */
		  ;

statement: assignment
		| returnStatement
		| ID '.' ID '=' expression ';'
		| ID arrayConstructor '=' expression ';'
		| writeStatement ';'
		| readStatement ';'
		| ifElseStatement ';'
		| whileStatement
		| functionInvocation ';'
;

ifElseStatement: IF '(' expression ')' statement;

functionInvocation: ID '(' expressions ')'
;

expressions: expression expressionAux
		   | /* empty */
		   ;

expressionAux: ',' expression expressionAux
		     | /* empty */
			 ;

arrayConstructor :'['expression']' arrayConstructor
				 | '['expression']'
				 ;


writeStatement: WRITE expressions
			  ;

readStatement: READ expressions
			 ;

returnStatement: RETURN expression ';'

whileStatement: WHILE '(' expression ')' '{' statements '}'
			  ;

cast: '(' type ')' expression
	;

expression: expression '+' expression
          | expression '*' expression
          | expression '-' expression
          | expression '/' expression
          | expression '%' expression
          | expression '>' expression
          | expression '<' expression
          | '-' expression %prec UNARY_MINUS
          | '!' expression
          | expression AND expression
          | expression OR expression
          | expression EQUALS expression
          | expression GREATEREQUAL expression
          | expression LOWEREQUAL expression
          | expression DISTINCT expression
          | cast
          | INT_CONSTANT
          | CHAR_CONSTANT
          | REAL_CONSTANT
          | ID
          | '(' expression ')'
          | functionInvocation
          | returnStatement
          ;

assignment: expression '=' expression ';'


%%

// * Code
//   Members of the generated Parser class
// We must implement at least:
// - int yylex()
// - void yyerror(String)

// * Lexical analyzer
private Scanner scanner;

// * Root node of the tree
private ASTNode astRootNode;

// * Invocation to the scanner
private int yylex () {
    int token=0;
    try {
		token=scanner.yylex();
		this.yylval = scanner.getYylval();
    } catch(Throwable e) {
	    System.err.println ("Lexical error in line " + scanner.getLine()+
		" and column "+scanner.getColumn()+":\n\t"+e);
    }
    return token;
}

// * Syntax error handler
public void yyerror (String error) {
    System.err.println ("Syntax error in line " + scanner.getLine()+
		" and column "+scanner.getColumn()+":\n\t"+error );
	Token lastToken = (Token) yyval;
	System.err.println ("Token" + lastToken.getToken() + "lexema "
	+ lastToken.getLexeme()  + " start " + lastToken.getStart());

}

// * Constructor
public Parser(Scanner scanner) {
	this.scanner= scanner;
	//this.yydebug = true;
}