%union
{
  int   int_val;
  char *name_ptr;
}
%token ADDSY ANDSY ARRAYSY ASSIGNSY
%token BARSY BEGINSY BYSY
%token CARETSY CASESY CHARCONSTSY COLONSY COMMASY CONSTSY
%token DEFINITIONSY DIVIDESY DIVSY DOSY DOTDOTSY DOTSY
%token ELSIFSY ELSESY ENDSY EQSY EXITSY EXPORTSY
%token FORSY FROMSY
%token GESY GTSY
%token IDENTSY IFSY INTCONSTSY IMPLEMENTATIONSY IMPORTSY INSY
%token LBRACESY LBRACKETSY LPARENSY LESY LOOPSY LTSY
%token MINUSSY MODSY MODULESY
%token NESY NOTSY
%token OFSY ORSY
%token POINTERSY PROCEDURESY
%token QUALIFIEDSY
%token READSY RECORDSY REPEATSY RETURNSY RBRACKETSY RBRACESY RPARENSY 
%token SEMICOLONSY SETSY STRINGCONSTSY
%token THENSY TIMESSY TOSY TYPESY
%token UNTILSY
%token VARSY
%token WHILESY WITHSY WRITESY WRITELNSY
%nonassoc EQSY NESY GTSY GESY LTSY LESY
%left ADDSY MINUSSY ORSY
%left TIMESSY DIVIDESY DIVSY MODSY ANDSY
%nonassoc UNMINUSSY NOTSY
%start CompilationUnit
%%
CompilationUnit     : ProgramModule
		    ;

ProgramModule       : ModuleStart SEMICOLONSY Block IDENTSY DOTSY
		    ;

ModuleStart         : MODULESY IDENTSY
		    ;

Block               : DeclarationList BeginClause StatementSequence ENDSY
		    ;

BeginClause         : BEGINSY
		    ;

ProcedureHeading    : PROCEDURESY ProcedureName FormalParameters
		    ;

ProcedureName	    : IDENTSY
		    ;

FormalParameters    : LPARENSY OptFPSectionList RPARENSY COLONSY QualIdent
                    | LPARENSY OptFPSectionList RPARENSY
		    | /* empty */
		    ;

OptFPSectionList    : FPSectionList
		    | /* empty */
		    ;

FPSectionList	    : FPSection
		    | FPSectionList SEMICOLONSY FPSection
		    ;

FPSection           : VARSY IdentList COLONSY FormalType
  		    | IdentList COLONSY FormalType
		    ;

IdentList           : IDENTSY
                    | IDENTSY COMMASY IdentList
		    ;

FormalType          : QualIdent
		    ;

DeclarationList	    : Declaration DeclarationList
		    | /* empty */
		    ;

Declaration         : CONSTSY ConstDeclList
                    | TYPESY TypeDeclList
                    | VARSY VarDeclList
		    | ProcedureDeclaration
		    ;

ConstDeclList	    : ConstElement ConstDeclList
		    | /* empty */
		    ;

ConstElement	    : IDENTSY EQSY ConstExpression SEMICOLONSY
		    ;

TypeDeclList	    : TypeElement TypeDeclList
		    | /* empty */
		    ;

TypeElement         : IDENTSY EQSY Type SEMICOLONSY
		    ;

VarDeclList	    : VariableElement VarDeclList
		    | /* empty */
		    ;

VariableElement     : IdentList COLONSY Type SEMICOLONSY
		    ;

ProcedureDeclaration: ProcedureHeading SEMICOLONSY Block IDENTSY SEMICOLONSY
		    ;

ConstExpression     : ConstExpression ORSY ConstExpression
		    | ConstExpression ANDSY ConstExpression
		    | NOTSY ConstExpression
		    | ConstExpression EQSY ConstExpression
		    | ConstExpression NESY ConstExpression
		    | ConstExpression LESY ConstExpression
		    | ConstExpression GESY ConstExpression
		    | ConstExpression LTSY ConstExpression
		    | ConstExpression GTSY ConstExpression
		    | ConstExpression ADDSY ConstExpression
		    | ConstExpression MINUSSY ConstExpression
		    | ConstExpression TIMESSY ConstExpression
		    | ConstExpression DIVIDESY ConstExpression
		    | ConstExpression DIVSY ConstExpression
		    | ConstExpression MODSY ConstExpression
		    | MINUSSY ConstExpression %prec UNMINUSSY
		    | ADDSY ConstExpression %prec UNMINUSSY
		    | LPARENSY ConstExpression RPARENSY
		    | INTCONSTSY
		    | CHARCONSTSY
		    | STRINGCONSTSY
		    | QualIdent 
		    ;

Type                : SimpleType 
                    | ArrayType 
                    | RecordType 
		    ;

SimpleType          : QualIdent 
                    | SubrangeType
		    ;

ArrayType           : ARRAYSY SubrangeType OFSY Type
		    ;

RecordType          : RECORDSY FieldListSequence OptSemi ENDSY
		    ;

SubrangeType        : LBRACKETSY ConstExpression DOTDOTSY ConstExpression 
			RBRACKETSY
		    ;

FieldListSequence   : FieldList
		    | FieldListSequence SEMICOLONSY FieldList
		    ;

FieldList           : IdentList COLONSY Type
		    ;

OptSemi             : SEMICOLONSY
		    | /* empty */
		    ;

StatementSequence   : Statement
		    | StatementSequence SEMICOLONSY Statement
		    ;

Statement           : Assignment 
                    | ProcedureCall 
                    | IfStatement
                    | WhileStatement 
                    | RepeatStatement 
                    | ForStatement 
                    | ReturnStatement
		    | ReadStatement
		    | WriteStatement
		    | /* empty */
		    ;

Assignment          : Designator ASSIGNSY Expression
		    ;

ProcedureCall       : QualIdent ActualParameters
		    ;

IfStatement         : IfHead ThenPart ElsifSequence ElseClause ENDSY
		    ;

IfHead		    : IFSY Expression
		    ;

ThenPart	    : THENSY StatementSequence
		    ;

ElsifSequence       : ElsifSequence ElsifHead THENSY StatementSequence
		    | /* empty */
		    ;

ElsifHead	    : ELSIFSY Expression
		    ;

ElseClause	    : ELSESY StatementSequence
		    | /* empty */
		    ;

WhileStatement      : WhileHead WhileExpression DOSY StatementSequence ENDSY
		    ;

WhileHead	    : WHILESY 
		    ;

WhileExpression	    : Expression
		    ;

RepeatStatement     : RepeatHead StatementSequence UNTILSY Expression
		    ;

RepeatHead	    : REPEATSY
		    ;

ForStatement        : ForHead ToHead ForExpression ByClause DOSY 
                        StatementSequence ENDSY
		    ;

ForHead		    : FORSY IDENTSY ASSIGNSY Expression
 		    ;

ToHead              : TOSY
       		    ;

ForExpression       : Expression
		    ;

ByClause	    : BYSY ConstExpression
		    | /* empty */
		    ;

ReturnStatement	    : RETURNSY OptExpression
                    ;

ReadStatement       : READSY LPARENSY Designator RPARENSY
		    ;

WriteStatement      : WRITESY LPARENSY Expression RPARENSY
		    | WRITELNSY 
		    ;

Designator	    : Designator LBRACKETSY ExpressionList RBRACKETSY
		    | Designator DOTSY IDENTSY
		    | IDENTSY
		    ;
ExpressionList      : Expression
		    | ExpressionList COMMASY Expression
		    ;
OptExpression	    : Expression
		    | /* empty */
		    ;

Expression          : Expression ORSY Expression
		    | Expression ANDSY Expression
		    | NOTSY Expression
		    | Expression EQSY Expression
		    | Expression NESY Expression
		    | Expression LESY Expression
		    | Expression GESY Expression
		    | Expression LTSY Expression
		    | Expression GTSY Expression
		    | Expression ADDSY Expression
		    | Expression MINUSSY Expression
		    | Expression TIMESSY Expression
		    | Expression DIVIDESY Expression
		    | Expression DIVSY Expression
		    | Expression MODSY Expression
		    | MINUSSY Expression %prec UNMINUSSY
                    | ADDSY Expression %prec UNMINUSSY
		    | LPARENSY Expression RPARENSY
		    | INTCONSTSY
		    | CHARCONSTSY
		    | STRINGCONSTSY
                    | IDENTSY LPARENSY OptExpressionList RPARENSY
		    | Designator
		    ;

ActualParameters    : LPARENSY OptExpressionList RPARENSY
		    | /* empty */
		    ;

OptExpressionList   : ExpressionList
		    | /* empty */
		    ;

QualIdent           : IDENTSY 
		    ;
%%

/***************************/
/*****     yyerror     *****/
/***************************/

yyerror ()
{
} /* yyerror */