pas.grm

! -----------------------------------------------------------------------
! Standard Pascal Grammar
! -----------------------------------------------------------------------


"Name"    = 'Pascal' 
"Version" = '1.0'
"Author"  = 'Ibrahim Sharaf' 
"About"   = 'PASCAL Compiler'

"Case Sensitive" = False
"Start Symbol"   = <Program>

{Hex Digit}      = {Digit} + [abcdefABCDEF]

{Id Head}        = {Letter} + [_]
{Id Tail}        = {Id Head} + {Digit}

{String Ch}      = {Printable} - ['']
{Char Ch}        = {Printable} - ['']

DecLiteral       = {digit}*
HexLiteral       = '$'{Hex Digit}
FloatLiteral     = {Digit}*'.'{Digit}+

StringLiteral    = ''( {String Ch} | '\'{Printable} )* ''
CharLiteral      = '' ( {Char Ch} | '\'{Printable} )''

id               = {Id Head}{Id Tail}*

<constant>         ::= DecLiteral
                     | StringLiteral
                     | FloatLiteral
                     | HexLiteral
                     | CharLiteral


!=========================================== Program

<Program> ::= <ProgramHeader> <Declarations> <CompoundStatement> '.'

<ProgramHeader> ::= PROGRAM id ';'
                  | PROGRAM id '(' <IdList> ')' ';'

<Declarations> ::= <ConstantDefinitions> <TypeDefinitions> <VariableDeclarations> <ProcedureDeclarations>

<ConstantDefinitions> ::= CONST <ConstantDefinitionList>
                        |  

<ConstantDefinitionList> ::= <ConstantDef>
                           | <ConstantDef> <ConstantDefinitionList>

<ConstantDef> ::= id '=' <constant> ';'

<TypeDefinitions> ::= TYPE <TypeDefinitionList>
                     |

<TypeDefinitionList> ::= <TypeDef>
                       | <TypeDef> <TypeDefinitionList>

<TypeDef> ::= id '=' <TypeSpecifier> ';'

<VariableDeclarations> ::= VAR <VariableDeclarationList>
                        | 

<VariableDeclarationList> ::= <VariableDec>
                            | <VariableDec> <VariableDeclarationList>

<VariableDec> ::= <IdList> ':' <TypeSpecifier> ';'

<ProcedureDeclarations> ::= <ProcedureDec> <ProcedureDeclarations>
                          | 

<ProcedureDec> ::= <ProcedureHeader> FORWARD ';'
                 | <ProcedureHeader> <Declarations> <CompoundStatement> ';'
                 | <FunctionHeader> FORWARD ';'
                 | <FunctionHeader> <Declarations> <CompoundStatement> ';'

<ProcedureHeader> ::= PROCEDURE id <Arguments> ';'

<FunctionHeader> ::= FUNCTION id <Arguments> ':' <TypeSpecifier> ';'

<Arguments> ::= '(' <ArgumentList> ')'
              | 

<ArgumentList> ::= <Arg>
                 | <Arg> ';' <ArgumentList>

<Arg> ::= <IdList> ':' <TypeSpecifier>
        | VAR <IdList> ':' <TypeSpecifier>

<CompoundStatement> ::= BEGIN <StatementList> END

<StatementList> ::= <Statement>
                  | <Statement> ';' <StatementList>

<Statement> ::= <CompoundStatement>
              | <AssignmentStatement>
              | <ProcedureCall>
              | <ForStatement>
              | <WhileStatement>
              | <IfStatement>
              | <CaseStatement>
              | <RepeatStatement>
              | 

<AssignmentStatement> ::= <Variable> ':=' <Expression>

<ProcedureCall> ::= id <Actuals>

<ForStatement> ::= FOR id ':=' <Expression> TO <Expression> DO <Statement>
                 | FOR id ':=' <Expression> DOWNTO <Expression> DO <Statement>

<WhileStatement> ::= WHILE <Expression> DO <Statement>

<IfStatement> ::= IF <Expression> THEN <Statement> ELSE <Statement>

<RepeatStatement> ::= REPEAT <StatementList> UNTIL <Expression>

<CaseStatement> ::= CASE <Expression> OF <CaseList> END

<CaseList> ::= <Case>
             | <Case> ';' <CaseList>

<Case> ::= <ConstantList> ':' <Statement>

<ConstantList> ::= <constant>
                 | <constant> ',' <ConstantList>

<Expression> ::= <SimpleExpression>
               | <SimpleExpression> '=' <SimpleExpression>
               | <SimpleExpression> '<>' <SimpleExpression>
               | <SimpleExpression> '<' <SimpleExpression>
               | <SimpleExpression> '<=' <SimpleExpression>
               | <SimpleExpression> '>' <SimpleExpression>
               | <SimpleExpression> '>=' <SimpleExpression>

<SimpleExpression> ::= <Term>
                    | <SimpleExpression> '+' <Term>
                    | <SimpleExpression> '-' <Term>
                    | <SimpleExpression> OR <Term>

<Term> ::= <Factor>
         | <Term> '*' <Factor>
         | <Term> '/' <Factor>
         | <Term> 'DIV' <Factor>
         | <Term> 'MOD' <Factor>
         | <Term> 'AND' <Factor>

<Factor> ::= '(' <Expression> ')'
           | '+' <Factor>
           | '-' <Factor>
           | NOT <Factor>
           | <constant>
           | <Variable>

<Actuals> ::= '(' <ExpressionList> ')'
            | 

<ExpressionList> ::= <Expression>
                   | <Expression> ',' <ExpressionList>

<Variable> ::= id
             | <Variable> '.' id
             | <Variable> '^'
             | <Variable> '[' <ExpressionList> ']'

<TypeSpecifier> ::= id
                  | '^' <TypeSpecifier>
                  | '(' <IdList> ')'
                  | <constant> '..' <constant>
                  | ARRAY '[' <DimensionList> ']' OF <TypeSpecifier>
                  | RECORD <FieldList> END
                  | FILE OF <TypeSpecifier>

<DimensionList> ::= <Dimension>
                  | <Dimension> ',' <DimensionList>

<Dimension> ::= <constant> '..' <constant>
              | id

<FieldList> ::= <Field>
              | <Field> ';' <FieldList>

<Field> ::= <IdList> ':' <TypeSpecifier>

<IdList> ::= id
           | id ',' <IdList>