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Also [[wp:Van Wijngaarden grammar|Van Wijngaarden's grammar]] can be used to define
[[Pascal]]'s grammar[http://www-users.cs.york.ac.uk/~fisher/software/yoyovwg/exs/pascal.vwg].
<div style="height:30ex;overflow:scroll"><pre>
! -----------------------------------------------------------------------
! Standard Pascal Grammar
! -----------------------------------------------------------------------
"Name" = 'Pascal'
"Version" = '1973'
"Author" = 'Niklaus Wirth'
"About" = 'PASCAL was developed by NIKLAUS WIRTH of the ETH Technical Institute of Zuerich in 1970-1971.(published in 1973)'
"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 = [123456789]{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>
<FunctionCall> ::= id <Actuals>
<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>
</pre></div>
=={{header|Perl}}==
|