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BNF Grammar: Difference between revisions
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{{DeprecatedTask}}
In computer science, Backus–Naur Form (BNF) is a metasyntax used to express context-free grammars: that is, a formal way to describe formal languages. John Backus and Peter Naur developed a context free grammar to define the syntax of a programming language by using two sets of rules: i.e., lexical rules and syntactic rules.
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There are many extensions and variants of BNF, including Extended and Augmented Backus–Naur Forms (EBNF and ABNF).
'''This is a deprecated task. Please move these grammars to the language's category page, or somewhere else.'''
==[[:Category:BASIC|BASIC]]==
<div style="height:30ex;overflow:scroll"><pre>
! -----------------------------------------------------------------------
! BASIC '64
Line 688 ⟶ 173:
| String
| Real
</pre></div>
==[[:Category:BASIC Commodore PET|BASIC Commodore PET]]==
<div style="height:30ex;overflow:scroll"><pre>
! -----------------------------------------------------------------------
! Commodore PET BASIC
!
! Beginner's All-purpose Symbolic Instruction Code
!
! "It is practically impossible to teach good programming style to students
! that have had prior exposure to BASIC; as potential programmers they are
! mentally mutilated beyond hope of regeneration."
!
! - Edsger W. Dijkstra
!
!
! BASIC is one of the oldest programming language and one of the most popular.
! It was developed in 1964 by John G. Kemeny and Thomas E. Kurtz to teach
! students the basics of programming concepts. At the advent of the microcomputer,
! BASIC was implemented on numerous platforms such as the Commodore, Atari,
! Apple II, Altair, IBM PC computers. Over time, BASIC evolved into GW-BASIC,
! QBasic, Visual Basic, and recently Visual Basic .NET.
!
! In practically all programming languages, the reserved word/symbol that denotes
! a comment is treated as a form of whitespace - having no effect in the manner in
! which the program runs. Once such type of comment is used to indicate the remainder
! of the line is to be ignored. These can be added to the end of any line without
! changing the meaning of the program. In C++, it is the '//' symbol.
!
! However, in the BASIC programming language, the line comment is treated like a
! statement. For instance, if 'REM' was a normal line comment:
!
! 10 PRINT "Hello World" REM Common first program
!
! would be a valid statement. However, in BASIC, this is illegal. In the example
! above, the comment must be added as an additional statement.
!
! 10 PRINT "Hello World" : REM Common first program
!
! As a result, the Line Comment terminal that is used in the GOLD Parser cannot be
! used here. In the grammar below, a 'Remark' terminal was created that accepts all
! series of printable characters starting with the characters "REM ". In some
! implementations of BASIC, any string starting with "REM" is a comment statement.
! Examples include "REMARK", "REMARKABLE" and "REMODEL". This grammar requires the space.
!
! -----------------------------------------------------------------------
"Name" = 'Commodore PET BASIC'
"Author" = 'Commodore Business Machines'
"Version" = '2.0'
"About" = 'This is the version of BASIC that was used on the Commodore 64.'
"Case Sensitive" = False
"Start Symbol" = <Lines>
{String Chars} = {Printable} - ["]
{WS} = {Whitespace} - {CR} - {LF}
NewLine = {CR}{LF}|{CR}
Whitespace = {WS}+
Remark = REM{Space}{Printable}*
ID = {Letter}{Alphanumeric}?[$%]? !IDs are can only have a maximum of 2 characters
FunctionID = FN {Letter}{Letter}?
String = '"'{String Chars}*'"'
Integer = {Digit}+
Real = {Digit}+'.'{Digit}+
<Lines> ::= <Lines> <Line>
| <Line>
<Line> ::= Integer <Statements> NewLine
<Statements> ::= <Statements> ':' <Statement>
| <Statement>
<Statement> ::= CLOSE Integer
| CLR
| CMD <Expression>
| CONT !Continue
| DATA <Constant List>
| DEF FunctionID '(' <ID List> ')' '=' <Expression> !The ID must start with FN
| DIM ID '(' <Expression List> ')'
| END
| FOR ID '=' <Expression> TO <Expression> <Step Opt>
| GET ID
| GET '#' Integer ',' ID
| GOSUB <Expression>
| GOTO <Expression>
| IF <Expression> THEN <Then Clause>
| INPUT <ID List>
| INPUT '#' Integer ',' <ID List>
| LET ID '=' <Expression>
| LIST <Line Range>
| LOAD <Value List>
| ID '=' <Expression>
| NEW
| NEXT <ID List>
| ON ID GOTO <Expression List>
| OPEN <Expression List>
| POKE <Expression> ',' <Expression>
| PRINT <Print list>
| PRINT '#' Integer ',' <Print List>
| READ <ID List>
| RETURN
| RESTORE
| RUN
| RUN <Expression>
| STOP
| SYS <Expression>
| WAIT <Expression List>
| VERIFY <Expression List>
| Remark
<Step Opt> ::= STEP <Expression>
|
<ID List> ::= ID ',' <ID List>
| ID
<Value List> ::= <Value> ',' <Value List>
| <Value>
<Constant List> ::= <Constant> ',' <Constant List>
| <Constant>
<Expression List> ::= <Expression> ',' <Expression List>
| <Expression>
<Print List> ::= <Expression> ';' <Print List>
| <Expression>
|
<Line Range> ::= Integer
| Integer '-'
| Integer '-' Integer
<Then Clause> ::= Integer
| <Statement>
! ----------------------------------------------- Expressions
<Expression> ::= <And Exp> OR <Expression>
| <And Exp>
<And Exp> ::= <Not Exp> AND <And Exp>
| <Not Exp>
<Not Exp> ::= NOT <Compare Exp>
| <Compare Exp>
<Compare Exp> ::= <Add Exp> '=' <Compare Exp>
| <Add Exp> '<>' <Compare Exp>
| <Add Exp> '>' <Compare Exp>
| <Add Exp> '>=' <Compare Exp>
| <Add Exp> '<' <Compare Exp>
| <Add Exp> '<=' <Compare Exp>
| <Add Exp>
<Add Exp> ::= <Mult Exp> '+' <Add Exp>
| <Mult Exp> '-' <Add Exp>
| <Mult Exp>
<Mult Exp> ::= <Negate Exp> '*' <Mult Exp>
| <Negate Exp> '/' <Mult Exp>
| <Negate Exp>
<Negate Exp> ::= '-' <Power Exp>
| <Power Exp>
<Power Exp> ::= <Power Exp> '^' <Sub Exp> !On the Commodore, the symbol was an up-arrow
| <Sub Exp>
<Sub Exp> ::= '(' <Expression> ')'
| <Value>
<Value> ::= ID
| ABS '(' <Expression> ')'
| ASC '(' <Expression> ')'
| ATN '(' <Expression> ')'
| 'CHR$' '(' <Expression> ')'
| COS '(' <Expression> ')'
| EXP '(' <Expression> ')'
| FunctionID '(' <Expression List> ')'
| FRE '(' <Value> ')' !The <Value> is irrelevant
| INT '(' <Expression> ')'
| 'LEFT$' '(' <Expression> ',' <Expression> ')'
| LEN '(' <Expression> ')'
| PEEK '(' <Expression> ')'
| POS '(' <Value> ')' !The <Value> is irrelevant
| 'RIGHT$' '(' <Expression> ',' <Expression> ')'
| RND '(' <Expression> ')'
| SGN '(' <Expression> ')'
| SPC '(' <Expression> ')'
| SQR '(' <Expression> ')'
| TAB '(' <Expression> ')'
| TAN '(' <Expression> ')'
| VAL '(' <Expression> ')'
| <Constant>
<Constant> ::= Integer
| String
| Real
</pre></div>
==[[:Category:Brainf***|Brainf***]]==
Code ::= Command Code | <NONE>
Command ::= "+" | "-" | "<" | ">" | "," | "." | "[" Code "]" | <ANY>
==[[:Category:PARI/GP|PARI/GP]]==
[http://pari.math.u-bordeaux.fr/cgi-bin/viewcvs.cgi/trunk/src/language/parse.y?view=markup&revision=12950&root=pari parse.y] contains a grammar for GP. The grammar for PARI is that of [http://c.comsci.us/syntax/ C].
==[[:Category:PowerShell|PowerShell]]==
An annotated version of the PowerShell grammar can be found in Bruce Payette's book ''Windows PowerShell in Action''. The appendix containing the grammar is available in [http://www.manning.com/payette/AppCexcerpt.pdf PDF form] on the publisher's site.
This grammar does not accurately represent the PowerShell language, though, as for example the <code>for</code> loop mandates semicolons in the grammar but in practice does not require them when arguments are omitted. The infinite loop may be represented by
<lang powershell>for () {}</lang>
but the grammar would require
<lang powershell>for (;;) {}</lang>
==[[:Category:VBScript|VBScript]]==
<div style="height:30ex;overflow:scroll"><pre>
!===============================
! VB Script grammar.
!
! To create the grammar I was using Microsoft's VB Script documentation
! available from http://msdn.microsoft.com/scripting,
! VB Script parser from ArrowHead project http://www.tripi.com/arrowhead/,
! and Visual Basic .Net grammar file written by Devin Cook.
!
! This grammar cannot cover all aspects of VBScript and may have some errors.
! Feel free to contact me if you find any flaws in the grammar.
!
! Vladimir Morozov vmoroz@hotmail.com
!
! Special thanks to Nathan Baulch for the grammar updates.
!
! USE GOLD PARSER BUILDER VERSION 2.1 AND LATER TO COMPILE THIS GRAMMAR.
!===============================
"Name" = 'VB Script'
"Author" = 'John G. Kemeny and Thomas E. Kurtz'
"Version" = '5.0'
"About" = 'VB Script grammar.'
"Case Sensitive" = False
"Start Symbol" = <Program>
!===============================
! Character sets
!===============================
{String Char} = {All Valid} - ["]
{Date Char} = {Printable} - [#]
{ID Name Char} = {Printable} - ['['']']
{Hex Digit} = {Digit} + [abcdef]
{Oct Digit} = [01234567]
{WS} = {Whitespace} - {CR} - {LF}
{ID Tail} = {Alphanumeric} + [_]
!===============================
! Terminals
!===============================
NewLine = {CR} {LF}
| {CR}
| {LF}
| ':'
! Special white space definition. Whitespace is either space or tab, which
! can be followed by continuation symbol '_' followed by new line character
Whitespace = {WS}+
| '_' {WS}* {CR}? {LF}?
! Special comment definition
Comment Line = ''
| 'Rem'
! Literals
StringLiteral = '"' ( {String Char} | '""' )* '"'
IntLiteral = {Digit}+
HexLiteral = '&H' {Hex Digit}+ '&'?
OctLiteral = '&' {Oct Digit}+ '&'?
FloatLiteral = {Digit}* '.' {Digit}+ ( 'E' [+-]? {Digit}+ )?
| {Digit}+ 'E' [+-]? {Digit}+
DateLiteral = '#' {Date Char}+ '#'
! Identifier is either starts with letter and followed by letter,
! number or underscore, or it can be escaped sequence of any printable
! characters ([] and [_$% :-) @] are valid identifiers)
ID = {Letter} {ID Tail}*
| '[' {ID Name Char}* ']'
! White space is not allowed to be before dot, but allowed to be after it.
IDDot = {Letter} {ID Tail}* '.'
| '[' {ID Name Char}* ']' '.'
| 'And.'
| 'ByRef.'
| 'ByVal.'
| 'Call.'
| 'Case.'
| 'Class.'
| 'Const.'
| 'Default.'
| 'Dim.'
| 'Do.'
| 'Each.'
| 'Else.'
| 'ElseIf.'
| 'Empty.'
| 'End.'
| 'Eqv.'
| 'Erase.'
| 'Error.'
| 'Exit.'
| 'Explicit.'
| 'False.'
| 'For.'
| 'Function.'
| 'Get.'
| 'GoTo.'
| 'If.'
| 'Imp.'
| 'In.'
| 'Is.'
| 'Let.'
| 'Loop.'
| 'Mod.'
| 'New.'
| 'Next.'
| 'Not.'
| 'Nothing.'
| 'Null.'
| 'On.'
| 'Option.'
| 'Or.'
| 'Preserve.'
| 'Private.'
| 'Property.'
| 'Public.'
| 'Redim.'
| 'Rem.'
| 'Resume.'
| 'Select.'
| 'Set.'
| 'Step.'
| 'Sub.'
| 'Then.'
| 'To.'
| 'True.'
| 'Until.'
| 'WEnd.'
| 'While.'
| 'With.'
| 'Xor.'
! The following identifiers should only be used in With statement.
! This rule must be checked by contextual analyzer.
DotID = '.' {Letter} {ID Tail}*
| '.' '[' {ID Name Char}* ']'
| '.And'
| '.ByRef'
| '.ByVal'
| '.Call'
| '.Case'
| '.Class'
| '.Const'
| '.Default'
| '.Dim'
| '.Do'
| '.Each'
| '.Else'
| '.ElseIf'
| '.Empty'
| '.End'
| '.Eqv'
| '.Erase'
| '.Error'
| '.Exit'
| '.Explicit'
| '.False'
| '.For'
| '.Function'
| '.Get'
| '.GoTo'
| '.If'
| '.Imp'
| '.In'
| '.Is'
| '.Let'
| '.Loop'
| '.Mod'
| '.New'
| '.Next'
| '.Not'
| '.Nothing'
| '.Null'
| '.On'
| '.Option'
| '.Or'
| '.Preserve'
| '.Private'
| '.Property'
| '.Public'
| '.Redim'
| '.Rem'
| '.Resume'
| '.Select'
| '.Set'
| '.Step'
| '.Sub'
| '.Then'
| '.To'
| '.True'
| '.Until'
| '.WEnd'
| '.While'
| '.With'
| '.Xor'
DotIDDot = '.' {Letter}{ID Tail}* '.'
| '.' '[' {ID Name Char}* ']' '.'
| '.And.'
| '.ByRef.'
| '.ByVal.'
| '.Call.'
| '.Case.'
| '.Class.'
| '.Const.'
| '.Default.'
| '.Dim.'
| '.Do.'
| '.Each.'
| '.Else.'
| '.ElseIf.'
| '.Empty.'
| '.End.'
| '.Eqv.'
| '.Erase.'
| '.Error.'
| '.Exit.'
| '.Explicit.'
| '.False.'
| '.For.'
| '.Function.'
| '.Get.'
| '.GoTo.'
| '.If.'
| '.Imp.'
| '.In.'
| '.Is.'
| '.Let.'
| '.Loop.'
| '.Mod.'
| '.New.'
| '.Next.'
| '.Not.'
| '.Nothing.'
| '.Null.'
| '.On.'
| '.Option.'
| '.Or.'
| '.Preserve.'
| '.Private.'
| '.Property.'
| '.Public.'
| '.Redim.'
| '.Rem.'
| '.Resume.'
| '.Select.'
| '.Set.'
| '.Step.'
| '.Sub.'
| '.Then.'
| '.To.'
| '.True.'
| '.Until.'
| '.WEnd.'
| '.While.'
| '.With.'
| '.Xor.'
!===============================
! Rules
!===============================
<NL> ::= NewLine <NL>
| NewLine
<Program> ::= <NLOpt> <GlobalStmtList>
!===============================
! Rules : Declarations
!===============================
<ClassDecl> ::= 'Class' <ExtendedID> <NL> <MemberDeclList> 'End' 'Class' <NL>
<MemberDeclList> ::= <MemberDecl> <MemberDeclList>
|
<MemberDecl> ::= <FieldDecl>
| <VarDecl>
| <ConstDecl>
| <SubDecl>
| <FunctionDecl>
| <PropertyDecl>
<FieldDecl> ::= 'Private' <FieldName> <OtherVarsOpt> <NL>
| 'Public' <FieldName> <OtherVarsOpt> <NL>
<FieldName> ::= <FieldID> '(' <ArrayRankList> ')'
| <FieldID>
<FieldID> ::= ID
| 'Default'
| 'Erase'
| 'Error'
| 'Explicit'
| 'Step'
<VarDecl> ::= 'Dim' <VarName> <OtherVarsOpt> <NL>
<VarName> ::= <ExtendedID> '(' <ArrayRankList> ')'
| <ExtendedID>
<OtherVarsOpt> ::= ',' <VarName> <OtherVarsOpt>
|
<ArrayRankList> ::= <IntLiteral> ',' <ArrayRankList>
| <IntLiteral>
|
<ConstDecl> ::= <AccessModifierOpt> 'Const' <ConstList> <NL>
<ConstList> ::= <ExtendedID> '=' <ConstExprDef> ',' <ConstList>
| <ExtendedID> '=' <ConstExprDef>
<ConstExprDef> ::= '(' <ConstExprDef> ')'
| '-' <ConstExprDef>
| '+' <ConstExprDef>
| <ConstExpr>
<SubDecl> ::= <MethodAccessOpt> 'Sub' <ExtendedID> <MethodArgList> <NL> <MethodStmtList> 'End' 'Sub' <NL>
| <MethodAccessOpt> 'Sub' <ExtendedID> <MethodArgList> <InlineStmt> 'End' 'Sub' <NL>
<FunctionDecl> ::= <MethodAccessOpt> 'Function' <ExtendedID> <MethodArgList> <NL> <MethodStmtList> 'End' 'Function' <NL>
| <MethodAccessOpt> 'Function' <ExtendedID> <MethodArgList> <InlineStmt> 'End' 'Function' <NL>
<MethodAccessOpt> ::= 'Public' 'Default'
| <AccessModifierOpt>
<AccessModifierOpt> ::= 'Public'
| 'Private'
|
<MethodArgList> ::= '(' <ArgList> ')'
| '(' ')'
|
<ArgList> ::= <Arg> ',' <ArgList>
| <Arg>
<Arg> ::= <ArgModifierOpt> <ExtendedID> '(' ')'
| <ArgModifierOpt> <ExtendedID>
<ArgModifierOpt> ::= 'ByVal'
| 'ByRef'
|
<PropertyDecl> ::= <MethodAccessOpt> 'Property' <PropertyAccessType> <ExtendedID> <MethodArgList> <NL> <MethodStmtList> 'End' 'Property' <NL>
<PropertyAccessType> ::= 'Get'
| 'Let'
| 'Set'
!===============================
! Rules : Statements
!===============================
<GlobalStmt> ::= <OptionExplicit>
| <ClassDecl>
| <FieldDecl>
| <ConstDecl>
| <SubDecl>
| <FunctionDecl>
| <BlockStmt>
<MethodStmt> ::= <ConstDecl>
| <BlockStmt>
<BlockStmt> ::= <VarDecl>
| <RedimStmt>
| <IfStmt>
| <WithStmt>
| <SelectStmt>
| <LoopStmt>
| <ForStmt>
| <InlineStmt> <NL>
<InlineStmt> ::= <AssignStmt>
| <CallStmt>
| <SubCallStmt>
| <ErrorStmt>
| <ExitStmt>
| 'Erase' <ExtendedID>
<GlobalStmtList> ::= <GlobalStmt> <GlobalStmtList>
|
<MethodStmtList> ::= <MethodStmt> <MethodStmtList>
|
<BlockStmtList> ::= <BlockStmt> <BlockStmtList>
|
<OptionExplicit> ::= 'Option' 'Explicit' <NL>
<ErrorStmt> ::= 'On' 'Error' 'Resume' 'Next'
| 'On' 'Error' 'GoTo' IntLiteral ! must be 0
<ExitStmt> ::= 'Exit' 'Do'
| 'Exit' 'For'
| 'Exit' 'Function'
| 'Exit' 'Property'
| 'Exit' 'Sub'
<AssignStmt> ::= <LeftExpr> '=' <Expr>
| 'Set' <LeftExpr> '=' <Expr>
| 'Set' <LeftExpr> '=' 'New' <LeftExpr>
! Hack: VB Script allows to have construct a = b = c, which means a = (b = c)
! In this grammar we do not allow it in order to prevent complications with
! interpretation of a(1) = 2, which may be considered as array element assignment
! or a subroutine call: a ((1) = 2).
! Note: VBScript allows to have missed parameters: a ,,2,3,
! VM: If somebody knows a better way to do it, please let me know
<SubCallStmt> ::= <QualifiedID> <SubSafeExprOpt> <CommaExprList>
| <QualifiedID> <SubSafeExprOpt>
| <QualifiedID> '(' <Expr> ')' <CommaExprList>
| <QualifiedID> '(' <Expr> ')'
| <QualifiedID> '(' ')'
| <QualifiedID> <IndexOrParamsList> '.' <LeftExprTail> <SubSafeExprOpt> <CommaExprList>
| <QualifiedID> <IndexOrParamsListDot> <LeftExprTail> <SubSafeExprOpt> <CommaExprList>
| <QualifiedID> <IndexOrParamsList> '.' <LeftExprTail> <SubSafeExprOpt>
| <QualifiedID> <IndexOrParamsListDot> <LeftExprTail> <SubSafeExprOpt>
! This very simplified case - the problem is that we cannot use parenthesis in aaa(bbb).ccc (ddd)
<SubSafeExprOpt> ::= <SubSafeExpr>
|
<CallStmt> ::= 'Call' <LeftExpr>
<LeftExpr> ::= <QualifiedID> <IndexOrParamsList> '.' <LeftExprTail>
| <QualifiedID> <IndexOrParamsListDot> <LeftExprTail>
| <QualifiedID> <IndexOrParamsList>
| <QualifiedID>
| <SafeKeywordID>
<LeftExprTail> ::= <QualifiedIDTail> <IndexOrParamsList> '.' <LeftExprTail>
| <QualifiedIDTail> <IndexOrParamsListDot> <LeftExprTail>
| <QualifiedIDTail> <IndexOrParamsList>
| <QualifiedIDTail>
! VB Script does not allow to have space between Identifier and dot:
! a . b - Error ; a. b or a.b - OK
<QualifiedID> ::= IDDot <QualifiedIDTail>
| DotIDDot <QualifiedIDTail>
| ID
| DotID
<QualifiedIDTail> ::= IDDot <QualifiedIDTail>
| ID
| <KeywordID>
<KeywordID> ::= <SafeKeywordID>
| 'And'
| 'ByRef'
| 'ByVal'
| 'Call'
| 'Case'
| 'Class'
| 'Const'
| 'Dim'
| 'Do'
| 'Each'
| 'Else'
| 'ElseIf'
| 'Empty'
| 'End'
| 'Eqv'
| 'Exit'
| 'False'
| 'For'
| 'Function'
| 'Get'
| 'GoTo'
| 'If'
| 'Imp'
| 'In'
| 'Is'
| 'Let'
| 'Loop'
| 'Mod'
| 'New'
| 'Next'
| 'Not'
| 'Nothing'
| 'Null'
| 'On'
| 'Option'
| 'Or'
| 'Preserve'
| 'Private'
| 'Public'
| 'Redim'
| 'Resume'
| 'Select'
| 'Set'
| 'Sub'
| 'Then'
| 'To'
| 'True'
| 'Until'
| 'WEnd'
| 'While'
| 'With'
| 'Xor'
<SafeKeywordID> ::= 'Default'
| 'Erase'
| 'Error'
| 'Explicit'
| 'Property'
| 'Step'
<ExtendedID> ::= <SafeKeywordID>
| ID
<IndexOrParamsList> ::= <IndexOrParams> <IndexOrParamsList>
| <IndexOrParams>
<IndexOrParams> ::= '(' <Expr> <CommaExprList> ')'
| '(' <CommaExprList> ')'
| '(' <Expr> ')'
| '(' ')'
<IndexOrParamsListDot> ::= <IndexOrParams> <IndexOrParamsListDot>
| <IndexOrParamsDot>
<IndexOrParamsDot> ::= '(' <Expr> <CommaExprList> ').'
| '(' <CommaExprList> ').'
| '(' <Expr> ').'
| '(' ').'
<CommaExprList> ::= ',' <Expr> <CommaExprList>
| ',' <CommaExprList>
| ',' <Expr>
| ','
!========= Redim Statement
<RedimStmt> ::= 'Redim' <RedimDeclList> <NL>
| 'Redim' 'Preserve' <RedimDeclList> <NL>
<RedimDeclList> ::= <RedimDecl> ',' <RedimDeclList>
| <RedimDecl>
<RedimDecl> ::= <ExtendedID> '(' <ExprList> ')'
!========= If Statement
<IfStmt> ::= 'If' <Expr> 'Then' <NL> <BlockStmtList> <ElseStmtList> 'End' 'If' <NL>
| 'If' <Expr> 'Then' <InlineStmt> <ElseOpt> <EndIfOpt> <NL>
<ElseStmtList> ::= 'ElseIf' <Expr> 'Then' <NL> <BlockStmtList> <ElseStmtList>
| 'ElseIf' <Expr> 'Then' <InlineStmt> <NL> <ElseStmtList>
| 'Else' <InlineStmt> <NL>
| 'Else' <NL> <BlockStmtList>
|
<ElseOpt> ::= 'Else' <InlineStmt>
|
<EndIfOpt> ::= 'End' 'If'
|
!========= With Statement
<WithStmt> ::= 'With' <Expr> <NL> <BlockStmtList> 'End' 'With' <NL>
!========= Loop Statement
<LoopStmt> ::= 'Do' <LoopType> <Expr> <NL> <BlockStmtList> 'Loop' <NL>
| 'Do' <NL> <BlockStmtList> 'Loop' <LoopType> <Expr> <NL>
| 'Do' <NL> <BlockStmtList> 'Loop' <NL>
| 'While' <Expr> <NL> <BlockStmtList> 'WEnd' <NL>
<LoopType> ::= 'While'
| 'Until'
!========= For Statement
<ForStmt> ::= 'For' <ExtendedID> '=' <Expr> 'To' <Expr> <StepOpt> <NL> <BlockStmtList> 'Next' <NL>
| 'For' 'Each' <ExtendedID> 'In' <Expr> <NL> <BlockStmtList> 'Next' <NL>
<StepOpt> ::= 'Step' <Expr>
|
!========= Select Statement
<SelectStmt> ::= 'Select' 'Case' <Expr> <NL> <CaseStmtList> 'End' 'Select' <NL>
<CaseStmtList> ::= 'Case' <ExprList> <NLOpt> <BlockStmtList> <CaseStmtList>
| 'Case' 'Else' <NLOpt> <BlockStmtList>
|
<NLOpt> ::= <NL>
|
<ExprList> ::= <Expr> ',' <ExprList>
| <Expr>
!===============================
! Rules : Expressions
!===============================
<SubSafeExpr> ::= <SubSafeImpExpr>
<SubSafeImpExpr> ::= <SubSafeImpExpr> 'Imp' <EqvExpr>
| <SubSafeEqvExpr>
<SubSafeEqvExpr> ::= <SubSafeEqvExpr> 'Eqv' <XorExpr>
| <SubSafeXorExpr>
<SubSafeXorExpr> ::= <SubSafeXorExpr> 'Xor' <OrExpr>
| <SubSafeOrExpr>
<SubSafeOrExpr> ::= <SubSafeOrExpr> 'Or' <AndExpr>
| <SubSafeAndExpr>
<SubSafeAndExpr> ::= <SubSafeAndExpr> 'And' <NotExpr>
| <SubSafeNotExpr>
<SubSafeNotExpr> ::= 'Not' <NotExpr>
| <SubSafeCompareExpr>
<SubSafeCompareExpr> ::= <SubSafeCompareExpr> 'Is' <ConcatExpr>
| <SubSafeCompareExpr> 'Is' 'Not' <ConcatExpr>
| <SubSafeCompareExpr> '>=' <ConcatExpr>
| <SubSafeCompareExpr> '=>' <ConcatExpr>
| <SubSafeCompareExpr> '<=' <ConcatExpr>
| <SubSafeCompareExpr> '=<' <ConcatExpr>
| <SubSafeCompareExpr> '>' <ConcatExpr>
| <SubSafeCompareExpr> '<' <ConcatExpr>
| <SubSafeCompareExpr> '<>' <ConcatExpr>
| <SubSafeCompareExpr> '=' <ConcatExpr>
| <SubSafeConcatExpr>
<SubSafeConcatExpr> ::= <SubSafeConcatExpr> '&' <AddExpr>
| <SubSafeAddExpr>
<SubSafeAddExpr> ::= <SubSafeAddExpr> '+' <ModExpr>
| <SubSafeAddExpr> '-' <ModExpr>
| <SubSafeModExpr>
<SubSafeModExpr> ::= <SubSafeModExpr> 'Mod' <IntDivExpr>
| <SubSafeIntDivExpr>
<SubSafeIntDivExpr> ::= <SubSafeIntDivExpr> '\' <MultExpr>
| <SubSafeMultExpr>
<SubSafeMultExpr> ::= <SubSafeMultExpr> '*' <UnaryExpr>
| <SubSafeMultExpr> '/' <UnaryExpr>
| <SubSafeUnaryExpr>
<SubSafeUnaryExpr> ::= '-' <UnaryExpr>
| '+' <UnaryExpr>
| <SubSafeExpExpr>
<SubSafeExpExpr> ::= <SubSafeValue> '^' <ExpExpr>
| <SubSafeValue>
<SubSafeValue> ::= <ConstExpr>
| <LeftExpr>
! | '(' <Expr> ')'
<Expr> ::= <ImpExpr>
<ImpExpr> ::= <ImpExpr> 'Imp' <EqvExpr>
| <EqvExpr>
<EqvExpr> ::= <EqvExpr> 'Eqv' <XorExpr>
| <XorExpr>
<XorExpr> ::= <XorExpr> 'Xor' <OrExpr>
| <OrExpr>
<OrExpr> ::= <OrExpr> 'Or' <AndExpr>
| <AndExpr>
<AndExpr> ::= <AndExpr> 'And' <NotExpr>
| <NotExpr>
<NotExpr> ::= 'Not' <NotExpr>
| <CompareExpr>
<CompareExpr> ::= <CompareExpr> 'Is' <ConcatExpr>
| <CompareExpr> 'Is' 'Not' <ConcatExpr>
| <CompareExpr> '>=' <ConcatExpr>
| <CompareExpr> '=>' <ConcatExpr>
| <CompareExpr> '<=' <ConcatExpr>
| <CompareExpr> '=<' <ConcatExpr>
| <CompareExpr> '>' <ConcatExpr>
| <CompareExpr> '<' <ConcatExpr>
| <CompareExpr> '<>' <ConcatExpr>
| <CompareExpr> '=' <ConcatExpr>
| <ConcatExpr>
<ConcatExpr> ::= <ConcatExpr> '&' <AddExpr>
| <AddExpr>
<AddExpr> ::= <AddExpr> '+' <ModExpr>
| <AddExpr> '-' <ModExpr>
| <ModExpr>
<ModExpr> ::= <ModExpr> 'Mod' <IntDivExpr>
| <IntDivExpr>
<IntDivExpr> ::= <IntDivExpr> '\' <MultExpr>
| <MultExpr>
<MultExpr> ::= <MultExpr> '*' <UnaryExpr>
| <MultExpr> '/' <UnaryExpr>
| <UnaryExpr>
<UnaryExpr> ::= '-' <UnaryExpr>
| '+' <UnaryExpr>
| <ExpExpr>
<ExpExpr> ::= <Value> '^' <ExpExpr>
| <Value>
<Value> ::= <ConstExpr>
| <LeftExpr>
| '(' <Expr> ')'
<ConstExpr> ::= <BoolLiteral>
| <IntLiteral>
| FloatLiteral
| StringLiteral
| DateLiteral
| <Nothing>
<BoolLiteral> ::= 'True'
| 'False'
<IntLiteral> ::= IntLiteral
| HexLiteral
| OctLiteral
<Nothing> ::= 'Nothing'
| 'Null'
| 'Empty'
</pre></div>
==[[:Category:Visual Basic .NET|Visual Basic .NET]]==
The following link (Appedix B) has a simple BNF Syntax [http://laser.physics.sunysb.edu/~amol/papers/mollypaper.pdf VB Syntax]
<div style="height:30ex;overflow:scroll"><pre>
! -----------------------------------------------------------------------
! Visual Basic .NET
!
! Visual Basic .NET is the latest version in the long evoluation of the
! BASIC programming language. The Visual Basic .NET programming language
! is far more "clean" and orthagonal than its predecessors. Although some
! of the old constructs exist, the language is far easier to read and write.
!
! Major syntax changes include, but are not limited to:
!
! 1. The primative file access of VB6 was replaced by a class library. As
! a result, special statements such as
!
! Open "test" For Input As #1
!
! no longer exist.
!
! 2. Class module files were replaced by 'Class ... End Class' declarations
!
! 3. Module files were replaced by 'Module ... End Module' declarations
!
! 4. Structured error handling was added with C++ style Try ... Catch
! statements. The old nonstructured approach is still, unfortunately,
! available.
!
! Unfortnately, the designers of Visual Basic .NET did not remove the
! datatype postfix characters on identifiers. In the original BASIC,
! variables types were determined by $ for strings and % for integers.
! QuickBasic expanded the postix notation to include other symbols
! for long integers, singles, etc...
!
! Part of the ID terminal definition was commented out to prevent the
! old format. You can allow the postfix characters if you like.
!
! This grammar also does not contain the compiler directives.
!
! Note: This is an ad hoc version of the language. If there are any flaws,
! please visit www.DevinCook.com/GOLDParser
!
! Updates:
! 04/082005
! Devin Cook
! 1. Removed minus sign from the IntLiteral and RealLiteral
! definitions. These can cause some parse errors when expressions
! like "2-2" are read. In this case it would have been interpreted
! as "2" and "-2" rather than "2", "-" and "2".
! 2. Members of an enumeration can be defined with any expression.
! 3. Made some very minor comment changes - mainly for readability.
!
!
! Adrian Moore [adrianrob@hotmail.com]
! 1. Add support for Implements in Class
! 2. Add support for AddressOf keyword
! 3. No longer fails if variable starts with _
!
!
! Vladimir Morozov [vmoroz@hotmail.com] fixed a few flaws in the
! grammar. 1. The definition for strings did not allow the double
! double-quote override. 2. A real literal does not need to have a
! fraction if followed by an exponent. 3. Escaped identifiers can
! contain a null string and 4. Rem works the same as the '
!
!
! USE GOLD PARSER BUILDER VERSION 2.1 AND LATER TO COMPILE THIS GRAMMAR.
! Earlier versions cannot handle the complexity.
! -----------------------------------------------------------------------
"Name" = 'Visual Basic .NET'
"Author" = 'John G. Kemeny and Thomas E. Kurtz'
"Version" = '.NET'
"About" = 'Visual Basic .NET is the latest version in the long evoluation of the'
| 'BASIC programming language.'
"Case Sensitive" = False
"Start Symbol" = <Program>
! ----------------------------------------------------------------- Sets
{
{
{ID Name Chars} = {Printable} - ['['']']
{Hex Digit} = {Digit} + [abcdef]
{Oct Digit} = [01234567]
{
{Id Tail}
! ----------------------------------------------------------------- Terminals
NewLine = {CR}{LF} | {CR} | ':'
Comment Line = '' | Rem !Fixed by Vladimir Morozov
!Fixed by Vladimir Morozov
ID = [_]?{Letter}{ID Tail}* ! [%&@!#$]? !Archaic postfix chars
| '[' {ID Name Chars}* ']'
QualifiedID = ({Letter}{ID Tail}* | '['{ID Name Chars}*']') ( '.'({Letter}{ID Tail}* | '['{ID Name Chars}*']') )+
MemberID = '.' {Letter}{ID Tail}*
| '.[' {ID Name Chars}* ']'
!Fixed by Vladimir Morozov
StringLiteral = '"' ( {String Chars} | '""' )* '"'
CharLiteral = '"' {String Chars}* '"C'
IntLiteral = {digit}+ [FRDSIL]?
RealLiteral = {digit}* '.' {digit}+ ( 'E' [+-]? {Digit}+ )? [FR]?
| {digit}+ 'E' [+-]? {Digit}+ [FR]?
DateLiteral = '#'{Date chars}'#'
HexLiteral = '&H'{Hex Digit}+ [SIL]?
OctLiteral = '&O'{Oct Digit}+ [SIL]?
! ----------------------------------------------------------------- Rules
<Program> ::= <NameSpace Item> <Program>
| <Imports> <Program>
| <Option Decl> <Program>
|
! -------------------------------------------------------------------
! (Shared attributes)
! -------------------------------------------------------------------
<NL> ::= NewLine <NL>
| NewLine
<Modifiers> ::= <Modifier> <Modifiers>
|
<Modifier> ::= Shadows
| Shared
| MustInherit
| NotInheritable
| Overridable
| NotOverridable
| MustOverride
| Overrides
| Overloads
| Default
| ReadOnly
| WriteOnly
| <Access>
<Access Opt> ::= <Access>
|
<Access> ::= Public
| Private
| Friend
| Protected
<Var Member> ::= <Attributes> <Access> <Var Decl> <NL> !Variables
| <Attributes> <Access Opt> Const <Var Decl> <NL> !Constants
| <Attributes> <Access Opt> Static <Var Decl> <NL>
<Implements> ::= Implements <ID List>
<ID List> ::= <Identifier> ',' <ID List>
| <Identifier>
<Option Decl> ::= Option <IDs> <NL>
<IDs> ::= ID <IDs>
| ID
<Type> ::= As <Attributes> <Identifier>
|
<Compare Op> ::= '=' | '<>' | '<' | '>' | '>=' | '<='
! -------------------------------------------------------------------
! NameSpace
! -------------------------------------------------------------------
<
<NameSpace Items> ::= <NameSpace Item> <NameSpace Items>
|
<
| <
| <Delegate>
| <Enumeration>
| <Interface>
| <Structure>
| <Module>
| <Namespace>
! -------------------------------------------------------------------
! Attributes
! -------------------------------------------------------------------
<Attributes> ::= '<' <Attribute List> '>'
|
<Attribute List> ::= <Attribute> ',' <Attribute List>
| <Attribute>
<Attribute> ::= <Attribute Mod> ID <Argument List Opt>
<Attribute Mod> ::= Assembly
| Module
|
! -------------------------------------------------------------------
! Delegates
! -------------------------------------------------------------------
<Delegate> ::= <Attributes> <Modifiers> Delegate <Method>
| <Attributes> <Modifiers> Delegate <Declare>
! -------------------------------------------------------------------
! Imports
! -------------------------------------------------------------------
<Imports> ::= Imports <Identifier> <NL>
| Imports ID '=' <Identifier> <NL>
! -------------------------------------------------------------------
! Events
! -------------------------------------------------------------------
<Event Member> ::= <Attributes> <Modifiers> Event ID <Parameters Or Type> <Implements Opt> <NL>
<Parameters Or Type> ::= <Param List>
| As <Identifier>
<Implements Opt> ::= <Implements>
|
! -------------------------------------------------------------------
! Class
! -------------------------------------------------------------------
<Class> ::= <Attributes> <Modifiers> Class ID <NL> <Class Items> End Class <NL>
<Class Items> ::= <Class Item> <Class Items>
|
<Class Item> ::= <Declare>
| <Method>
| <Property>
| <Var Member>
| <Enumeration>
| <Inherits>
| <Class Implements>
<Inherits> ::= Inherits <Identifier> <NL>
<
! -------------------------------------------------------------------
! Structures
! -------------------------------------------------------------------
<Structure> ::= <Attributes> <Modifiers> Structure ID <NL> <Structure List> End Structure <NL>
<Structure List> ::= <Structure Item> <Structure List>
|
<Structure Item> ::= <Implements>
| <Enumeration>
| <Structure>
| <Class>
| <Delegate>
| <Var Member>
| <Event Member>
| <Declare>
| <Method>
| <Property>
! -------------------------------------------------------------------
! Module
! -------------------------------------------------------------------
<Module> ::= <Attributes> <Modifiers> Module ID <NL> <Module Items> End Module <NL>
<Module Items> ::= <Module Item> <Module Items>
|
<Module Item> ::= <Declare>
| <Method>
| <Property>
| <Var Member>
| <Enumeration>
| <Option Decl>
! -------------------------------------------------------------------
! Interface
! -------------------------------------------------------------------
<Interface> ::= <Attributes> <Modifiers> Interface ID <NL> <Interface Items> End Interface <NL>
<Interface Items> ::= <Interface Item> <Interface Items>
|
<
| <
| <Enum Member>
| <Method Member>
|
<
<Method Member> ::= <Attributes> <Modifiers> Sub <Sub ID> <Param List> <Handles Or Implements> <NL>
| <Attributes> <Modifiers> Function ID <Param List> <Type> <Handles Or Implements> <NL>
<Property Member> ::= <Attributes> <Modifiers> Property ID <Param List> <Type> <Handles Or Implements> <NL>
! -------------------------------------------------------------------
! Parameters
! -------------------------------------------------------------------
<Param List Opt> ::= <Param List>
|
<
| '(' ')'
<Param Items> ::= <Param Item> ',' <Param Items>
| <Param Item>
<Param Item> ::= <Param Passing> ID <Type>
<Param Passing> ::= ByVal
| ByRef
| Optional
| ParamArray
|
! -------------------------------------------------------------------
! Arguments
! -------------------------------------------------------------------
<
<Argument List> ::= '(' <Argument Items> ')'
<Argument Items> ::= <Argument> ',' <Argument Items>
| <Argument>
<Argument> ::= <Expression>
| Id ':=' <Expression>
| !NULL
! -------------------------------------------------------------------
! Declares (External Procedures)
! -------------------------------------------------------------------
<Declare> ::= <Attributes> <Modifiers> Declare <Charset> Sub ID Lib StringLiteral <Alias> <Param List Opt> <NL>
| <Attributes> <Modifiers> Declare <Charset> Function ID Lib StringLiteral <Alias> <Param List Opt> <Type> <NL>
<Charset> ::= Ansi | Unicode | Auto | !Null
<Alias> ::= Alias StringLiteral
|
! -------------------------------------------------------------------
! Methods
! -------------------------------------------------------------------
<Method> ::= <Attributes> <Modifiers> Sub <Sub ID> <Param List> <Handles Or Implements> <NL> <Statements> End Sub <NL>
| <Attributes> <Modifiers> Function ID <Param List> <Type> <Handles Or Implements> <NL> <Statements> End Function <NL>
<Sub ID> ::= ID
| New !Class creation
<Handles Or Implements> ::= <Implements>
| <Handles>
|
<Handles> ::= Handles <ID List>
! -------------------------------------------------------------------
! Properties
! -------------------------------------------------------------------
<Property> ::= <Attributes> <Modifiers> Property ID <Param List> <Type> <NL> <Property Items> End Property <NL>
<Property Items> ::= <Property Item> <Property Items>
|
<
| Set <Param List> <NL> <Statements> End Set <NL>
! -------------------------------------------------------------------
! Enumerations
! -------------------------------------------------------------------
<
<Enum
|
<Enum Item> ::= Id '=' <Expression> <NL>
| Id <NL>
! -------------------------------------------------------------------
! Variable Declaration
! -------------------------------------------------------------------
<
| <Var Decl Item>
<Var Decl Item> ::= <Var Decl ID> As <Identifier> <Argument List Opt>
| <Var Decl ID> As <Identifier> '=' <Expression> !Initialize
| <Var Decl ID> As New <Identifier> <Argument List Opt>
| <Var Decl ID>
| <Var Decl ID> '=' <Expression> !Initialize
<
! -------------------------------------------------------------------
! Normal Statements
! -------------------------------------------------------------------
<Statements> ::= <Statement> <Statements>
|
<
|
| <If Stm>
| <Select Stm>
| <SyncLock Stm>
| <Try Stm>
| <With Stm>
| <Option Decl>
| <Local Decl>
| <Non-Block Stm> <NL> !Note the <NL>. A non-block statement can be a full statement
| LABEL <NL>
<Non-Block Stm> ::= Call <Variable>
| ReDim <Var Decl>
| ReDim Preserve <Var Decl>
| Erase ID
| Throw <Value>
| RaiseEvent <Identifier> <Argument List Opt>
| AddHandler <Expression> ',' <Expression>
| RemoveHandler <Expression> ',' <Expression>
| Exit Do
| Exit For
| Exit Function
| Exit Property
| Exit Select
| Exit Sub
| Exit Try
| Exit While
| GoTo ID !Argh - they still have this
| Return <Value>
| Error <Value> !Raise an error by number
| On Error GoTo IntLiteral ! 0 This is obsolete.
| On Error GoTo '-' IntLiteral !-1 This is obsolete.
|
|
|
|
| <Variable>
| <Method Call>
<Assign Op> ::= '=' | '^=' | '*=' | '/=' | '\=' | '+=' | '-=' | '&=' | '<<=' | '>>='
! -------------------------------------------------------------------
! Local declarations
! -------------------------------------------------------------------
<
|
|
! -------------------------------------------------------------------
! Do Statement
! -------------------------------------------------------------------
<Loop Stm> ::= Do <Test Type> <Expression> <NL> <Statements> Loop <NL>
| Do <NL> <Statements> Loop <Test Type> <Expression> <NL>
| While <Expression> <NL> <Statements> End While <NL>
<
| Until
! -------------------------------------------------------------------
! For Statement
! -------------------------------------------------------------------
<For Stm> ::= For <Identifier> '=' <Expression> To <Expression> <Step Opt> <NL> <Statements> Next <NL>
| For Each <Variable> In <Variable> <NL> <Statements> Next <NL>
<Step Opt> ::= Step <Expression>
|
! -------------------------------------------------------------------
! If Statement
! -------------------------------------------------------------------
<If Stm> ::= If <Expression> <Then Opt> <NL> <Statements> <If Blocks> End If <NL>
| If <Expression> Then <Non-Block Stm> <NL>
| If <Expression> Then <Non-Block Stm> Else <Non-Block Stm> <NL>
<Then Opt> ::= Then !!The reserved word 'Then' is optional for Block-If statements
|
<If Blocks> ::= ElseIf <Expression> <Then Opt> <NL> <Statements> <If Blocks>
|
! -------------------------------------------------------------------
! Select Statement
! -------------------------------------------------------------------
<
<Case Opt> ::= Case !!The "Case" after Select is optional in VB.NEt
<
| Case Else <
|
<
| <
<
| <
| <Expression> To <Expression>
<Is Opt> ::= Is
! -------------------------------------------------------------------
! SyncLock Statement
! -------------------------------------------------------------------
<SyncLock Stm> ::= SyncLock <NL> <Statements> End SyncLock <NL>
! -------------------------------------------------------------------
! Try Statement
! -------------------------------------------------------------------
<Try Stm> ::= Try <NL> <Statements> <Catch Blocks> End Try <NL>
<Catch Blocks> ::= <Catch Block> <Catch Blocks>
| <Catch Block>
<Catch Block> ::= Catch <Identifier> As ID <NL> <Statements>
| Catch <NL> <Statements>
! -------------------------------------------------------------------
! With Statement
! -------------------------------------------------------------------
<With Stm> ::= With <Value> <NL> <Statements> End With <NL>
! -------------------------------------------------------------------
! Expressions
! -------------------------------------------------------------------
<Expression> ::= <And Exp> Or <Expression>
| <And Exp> OrElse <Expression>
| <And Exp> XOr <Expression>
| <And Exp>
<And Exp> ::= <Not Exp> And <And Exp>
| <Not Exp> AndAlso <And Exp>
| <Not Exp>
<Not Exp> ::= NOT <Compare Exp>
| <Compare Exp>
<Compare Exp> ::= <Shift Exp> <Compare Op> <Compare Exp> !e.g. x < y
| TypeOf <Add Exp> Is <Object>
| <Shift Exp> Is <Object>
| <Shift Exp> Like <Value>
| <Shift Exp>
<Shift Exp> ::= <Concat Exp> '<<' <Shift Exp>
| <Concat Exp> '>>' <Shift Exp>
| <Concat Exp>
<Concat Exp> ::= <Add Exp> '&' <Concat Exp>
| <Add Exp>
<Add Exp> ::= <Modulus Exp> '+' <Add Exp>
| <Modulus Exp> '-' <Add Exp>
| <Modulus Exp>
<Modulus Exp> ::= <Int Div Exp> Mod <Modulus Exp>
| <Int Div Exp>
<Int Div Exp> ::= <Mult Exp> '\' <Int Div Exp>
| <Mult Exp>
<Mult Exp> ::= <Negate Exp> '*' <Mult Exp>
| <Negate Exp> '/' <Mult Exp>
| <Negate Exp>
<Negate Exp> ::= '-' <Power Exp>
| <Power Exp>
<Power Exp> ::= <Power Exp> '^' <Value>
| <Value>
<
|
|
| OctLiteral
| StringLiteral
| CharLiteral
| RealLiteral
| DateLiteral
| True
| False
| Me
| MyClass
| MyBase
| Nothing
| <Variable>
| AddressOf <Identifier>
<
|
|
|
|
<Variable> ::= <Identifier> <Argument List Opt> <Method Calls>
<Method Calls> ::= <Method Call> <Method Calls>
|
<Method Call> ::= MemberID <Argument List Opt>
<Identifier> ::= ID | QualifiedID !Any type of identifier
</pre></div>
| |||