A NPL Syntax and Reserved Words

This appendix provides the NPL syntax and reserved words.

Table A-1 lists all the NPL methods and the corresponding syntax.

EBNF for NPL

Table A-1 NPL Methods, Operator and Syntax

Method Operator Syntax

Program

::=

( MethodHandlerImportDecl )?

( ConfigDeclaration )?

( VariableDeclaration )+

( ExposeDeclaration )*

( Statement )

+<EOF>

MethodHandlerImportDecl

::=

"import" <IDENTIFIER> ( "." <IDENTIFIER> )* ";"

ConfigDeclaration

::=

"Config" "{" ( ConfigAttribute )? "}"

ConfigAttribute

::=

<IDENTIFIER> <STRING_LITERAL> ";"

VariableDeclaration

::=

CompositeVariableDecl | SimpleVariableDecl

CompositeVariableDecl

::=

InputRecDecl | OutputRecDecl

InputRecDecl

::=

"InputRec" "{" ( AttributeVariableDecl )+ "}"

<IDENTIFIER> ";"

OutputRecDecl

::=

"OutputRec" "{" ( AttributeVariableDecl )+ "}"

<IDENTIFIER> ";"

AttributeVariableDecl

::=

AttributeType ( <ATTRIBUTE_NAME>

| <IDENTIFIER> | <INTEGER_LITERAL> ) ";"

SimpleVariableDecl

::=

AttributeType <IDENTIFIER>

( SimpleVariableInit )? ";"

SimpleVariableInit

::=

"=" Expression

AttributeType

::=

"String"

| "Integer"

| "Long"

| "TimeInSecs"

| "IP"

| "TimeInMilliSecs"

| "MAC"

| "UInt128"

| "Byte"

| "Short"

| "IPv6"

| "Float"

| "Double"

| "Bytes"

| "Object"

| "List"

ExposeDeclaration

::=

"Expose for" <IDENTIFIER> "{"

( ExposeAttribute )+ "}"

ExposeAttribute

::=

<IDENTIFIER> "." ( <ATTRIBUTE_NAME>

| <IDENTIFIER>

| <INTEGER_LITERAL> )

( <STRING_LITERAL> )? ";"

Statement

::=

IfStatement | AssignmentStmt

| FunctionStmt | JavaHookStmt

IfStatement

::=

"if" "(" ConditionalExpression ")" IfAction

( "else" "if" "(" ConditionalExpression ")" IfAction )*

( "else" IfAction )?

ConditionalExpression

::=

RelationalExpression ( ConditionalOperator

RelationalExpression )*

ConditionalOperator

::=

<OR> | <AND>

RelationalExpression

::=

NestedRelationalExpression

| SimpleRelationalExpression

| BooleanFunctionExpr

BooleanFunctionExpr

::=

FunctionExpression

NestedRelationalExpression

::=

"(" ConditionalExpression ")"

SimpleRelationalExpression

::=

Expression RelationalOperator Expression

RelationalOperator

::=

<EQ> | <NE> | <LT> | <LE> | <GT> | <GE>

IfAction

::=

StatementBlock | Statement

StatementBlock

::=

"{" ( Statement )* "}"

AssignmentStmt

::=

Variable "=" Expression ";"

Variable

::=

<IDENTIFIER> ( "." ( <ATTRIBUTE_NAME>

| <IDENTIFIER>

| <INTEGER_LITERAL> ) )?

Expression

::=

AdditiveExpression

AdditiveExpression

::=

SubtractiveExpression

( "+" SubtractiveExpression )*

SubtractiveExpression

::=

MultiplicativeExpression

( "-" MultiplicativeExpression )*

MultiplicativeExpression

::=

DivisionalExpression ( "*" DivisionalExpression )*

DivisionalExpression

::=

UnaryExpression ( "/" UnaryExpression )*

UnaryExpression

::=

( "(" AttributeType ")" )?

( NestedExpression

| VariableExpression

| IntLiteralExpression

| FloatingPointLiteralExpression

| StringLiteralExpression

| FunctionExpression

| JavaHookExpression )

NestedExpression

::=

( UnaryOperator )? "(" Expression ")"

VariableExpression

::=

( UnaryOperator )? Variable

IntLiteralExpression

::=

( UnaryOperator )? <STRING_LITERAL>

FloatingPointLiteralExpression

::=

( UnaryOperator )? <FLOATING_POINT_LITERAL>

StringLiteralExpression

::=

<STRING_LITERAL>

FunctionExpression

::=

( "byte2bytes"

| "byte2str"

| "bytes2byte"

| "bytes2double"

| "bytes2float"

| "bytes2hexstr"

| "bytes2int"

| "bytes2IP"

| "bytes2long"

| "bytes2short"

| "bytes2str"

| "bytes2TimeInMilliSecs"

| "bytes2TimeInSecs"

| "clone"

| "convertDateTime"

| "copyBits"

| "currentTime"

| "double2bytes"

| "double2str"

| "fieldExists"

| "float2bytes"

| "float2str"

| "int2bytes"

| "int2str"

| "IP2bytes"

| "IP2str"

| "list2str"

| "long2bytes"

| "long2str"

| "object2str"

| "randomInt"

| "randomDouble"

| "short2bytes"

| "short2str"

| "strpos"

| "str2byte"

| "str2bytes"
   

| "str2double"

| "str2float"

| "str2int"

| "str2IP"

| "str2long"

| "str2lower"

| "str2short"

| "str2TimeInMilliSecs"

| "str2TimeInSecs"

| "str2upper"

| "strlen"

| "subbytes"

| "substr"

| "time2bytes"

| "time2str" )

"(" ( Expression ( "," Expression )* )? ")"

UnaryOperator

::=

"+" | "-"

FunctionStmt

::=

( "logError"

| "logWarning"

| "logInfo"

| "logTrace"

| "write" )

"(" ( Expression ( "," Expression )* )? ")" ";"

JavaHookStmt

::=

JavaHookExpression ";"

JavaHookExpression

::=

"Java" "." <IDENTIFIER>

"(" ( Expression ( "," Expression )* )? ")"

<IDENTIFIER>

::=

( <LETTER> | <UNDERSCORE> )

( <LETTER> | <DIGIT> | <UNDERSCORE>)*

<ATTRIBUTE_NAME>

::=

( <LETTER> | <UNDERSCORE> | <COLON> )

( <LETTER> | <DIGIT> | <UNDERSCORE>

| <COLON> | <HYPHEN> )*

<FUNCTION_NAME>

::=

<LETTER> ( <LETTER> | <DIGIT> )*

<LETTER>

::=

["a"-"z", "A"-"Z"]

<UNDERSCORE>

::=

"_"

<COLON>

::=

":"

<DIGIT>

::=

["0"-"9"]

<HYPHEN>

::=

<MINUS>

<INTEGER_LITERAL>

::=

<DECIMAL_LITERAL>

| <HEX_LITERAL>

| <OCTAL_LITERAL>

<DECIMAL_LITERAL>

::=

["1"-"9"] (["0"-"9"])*

<HEX_LITERAL>

::=

"0" ["x","X"] (["0"-"9","a"-"f","A"-"F"])+

<OCTAL_LITERAL>

::=

"0" (["0"-"7"])*

<FLOATING_POINT_LITERAL>

::=

(["0"-"9"])+ "." (["0"-"9"])* (<EXPONENT>)?

<EXPONENT>

::=

["e","E"] (["+","-"])? (["0"-"9"])+

<STRING_LITERAL>

::=

"\""

( (~["\"","\\","\n","\r"])

  | ("\\"

        ( ["n","t","b","r","f","\\","'","\""]

        | ["0"-"7"] ( ["0"-"7"] )?

        | ["0"-"3"] ["0"-"7"] ["0"-"7"]

      )

    )

)*

"\""

<OR>

::=

"||"

<AND>

::=

"&&"

<EQ>

::=

"=="

<NE>

::=

"!="

<LT>

::=

"<"

<LE>

::=

"<="

<GT>

::=

">"

<GE>

::=

">="

<MINUS>

::=

"-"

NPL reserved words

  • Byte

  • byte2bytes

  • byte2str

  • Bytes

  • bytes2byte

  • bytes2double

  • bytes2float

  • bytes2hexstr

  • bytes2int

  • bytes2IP

  • bytes2long

  • bytes2short

  • bytes2str

  • bytes2TimeInMilliSecs

  • bytes2TimeInSecs

  • Config

  • convertDateTime

  • copyBits

  • currentTime

  • Double

  • double2bytes

  • double2str

  • else

  • Expose

  • fieldExists

  • Float

  • float2bytes

  • float2str

  • for

  • if

  • import

  • InputRec

  • int2bytesint2str

  • Integer

  • IP

  • IP2bytes

  • IP2str

  • IPv6

  • Java

  • List

  • list2str

  • logError

  • logInfo

  • logTrace

  • logWarning

  • Long

  • long2bytes

  • long2str

  • MAC

  • null

  • Object

  • object2str

  • OutputRec

  • randomInt

  • randomDouble

  • Short

  • short2bytes

  • short2str

  • str2byte

  • str2bytes

  • str2double

  • str2float

  • str2int

  • str2IP

  • str2long

  • str2lower

  • str2short

  • str2TimeInMilliSecs

  • str2TimeInSecs

  • str2upper

  • String

  • strlen

  • strpos

  • subbytes

  • substr

  • time2bytes

  • time2str

  • TimeInMilliSecs

  • TimeInSecs

  • UInt128

  • write