Grammar railroad diagram #1
Description
Using this tool https://www.bottlecaps.de/convert/ and manually adding the tokens from p4/p4lexer.ll we can see a railroad diagram for the grammar in p4/p4parser.ypp copy and paste the EBNF shown bellow on https://www.bottlecaps.de/rr/ui in the tab Edit Grammar then switching to the tab View Diagram.
/*
From https://raw.githubusercontent.com/p4lang/p4c/530d3f0afd8cd6773646fc0294668cacefa98042/frontends/parsers/p4/p4parser.ypp
*/
/* converted on Mon Jul 12, 2021, 11:43 (UTC+02) by bison-to-w3c v0.52 which is Copyright (c) 2011-2021 by Gunther Rademacher <grd@gmx.net> */
start ::= fragment END_ANNOTATION
| START_PROGRAM program
fragment ::= START_EXPRESSION_LIST expressionList
| START_KV_LIST kvList
| ( START_INTEGER_LIST ( INTEGER ',' )* | START_INTEGER | ( START_INTEGER_PAIR | START_INTEGER_TRIPLE INTEGER ',' ) INTEGER ',' ) INTEGER
| ( START_INTEGER_OR_STRING_LITERAL_LIST ( intOrStr ',' )* | START_INTEGER_OR_STRING_LITERAL ) intOrStr
| ( START_STRING_LITERAL_LIST ( STRING_LITERAL ',' )* | START_STRING_LITERAL | ( START_STRING_LITERAL_PAIR | START_STRING_LITERAL_TRIPLE STRING_LITERAL ',' ) STRING_LITERAL ',' ) STRING_LITERAL
| ( START_EXPRESSION | ( START_EXPRESSION_PAIR | START_EXPRESSION_TRIPLE expression ',' ) expression ',' ) expression
| START_P4RT_TRANSLATION_ANNOTATION STRING_LITERAL ',' p4rtControllerType
p4rtControllerType
::= STRING
| BIT l_angle INTEGER r_angle
| INTEGER
program ::= ( declaration | ';' )* END
declaration
::= constantDeclaration
| externDeclaration
| actionDeclaration
| parserDeclaration
| typeDeclaration
| controlDeclaration
| instantiation
| errorDeclaration
| matchKindDeclaration
| functionDeclaration
nonTypeName
::= IDENTIFIER
| APPLY
| KEY
| ACTIONS
| STATE
| ENTRIES
| TYPE
name ::= nonTypeName
| TYPE_IDENTIFIER
nonTableKwName
::= IDENTIFIER
| TYPE_IDENTIFIER
| APPLY
| STATE
| TYPE
optCONST ::= CONST?
optAnnotations
::= annotations?
annotations
::= annotation+
annotation
::= '@' name ( '(' annotationBody ')' | '[' ( expressionList | kvList ) ']' )?
| PRAGMA name annotationBody END_PRAGMA
annotationBody
::= ( annotationBody ( '(' annotationBody ')' | annotationToken ) )?
annotationToken
::= UNEXPECTED_TOKEN
| ABSTRACT
| ACTION
| ACTIONS
| APPLY
| BOOL
| BIT
| CONST
| CONTROL
| DEFAULT
| ELSE
| ENTRIES
| ENUM
| ERROR
| EXIT
| EXTERN
| FALSE
| HEADER
| HEADER_UNION
| IF
| IN
| INOUT
| INT
| KEY
| MATCH_KIND
| TYPE
| OUT
| PARSER
| PACKAGE
| PRAGMA
| RETURN
| SELECT
| STATE
| STRING
| STRUCT
| SWITCH
| TABLE
| THIS
| TRANSITION
| TRUE
| TUPLE
| TYPEDEF
| VARBIT
| VALUESET
| VOID
| '_'
| IDENTIFIER
| TYPE_IDENTIFIER
| STRING_LITERAL
| INTEGER
| '&&&'
| '..'
| '<<'
| '&&'
| '||'
| '=='
| '!='
| '>='
| '<='
| '++'
| '+'
| '|+|'
| '-'
| '|-|'
| '*'
| '/'
| '%'
| '|'
| '&'
| '^'
| '~'
| '['
| ']'
| '{'
| '}'
| '<'
| L_ANGLE_ARGS
| '>'
| R_ANGLE_SHIFT
| '!'
| ':'
| ','
| '?'
| '.'
| '='
| ';'
| '@'
kvList ::= kvPair ( ',' kvPair )*
kvPair ::= name '=' expression
parameterList
::= ( parameter ( ',' parameter )* )?
parameter
::= optAnnotations direction typeRef name ( '=' expression )?
direction
::= ( IN | OUT | INOUT )?
packageTypeDeclaration
::= optAnnotations PACKAGE name optTypeParameters '(' parameterList ')'
instantiation
::= annotations? typeRef '(' argumentList ')' name ( '=' objInitializer )? ';'
objInitializer
::= '{' objDeclaration* '}'
objDeclaration
::= functionDeclaration
| instantiation
optConstructorParameters
::= ( '(' parameterList ')' )?
parserDeclaration
::= parserTypeDeclaration optConstructorParameters '{' parserLocalElement* parserState+ '}'
parserLocalElement
::= constantDeclaration
| instantiation
| variableDeclaration
| valueSetDeclaration
parserTypeDeclaration
::= optAnnotations PARSER name optTypeParameters '(' parameterList ')'
parserState
::= optAnnotations STATE name '{' parserStatements transitionStatement '}'
parserStatements
::= parserStatement*
parserStatement
::= assignmentOrMethodCallStatement
| directApplication
| ';'
| variableDeclaration
| constantDeclaration
| parserBlockStatement
| conditionalStatement
parserBlockStatement
::= optAnnotations '{' parserStatements '}'
transitionStatement
::= ( TRANSITION stateExpression )?
stateExpression
::= name ';'
| selectExpression
selectExpression
::= SELECT '(' expressionList ')' '{' selectCase* '}'
selectCase
::= keysetExpression ':' name ';'
keysetExpression
::= tupleKeysetExpression
| simpleKeysetExpression
tupleKeysetExpression
::= '(' ( simpleKeysetExpression ( ',' simpleKeysetExpression )+ | reducedSimpleKeysetExpression ) ')'
reducedSimpleKeysetExpression
::= expression ( '&&&' | '..' ) expression
| DEFAULT
| '_'
simpleKeysetExpression
::= expression ( ( '&&&' | '..' ) expression )?
| DEFAULT
| '_'
valueSetDeclaration
::= optAnnotations VALUESET l_angle ( baseType | tupleType | typeName ) r_angle '(' expression ')' name ';'
controlDeclaration
::= controlTypeDeclaration optConstructorParameters '{' controlLocalDeclaration* APPLY controlBody '}'
controlTypeDeclaration
::= optAnnotations CONTROL name optTypeParameters '(' parameterList ')'
controlLocalDeclaration
::= constantDeclaration
| actionDeclaration
| tableDeclaration
| instantiation
| variableDeclaration
controlBody
::= blockStatement
externDeclaration
::= optAnnotations EXTERN ( nonTypeName optTypeParameters '{' methodPrototype* '}' | ( functionPrototype | name ) ';' )
functionPrototype
::= typeOrVoid name optTypeParameters '(' parameterList ')'
methodPrototype
::= optAnnotations ( ABSTRACT? functionPrototype | TYPE_IDENTIFIER '(' parameterList ')' ) ';'
typeRef ::= baseType
| typeName
| specializedType
| headerStackType
| tupleType
namedType
::= typeName
| specializedType
prefixedType
::= '.'? TYPE_IDENTIFIER
typeName ::= prefixedType
tupleType
::= TUPLE l_angle typeArgumentList r_angle
headerStackType
::= ( typeName | specializedType ) '[' expression ']'
specializedType
::= typeName l_angle typeArgumentList r_angle
baseType ::= BOOL
| ERROR
| ( BIT | INT ) ( l_angle ( INTEGER | '(' expression ')' ) r_angle )?
| STRING
| VARBIT l_angle ( INTEGER | '(' expression ')' ) r_angle
typeOrVoid
::= typeRef
| VOID
| IDENTIFIER
optTypeParameters
::= typeParameters?
typeParameters
::= l_angle name ( ',' name )* r_angle
typeArg ::= typeRef
| nonTypeName
| VOID
| '_'
typeArgumentList
::= typeArg? ( ',' typeArg )*
realTypeArg
::= typeRef
| VOID
| '_'
realTypeArgumentList
::= realTypeArg ( ',' typeArg )*
typeDeclaration
::= derivedTypeDeclaration
| ( typedefDeclaration | parserTypeDeclaration | controlTypeDeclaration | packageTypeDeclaration ) ';'
derivedTypeDeclaration
::= headerTypeDeclaration
| headerUnionDeclaration
| structTypeDeclaration
| enumDeclaration
headerTypeDeclaration
::= optAnnotations HEADER name optTypeParameters '{' structFieldList '}'
structTypeDeclaration
::= optAnnotations STRUCT name optTypeParameters '{' structFieldList '}'
headerUnionDeclaration
::= optAnnotations HEADER_UNION name optTypeParameters '{' structFieldList '}'
structFieldList
::= structField*
structField
::= optAnnotations typeRef name ';'
enumDeclaration
::= optAnnotations ENUM ( name '{' identifierList | typeRef name '{' specifiedIdentifier ( ',' specifiedIdentifier )* ) '}'
specifiedIdentifier
::= name '=' initializer
errorDeclaration
::= ERROR '{' identifierList '}'
matchKindDeclaration
::= MATCH_KIND '{' identifierList '}'
identifierList
::= name ( ',' name )*
typedefDeclaration
::= optAnnotations ( TYPEDEF | TYPE ) ( typeRef | derivedTypeDeclaration ) name
assignmentOrMethodCallStatement
::= lvalue ( ( l_angle typeArgumentList r_angle )? '(' argumentList ')' | '=' expression ) ';'
exitStatement
::= EXIT ';'
returnStatement
::= RETURN expression? ';'
conditionalStatement
::= IF '(' expression ')' statement ( ELSE statement )?
directApplication
::= typeName '.' APPLY '(' argumentList ')' ';'
statement
::= assignmentOrMethodCallStatement
| directApplication
| conditionalStatement
| ';'
| blockStatement
| returnStatement
| exitStatement
| switchStatement
blockStatement
::= optAnnotations '{' statementOrDeclaration* '}'
switchStatement
::= SWITCH '(' expression ')' '{' switchCase* '}'
switchCase
::= switchLabel ':' blockStatement?
switchLabel
::= DEFAULT
| ( INTEGER | STRING_LITERAL | TRUE | FALSE | THIS | '.'? nonTypeName | '(' ( expression ')' | typeRef ')' expression ) | ( '!' | '~' | '-' | '+' ) expression | typeName dot_name | ERROR '.' name | namedType '(' argumentList ')' ) ( '[' expression ( ':' expression )? ']' | dot_name | ( '*' | '/' | '%' | '+' | '-' | '|+|' | '|-|' | '<<' | R_ANGLE_SHIFT? '>' | '<=' | '>=' | '!=' | '==' | '&' | '^' | '|' | '++' | '&&' | '||' | '?' expression ':' ) expression | l_angle ( expression | realTypeArgumentList r_angle '(' argumentList ')' ) | '(' argumentList ')' )*
statementOrDeclaration
::= variableDeclaration
| constantDeclaration
| statement
| instantiation
tableDeclaration
::= optAnnotations TABLE name '{' tableProperty+ '}'
tableProperty
::= ( KEY '=' '{' keyElement* | ACTIONS '=' '{' ( optAnnotations actionRef ';' )* ) '}'
| optAnnotations optCONST ( ENTRIES '=' '{' entry+ '}' | nonTableKwName '=' initializer ';' )
keyElement
::= expression ':' name optAnnotations ';'
actionRef
::= prefixedNonTypeName ( '(' argumentList ')' )?
entry ::= keysetExpression ':' actionRef optAnnotations ';'
actionDeclaration
::= optAnnotations ACTION name '(' parameterList ')' blockStatement
variableDeclaration
::= annotations? typeRef name optInitializer ';'
constantDeclaration
::= optAnnotations CONST typeRef name '=' initializer ';'
optInitializer
::= ( '=' initializer )?
initializer
::= expression
functionDeclaration
::= functionPrototype blockStatement
argumentList
::= ( argument ( ',' argument )* )?
argument ::= ( name '=' )? expression
| '_'
expressionList
::= expression? ( ',' expression )*
prefixedNonTypeName
::= '.'? nonTypeName
dot_name ::= '.' name
lvalue ::= ( prefixedNonTypeName | THIS ) ( dot_name | '[' expression ( ':' expression )? ']' )*
expression
::= INTEGER
| STRING_LITERAL
| TRUE
| FALSE
| THIS
| '.'? nonTypeName
| expression ( '[' expression ( ':' expression )? ']' | dot_name | ( '*' | '/' | '%' | '+' | '-' | '|+|' | '|-|' | '<<' | R_ANGLE_SHIFT? '>' | '<=' | '>=' | '!=' | '==' | '&' | '^' | '|' | '++' | '&&' | '||' | '?' expression ':' ) expression | l_angle ( expression | realTypeArgumentList r_angle '(' argumentList ')' ) | '(' argumentList ')' )
| '{' ( expressionList | kvList ) '}'
| '(' ( expression ')' | typeRef ')' expression )
| ( '!' | '~' | '-' | '+' ) expression
| typeName dot_name
| ERROR '.' name
| namedType '(' argumentList ')'
intOrStr ::= INTEGER
| STRING_LITERAL
l_angle ::= '<'
| L_ANGLE_ARGS
r_angle ::= '>'
| R_ANGLE_SHIFT
// Tokens from https://github.com/p4lang/p4c/blob/530d3f0afd8cd6773646fc0294668cacefa98042/frontends/parsers/p4/p4lexer.ll
PRAGMA ::= "@pragma"
ABSTRACT ::= "abstract"
ACTION ::= "action"
ACTIONS ::= "actions"
APPLY ::= "apply"
BOOL ::= "bool"
BIT ::= "bit"
CONST ::= "const"
CONTROL ::= "control"
DEFAULT ::= "default"
ELSE ::= "else"
ENTRIES ::= "entries"
ENUM ::= "enum"
ERROR ::= "error"
EXIT ::= "exit"
EXTERN ::= "extern"
FALSE ::= "false"
HEADER ::= "header"
HEADER_UNION ::= "header_union"
IF ::= "if"
IN ::= "in"
INOUT ::= "inout"
INT ::= "int"
KEY ::= "key"
MATCH_KIND ::= "match_kind"
TYPE ::= "type"
OUT ::= "out"
PARSER ::= "parser"
PACKAGE ::= "package"
RETURN ::= "return"
SELECT ::= "select"
STATE ::= "state"
STRING ::= "string"
STRUCT ::= "struct"
SWITCH ::= "switch"
TABLE ::= "table"
THIS ::= "this"
TRANSITION ::= "transition"
TRUE ::= "true"
TUPLE ::= "tuple"
TYPEDEF ::= "typedef"
VARBIT ::= "varbit"
VALUESET ::= "value_set"
VOID ::= "void"
DONTCARE ::= "_"
MASK ::= "&&&"
RANGE ::= ".."
SHL ::= "<<"
AND ::= "&&"
OR ::= "||"
EQ ::= "=="
NE ::= "!="
GE ::= ">="
LE ::= "<="
PP ::= "++"
PLUS ::= "+"
PLUS_SAT ::= "|+|"
MINUS ::= "-"
MINUS_SAT ::= "|-|"
MUL ::= "*"
DIV ::= "/"
MOD ::= "%"
BIT_OR ::= "|"
BIT_AND ::= "&"
BIT_XOR ::= "^"
COMPLEMENT ::= "~"
L_PAREN ::= "("
R_PAREN ::= ")"
L_BRACKET ::= "["
R_BRACKET ::= "]"
L_BRACE ::= "{"
R_BRACE ::= "}"
L_ANGLE ::= "<"
R_ANGLE_SHIFT ::= ">"
R_ANGLE ::= ">"
NOT ::= "!"
COLON ::= ":"
COMMA ::= ","
QUESTION ::= "?"
DOT ::= "."
ASSIGN ::= "="
SEMICOLON ::= ";"
AT ::= "@"