Grammar railroad diagram

[mingodad]

Using some online tools like https://www.bottlecaps.de/rr/ui and https://www.bottlecaps.de/convert/ with https://github.com/p-org/P/blob/master/Src/PCompiler/CompilerCore/Parser/PParser.g4 and https://github.com/p-org/P/blob/master/Src/PCompiler/CompilerCore/Parser/PLexer.g4 joined and commenting //lexer grammar PLexer; we can have a nice navigable railroad diagram.

Copy and paste the EBNF shown bellow on https://www.bottlecaps.de/rr/ui on the tab Edit Grammar the click on the tab View Diagram to see/download a navigable railroad diagram.

/* converted on Fri Jan 6, 2023, 16:50 (UTC+01) by antlr_4-to-w3c v0.62 which is Copyright (c) 2011-2022 by Gunther Rademacher <[email protected]> */

program  ::= topDecl* EOF
iden     ::= Iden
int      ::= IntLiteral
type     ::= ( ( 'seq' | 'set' ) '[' | 'map' '[' type ',' ) type ']'
           | '(' ( type ( ',' type )* | idenTypeList ) ')'
           | 'bool'
           | 'int'
           | 'float'
           | 'string'
           | 'event'
           | 'machine'
           | 'data'
           | 'any'
           | iden
idenTypeList
         ::= idenType ( ',' idenType )*
idenType ::= iden ':' type
funParamList
         ::= funParam ( ',' funParam )*
funParam ::= iden ':' type
topDecl  ::= typeDefDecl
           | enumTypeDefDecl
           | eventDecl
           | eventSetDecl
           | interfaceDecl
           | implMachineDecl
           | specMachineDecl
           | funDecl
           | namedModuleDecl
           | testDecl
           | implementationDecl
typeDefDecl
         ::= 'type' iden ( '=' type )? ';'
enumTypeDefDecl
         ::= 'enum' iden '{' ( enumElemList | numberedEnumElemList ) '}'
enumElemList
         ::= enumElem ( ',' enumElem )*
enumElem ::= iden
numberedEnumElemList
         ::= numberedEnumElem ( ',' numberedEnumElem )*
numberedEnumElem
         ::= iden '=' IntLiteral
eventDecl
         ::= 'event' iden cardinality? ( ':' type )? ';'
cardinality
         ::= ( 'assert' | 'assume' ) IntLiteral
eventSetDecl
         ::= 'eventset' iden '=' '{' eventSetLiteral '}' ';'
eventSetLiteral
         ::= nonDefaultEvent ( ',' nonDefaultEvent )*
interfaceDecl
         ::= 'interface' iden '(' type? ')' 'receives' nonDefaultEventList? ';'
implMachineDecl
         ::= 'machine' iden cardinality? receivesSends* machineBody
idenList ::= iden ( ',' iden )*
receivesSends
         ::= ( 'receives' | 'sends' ) eventSetLiteral? ';'
specMachineDecl
         ::= 'spec' iden 'observes' eventSetLiteral machineBody
machineBody
         ::= '{' machineEntry* '}'
machineEntry
         ::= varDecl
           | funDecl
           | stateDecl
varDecl  ::= 'var' idenList ':' type ';'
funDecl  ::= 'fun' iden '(' funParamList? ')' ( ':' type )? ( ( 'creates' iden )? ';' | functionBody )
stateDecl
         ::= 'start'? ( 'hot' | 'cold' )? 'state' iden '{' stateBodyItem* '}'
stateBodyItem
         ::= 'entry' ( anonEventHandler | iden ';' )
           | 'exit' ( noParamAnonEventHandler | iden ';' )
           | ( 'defer' | 'ignore' ) nonDefaultEventList ';'
           | 'on' eventList ( 'do' ( iden ';' | anonEventHandler ) | 'goto' stateName ( ';' | 'with' ( anonEventHandler | iden ';' ) ) )
nonDefaultEventList
         ::= nonDefaultEvent ( ',' nonDefaultEvent )*
nonDefaultEvent
         ::= 'halt'
           | iden
eventList
         ::= eventId ( ',' eventId )*
eventId  ::= 'null'
           | 'halt'
           | iden
stateName
         ::= iden
functionBody
         ::= '{' varDecl* statement* '}'
statement
         ::= ( '{' statement* | 'receive' '{' recvCase+ ) '}'
           | ( ( 'assert' ( expr ',' )? | 'print' ) expr | 'return' expr? | 'break' | 'continue' | 'new'? iden '(' rvalueList? ')' | ( ( 'raise' | 'send' expr ',' | 'announce' ) expr | 'goto' stateName ) ( ',' rvalueList )? | iden ( '.' ( iden | int ) | '[' expr ']' )* ( '=' rvalue | '-=' expr | '+=' '(' ( expr ',' )? rvalue ')' ) )? ';'
           | ( ( 'while' '(' | 'foreach' '(' iden 'in' ) expr ')' | 'if' '(' expr ')' ( statement 'else' )? ) statement
recvCase ::= 'case' eventList ':' anonEventHandler
anonEventHandler
         ::= ( '(' funParam ')' )? functionBody
noParamAnonEventHandler
         ::= functionBody
expr     ::= primitive
           | ( '(' ( unnamedTupleBody | namedTupleBody | expr ) | ( 'keys' | 'values' | 'sizeof' ) '(' expr | 'default' '(' type | 'new'? iden '(' rvalueList? | 'choose' '(' expr? ) ')'
           | expr ( '.' ( iden | int ) | '[' expr ']' | ( '*' | '/' | '%' | '+' | '-' | '<' | '>' | '>=' | '<=' | 'in' | '==' | '!=' | '&&' | '||' ) expr | ( 'as' | 'to' ) type )
           | ( '-' | '!' ) expr
           | formatedString
formatedString
         ::= StringLiteral
           | 'format' '(' StringLiteral ( ',' rvalueList )? ')'
primitive
         ::= iden
           | floatLiteral
           | BoolLiteral
           | IntLiteral
           | 'null'
           | '$'
           | '$$'
           | 'halt'
           | 'this'
floatLiteral
         ::= IntLiteral? '.' IntLiteral
           | 'float' '(' IntLiteral ',' IntLiteral ')'
unnamedTupleBody
         ::= rvalue ( ',' | ( ',' rvalue )+ )
namedTupleBody
         ::= iden '=' rvalue ( ',' | ( ',' iden '=' rvalue )+ )
rvalueList
         ::= rvalue ( ',' rvalue )*
rvalue   ::= expr
modExpr  ::= '(' modExpr ')'
           | '{' bindExpr ( ',' bindExpr )* '}'
           | iden
           | ( ( 'compose' | 'union' ) ( modExpr ',' )+ | ( 'hidee' nonDefaultEventList | ( 'hidei' | 'assert' ) idenList | ( 'rename' iden 'to' | 'main' ) iden ) 'in' ) modExpr
bindExpr ::= iden ( '->' iden )?
namedModuleDecl
         ::= 'module' iden '=' modExpr ';'
testDecl ::= 'test' iden '[' 'main' '=' iden ']' ':' modExpr ( 'refines' modExpr )? ';'
implementationDecl
         ::= 'implementation' iden ( '[' 'main' '=' iden ']' )? ':' modExpr ';'
_        ::= Whitespace
           | BlockComment
           | LineComment
          /* ws: definition */

<?TOKENS?>

BoolLiteral
         ::= 'true'
           | 'false'
IntLiteral
         ::= [0-9]+
StringLiteral
         ::= '"' StringCharacters? '"'
StringCharacters
         ::= StringCharacter+
StringCharacter
         ::= [^"\]
           | EscapeSequence
EscapeSequence
         ::= '\' .
Iden     ::= PLetter PLetterOrDigit*
PLetter  ::= [a-zA-Z_]
PLetterOrDigit
         ::= [a-zA-Z0-9_]
Whitespace
         ::= [ #x9#xd#xa#xc]+
BlockComment?
         ::= '/*' .* '*/'
LineComment
         ::= '//' [^#xd#xa]*
EOF      ::= $

[ankushdesai]

This is so cool! It would be great to add these diagrams to the language manual. Thanks for sharing!

[mingodad]

I've also just added a partially working P grammar at https://mingodad.github.io/parsertl-playground/playground/ (select P parser (partially working) then click Parse to see a parse tree for the content in Input source).