Grammar railroad diagram

[mingodad]

Using some online tools like https://www.bottlecaps.de/rr/ui and https://www.bottlecaps.de/convert/ 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 Sun Feb 26, 2023, 17:44 (UTC+01) by bison-to-w3c v0.62 which is Copyright (c) 2011-2022 by Gunther Rademacher <grd@gmx.net> */
// From: https://github.com/UoYCS-plasma/GP2/blob/master/src/parser.y
Initialise
         ::= GP_PROGRAM Declaration+
           | GP_GRAPH HostGraph
           | GP_RULE RuleDecl
Declaration
         ::= MainDecl
           | ProcDecl
           | RuleDecl
MainDecl ::= MAIN '=' ComSeq
ProcDecl ::= ( ProcID '=' ( '[' LocalDecls ']' )? | RuleID '=' '[' LocalDecls ']' ) ComSeq
LocalDecls
         ::= ( RuleDecl | ProcDecl )*
ComSeq   ::= Command ( ( ';' | ',' ) Command )*
Command  ::= ( Block OR | IF Block ( THEN ( Block ELSE )? | ELSE ) | TRY ( Block THEN )? ( Block ELSE )? )? Block
Block    ::= ( '(' ComSeq ')' | SimpleCommand ) '!'?
           | error ')'
           | SKIP
           | FAIL
           | BREAK
SimpleCommand
         ::= RuleSetCall
           | RuleID
           | ProcID
RuleSetCall
         ::= ( '{' ( RuleID | ProcID ) ( ( ',' | ';' ) RuleID )* | error ) '}'
RuleDecl ::= ( RuleID '(' ( VarDecls ';'? )? | ProcID '(' VarDecls ) ')' Graph ARROW Graph Inter CondDecl
VarDecls ::= VarList ':' Type ( ';' VarList ':' Type )*
VarList  ::= Variable ( ',' Variable )*
Inter    ::= ( INTERFACE '=' '{' ( NodeID ( ',' NodeID )* )? | error ) '}'
Type     ::= INT
           | CHARACTER
           | STRING
           | ATOM
           | LIST
Graph    ::= '[' ( Position '|' )? ( '|' | NodeList '|' EdgeList? ) ']'
NodeList ::= Node+
Node     ::= '(' NodeID RootNode ',' Label Position? ')'
EdgeList ::= Edge+
Edge     ::= '(' EdgeID Bidirection ',' NodeID ',' NodeID ',' Label ')'
Position ::= '<' ( DNUM ',' ( DNUM | '-'? NUM ) | '-'? NUM ',' ( '-'? NUM | DNUM ) ) '>'
RootNode ::= ROOT?
Bidirection
         ::= BIDIRECTIONAL?
CondDecl ::= ( WHERE Condition )?
Condition
         ::= ( Subtype '(' Variable | EDGETEST '(' NodeID ',' NodeID LabelArg | '(' Condition ) ')'
           | List ( '=' | NEQ ) List
           | AtomExp ( '>' | GTEQ | '<' | LTEQ ) AtomExp
           | ( NOT | Condition ( OR | AND ) ) Condition
Subtype  ::= INT
           | CHARACTER
           | STRING
           | ATOM
LabelArg ::= ( ',' Label )?
Label    ::= List ( '#' ( MARK | ANY_MARK ) )?
List     ::= ( AtomExp | _EMPTY ) ( ':' ( AtomExp | _EMPTY ) )*
AtomExp  ::= Variable
           | NUM
           | STR
           | ( ( INDEG | OUTDEG ) '(' NodeID | _LENGTH '(' Variable | '(' AtomExp ) ')'
           | ( '-' | AtomExp ( '+' | '-' | '*' | '/' | '.' ) ) AtomExp
ProcID   ::= PROCID
RuleID   ::= ID
NodeID   ::= ID
           | NUM
EdgeID   ::= ID
           | NUM
Variable ::= ID
HostGraph
         ::= '[' ( Position '|' )? ( '|' | HostNodeList '|' HostEdgeList? ) ']'
HostNodeList
         ::= HostNode+
HostNode ::= '(' HostID RootNode ',' HostLabel Position? ')'
HostEdgeList
         ::= HostEdge+
HostEdge ::= '(' HostID ',' HostID ',' HostID ',' HostLabel ')'
HostID   ::= NUM
HostLabel
         ::= HostList ( '#' MARK )?
HostList ::= ( HostExp | _EMPTY ) ( ':' ( HostExp | _EMPTY ) )*
HostExp  ::= '-'? NUM
           | STR
	   
// Tokens
//\(\S+\)\s+return \(\S[^;]+\);

 /* GP2 keywords */ 
MAIN ::= "Main"
IF ::= "if"
TRY ::= "try"
THEN ::= "then"
ELSE ::= "else"
SKIP ::= "skip"
FAIL ::= "fail"
BREAK ::= "break"
WHERE ::= "where"
AND ::= "and"
OR ::= "or"
NOT ::= "not"
EDGETEST ::= "edge"
INDEG ::= "indeg"
OUTDEG ::= "outdeg"
INTERFACE ::= "interface"
_EMPTY ::= "empty"
_LENGTH ::= "length"

 /* Keywords for node and edge marks */
MARK ::= "red" | "green" |	 "blue" | "grey" | "dashed"
 /* Any has a distinct token since it cannot appear in the host graph and
    therefore must be distinguished from the other marks. */
ANY_MARK ::= "any"

 /* Keywords for GP2 types */
INT ::= "int"
CHARACTER ::= "char"
STRING ::= "string"  
ATOM ::= "atom"  
LIST ::= "list"  

ARROW ::= "=>"
ROOT ::= "(R)"
BIDIRECTIONAL ::= "(B)"
NEQ ::= "!=" 
GTEQ ::= ">=" 
LTEQ ::= "<="