After doing several grammar conversions to the kind of EBNF understood by https://www.bottlecaps.de/rr/ui to generate railroad diagrams see bellow the converted src/parser.y with some hand made changes to allow view it at https://www.bottlecaps.de/rr/ui the order of the rules could be changed to a better view of the railroad diagram. Copy and paste the EBNF bellow on https://www.bottlecaps.de/rr/ui tab Edit Grammar then switch to the tab View Diagram.
This script that uses Lua pattern matching to process src/parser.y:
====
auto fname = "sqlite3/src/parse.y";
auto txt = readfile(fname);
txt = txt.gsub("%%include%s*%b{}", "");
txt = txt.gsub("%%syntax_error%s*%b{}", "");
txt = txt.gsub("%%stack_overflow%s*%b{}", "");
txt = txt.gsub("%%default_type%s*%b{}", "");
txt = txt.gsub("%%extra_context%s*%b{}", "");
txt = txt.gsub("//[^\n]*", "");
txt = txt.gsub("/%*.-%*/", "");
txt = txt.gsub("%%token[^\n]+", "");
txt = txt.gsub("%%name[^\n]+", "");
txt = txt.gsub("%%left[^\n]+", "");
txt = txt.gsub("%%right[^\n]+", "");
txt = txt.gsub("%%nonassoc[^\n]+", "");
txt = txt.gsub("%%wildcard[^\n]+", "");
txt = txt.gsub("%%type%s+.-%b{}", "");
txt = txt.gsub("%%destructor%s+.-%b{}", "");
txt = txt.gsub("%.%s*%b{}", ".");
txt = txt.gsub("%b{}", " ");
txt = txt.gsub("%b()", " ");
print(txt);
auto rules = {};
auto rule_order = [];
txt.gmatch(
"([%w_]+)%s*::=([^.]+)%.",
function(k, v)
{
v = v.trim();
if(v.len() == 0) v = "/* empty */";
v = v.gsub("%s+", " ");
if(v.indexOf("|") >= 0) v = "(" + v + ")";
auto ev = table_rawget(rules, k, null);
if(!ev) {
rules[k] <- v;
rule_order.append(k);
}
else
{
rules[k] = ev + "\n\t| " + v;
}
return true;
}
);
foreach(idx, k in rule_order) print(/*idx,*/ k, "::=", rules[k]);
====
EBNF for https://www.bottlecaps.de/rr/ui :
====
/*
From src/parser.y
*/
input ::= cmdlist
cmdlist ::= cmdlist ecmd
| ecmd
ecmd ::= SEMI
| cmdx SEMI
| explain cmdx SEMI
explain ::= EXPLAIN
| EXPLAIN QUERY PLAN
cmdx ::= cmd
cmd ::= BEGIN transtype trans_opt
| (COMMIT|END trans_opt)
| ROLLBACK trans_opt
| SAVEPOINT nm
| RELEASE savepoint_opt nm
| ROLLBACK trans_opt TO savepoint_opt nm
| create_table create_table_args
| DROP TABLE ifexists fullname
| createkw temp VIEW ifnotexists nm dbnm eidlist_opt AS select
| DROP VIEW ifexists fullname
| select
| with DELETE FROM xfullname indexed_opt where_opt_ret orderby_opt limit_opt
| with DELETE FROM xfullname indexed_opt where_opt_ret
| with UPDATE orconf xfullname indexed_opt SET setlist from where_opt_ret orderby_opt limit_opt
| with UPDATE orconf xfullname indexed_opt SET setlist from where_opt_ret
| with insert_cmd INTO xfullname idlist_opt select upsert
| with insert_cmd INTO xfullname idlist_opt DEFAULT VALUES returning
| createkw uniqueflag INDEX ifnotexists nm dbnm ON nm LP sortlist RP where_opt
| DROP INDEX ifexists fullname
| VACUUM vinto
| VACUUM nm vinto
| PRAGMA nm dbnm
| PRAGMA nm dbnm EQ nmnum
| PRAGMA nm dbnm LP nmnum RP
| PRAGMA nm dbnm EQ minus_num
| PRAGMA nm dbnm LP minus_num RP
| createkw trigger_decl BEGIN trigger_cmd_list END
| DROP TRIGGER ifexists fullname
| ATTACH database_kw_opt expr AS expr key_opt
| DETACH database_kw_opt expr
| REINDEX
| REINDEX nm dbnm
| ANALYZE
| ANALYZE nm dbnm
| ALTER TABLE fullname RENAME TO nm
| ALTER TABLE add_column_fullname ADD kwcolumn_opt columnname carglist
| ALTER TABLE fullname DROP kwcolumn_opt nm
| ALTER TABLE fullname RENAME kwcolumn_opt nm TO nm
| create_vtab
| create_vtab LP vtabarglist RP
trans_opt ::= /* empty */
| TRANSACTION
| TRANSACTION nm
transtype ::= /* empty */
| DEFERRED
| IMMEDIATE
| EXCLUSIVE
savepoint_opt ::= SAVEPOINT
| /* empty */
create_table ::= createkw temp TABLE ifnotexists nm dbnm
createkw ::= CREATE
ifnotexists ::= /* empty */
| IF NOT EXISTS
temp ::= TEMP
| /* empty */
create_table_args ::= LP columnlist conslist_opt RP table_options
| AS select
table_options ::= /* empty */
| WITHOUT nm
columnlist ::= columnlist COMMA columnname carglist
| columnname carglist
columnname ::= nm typetoken
nm ::= id
| STRING
| JOIN_KW
typetoken ::= /* empty */
| typename
| typename LP signed RP
| typename LP signed COMMA signed RP
typename ::= ids
| typename ids
signed ::= plus_num
| minus_num
scanpt ::= /* empty */
scantok ::= /* empty */
carglist ::= carglist ccons
| /* empty */
ccons ::= CONSTRAINT nm
| DEFAULT scantok term
| DEFAULT LP expr RP
| DEFAULT PLUS scantok term
| DEFAULT MINUS scantok term
| DEFAULT scantok id
| NULL onconf
| NOT NULL onconf
| PRIMARY KEY sortorder onconf autoinc
| UNIQUE onconf
| CHECK LP expr RP
| REFERENCES nm eidlist_opt refargs
| defer_subclause
| COLLATE ids
| GENERATED ALWAYS AS generated
| AS generated
generated ::= LP expr RP
| LP expr RP ID
autoinc ::= /* empty */
| AUTOINCR
refargs ::= /* empty */
| refargs refarg
refarg ::= MATCH nm
| ON INSERT refact
| ON DELETE refact
| ON UPDATE refact
refact ::= SET NULL
| SET DEFAULT
| CASCADE
| RESTRICT
| NO ACTION
defer_subclause ::= NOT DEFERRABLE init_deferred_pred_opt
| DEFERRABLE init_deferred_pred_opt
init_deferred_pred_opt ::= /* empty */
| INITIALLY DEFERRED
| INITIALLY IMMEDIATE
conslist_opt ::= /* empty */
| COMMA conslist
conslist ::= conslist tconscomma tcons
| tcons
tconscomma ::= COMMA
| /* empty */
tcons ::= CONSTRAINT nm
| PRIMARY KEY LP sortlist autoinc RP onconf
| UNIQUE LP sortlist RP onconf
| CHECK LP expr RP onconf
| FOREIGN KEY LP eidlist RP REFERENCES nm eidlist_opt refargs defer_subclause_opt
defer_subclause_opt ::= /* empty */
| defer_subclause
onconf ::= /* empty */
| ON CONFLICT resolvetype
orconf ::= /* empty */
| OR resolvetype
resolvetype ::= raisetype
| IGNORE
| REPLACE
ifexists ::= IF EXISTS
| /* empty */
select ::= WITH wqlist selectnowith
| WITH RECURSIVE wqlist selectnowith
| selectnowith
selectnowith ::= oneselect
| selectnowith multiselect_op oneselect
multiselect_op ::= UNION
| UNION ALL
| (EXCEPT|INTERSECT)
oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt orderby_opt limit_opt
| SELECT distinct selcollist from where_opt groupby_opt having_opt window_clause orderby_opt limit_opt
| values
values ::= VALUES LP nexprlist RP
| values COMMA LP nexprlist RP
distinct ::= DISTINCT
| ALL
| /* empty */
sclp ::= selcollist COMMA
| /* empty */
selcollist ::= sclp scanpt expr scanpt as
| sclp scanpt STAR
| sclp scanpt nm DOT STAR
as ::= AS nm
| ids
| /* empty */
from ::= /* empty */
| FROM seltablist
stl_prefix ::= seltablist joinop
| /* empty */
seltablist ::= stl_prefix nm dbnm as indexed_opt on_opt using_opt
| stl_prefix nm dbnm LP exprlist RP as on_opt using_opt
| stl_prefix LP select RP as on_opt using_opt
| stl_prefix LP seltablist RP as on_opt using_opt
dbnm ::= /* empty */
| DOT nm
fullname ::= nm
| nm DOT nm
xfullname ::= nm
| nm DOT nm
| nm DOT nm AS nm
| nm AS nm
joinop ::= (COMMA|JOIN)
| JOIN_KW JOIN
| JOIN_KW nm JOIN
| JOIN_KW nm nm JOIN
on_opt ::= ON expr
| /* empty */
indexed_opt ::= /* empty */
| INDEXED BY nm
| NOT INDEXED
using_opt ::= USING LP idlist RP
| /* empty */
orderby_opt ::= /* empty */
| ORDER BY sortlist
sortlist ::= sortlist COMMA expr sortorder nulls
| expr sortorder nulls
sortorder ::= ASC
| DESC
| /* empty */
nulls ::= NULLS FIRST
| NULLS LAST
| /* empty */
groupby_opt ::= /* empty */
| GROUP BY nexprlist
having_opt ::= /* empty */
| HAVING expr
limit_opt ::= /* empty */
| LIMIT expr
| LIMIT expr OFFSET expr
| LIMIT expr COMMA expr
where_opt ::= /* empty */
| WHERE expr
where_opt_ret ::= /* empty */
| WHERE expr
| RETURNING selcollist
| WHERE expr RETURNING selcollist
setlist ::= setlist COMMA nm EQ expr
| setlist COMMA LP idlist RP EQ expr
| nm EQ expr
| LP idlist RP EQ expr
upsert ::= /* empty */
| RETURNING selcollist
| ON CONFLICT LP sortlist RP where_opt DO UPDATE SET setlist where_opt upsert
| ON CONFLICT LP sortlist RP where_opt DO NOTHING upsert
| ON CONFLICT DO NOTHING returning
| ON CONFLICT DO UPDATE SET setlist where_opt returning
returning ::= RETURNING selcollist
| /* empty */
insert_cmd ::= INSERT orconf
| REPLACE
idlist_opt ::= /* empty */
| LP idlist RP
idlist ::= idlist COMMA nm
| nm
expr ::= term
| LP expr RP
| id
| JOIN_KW
| nm DOT nm
| nm DOT nm DOT nm
| VARIABLE
| expr COLLATE ids
| CAST LP expr AS typetoken RP
| id LP distinct exprlist RP
| id LP STAR RP
| id LP distinct exprlist RP filter_over
| id LP STAR RP filter_over
| LP nexprlist COMMA expr RP
| expr AND expr
| expr OR expr
| (expr LT|GT|GE|LE expr)
| (expr EQ|NE expr)
| (expr BITAND|BITOR|LSHIFT|RSHIFT expr)
| (expr PLUS|MINUS expr)
| (expr STAR|SLASH|REM expr)
| expr CONCAT expr
| expr likeop expr
| expr likeop expr ESCAPE expr
| (expr ISNULL|NOTNULL)
| expr NOT NULL
| expr IS expr
| expr IS NOT expr
| NOT expr
| BITNOT expr
| (PLUS|MINUS expr)
| expr between_op expr AND expr
| expr in_op LP exprlist RP
| LP select RP
| expr in_op LP select RP
| expr in_op nm dbnm paren_exprlist
| EXISTS LP select RP
| CASE case_operand case_exprlist case_else END
| RAISE LP IGNORE RP
| RAISE LP raisetype COMMA nm RP
term ::= (NULL|FLOAT|BLOB)
| STRING
| INTEGER
| CTIME_KW
likeop ::= (LIKE_KW|MATCH)
| (NOT LIKE_KW|MATCH)
between_op ::= BETWEEN
| NOT BETWEEN
in_op ::= IN
| NOT IN
case_exprlist ::= case_exprlist WHEN expr THEN expr
| WHEN expr THEN expr
case_else ::= ELSE expr
| /* empty */
case_operand ::= expr
| /* empty */
exprlist ::= nexprlist
| /* empty */
nexprlist ::= nexprlist COMMA expr
| expr
paren_exprlist ::= /* empty */
| LP exprlist RP
uniqueflag ::= UNIQUE
| /* empty */
eidlist_opt ::= /* empty */
| LP eidlist RP
eidlist ::= eidlist COMMA nm collate sortorder
| nm collate sortorder
collate ::= /* empty */
| COLLATE ids
vinto ::= INTO expr
| /* empty */
nmnum ::= plus_num
| nm
| ON
| DELETE
| DEFAULT
plus_num ::= PLUS number
| number
minus_num ::= MINUS number
trigger_decl ::= temp TRIGGER ifnotexists nm dbnm trigger_time trigger_event ON fullname foreach_clause when_clause
trigger_time ::= (BEFORE|AFTER)
| INSTEAD OF
| /* empty */
trigger_event ::= (DELETE|INSERT)
| UPDATE
| UPDATE OF idlist
foreach_clause ::= /* empty */
| FOR EACH ROW
when_clause ::= /* empty */
| WHEN expr
trigger_cmd_list ::= trigger_cmd_list trigger_cmd SEMI
| trigger_cmd SEMI
trnm ::= nm
| nm DOT nm
tridxby ::= /* empty */
| INDEXED BY nm
| NOT INDEXED
trigger_cmd ::= UPDATE orconf trnm tridxby SET setlist from where_opt scanpt
| scanpt insert_cmd INTO trnm idlist_opt select upsert scanpt
| DELETE FROM trnm tridxby where_opt scanpt
| scanpt select scanpt
raisetype ::= ROLLBACK
| ABORT
| FAIL
key_opt ::= /* empty */
| KEY expr
database_kw_opt ::= DATABASE
| /* empty */
add_column_fullname ::= fullname
kwcolumn_opt ::= /* empty */
| COLUMNKW
create_vtab ::= createkw VIRTUAL TABLE ifnotexists nm dbnm USING nm
vtabarglist ::= vtabarg
| vtabarglist COMMA vtabarg
vtabarg ::= /* empty */
| vtabarg vtabargtoken
vtabargtoken ::= ANY
| lp anylist RP
lp ::= LP
anylist ::= /* empty */
| anylist LP anylist RP
| anylist ANY
with ::= /* empty */
| WITH wqlist
| WITH RECURSIVE wqlist
wqas ::= AS
| AS MATERIALIZED
| AS NOT MATERIALIZED
wqitem ::= nm eidlist_opt wqas LP select RP
wqlist ::= wqitem
| wqlist COMMA wqitem
windowdefn_list ::= windowdefn
| windowdefn_list COMMA windowdefn
windowdefn ::= nm AS LP window RP
window ::= PARTITION BY nexprlist orderby_opt frame_opt
| nm PARTITION BY nexprlist orderby_opt frame_opt
| ORDER BY sortlist frame_opt
| nm ORDER BY sortlist frame_opt
| frame_opt
| nm frame_opt
frame_opt ::= /* empty */
| range_or_rows frame_bound_s frame_exclude_opt
| range_or_rows BETWEEN frame_bound_s AND frame_bound_e frame_exclude_opt
range_or_rows ::= (RANGE|ROWS|GROUPS)
frame_bound_s ::= frame_bound
| UNBOUNDED PRECEDING
frame_bound_e ::= frame_bound
| UNBOUNDED FOLLOWING
frame_bound ::= (expr PRECEDING|FOLLOWING)
| CURRENT ROW
frame_exclude_opt ::= /* empty */
| EXCLUDE frame_exclude
frame_exclude ::= NO OTHERS
| CURRENT ROW
| (GROUP|TIES)
window_clause ::= WINDOW windowdefn_list
filter_over ::= filter_clause over_clause
| over_clause
| filter_clause
over_clause ::= OVER LP window RP
| OVER nm
filter_clause ::= FILTER LP WHERE expr RP
// Tokens
ABORT ::= "ABORT"
ACTION ::= "ACTION"
ADD ::= "ADD"
AFTER ::= "AFTER"
ALL ::= "ALL"
ALTER ::= "ALTER"
ALWAYS ::= "ALWAYS"
ANALYZE ::= "ANALYZE"
AND ::= "AND"
AS ::= "AS"
ASC ::= "ASC"
ATTACH ::= "ATTACH"
AUTOINCREMENT ::= "AUTOINCREMENT"
BEFORE ::= "BEFORE"
BEGIN ::= "BEGIN"
BETWEEN ::= "BETWEEN"
BY ::= "BY"
CASCADE ::= "CASCADE"
CASE ::= "CASE"
CAST ::= "CAST"
CHECK ::= "CHECK"
COLLATE ::= "COLLATE"
COLUMN ::= "COLUMN"
COMMIT ::= "COMMIT"
CONFLICT ::= "CONFLICT"
CONSTRAINT ::= "CONSTRAINT"
CREATE ::= "CREATE"
CROSS ::= "CROSS"
CURRENT ::= "CURRENT"
CURRENT_DATE ::= "CURRENT_DATE"
CURRENT_TIME ::= "CURRENT_TIME"
CURRENT_TIMESTAMP ::= "CURRENT_TIMESTAMP"
DATABASE ::= "DATABASE"
DEFAULT ::= "DEFAULT"
DEFERRED ::= "DEFERRED"
DEFERRABLE ::= "DEFERRABLE"
DELETE ::= "DELETE"
DESC ::= "DESC"
DETACH ::= "DETACH"
DISTINCT ::= "DISTINCT"
DO ::= "DO"
DROP ::= "DROP"
END ::= "END"
EACH ::= "EACH"
ELSE ::= "ELSE"
ESCAPE ::= "ESCAPE"
EXCEPT ::= "EXCEPT"
EXCLUSIVE ::= "EXCLUSIVE"
EXCLUDE ::= "EXCLUDE"
EXISTS ::= "EXISTS"
EXPLAIN ::= "EXPLAIN"
FAIL ::= "FAIL"
FILTER ::= "FILTER"
FIRST ::= "FIRST"
FOLLOWING ::= "FOLLOWING"
FOR ::= "FOR"
FOREIGN ::= "FOREIGN"
FROM ::= "FROM"
FULL ::= "FULL"
GENERATED ::= "GENERATED"
GLOB ::= "GLOB"
GROUP ::= "GROUP"
GROUPS ::= "GROUPS"
HAVING ::= "HAVING"
IF ::= "IF"
IGNORE ::= "IGNORE"
IMMEDIATE ::= "IMMEDIATE"
IN ::= "IN"
INDEX ::= "INDEX"
INDEXED ::= "INDEXED"
INITIALLY ::= "INITIALLY"
INNER ::= "INNER"
INSERT ::= "INSERT"
INSTEAD ::= "INSTEAD"
INTERSECT ::= "INTERSECT"
INTO ::= "INTO"
IS ::= "IS"
ISNULL ::= "ISNULL"
JOIN ::= "JOIN"
KEY ::= "KEY"
LAST ::= "LAST"
LEFT ::= "LEFT"
LIKE ::= "LIKE"
LIMIT ::= "LIMIT"
MATCH ::= "MATCH"
MATERIALIZED ::= "MATERIALIZED"
NATURAL ::= "NATURAL"
NO ::= "NO"
NOT ::= "NOT"
NOTHING ::= "NOTHING"
NOTNULL ::= "NOTNULL"
NULL ::= "NULL"
NULLS ::= "NULLS"
OF ::= "OF"
OFFSET ::= "OFFSET"
ON ::= "ON"
OR ::= "OR"
ORDER ::= "ORDER"
OTHERS ::= "OTHERS"
OUTER ::= "OUTER"
OVER ::= "OVER"
PARTITION ::= "PARTITION"
PLAN ::= "PLAN"
PRAGMA ::= "PRAGMA"
PRECEDING ::= "PRECEDING"
PRIMARY ::= "PRIMARY"
QUERY ::= "QUERY"
RAISE ::= "RAISE"
RANGE ::= "RANGE"
RECURSIVE ::= "RECURSIVE"
REFERENCES ::= "REFERENCES"
REGEXP ::= "REGEXP"
REINDEX ::= "REINDEX"
RELEASE ::= "RELEASE"
RENAME ::= "RENAME"
REPLACE ::= "REPLACE"
RESTRICT ::= "RESTRICT"
RETURNING ::= "RETURNING"
RIGHT ::= "RIGHT"
ROLLBACK ::= "ROLLBACK"
ROW ::= "ROW"
ROWS ::= "ROWS"
SAVEPOINT ::= "SAVEPOINT"
SELECT ::= "SELECT"
SET ::= "SET"
TABLE ::= "TABLE"
TEMP ::= "TEMP"
TEMPORARY ::= "TEMPORARY"
THEN ::= "THEN"
TIES ::= "TIES"
TO ::= "TO"
TRANSACTION ::= "TRANSACTION"
TRIGGER ::= "TRIGGER"
UNBOUNDED ::= "UNBOUNDED"
UNION ::= "UNION"
UNIQUE ::= "UNIQUE"
UPDATE ::= "UPDATE"
USING ::= "USING"
VACUUM ::= "VACUUM"
VALUES ::= "VALUES"
VIEW ::= "VIEW"
VIRTUAL ::= "VIRTUAL"
WHEN ::= "WHEN"
WHERE ::= "WHERE"
WINDOW ::= "WINDOW"
WITH ::= "WITH"
WITHOUT ::= "WITHOUT"
PIPE ::= '|'
MINUS ::= '-'
LT ::= '<'
GT ::= '>'
EQ ::= '='
BANG ::= '!'
SLASH ::= '/'
LP ::= '('
RP ::= ')'
SEMI ::= ';'
PLUS ::= '+'
STAR ::= '*'
PERCENT ::= '%'
COMMA ::= ','
AND ::= '&'
TILDA ::= '~'
DOT ::= '.'
====