toml: support multi-level map keys in arrays-of-tables (#12641)

vlib/toml/parser/parser.v

@@ -575,8 +575,8 @@ pub fn (mut p Parser) root_table() ? {
 					//
 					// `table.key` now shape shifts into being a *double array of tables* key...
 					// ... but with a different set of rules - making it hard to reuse the code we already have for that ...
-					// See `testdata/array_of_tables_edge_case_1_test.toml` for the type of construct parsed.
+					// See `testdata/array_of_tables_edge_case_<N>_test.toml` for the type of constructs parsed.
-					if p.last_aot.len == 1 && dotted_key.len == 2
+					if p.last_aot.len == 1 && dotted_key.len > 1
 						&& dotted_key[0] == p.last_aot.str() {
 						// Disallow re-declaring the key
 						p.check_explicitly_declared_array_of_tables(dotted_key) ?
@@ -589,7 +589,20 @@ pub fn (mut p Parser) root_table() ? {
 								p.table_contents(mut m) ?
 								unsafe {
 									mut mut_val := &val
-									mut_val[dotted_key[1].str()] = m
+									if dotted_key.len == 2 {
+										// [table.key]
+										mut_val[dotted_key[1].str()] = m
+									} else {
+										// [table.key.key.etc]
+										mut dotted_key_copy := dotted_key.clone()
+										dotted_key_copy.delete(0)
+										new_key := todo_msvc_astring2dkey(dotted_key_copy)
+										sub_table, key := p.sub_table_key(new_key)
+										t := p.find_in_table(mut mut_val, sub_table) ?
+										util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN,
+											'setting "$key" = $val in table ${ptr_str(t)}')
+										t[new_key.last().str()] = m
+									}
 								}
 							} else {
 								return error(@MOD + '.' + @STRUCT + '.' + @FN +
@@ -606,6 +619,7 @@ pub fn (mut p Parser) root_table() ? {
 					p.check_implicitly_declared(dotted_key) ?
 
 					p.ignore_while(parser.space_formatting)
+
 					util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'setting root map key to `$dotted_key` at "$p.tok.kind" "$p.tok.lit"')
 					p.root_map_key = dotted_key
 					p.allocate_table(p.root_map_key) ?
@@ -628,6 +642,9 @@ pub fn (mut p Parser) root_table() ? {
 							' key `$dotted_key` has already been explicitly declared. Unexpected redeclaration at "$p.tok.kind" "$p.tok.lit" in this (excerpt): "...${p.excerpt()}..."')
 					}
 
+					// Allow [ key ]
+					p.ignore_while(parser.space_formatting)
+
 					util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'setting root map key to `$dotted_key` at "$p.tok.kind" "$p.tok.lit"')
 					p.root_map_key = dotted_key
 					p.allocate_table(p.root_map_key) ?
@@ -805,6 +822,7 @@ pub fn (mut p Parser) array_of_tables(mut table map[string]ast.Value) ? {
 	// NOTE this is starting to get ugly. TOML isn't simple at this point
 	p.check(.lsbr) ? // '[' bracket
 
+	// Allow [[ key]]
 	p.ignore_while(parser.space_formatting)
 	peek_tok, _ := p.peek_over(1, parser.space_formatting) ?
 	p.ignore_while(parser.space_formatting)
@@ -817,6 +835,10 @@ pub fn (mut p Parser) array_of_tables(mut table map[string]ast.Value) ? {
 
 	key := p.key() ?
 	p.next() ?
+
+	// Allow [[key ]]
+	p.ignore_while(parser.space_formatting)
+
 	p.check(.rsbr) ?
 	p.peek_for_correct_line_ending_or_fail() ?
 	p.expect(.rsbr) ?

vlib/toml/tests/alexcrichton.toml-rs-tests_test.v

@@ -13,7 +13,6 @@ const (
 		'valid/example-v0.3.0.toml',
 		'valid/example-v0.4.0.toml',
 		'valid/datetime-truncate.toml', // Not considered valid since RFC 3339 doesn't permit > 6 ms digits ??
-		'valid/table-array-nest-no-keys.toml',
 	]
 	invalid_exceptions     = [
 		'invalid/string-bad-line-ending-escape.toml',
@@ -31,6 +30,7 @@ const (
 		'valid/table-array-many.toml',
 		'valid/table-array-one.toml',
 		'valid/table-array-nest.toml',
+		'valid/table-array-nest-no-keys.toml',
 	]
 
 	jq                     = os.find_abs_path_of_executable('jq') or { '' }

vlib/toml/tests/array_of_tables_edge_case_2_test.v

@@ -0,0 +1,18 @@
+import os
+import toml
+import toml.to
+
+fn test_array_of_tables_edge_case_file() {
+	toml_file :=
+		os.real_path(os.join_path(os.dir(@FILE), 'testdata', os.file_name(@FILE).all_before_last('.'))) +
+		'.toml'
+	toml_doc := toml.parse(toml_file) or { panic(err) }
+
+	toml_json := to.json(toml_doc)
+	out_file :=
+		os.real_path(os.join_path(os.dir(@FILE), 'testdata', os.file_name(@FILE).all_before_last('.'))) +
+		'.out'
+	out_file_json := os.read_file(out_file) or { panic(err) }
+	println(toml_json)
+	assert toml_json == out_file_json
+}

vlib/toml/tests/testdata/array_of_tables_edge_case_2_test.out

@@ -0,0 +1 @@
+{ "albums": [ { "songs": [ { }, { } ] } ], "artists": [ { "home": { "address": { } } } ] }

vlib/toml/tests/testdata/array_of_tables_edge_case_2_test.toml

@@ -0,0 +1,6 @@
+[[ albums ]]
+  [[ albums.songs ]]
+  [[ albums.songs ]]
+
+[[ artists ]]
+  [ artists.home.address ]