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| 1 | namespace Syntax.Parsers.Definitions is | |
| 2 | use Source | |
| 3 | use Logging | |
| 4 | ||
| 5 | class VARIANT( | |
| 6 | identifier_parser: Parser[Trees.Identifiers.Identifier], | |
| 7 | variable_list_parser: Parser[Trees.Variables.LIST], | |
| 8 | modifier_parser: Parser[Trees.Modifiers.LIST] | |
| 9 | ): Base[Trees.Definitions.VARIANT] is | |
| 10 | super() | |
| 11 | ||
| 12 | parse(context: CONTEXT) -> Trees.Definitions.VARIANT? is | |
| 13 | let start = context.location | |
| 14 | context.in_classy = true | |
| 15 | context.global_indent = start.start_column | |
| 16 | ||
| 17 | /* | |
| 18 | parse a typed-union variant, which is of the form | |
| 19 | ||
| 20 | variant_definition ::= identifier variant_fields? "default"? ";" | |
| 21 | variant_fields ::= "(" variant_field ("," variant_field)* ")" | |
| 22 | variant_field ::= identifier ":" type_expression | |
| 23 | ||
| 24 | A trailing `default` nominates this variant as the union's | |
| 25 | default variant — the one `?` and `!` test and unwrap. | |
| 26 | */ | |
| 27 | ||
| 28 | try | |
| 29 | let identifier = identifier_parser.parse(context) | |
| 30 | ||
| 31 | let should_poison mut = false | |
| 32 | ||
| 33 | if !identifier? then | |
| 34 | return null | |
| 35 | fi | |
| 36 | ||
| 37 | should_poison = identifier.is_poisoned | |
| 38 | ||
| 39 | let members: Trees.Variables.LIST mut = Trees.Variables.LIST(start::context.location, System.Array.empty`[Trees.Variables.VARIABLE]()) | |
| 40 | ||
| 41 | if context.current_token == Lexical.TOKEN.PAREN_OPEN then | |
| 42 | context.next_token() | |
| 43 | ||
| 44 | let previous_in_init_arguments = context.in_init_arguments | |
| 45 | context.in_init_arguments = true | |
| 46 | try | |
| 47 | members = variable_list_parser.parse(context)! | |
| 48 | finally | |
| 49 | context.in_init_arguments = previous_in_init_arguments | |
| 50 | yrt | |
| 51 | ||
| 52 | should_poison = should_poison \/ members.is_poisoned | |
| 53 | ||
| 54 | if !should_poison \/ context.current_token == Lexical.TOKEN.PAREN_CLOSE then | |
| 55 | context.next_token(Lexical.TOKEN.PAREN_CLOSE) | |
| 56 | fi | |
| 57 | else | |
| 58 | ||
| 59 | for m in members do | |
| 60 | if !m.is_explicit_type then | |
| 61 | context.error(m.location, "variant field must have an explicit type") | |
| 62 | should_poison = true | |
| 63 | fi | |
| 64 | od | |
| 65 | fi | |
| 66 | ||
| 67 | let modifiers = Trees.Modifiers.LIST( | |
| 68 | context.location, | |
| 69 | Trees.Modifiers.PUBLIC(context.location), | |
| 70 | Trees.Modifiers.FIELD(context.location) | |
| 71 | ) | |
| 72 | ||
| 73 | let is_default mut = false | |
| 74 | ||
| 75 | if context.current_token == Lexical.TOKEN.DEFAULT then | |
| 76 | is_default = true | |
| 77 | context.next_token() | |
| 78 | fi | |
| 79 | ||
| 80 | if !should_poison \/ context.current_token == Lexical.TOKEN.SEMICOLON then | |
| 81 | context.accept_terminator() | |
| 82 | fi | |
| 83 | ||
| 84 | // Read once the variant is parsed, so the extent ends at the | |
| 85 | // variant's own last token rather than at whatever follows it. | |
| 86 | let semicolon_end = context.previous_end | |
| 87 | ||
| 88 | let result = Trees.Definitions.VARIANT( | |
| 89 | start::semicolon_end, | |
| 90 | identifier!, | |
| 91 | members, | |
| 92 | modifiers | |
| 93 | ) | |
| 94 | ||
| 95 | result.is_default = is_default | |
| 96 | result.poison(should_poison) | |
| 97 | ||
| 98 | return result | |
| 99 | finally | |
| 100 | context.in_classy = false | |
| 101 | yrt | |
| 102 | si | |
| 103 | si | |
| 104 | si |