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| 1 | namespace Semantic.Types is | |
| 2 | use IO.Std | |
| 3 | ||
| 4 | use Logging | |
| 5 | ||
| 6 | class NAMED: Type is | |
| 7 | _compare_count: int static | |
| 8 | _same_count: int static | |
| 9 | _named_count: int static | |
| 10 | _hit_count: int static | |
| 11 | _miss_count: int static | |
| 12 | ||
| 13 | // Keyed on the symbols themselves. A pair of their hash codes | |
| 14 | // is not a key: two unrelated pairs that collide on it read | |
| 15 | // each other's answer, and a wrong SAME or ASSIGNABLE surfaces | |
| 16 | // far from here with nothing pointing back. | |
| 17 | _cache: Collections.MutableMap[(Symbols.Symbol,Symbols.Symbol), Types.MATCH] static | |
| 18 | ||
| 19 | name: string => symbol.name | |
| 20 | scope: Scope => symbol | |
| 21 | ||
| 22 | _symbol: Symbols.Symbol | |
| 23 | ||
| 24 | // Set when this reference type was written with a `?` | |
| 25 | // nullability annotation. Directional: a `T?` slot accepts a | |
| 26 | // `T` value (widening); a `T` slot does not accept a `T?` | |
| 27 | // value (would lose the discriminator). | |
| 28 | _is_optional: bool | |
| 29 | ||
| 30 | symbol: Symbols.Symbol => _symbol | |
| 31 | ||
| 32 | is_optional: bool => _is_optional | |
| 33 | ||
| 34 | optional_inner_type: Type? => | |
| 35 | if _is_optional then as_non_optional() else null fi | |
| 36 | ||
| 37 | short_description: string => | |
| 38 | if _is_optional then | |
| 39 | "{symbol.name}?" | |
| 40 | else | |
| 41 | symbol.name | |
| 42 | fi | |
| 43 | ||
| 44 | is_type_variable: bool => | |
| 45 | symbol.is_type_variable | |
| 46 | ||
| 47 | is_named: bool => true | |
| 48 | ||
| 49 | is_value_type: bool => symbol.is_value_type | |
| 50 | is_trait: bool => symbol.is_trait | |
| 51 | is_inheritable: bool => symbol.is_inheritable | |
| 52 | is_class: bool => symbol.is_class | |
| 53 | is_object: bool => symbol.is_object | |
| 54 | is_root_value_type: bool => symbol.is_root_value_type | |
| 55 | is_void: bool => symbol.is_void | |
| 56 | ||
| 57 | init(symbol: Symbols.Symbol) is | |
| 58 | super.init() | |
| 59 | ||
| 60 | _symbol = symbol | |
| 61 | si | |
| 62 | ||
| 63 | matches(other: Type) -> bool => | |
| 64 | if other.is_sentinel then | |
| 65 | true | |
| 66 | elif isa ONE_OF(other) /\ !isa ONE_OF(self) then | |
| 67 | // ONE_OF carries the underlying union's symbol but | |
| 68 | // narrows to a proper variant subset — never matches | |
| 69 | // the plain union it was built over. ONE_OF's own `matches` | |
| 70 | // override handles the ONE_OF-against-ONE_OF case. | |
| 71 | false | |
| 72 | elif isa INTERSECTION(other) /\ !isa INTERSECTION(self) then | |
| 73 | // INTERSECTION inherits NAMED with members[0].symbol | |
| 74 | // as its "primary" symbol, but the intersection is | |
| 75 | // not the same type as a plain NAMED holding that | |
| 76 | // symbol — `Symbol` does not match `Symbol & Trait`. | |
| 77 | // INTERSECTION's own `matches` override handles the | |
| 78 | // INTERSECTION-against-INTERSECTION case. | |
| 79 | false | |
| 80 | elif isa NAMED(other) then | |
| 81 | let other_symbol = other | |
| 82 | symbol == other_symbol.symbol | |
| 83 | else | |
| 84 | false | |
| 85 | fi | |
| 86 | ||
| 87 | is_equivalent_to(other: Type) -> bool => | |
| 88 | self.matches(other) /\ (other.is_sentinel \/ is_optional == other.is_optional) | |
| 89 | ||
| 90 | specialize(type_map: Collections.Map[Symbols.Symbol,Type]) -> Type => | |
| 91 | if type_map.contains_key(symbol) then | |
| 92 | // A flagged `T?` keeps its nullability when `T` is | |
| 93 | // substituted — `T?` with `T := Foo` is `Foo?`. | |
| 94 | if _is_optional then | |
| 95 | type_map[symbol].as_optional() | |
| 96 | else | |
| 97 | type_map[symbol] | |
| 98 | fi | |
| 99 | else | |
| 100 | self | |
| 101 | fi | |
| 102 | ||
| 103 | _cache_result(other: Type, result: Types.MATCH) -> Types.MATCH is | |
| 104 | _cache[(self.symbol, other.symbol)] = result | |
| 105 | ||
| 106 | return result | |
| 107 | si | |
| 108 | ||
| 109 | dump_stats() static is | |
| 110 | debug_always("cache size: {_cache.count} named ratio: {cast double(_hit_count) / cast double(_named_count)}") | |
| 111 | ||
| 112 | debug_always("total: {_compare_count} named: {_named_count} same: {_same_count} misses: {_miss_count} hits: {_hit_count}") | |
| 113 | si | |
| 114 | ||
| 115 | init() static is | |
| 116 | _cache = Collections.MAP[(Symbols.Symbol,Symbols.Symbol), Types.MATCH]() | |
| 117 | si | |
| 118 | ||
| 119 | clear_cache() static is | |
| 120 | _cache.clear() | |
| 121 | si | |
| 122 | ||
| 123 | compare(other: Type) -> Types.MATCH is | |
| 124 | _compare_count = _compare_count + 1 | |
| 125 | if other.is_sentinel then | |
| 126 | return Types.MATCH.ASSIGNABLE | |
| 127 | fi | |
| 128 | ||
| 129 | // `null` is a value of an optional type and of no other, | |
| 130 | // so only an optional slot accepts one. A `class`- | |
| 131 | // constrained type variable written `T?` is covered by the | |
| 132 | // same test, though it reports is_value_type. | |
| 133 | // | |
| 134 | // Error types and the sentinels standing in for a type | |
| 135 | // still being inferred also answer `is_null`, but they are | |
| 136 | // already assignable from the sentinel test above, so this | |
| 137 | // reaches a written `null` alone. | |
| 138 | if other.is_null /\ accepts_null then | |
| 139 | return Types.MATCH.ASSIGNABLE | |
| 140 | fi | |
| 141 | ||
| 142 | // Ghul.MAYBE[T] → reference-T? widening. The carrier's | |
| 143 | // `value` field already holds the reference (null when | |
| 144 | // absent, the user's reference when present), so a single | |
| 145 | // property load at the slot boundary is the whole coercion. | |
| 146 | if _is_optional /\ !is_value_type /\ other.is_maybe then | |
| 147 | let other_inner = other.optional_inner_type | |
| 148 | ||
| 149 | if other_inner? /\ self.as_non_optional().is_assignable_from(other_inner) then | |
| 150 | return Types.MATCH.ASSIGNABLE | |
| 151 | fi | |
| 152 | fi | |
| 153 | ||
| 154 | if other.is_named then | |
| 155 | _named_count = _named_count + 1 | |
| 156 | ||
| 157 | // Strict non-nullable-by-default: a `T` slot never | |
| 158 | // accepts a `T?` value. The caller must narrow first | |
| 159 | // (`x!`, `if let`, `if x?`). This applies uniformly | |
| 160 | // — symbol equality and subtype relationships below | |
| 161 | // don't loosen it. Without this check, the ancestor | |
| 162 | // walk below silently drops the optional flag because | |
| 163 | // ancestor types are bare (see `Symbol.ancestors`). | |
| 164 | // | |
| 165 | // Wild placeholders (unbound type variables) skip | |
| 166 | // this — a wild `T` matches anything during overload | |
| 167 | // resolution's first pass, and binding picks up the | |
| 168 | // optional flag from the actual. | |
| 169 | if !is_wild /\ !_is_optional /\ other.is_optional then | |
| 170 | return Types.MATCH.DIFFERENT | |
| 171 | fi | |
| 172 | ||
| 173 | if symbol == other.symbol then | |
| 174 | if _is_optional == other.is_optional then | |
| 175 | _same_count = _same_count + 1 | |
| 176 | return Types.MATCH.SAME | |
| 177 | else | |
| 178 | // `T?` slot accepts `T` value via the implicit | |
| 179 | // widening — null becomes the absent marker, a | |
| 180 | // non-null reference flows through unchanged. | |
| 181 | // (The `T` slot accepting `T?` case is already | |
| 182 | // rejected by the strict check above.) | |
| 183 | return Types.MATCH.ASSIGNABLE | |
| 184 | fi | |
| 185 | fi | |
| 186 | ||
| 187 | // System.Array is the base class of every array in | |
| 188 | // .NET, which the array type's own ancestors, being | |
| 189 | // traits, have no way to say. | |
| 190 | if symbol.is_root_array_type /\ isa Types.ARRAY(other) then | |
| 191 | return Types.MATCH.ASSIGNABLE | |
| 192 | fi | |
| 193 | ||
| 194 | let result: Types.MATCH mut = _ | |
| 195 | ||
| 196 | if _cache.try_get_value((self.symbol, other.symbol), result ref) then | |
| 197 | _hit_count = _hit_count + 1 | |
| 198 | return result | |
| 199 | fi | |
| 200 | ||
| 201 | _miss_count = _miss_count + 1 | |
| 202 | ||
| 203 | for a in other.symbol.ancestors do | |
| 204 | let match = self.compare(a) | |
| 205 | ||
| 206 | if cast int(match) <= cast int(Types.MATCH.ASSIGNABLE) then | |
| 207 | return _cache_result(other, Types.MATCH.ASSIGNABLE) | |
| 208 | elif match == Types.MATCH.CONVERTABLE then | |
| 209 | return _cache_result(other, Types.MATCH.CONVERTABLE) | |
| 210 | fi | |
| 211 | od | |
| 212 | ||
| 213 | if is_wild \/ other.is_wild then | |
| 214 | return _cache_result(other, Types.MATCH.WILD) | |
| 215 | fi | |
| 216 | ||
| 217 | return _cache_result(other, Types.MATCH.DIFFERENT) | |
| 218 | fi | |
| 219 | ||
| 220 | // FIXME: should we be caching this result? | |
| 221 | return Types.MATCH.DIFFERENT | |
| 222 | si | |
| 223 | ||
| 224 | find_member(name: string) -> Symbols.Symbol? => symbol.find_member(name) | |
| 225 | ||
| 226 | get_destructure_member_name(index: int) -> string? => symbol.get_destructure_member_name(index) | |
| 227 | ||
| 228 | find_ancestor(type: Type) -> Type? => symbol.find_ancestor(type) | |
| 229 | ||
| 230 | freeze() -> Type? => | |
| 231 | let result = symbol.freeze() in | |
| 232 | if result? then result.type else null fi | |
| 233 | ||
| 234 | walk(action: (Type) -> void) is | |
| 235 | action(self) | |
| 236 | si | |
| 237 | ||
| 238 | as_optional() -> Type is | |
| 239 | // A genuine value type carries optionality as NULLABLE[T], | |
| 240 | // never the reference flag. A type variable reports | |
| 241 | // is_value_type spuriously (every GenericArgument does), | |
| 242 | // so exclude it — a `class`-constrained `T?` is flagged. | |
| 243 | if _is_optional \/ (is_value_type /\ !is_type_variable) then | |
| 244 | return self | |
| 245 | fi | |
| 246 | ||
| 247 | return as_optional_unchecked() | |
| 248 | si | |
| 249 | ||
| 250 | // Reflected-import variant of `as_optional` that skips the | |
| 251 | // is_value_type / is_type_variable guards. Those guards are | |
| 252 | // about preventing source-side `as_optional()` from flagging a | |
| 253 | // value type as a reference optional. At reflection time the | |
| 254 | // caller already knows the slot was marked by the emitter, | |
| 255 | // which only emits NullableAttribute on reference-`?` slots | |
| 256 | // (Semantic.DotNet.NULLABILITY.needs_attribute filters value | |
| 257 | // types out). Skipping the guards avoids forcing materialization | |
| 258 | // of a lazy TYPE_WRAPPER's symbol during bootstrap — the | |
| 259 | // re-entrant `get_array_type` lookups it triggers would crash | |
| 260 | // before the innate-symbol table is populated. | |
| 261 | as_optional_unchecked() -> Type is | |
| 262 | let result = cast NAMED?(memberwise_clone())! | |
| 263 | ||
| 264 | result._is_optional = true | |
| 265 | ||
| 266 | return result | |
| 267 | si | |
| 268 | ||
| 269 | as_non_optional() -> Type is | |
| 270 | if !_is_optional then | |
| 271 | return self | |
| 272 | fi | |
| 273 | ||
| 274 | let result = cast NAMED?(memberwise_clone())! | |
| 275 | ||
| 276 | result._is_optional = false | |
| 277 | ||
| 278 | return result | |
| 279 | si | |
| 280 | ||
| 281 | to_string() -> string => | |
| 282 | if _is_optional then | |
| 283 | "{IoC.CONTAINER.instance.name_display.name_for(symbol)}?" | |
| 284 | else | |
| 285 | IoC.CONTAINER.instance.name_display.name_for(symbol) | |
| 286 | fi | |
| 287 | si | |
| 288 | si |