Appearance
| 1 | namespace Syntax.Process is | |
| 2 | ||
| 3 | class YIELD_SCANNER: Visitor is | |
| 4 | _found: bool | |
| 5 | ||
| 6 | init() is | |
| 7 | super.init() | |
| 8 | si | |
| 9 | ||
| 10 | body_has_yield(body: Trees.Bodies.Body?) -> bool is | |
| 11 | if !body? then | |
| 12 | return false | |
| 13 | fi | |
| 14 | ||
| 15 | _found = false | |
| 16 | ||
| 17 | body.walk(self) | |
| 18 | ||
| 19 | return _found | |
| 20 | si | |
| 21 | ||
| 22 | pre(`yield: Trees.Statements.YIELD) -> bool is | |
| 23 | _found = true | |
| 24 | ||
| 25 | return true | |
| 26 | si | |
| 27 | ||
| 28 | pre(`yield: Trees.Statements.YIELD_ALL) -> bool is | |
| 29 | _found = true | |
| 30 | ||
| 31 | return true | |
| 32 | si | |
| 33 | ||
| 34 | pre(function: Trees.Definitions.FUNCTION) -> bool => true | |
| 35 | pre(function: Trees.Expressions.FUNCTION) -> bool => true | |
| 36 | si | |
| 37 | ||
| 38 | // Scans a generator body for `for` loops. `let` bindings ARE | |
| 39 | // supported now (locals are lifted onto state-machine frame | |
| 40 | // fields via state_machine_field), but `for` lowers to a hidden | |
| 41 | // iterator TEMP that doesn't yet route through frame fields, so | |
| 42 | // the iterator gets re-created on every MoveNext re-entry. Until | |
| 43 | // TEMPs gain state-machine awareness, ask users to write the | |
| 44 | // expansion by hand: | |
| 45 | // | |
| 46 | // let it = xs.iterator; | |
| 47 | // while it.move_next() do | |
| 48 | // yield it.current; | |
| 49 | // od | |
| 50 | class GENERATOR_FOR_SCANNER: Visitor is | |
| 51 | _logger: Logging.Logger | |
| 52 | ||
| 53 | init(logger: Logging.Logger) is | |
| 54 | super.init() | |
| 55 | ||
| 56 | _logger = logger | |
| 57 | si | |
| 58 | ||
| 59 | scan(body: Trees.Bodies.Body?) is | |
| 60 | if !body? then | |
| 61 | return | |
| 62 | fi | |
| 63 | ||
| 64 | body.walk(self) | |
| 65 | si | |
| 66 | ||
| 67 | pre(`for: Trees.Statements.FOR) -> bool is | |
| 68 | _logger.error( | |
| 69 | `for.location, | |
| 70 | "for loop inside generator body is not yet supported" | |
| 71 | ) | |
| 72 | ||
| 73 | return false | |
| 74 | si | |
| 75 | ||
| 76 | pre(function: Trees.Definitions.FUNCTION) -> bool => true | |
| 77 | pre(function: Trees.Expressions.FUNCTION) -> bool => true | |
| 78 | si | |
| 79 | ||
| 80 | // Scans a generator body for `yield` inside a `catch` or | |
| 81 | // `finally` HANDLER body. Yield in a try BODY is fine — | |
| 82 | // state-machine codegen handles it via per-region dispatch + the | |
| 83 | // `'.gen_state'` local + state-guarded finally. Handlers | |
| 84 | // (catch / finally) still need an AST-level rewrite (pend | |
| 85 | // exception, yield outside the handler, restore), so flag those | |
| 86 | // with a clean compile-time error. | |
| 87 | class YIELD_IN_TRY_SCANNER: HANDLER_DEPTH_SCANNER is | |
| 88 | init(logger: Logging.Logger) is | |
| 89 | super.init(logger) | |
| 90 | si | |
| 91 | ||
| 92 | pre(`yield: Trees.Statements.YIELD) -> bool is | |
| 93 | if handler_depth > 0 then | |
| 94 | logger.error(`yield.location, "yield inside a catch or finally handler is not yet supported") | |
| 95 | fi | |
| 96 | return true | |
| 97 | si | |
| 98 | ||
| 99 | pre(`yield: Trees.Statements.YIELD_ALL) -> bool is | |
| 100 | if handler_depth > 0 then | |
| 101 | logger.error(`yield.location, "yield inside a catch or finally handler is not yet supported") | |
| 102 | fi | |
| 103 | return true | |
| 104 | si | |
| 105 | si | |
| 106 | si |