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| 1 | namespace Syntax.Process is | |
| 2 | use Source | |
| 3 | use Logging | |
| 4 | use Trees | |
| 5 | ||
| 6 | // Synthesises a global entry point from a file's top-level statements. | |
| 7 | // | |
| 8 | // A file with no namespace may carry bare statements at file scope. The | |
| 9 | // parser collects them, in source order, onto the root definition list; | |
| 10 | // this rewriter wraps them into a global function named after the | |
| 11 | // configured entry point, so every downstream phase sees an ordinary | |
| 12 | // function. Runs before expand_namespaces, which then wraps the | |
| 13 | // synthesised function into the file's root namespace alongside any other | |
| 14 | // global definitions. | |
| 15 | // | |
| 16 | // Top-level statements and namespaces are mutually exclusive in a file: | |
| 17 | // a file that carries both is a compile error and no entry is synthesised. | |
| 18 | // | |
| 19 | // The entry takes the two shapes the runtime can hand an entry point - | |
| 20 | // `args: string[]` and `env: Ghul.Environment` - so the statements can | |
| 21 | // read the command line and the process environment directly, and a | |
| 22 | // Main-compatible `_entry` wrapper is synthesised beside it to carry | |
| 23 | // both in. | |
| 24 | class SYNTHESISE_TOP_LEVEL_ENTRY(_ir_context: IR.CONTEXT, _logger: Logger) is | |
| 25 | apply(node: Node) is | |
| 26 | if !isa Definitions.LIST(node) then | |
| 27 | return | |
| 28 | fi | |
| 29 | ||
| 30 | let list = cast Definitions.LIST(node) | |
| 31 | let statements = list.top_level_statements | |
| 32 | ||
| 33 | if !statements? then | |
| 34 | return | |
| 35 | fi | |
| 36 | ||
| 37 | list.top_level_statements = null | |
| 38 | ||
| 39 | for definition in list do | |
| 40 | if isa Definitions.NAMESPACE(definition) then | |
| 41 | _logger.error( | |
| 42 | statements.location, | |
| 43 | "top-level statements cannot appear in a file with a namespace" | |
| 44 | ) | |
| 45 | ||
| 46 | return | |
| 47 | fi | |
| 48 | od | |
| 49 | ||
| 50 | for statement in statements do | |
| 51 | if isa Statements.LET(statement) then | |
| 52 | for variable in statement.variables do | |
| 53 | variable.is_top_level = true | |
| 54 | ||
| 55 | if _reject_entry_parameter_collision(variable) then | |
| 56 | statement.poison() | |
| 57 | variable.poison() | |
| 58 | fi | |
| 59 | od | |
| 60 | fi | |
| 61 | od | |
| 62 | ||
| 63 | // Pushed to the front so compile-expressions walks the entry | |
| 64 | // before any other function in the file: the top-level `let` | |
| 65 | // variables it declares settle their inferred types during the | |
| 66 | // entry's own walk, and every sibling function reads them | |
| 67 | // after that. | |
| 68 | list.push(_synthesise_entry(statements)) | |
| 69 | si | |
| 70 | ||
| 71 | // Whether a file's root definition list carries a synthesised | |
| 72 | // top-level entry. Consulted wherever that file needs treating | |
| 73 | // differently: it compiles first, and it takes the full-rebuild | |
| 74 | // path in analysis mode. | |
| 75 | has_top_level_entry(definition: Node?) -> bool static is | |
| 76 | if let list = cast Definitions.LIST?(definition) then | |
| 77 | for d in list do | |
| 78 | let unwrapped = d.without_pragmas | |
| 79 | ||
| 80 | if let function = cast Definitions.FUNCTION?(unwrapped) then | |
| 81 | if function.is_top_level_entry then | |
| 82 | return true | |
| 83 | fi | |
| 84 | elif let `namespace = cast Definitions.NAMESPACE?(unwrapped) then | |
| 85 | // Expand-namespaces wraps a namespace-less file's | |
| 86 | // definitions - the synthesised entry among them - | |
| 87 | // into a file-private namespace, so the entry sits | |
| 88 | // one list down once that pass has run. | |
| 89 | if has_top_level_entry(`namespace.body) then | |
| 90 | return true | |
| 91 | fi | |
| 92 | fi | |
| 93 | od | |
| 94 | fi | |
| 95 | ||
| 96 | return false | |
| 97 | si | |
| 98 | ||
| 99 | // The entry's implicit `args` and `env` formals are in scope across | |
| 100 | // the whole entry body, so a top-level `let` of either name would | |
| 101 | // shadow - and be shadowed by - them inside the statements. Name | |
| 102 | // resolution from the body finds the formal first, so the let's | |
| 103 | // inferred type lands on the formal and the global's type is never | |
| 104 | // set; reporting the collision here turns that silent mis-compile | |
| 105 | // into a diagnostic. | |
| 106 | _reject_entry_parameter_collision(variable: Variables.VARIABLE) -> bool is | |
| 107 | let name = variable.name | |
| 108 | ||
| 109 | if name? /\ (name.name =~ "args" \/ name.name =~ "env") then | |
| 110 | _logger.error( | |
| 111 | name.location, | |
| 112 | "a top-level '{name.name}' collides with the entry point's '{name.name}' parameter; use another name") | |
| 113 | ||
| 114 | return true | |
| 115 | fi | |
| 116 | ||
| 117 | return false | |
| 118 | si | |
| 119 | ||
| 120 | // A submission's entry returns the value of its final expression | |
| 121 | // to whatever ran it, so it is declared to return any value or | |
| 122 | // none and the ordinary tail rule does the rest: a final | |
| 123 | // expression of any type is assignable to it, and a final | |
| 124 | // statement with no value leaves the entry returning nothing. | |
| 125 | _return_type(location: LOCATION) -> TypeExpressions.TypeExpression => | |
| 126 | if IoC.CONTAINER.instance.build_flags.submission_name? then | |
| 127 | TypeExpressions.OPTIONAL( | |
| 128 | location, | |
| 129 | TypeExpressions.NAMED(location, Identifiers.Identifier(location, "object"))) | |
| 130 | else | |
| 131 | TypeExpressions.INFER(location) | |
| 132 | fi | |
| 133 | ||
| 134 | _synthesise_entry(statements: Statements.LIST) -> Definitions.FUNCTION is | |
| 135 | let location = statements.location | |
| 136 | ||
| 137 | let arguments = Collections.LIST[Variables.VARIABLE]() | |
| 138 | ||
| 139 | // The two shapes the runtime can hand an entry point (GHUL.md, | |
| 140 | // "functions"), so the statements can read the command line as | |
| 141 | // `args` and the process environment as `env`. The wrapper | |
| 142 | // synthesise-entry-environment-wrapper builds beside this | |
| 143 | // function is what carries them in. | |
| 144 | // | |
| 145 | // Like the entry's name below, the formals and their types | |
| 146 | // carry an internal location: at the statement span they would | |
| 147 | // record uses covering the whole region, and a hover or a | |
| 148 | // completion anywhere in the statements would land on them. | |
| 149 | let internal = LOCATION.internal | |
| 150 | ||
| 151 | let args_type = TypeExpressions.ARRAY_(internal, TypeExpressions.NAMED(internal, Identifiers.Identifier(internal, "string"))) | |
| 152 | let args_param = Variables.VARIABLE(internal, Identifiers.Identifier(internal, "args"), args_type, false, true, null) | |
| 153 | args_param.mark_argument() | |
| 154 | arguments.add(args_param) | |
| 155 | ||
| 156 | let env_type = TypeExpressions.NAMED( | |
| 157 | internal, | |
| 158 | Identifiers.QUALIFIED( | |
| 159 | internal, | |
| 160 | Identifiers.Identifier(internal, "Ghul"), | |
| 161 | "Environment", | |
| 162 | internal, | |
| 163 | internal)) | |
| 164 | let env_param = Variables.VARIABLE(internal, Identifiers.Identifier(internal, "env"), env_type, false, true, null) | |
| 165 | env_param.mark_argument() | |
| 166 | arguments.add(env_param) | |
| 167 | ||
| 168 | let result = Definitions.FUNCTION( | |
| 169 | location, | |
| 170 | // The entry has no declaration the source names, so its | |
| 171 | // identifier carries an internal location: a name at the | |
| 172 | // statement span would record a hover use covering the whole | |
| 173 | // region, and any hover on a non-symbol position there would | |
| 174 | // report the synthesised entry. | |
| 175 | Identifiers.Identifier(LOCATION.internal, _ir_context.entry_point_name), | |
| 176 | TypeExpressions.LIST(location, Collections.LIST[TypeExpressions.TypeExpression](0)), | |
| 177 | Variables.LIST(location, arguments), | |
| 178 | _return_type(LOCATION.internal), | |
| 179 | Modifiers.LIST(location, null, null), | |
| 180 | Bodies.BLOCK(location, statements) | |
| 181 | ) | |
| 182 | ||
| 183 | result.is_top_level_entry = true | |
| 184 | ||
| 185 | return result | |
| 186 | si | |
| 187 | si | |
| 188 | si |