├── .gitignore ├── LICENSE ├── README.md ├── interfaced.nim ├── interfaced.nimble ├── test.nim ├── test_exports.nim └── test_logsink.nim /.gitignore: -------------------------------------------------------------------------------- 1 | nimcache 2 | /test 3 | *.html 4 | *.exe -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | 2 | Apache License 3 | Version 2.0, January 2004 4 | http://www.apache.org/licenses/ 5 | 6 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 7 | 8 | 1. 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However, in accepting such obligations, You may act only 171 | on Your own behalf and on Your sole responsibility, not on behalf 172 | of any other Contributor, and only if You agree to indemnify, 173 | defend, and hold each Contributor harmless for any liability 174 | incurred by, or claims asserted against, such Contributor by reason 175 | of your accepting any such warranty or additional liability. 176 | 177 | END OF TERMS AND CONDITIONS -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # Interfaced 2 | 3 | Interfaces for Nim, thanks to [Krux02](https://forum.nim-lang.org/t/2422) 4 | 5 | For an example of usage, see `test.nim` -------------------------------------------------------------------------------- /interfaced.nim: -------------------------------------------------------------------------------- 1 | ## Go-Like Interfaces for Nim 2 | ## 3 | ## Example: 4 | ## ======== 5 | ## You can find more examples in the files ``test.nim``, ``test_logsink.nim`` and ``test_exports.nim``. 6 | ## 7 | ## .. code-block:: nim 8 | ## # interface definition: 9 | ## createInterface LogSink: 10 | ## proc log(this: LogSink, msg: string) 11 | ## proc messagesWritten(this: LogSink): int 12 | ## 13 | ## # interface implementation 14 | ## type MyLogSink = object 15 | ## messages: seq[string] 16 | ## 17 | ## proc log(this: var MyLogSink, msg: string) = this.messages.add(msg) 18 | ## proc messagesWritten(this: MyLogSink): int = this.messages.len 19 | ## 20 | ## # ... 21 | ## 22 | ## # the order of definition and implementation doesn't matter, as long both are defined at the point where the conversion happens 23 | ## 24 | ## var myLogSink = MyLogSink() 25 | ## 26 | ## let 27 | ## logSinkA = myLogSink.toLogSink() # explicit conversion 28 | ## logSinkB: LogSink = myLogSink # implicit conversion 29 | ## 30 | ## logSinkA.log("Hello World") 31 | ## logSinkB.log("Bye World") 32 | ## 33 | import macros 34 | 35 | proc exportIdent(ident: NimNode, exports: bool): NimNode {.compileTime.} = 36 | if exports: nnkPostfix.newTree(newIdentNode("*"), ident) else: ident 37 | 38 | macro implementInterface(interfaceName: typed, exports: static[bool]) : untyped = 39 | let 40 | interfaceNameStr = $interfaceName.symbol 41 | vtableSymbol = interfaceName.symbol.getImpl[2][2][1][1][0] 42 | vtableRecordList = vtableSymbol.symbol.getImpl[2][2] 43 | 44 | let 45 | objectConstructor = nnkObjConstr.newTree(vtableSymbol) 46 | 47 | for identDefs in vtableRecordList: 48 | let 49 | methodName = identDefs[0] 50 | params = identDefs[1][0] 51 | thisParameter = params[1][0] 52 | 53 | testThis = newIdentNode("x") 54 | lambdaBody = quote do: 55 | `methodName`(cast[T](`thisParameter`)) 56 | 57 | recursiveTest = quote do: 58 | `methodName`(`testThis`) 59 | 60 | for i in 2 ..< len(params): 61 | let param = params[i] 62 | param.expectKind(nnkIdentDefs) 63 | for j in 0 .. len(param) - 3: 64 | lambdaBody.add param[j] 65 | recursiveTest.add param[j] 66 | 67 | methodName.expectKind nnkIdent 68 | 69 | let recursiveCheck = quote do: 70 | var `testThis` = T(nil) 71 | when not(compiles(`recursiveTest`)): 72 | {.fatal: "recursive call".} 73 | 74 | objectConstructor.add nnkExprColonExpr.newTree( 75 | methodName, 76 | nnkLambda.newTree( 77 | newEmptyNode(),newEmptyNode(),newEmptyNode(), 78 | params.copy, 79 | newEmptyNode(),newEmptyNode(), 80 | newStmtList( 81 | nnkMixinStmt.newTree(methodName), 82 | recursiveCheck, 83 | lambdaBody 84 | ) 85 | ) 86 | ) 87 | 88 | let 89 | getVtableReturnStatement = 90 | nnkReturnStmt.newTree(newCall("addr", newIdentNode("theVtable"))) 91 | globalVtableIdent = newIdentNode("theVtable") 92 | getVtableProcIdent = newIdentNode("get" & interfaceNameStr & "Vtable") 93 | vtableType = newIdentNode(interfaceNameStr & "Vtable") 94 | getVtableProcDeclaration = quote do: 95 | proc `getVtableProcIdent`[T](): ptr `vtableType` = 96 | var `globalVtableIdent` {.global.} = `objectConstructor` 97 | `getVtableReturnStatement` 98 | 99 | result = newStmtList() 100 | result.add getVtableProcDeclaration 101 | 102 | let 103 | castIdent = exportIdent(newIdentNode("to" & $interfaceName.symbol), exports) 104 | result.add quote do: 105 | proc `castIdent`(this: ref) : `interfaceName` = 106 | `interfaceName`( 107 | objet : cast[RootRef](this), 108 | vtable : `getVtableProcIdent`[type(this)]() 109 | ) 110 | 111 | when defined(interfacedebug): 112 | echo result.repr 113 | 114 | macro createInterface*(name : untyped, methods : untyped) : untyped = 115 | ## Creates an interface named ``name``. By putting an asterix ``*`` before ``name``, the interface type will be exported. 116 | ## Methods need to be exported individually(see ``test_exports.nim``. 117 | ## 118 | ## Even if a method isn't *callable* from the current scope, it's possible to implement it(see ``test_logsinks.nim``). In the 119 | ## same way an implementation may follow the interface definition it is implementing or an unexported procedure can implement an exported method, 120 | ## as long it's visible at the point of the conversion. 121 | if name.kind != nnkPrefix: name.expectKind nnkIdent 122 | 123 | let 124 | exports = name.kind == nnkPrefix 125 | cleanedName = if exports: name[1] else: name 126 | nameStr = $cleanedName.ident 127 | markedName = if exports: newTree(nnkPostfix, newIdentNode("*"), cleanedName) else: name 128 | 129 | vtableRecordList = nnkRecList.newTree 130 | vtableIdent = newIdentNode(nameStr & "Vtable") 131 | vtableTypeDef = nnkTypeSection.newTree( 132 | nnkTypeDef.newTree( 133 | vtableIdent, 134 | newEmptyNode(), 135 | nnkObjectTy.newTree( 136 | newEmptyNode(), 137 | newEmptyNode(), 138 | vtableRecordList 139 | ) 140 | ) 141 | ) 142 | 143 | var newMethods = newSeq[NimNode]() 144 | 145 | for meth in methods: 146 | meth.expectKind(nnkProcDef) 147 | let 148 | methodIdent = if meth[0].kind == nnkPostfix: meth[0][1] else: meth[0] 149 | params = meth[3] 150 | thisParam = params[1] 151 | thisIdent = thisParam[0] 152 | thisType = thisParam[1] 153 | 154 | if thisType != cleanedName: 155 | error thisType.repr & " != " & cleanedName.repr 156 | 157 | let vtableEntryParams = params.copy 158 | vtableEntryParams[1][1] = newIdentNode("RootRef") 159 | 160 | vtableRecordList.add( 161 | nnkIdentDefs.newTree( 162 | methodIdent, 163 | nnkProcTy.newTree( 164 | vtableEntryParams, 165 | newEmptyNode(), 166 | ), 167 | newEmptyNode() 168 | ) 169 | ) 170 | 171 | let call = nnkCall.newTree( 172 | nnkDotExpr.newTree( nnkDotExpr.newTree(thisIdent, newIdentNode("vtable")), methodIdent ), 173 | nnkDotExpr.newTree( thisIdent, newIdentNode("objet") ), 174 | ) 175 | 176 | for i in 2 ..< len(params): 177 | let param = params[i] 178 | param.expectKind(nnkIdentDefs) 179 | for j in 0 .. len(param) - 3: 180 | call.add param[j] 181 | 182 | meth[6] = nnkStmtList.newTree(call) 183 | 184 | newMethods.add(meth) 185 | 186 | result = newStmtList() 187 | result.add(vtableTypeDef) 188 | result.add quote do: 189 | type `markedName` = object 190 | objet : RootRef 191 | vtable: ptr `vtableIdent` 192 | 193 | for meth in newMethods: 194 | result.add meth 195 | 196 | result.add newCall(bindSym"implementInterface", cleanedName, newIdentNode(if exports: "true" else: "false")) 197 | 198 | when defined(interfacedebug): 199 | echo result.repr 200 | -------------------------------------------------------------------------------- /interfaced.nimble: -------------------------------------------------------------------------------- 1 | # Package 2 | 3 | version = "0.2.0" 4 | author = "Andrea Ferretti" 5 | description = "Go-like interfaces" 6 | license = "Apache2" 7 | skipFiles = @["test.nim", "test_exports.nim", "test_logsink.nim"] 8 | 9 | # Dependencies 10 | 11 | requires "nim >= 0.16.0" 12 | 13 | task tests, "run tests": 14 | --hints: off 15 | --linedir: on 16 | --stacktrace: on 17 | --linetrace: on 18 | --debuginfo 19 | --path: "." 20 | --run 21 | setCommand "c", "test.nim" 22 | 23 | task test, "run tests": 24 | setCommand "tests" -------------------------------------------------------------------------------- /test.nim: -------------------------------------------------------------------------------- 1 | import interfaced 2 | 3 | import test_exports 4 | 5 | type 6 | Human = ref object 7 | name: string 8 | Dog = ref object 9 | 10 | proc makeNoise(human: Human): string = 11 | "Hello, my name is " & human.name 12 | 13 | proc legs(human: Human): int = 2 14 | 15 | proc greet(human: Human, other: string): string = 16 | "Nice to meet you, " & other 17 | 18 | proc makeNoise(dog: Dog): string = "Woof! Woof!" 19 | 20 | proc legs(dog: Dog): int = 4 21 | 22 | proc greet(dog: Dog, other: string): string = "Woof! Woooof... wof!?" 23 | 24 | createInterface(Animal): 25 | proc makeNoise(this: Animal): string 26 | proc legs(this: Animal): int 27 | proc greet(this: Animal, other: string): string 28 | 29 | proc interact(animal: Animal) = 30 | echo animal.makeNoise 31 | echo animal.greet("James Bond") 32 | 33 | proc interactAll(animals: varargs[Animal, toAnimal]) = 34 | for animal in animals: 35 | animal.interact() 36 | 37 | when isMainModule: 38 | var 39 | me = Human(name: "Andrea") 40 | bau = Dog() 41 | 42 | charmander = Charmander() 43 | espeon = Espeon() 44 | 45 | for animal in @[me.toAnimal, bau.toAnimal, charmander.toAnimal, espeon.toAnimal]: 46 | echo "Number of legs: ", legs(animal) 47 | for pokemon in @[charmander.toPokemon, espeon.toPokemon]: 48 | echo pokemon.name(), " is a ", pokemon.typ(), " Pokemon" 49 | 50 | interactAll(me, bau, charmander, espeon) 51 | -------------------------------------------------------------------------------- /test_exports.nim: -------------------------------------------------------------------------------- 1 | import interfaced 2 | 3 | type 4 | PokemonType* {.pure.} = enum 5 | Fire, Psychic # ... 6 | 7 | Charmander* = ref object 8 | Espeon* = ref object 9 | 10 | proc makeNoise*(this: Charmander): string = "Charmander, Charmander" 11 | proc legs*(this: Charmander): int = 2 12 | proc greet*(this: Charmander, other: string): string = "Charmander, Char, Charmander... (" & other & ")" 13 | 14 | proc makeNoise*(this: Espeon): string = "By using Telepathy I'm able to communicate with creatures of other species" 15 | proc legs*(this: Espeon): int = 4 16 | proc greet*(this: Espeon, other: string): string = "What a pleasure to meet you, " & other 17 | 18 | createInterface *Pokemon: # the * has to come before the name, due to limitations in Nim's lexer(as far as I know) 19 | proc name*(this: Pokemon): string # the visibility of each method is set individually 20 | proc typ*(this: Pokemon): PokemonType 21 | 22 | proc name*(this: Espeon): string = "Espeon" 23 | proc typ*(this: Espeon): PokemonType = PokemonType.Psychic 24 | 25 | proc name*(this: Charmander): string = "Charmander" 26 | proc typ*(this: Charmander): PokemonType = PokemonType.Fire 27 | 28 | createInterface *LogSink: 29 | proc log*(self: LogSink, msg: string) 30 | proc messagesWritten(self: LogSink): int 31 | 32 | proc echoSinkState*(sink: LogSink) = 33 | echo sink.messagesWritten() -------------------------------------------------------------------------------- /test_logsink.nim: -------------------------------------------------------------------------------- 1 | import interfaced 2 | 3 | import test_exports 4 | 5 | type MyLogSink = ref object 6 | messages: seq[string] 7 | 8 | proc log(self: var MyLogSink, msg: string) = self.messages.add(msg) 9 | proc messagesWritten(self: MyLogSink): int = self.messages.len 10 | 11 | when isMainModule: 12 | var myLogSink = MyLogSink(messages: @[]) 13 | 14 | myLogSink.log("Hello World") 15 | myLogSink.log("ABC") 16 | 17 | echoSinkstate(myLogSink.toLogSink) 18 | let i = myLogSink.toLogSink() 19 | myLogSink = nil 20 | GC_fullCollect() 21 | i.echoSinkState() --------------------------------------------------------------------------------