diff options
Diffstat (limited to 'lib/js')
| -rw-r--r-- | lib/js/asyncjs.nim | 141 | ||||
| -rw-r--r-- | lib/js/dom.nim | 4 | ||||
| -rw-r--r-- | lib/js/jsffi.nim | 22 |
3 files changed, 154 insertions, 13 deletions
diff --git a/lib/js/asyncjs.nim b/lib/js/asyncjs.nim new file mode 100644 index 000000000..ec410ee39 --- /dev/null +++ b/lib/js/asyncjs.nim @@ -0,0 +1,141 @@ +# +# +# Nim's Runtime Library +# (c) Copyright 2017 Nim Authors +# +# See the file "copying.txt", included in this +# distribution, for details about the copyright. + +## This module implements types and macros for writing asynchronous code +## for the JS backend. It provides tools for interaction with JavaScript async API-s +## and libraries, writing async procedures in Nim and converting callback-based code +## to promises. +## +## A Nim procedure is asynchronous when it includes the ``{.async.}`` pragma. It +## should always have a ``Future[T]`` return type or not have a return type at all. +## A ``Future[void]`` return type is assumed by default. +## +## This is roughly equivalent to the ``async`` keyword in JavaScript code. +## +## .. code-block:: nim +## proc loadGame(name: string): Future[Game] {.async.} = +## # code +## +## should be equivalent to +## +## .. code-block:: javascript +## async function loadGame(name) { +## // code +## } +## +## A call to an asynchronous procedure usually needs ``await`` to wait for +## the completion of the ``Future``. +## +## .. code-block:: nim +## var game = await loadGame(name) +## +## Often, you might work with callback-based API-s. You can wrap them with +## asynchronous procedures using promises and ``newPromise``: +## +## .. code-block:: nim +## proc loadGame(name: string): Future[Game] = +## var promise = newPromise() do (resolve: proc(response: Game)): +## cbBasedLoadGame(name) do (game: Game): +## resolve(game) +## return promise +## +## Forward definitions work properly, you just need to always add the ``{.async.}`` pragma: +## +## .. code-block:: nim +## proc loadGame(name: string): Future[Game] {.async.} +## +## JavaScript compatibility +## ~~~~~~~~~~~~~~~~~~~~~~~~~ +## +## Nim currently generates `async/await` JavaScript code which is supported in modern +## EcmaScript and most modern versions of browsers, Node.js and Electron. +## If you need to use this module with older versions of JavaScript, you can +## use a tool that backports the resulting JavaScript code, as babel. + +import jsffi +import macros + +when not defined(js) and not defined(nimdoc) and not defined(nimsuggest): + {.fatal: "Module asyncjs is designed to be used with the JavaScript backend.".} + +type + Future*[T] = ref object + future*: T + ## Wraps the return type of an asynchronous procedure. + + PromiseJs* {.importcpp: "Promise".} = ref object + ## A JavaScript Promise + +proc replaceReturn(node: var NimNode) = + var z = 0 + for s in node: + var son = node[z] + if son.kind == nnkReturnStmt: + node[z] = nnkReturnStmt.newTree(nnkCall.newTree(ident("jsResolve"), son[0])) + elif son.kind == nnkAsgn and son[0].kind == nnkIdent and $son[0] == "result": + node[z] = nnkAsgn.newTree(son[0], nnkCall.newTree(ident("jsResolve"), son[1])) + else: + replaceReturn(son) + inc z + +proc isFutureVoid(node: NimNode): bool = + result = node.kind == nnkBracketExpr and + node[0].kind == nnkIdent and $node[0] == "Future" and + node[1].kind == nnkIdent and $node[1] == "void" + +proc generateJsasync(arg: NimNode): NimNode = + assert arg.kind == nnkProcDef + result = arg + var isVoid = false + var jsResolveNode = ident("jsResolve") + + if arg.params[0].kind == nnkEmpty: + result.params[0] = nnkBracketExpr.newTree(ident("Future"), ident("void")) + isVoid = true + elif isFutureVoid(arg.params[0]): + isVoid = true + + var code = result.body + replaceReturn(code) + result.body = nnkStmtList.newTree() + + if len(code) > 0: + var awaitFunction = quote: + proc await[T](f: Future[T]): T {.importcpp: "(await #)".} + result.body.add(awaitFunction) + + var resolve: NimNode + if isVoid: + resolve = quote: + var `jsResolveNode` {.importcpp: "undefined".}: Future[void] + else: + resolve = quote: + proc jsResolve[T](a: T): Future[T] {.importcpp: "#".} + result.body.add(resolve) + else: + result.body = newEmptyNode() + for child in code: + result.body.add(child) + + if len(code) > 0 and isVoid: + var voidFix = quote: + return `jsResolveNode` + result.body.add(voidFix) + + result.pragma = quote: + {.codegenDecl: "async function $2($3)".} + + +macro async*(arg: untyped): untyped = + ## Macro which converts normal procedures into + ## javascript-compatible async procedures + generateJsasync(arg) + +proc newPromise*[T](handler: proc(resolve: proc(response: T))): Future[T] {.importcpp: "(new Promise(#))".} + ## A helper for wrapping callback-based functions + ## into promises and async procedures diff --git a/lib/js/dom.nim b/lib/js/dom.nim index cdefc772c..aa7f5d839 100644 --- a/lib/js/dom.nim +++ b/lib/js/dom.nim @@ -134,9 +134,9 @@ type # https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement HtmlElement* = ref object of Element - contentEditable*: string + contentEditable*: cstring isContentEditable*: bool - dir*: string + dir*: cstring offsetHeight*: int offsetWidth*: int offsetLeft*: int diff --git a/lib/js/jsffi.nim b/lib/js/jsffi.nim index 13eb1e759..f34efe9a2 100644 --- a/lib/js/jsffi.nim +++ b/lib/js/jsffi.nim @@ -177,7 +177,7 @@ proc `==`*(x, y: JsRoot): bool {. importcpp: "(# === #)" .} ## and not strings or numbers, this is a *comparison of references*. {. experimental .} -macro `.`*(obj: JsObject, field: static[cstring]): JsObject = +macro `.`*(obj: JsObject, field: untyped): JsObject = ## Experimental dot accessor (get) for type JsObject. ## Returns the value of a property of name `field` from a JsObject `x`. ## @@ -196,14 +196,14 @@ macro `.`*(obj: JsObject, field: static[cstring]): JsObject = helper(`obj`) else: if not mangledNames.hasKey($field): - mangledNames[$field] = $mangleJsName(field) + mangledNames[$field] = $mangleJsName($field) let importString = "#." & mangledNames[$field] result = quote do: proc helper(o: JsObject): JsObject {. importcpp: `importString`, gensym .} helper(`obj`) -macro `.=`*(obj: JsObject, field: static[cstring], value: untyped): untyped = +macro `.=`*(obj: JsObject, field, value: untyped): untyped = ## Experimental dot accessor (set) for type JsObject. ## Sets the value of a property of name `field` in a JsObject `x` to `value`. if validJsName($field): @@ -214,7 +214,7 @@ macro `.=`*(obj: JsObject, field: static[cstring], value: untyped): untyped = helper(`obj`, `value`) else: if not mangledNames.hasKey($field): - mangledNames[$field] = $mangleJsName(field) + mangledNames[$field] = $mangleJsName($field) let importString = "#." & mangledNames[$field] & " = #" result = quote do: proc helper(o: JsObject, v: auto) @@ -222,7 +222,7 @@ macro `.=`*(obj: JsObject, field: static[cstring], value: untyped): untyped = helper(`obj`, `value`) macro `.()`*(obj: JsObject, - field: static[cstring], + field: untyped, args: varargs[JsObject, jsFromAst]): JsObject = ## Experimental "method call" operator for type JsObject. ## Takes the name of a method of the JavaScript object (`field`) and calls @@ -245,7 +245,7 @@ macro `.()`*(obj: JsObject, importString = "#." & $field & "(@)" else: if not mangledNames.hasKey($field): - mangledNames[$field] = $mangleJsName(field) + mangledNames[$field] = $mangleJsName($field) importString = "#." & mangledNames[$field] & "(@)" result = quote: proc helper(o: JsObject): JsObject @@ -257,7 +257,7 @@ macro `.()`*(obj: JsObject, result[1].add args[idx].copyNimTree macro `.`*[K: string | cstring, V](obj: JsAssoc[K, V], - field: static[cstring]): V = + field: untyped): V = ## Experimental dot accessor (get) for type JsAssoc. ## Returns the value of a property of name `field` from a JsObject `x`. var importString: string @@ -265,7 +265,7 @@ macro `.`*[K: string | cstring, V](obj: JsAssoc[K, V], importString = "#." & $field else: if not mangledNames.hasKey($field): - mangledNames[$field] = $mangleJsName(field) + mangledNames[$field] = $mangleJsName($field) importString = "#." & mangledNames[$field] result = quote do: proc helper(o: type(`obj`)): `obj`.V @@ -273,7 +273,7 @@ macro `.`*[K: string | cstring, V](obj: JsAssoc[K, V], helper(`obj`) macro `.=`*[K: string | cstring, V](obj: JsAssoc[K, V], - field: static[cstring], + field: untyped, value: V): untyped = ## Experimental dot accessor (set) for type JsAssoc. ## Sets the value of a property of name `field` in a JsObject `x` to `value`. @@ -282,7 +282,7 @@ macro `.=`*[K: string | cstring, V](obj: JsAssoc[K, V], importString = "#." & $field & " = #" else: if not mangledNames.hasKey($field): - mangledNames[$field] = $mangleJsName(field) + mangledNames[$field] = $mangleJsName($field) importString = "#." & mangledNames[$field] & " = #" result = quote do: proc helper(o: type(`obj`), v: `obj`.V) @@ -290,7 +290,7 @@ macro `.=`*[K: string | cstring, V](obj: JsAssoc[K, V], helper(`obj`, `value`) macro `.()`*[K: string | cstring, V: proc](obj: JsAssoc[K, V], - field: static[cstring], + field: untyped, args: varargs[untyped]): auto = ## Experimental "method call" operator for type JsAssoc. ## Takes the name of a method of the JavaScript object (`field`) and calls |