├── package.lisp ├── cl-async-await.asd ├── utils.lisp ├── README.md ├── promise.lisp └── LICENSE.md /package.lisp: -------------------------------------------------------------------------------- 1 | (cl:defpackage :cl-async-await 2 | (:use :closer-common-lisp :bordeaux-threads :simple-actors/ipc) 3 | (:export :await :defun-async :lambda-async :promise) 4 | (:shadow assoc)) 5 | -------------------------------------------------------------------------------- /cl-async-await.asd: -------------------------------------------------------------------------------- 1 | (asdf:defsystem :cl-async-await 2 | :author ("Jeremy Phelps") 3 | :version "1" 4 | :license "AGPLv3" 5 | :description "An implementation of async/await for Common Lisp" 6 | :depends-on (:closer-mop :bordeaux-threads :simple-actors) 7 | :components 8 | ((:file "package") 9 | (:file "utils" :depends-on ("package")) 10 | (:file "promise" :depends-on ("package" "utils")))) 11 | -------------------------------------------------------------------------------- /utils.lisp: -------------------------------------------------------------------------------- 1 | (in-package :cl-async-await) 2 | 3 | (setf (symbol-function 'assoc) 4 | #'cl:assoc) 5 | 6 | (defmacro if-let (var cond if-true &optional if-false) 7 | `(let ((,var ,cond)) 8 | (if ,var ,if-true ,if-false))) 9 | 10 | (defmacro aif (cond if-true &optional if-false) 11 | `(if-let it ,cond ,if-true ,if-false)) 12 | 13 | (defmacro acond (&body clauses) 14 | (if (null clauses) 15 | nil 16 | `(aif ,(caar clauses) 17 | (progn ,@(cdar clauses)) 18 | (acond ,@(cdr clauses))))) 19 | 20 | (defun (setf assoc) (new-value key alist) 21 | (aif (assoc key alist) 22 | (progn 23 | (setf (cdr it) new-value) 24 | it) 25 | (push (cons key new-value) alist))) 26 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # CL-ASYNC-AWAIT 2 | 3 | This library allows you to have async functions similar to those 4 | in JavaScript, only these async functions are implemented with 5 | threads instead of an event dispatching mechanism. 6 | 7 | Cross-thread error handling is easy using `CL-ASYNC-AWAIT`, since 8 | the `AWAIT` operator propagates errors from the promise, and also 9 | propagates invoked restarts back to the promise. 10 | 11 | ## Simple example 12 | 13 | ``` 14 | (defun-async my-async-reader (stream) 15 | (read-byte stream)) 16 | 17 | (defvar *promise* (my-async-reader *some-stream*)) 18 | (defvar *my-byte* (await *promise*)) 19 | ``` 20 | 21 | ## Usage 22 | 23 | 24 | ``` 25 | (lambda-async lambda-list &body body) 26 | ``` 27 | 28 | Creates a `CL:LAMBDA` function that creates a `PROMISE` when FUNCALLed. 29 | 30 | ``` 31 | (defun-async name lambda-list &body body) 32 | ``` 33 | 34 | Like `LAMBDA-ASYNC` but expands to a `CL:DEFUN` form instead of a `CL:LAMBDA` form. 35 | 36 | ``` 37 | (await promise) 38 | ``` 39 | 40 | Wait for a `PROMISE` to resolve to one or more values. If the promise 41 | succeeds, the values will be returned using `CL:VALUES`. 42 | 43 | If an error occurs in the `PROMISE` thread and is not handled within the 44 | promise, execution of the `PROMISE` thread is suspended until the `AWAIT` 45 | method is called. 46 | 47 | That error will then be signalled in the thread from which `AWAIT` is called, in 48 | a context where all the same restarts are defined as are defined in the `PROMISE` 49 | thread. If `INVOKE-RESTART` is called with one of these restarts, that restart 50 | will be invoked in the `PROMISE` thread, and `AWAIT` will return that restart's value form. 51 | 52 | If the stack frame for the call to `AWAIT` is unwound without invoking a restart, 53 | the `PROMISE` thread will invoke its `CL:ABORT` restart. 54 | 55 | Whether the `PROMISE` succeeds or fails, the result is memoized. Calling `AWAIT` a second time 56 | on the same `PROMISE` will yield the same values. 57 | 58 | If an error occurred and `AWAIT` is called a second time, the same error will be signalled, but 59 | the restarts will not be available, since the `PROMISE` thread is expected to be dead as a result 60 | of invoking the `ABORT` restart. 61 | 62 | -------------------------------------------------------------------------------- /promise.lisp: -------------------------------------------------------------------------------- 1 | (in-package :cl-async-await) 2 | 3 | (defclass promise () 4 | ((resolution :type list 5 | :initarg :resolution 6 | :initform nil 7 | :documentation "The final values that the promise generated. 8 | Only valid if the RESOLVEDP slot is non-nil." 9 | :accessor promise-resolution) 10 | (mutex :type lock 11 | :initform (make-lock "PROMISE-MUTEX")) 12 | (error :type (or condition null) 13 | :initarg :error 14 | :initform nil 15 | :accessor promise-error) 16 | (thread :type (or thread null) 17 | :initarg :thread 18 | :initform nil 19 | :accessor promise-thread) 20 | (outbox :type simple-actors/ipc::simple-process-mailbox 21 | :initform (simple-actors/ipc:make-mailbox) 22 | :reader promise-outbox) 23 | (inbox :type simple-actors/ipc::simple-process-mailbox 24 | :initform (simple-actors/ipc:make-mailbox) 25 | :reader promise-inbox) 26 | (thunk :type function 27 | :initarg :thunk 28 | :reader promise-thunk))) 29 | 30 | (defmethod print-object ((promise promise) stream) 31 | (let ((resolution-string (acond ((promise-error promise) 32 | (format nil " Promise broken due to error: ~a" it)) 33 | ((promise-resolution promise) 34 | (format nil " ~a " it)) 35 | (t " Not awaited")))) 36 | 37 | (format stream "#<~s~a>" 38 | 'promise resolution-string))) 39 | 40 | (defun make-promise-handler (p) 41 | (lambda () 42 | (handler-bind ((error (lambda (exn) 43 | (send-message (promise-outbox p) 44 | `(:error ,exn 45 | :restarts ,(loop for r in (compute-restarts) 46 | collect `(:name ,(restart-name r) 47 | :report ,(format nil "~a" r))))) 48 | (let ((restart-invocation (get-message (promise-inbox p)))) 49 | (apply #'invoke-restart restart-invocation))))) 50 | (restart-case 51 | (let ((result 52 | (multiple-value-list (funcall (promise-thunk p))))) 53 | (send-message (promise-outbox p) 54 | `(:values ,@result))) 55 | (abort () 56 | :report "Terminate the promise's thread." 57 | (send-message (promise-outbox p) '(:values))))))) 58 | 59 | (defmethod initialize-instance :after ((p promise) &key) 60 | (setf (promise-thread p) 61 | (make-thread (make-promise-handler p) 62 | :name "PROMISE-THREAD"))) 63 | 64 | 65 | (defgeneric await (promise) 66 | (:documentation "Wait for a PROMISE to resolve to one or more values. If the promise 67 | succeeds, the values will be returned using CL:VALUES. 68 | 69 | If an error occurs in the PROMISE thread, that error will be signalled in the thread 70 | from which AWAIT is called, in a context where all the same restarts are defined 71 | as are defined in the PROMISE thread. If INVOKE-RESTART is called with one of the 72 | restarts defined in the PROMISE thread, that restart will be invoked in the PROMISE 73 | thread, and AWAIT will return that restart's value form. 74 | 75 | If the stack frame for the call to AWAIT is unwound without invoking a restart, 76 | the PROMISE thread will invoke its CL:ABORT restart. 77 | 78 | Whether the PROMISE succeeds or fails, the result is memoized. Calling AWAIT a second time 79 | on the same PROMISE will yield the same values. 80 | 81 | If an error occurred and AWAIT is called a second time, the restarts will not be available, 82 | since the PROMISE thread is expected to be dead as a result of invoking the ABORT restart.")) 83 | 84 | (defun raise-error-with-restarts (promise err restarts) 85 | (let ((p promise)) 86 | (eval `(let ((restart-invoked nil)) 87 | (unwind-protect 88 | (restart-case (error ,err) 89 | ,@(loop for restart-description in restarts 90 | collect `(,(getf restart-description :name) 91 | (&rest restart-arguments) 92 | :report ,(getf restart-description :report) 93 | (setf restart-invoked t) 94 | (send-message ,(promise-inbox p) 95 | (cons ',(getf restart-description :name) 96 | restart-arguments)) 97 | (setf (promise-resolution ,p) nil) 98 | (await-internal ,p)))) 99 | (unless restart-invoked 100 | (setf (promise-error ,p) ,err) 101 | (send-message (promise-inbox ,p) '(abort)))))))) 102 | 103 | (defun await-internal (p) 104 | (aif (promise-error p) 105 | (error it) 106 | (let ((message (or (promise-resolution p) 107 | (setf (promise-resolution p) 108 | (get-message (promise-outbox p)))))) 109 | (ecase (car message) 110 | (:values 111 | (apply #'values (cdr message))) 112 | (:error 113 | (raise-error-with-restarts p (getf message :error) 114 | (getf message :restarts))))))) 115 | 116 | (defmethod await ((p promise)) 117 | (with-lock-held ((slot-value p 'mutex)) 118 | (await-internal p))) 119 | 120 | (defmacro lambda-async (lambda-list &body body) 121 | "Creates a closure that creates a PROMISE when FUNCALLed. The BODY 122 | will run in its own thread. 123 | 124 | See also: AWAIT" 125 | `(lambda ,lambda-list 126 | (make-instance 'promise :thunk (lambda () 127 | ,@body)))) 128 | 129 | (defmacro defun-async (name lambda-list &body body) 130 | "Like LAMBDA-ASYNC but expands to a CL:DEFUN form instead of CL:LAMBDA." 131 | `(defun ,name ,lambda-list 132 | (make-instance 'promise :thunk (lambda () ,@body)))) 133 | -------------------------------------------------------------------------------- /LICENSE.md: -------------------------------------------------------------------------------- 1 | ### GNU AFFERO GENERAL PUBLIC LICENSE 2 | 3 | Version 3, 19 November 2007 4 | 5 | Copyright (C) 2007 Free Software Foundation, Inc. 6 | 7 | 8 | Everyone is permitted to copy and distribute verbatim copies of this 9 | license document, but changing it is not allowed. 10 | 11 | ### Preamble 12 | 13 | The GNU Affero General Public License is a free, copyleft license for 14 | software and other kinds of works, specifically designed to ensure 15 | cooperation with the community in the case of network server software. 16 | 17 | The licenses for most software and other practical works are designed 18 | to take away your freedom to share and change the works. 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If propagation of a covered 439 | work results from an entity transaction, each party to that 440 | transaction who receives a copy of the work also receives whatever 441 | licenses to the work the party's predecessor in interest had or could 442 | give under the previous paragraph, plus a right to possession of the 443 | Corresponding Source of the work from the predecessor in interest, if 444 | the predecessor has it or can get it with reasonable efforts. 445 | 446 | You may not impose any further restrictions on the exercise of the 447 | rights granted or affirmed under this License. For example, you may 448 | not impose a license fee, royalty, or other charge for exercise of 449 | rights granted under this License, and you may not initiate litigation 450 | (including a cross-claim or counterclaim in a lawsuit) alleging that 451 | any patent claim is infringed by making, using, selling, offering for 452 | sale, or importing the Program or any portion of it. 453 | 454 | #### 11. Patents. 455 | 456 | A "contributor" is a copyright holder who authorizes use under this 457 | License of the Program or a work on which the Program is based. The 458 | work thus licensed is called the contributor's "contributor version". 459 | 460 | A contributor's "essential patent claims" are all patent claims owned 461 | or controlled by the contributor, whether already acquired or 462 | hereafter acquired, that would be infringed by some manner, permitted 463 | by this License, of making, using, or selling its contributor version, 464 | but do not include claims that would be infringed only as a 465 | consequence of further modification of the contributor version. For 466 | purposes of this definition, "control" includes the right to grant 467 | patent sublicenses in a manner consistent with the requirements of 468 | this License. 469 | 470 | Each contributor grants you a non-exclusive, worldwide, royalty-free 471 | patent license under the contributor's essential patent claims, to 472 | make, use, sell, offer for sale, import and otherwise run, modify and 473 | propagate the contents of its contributor version. 474 | 475 | In the following three paragraphs, a "patent license" is any express 476 | agreement or commitment, however denominated, not to enforce a patent 477 | (such as an express permission to practice a patent or covenant not to 478 | sue for patent infringement). To "grant" such a patent license to a 479 | party means to make such an agreement or commitment not to enforce a 480 | patent against the party. 481 | 482 | If you convey a covered work, knowingly relying on a patent license, 483 | and the Corresponding Source of the work is not available for anyone 484 | to copy, free of charge and under the terms of this License, through a 485 | publicly available network server or other readily accessible means, 486 | then you must either (1) cause the Corresponding Source to be so 487 | available, or (2) arrange to deprive yourself of the benefit of the 488 | patent license for this particular work, or (3) arrange, in a manner 489 | consistent with the requirements of this License, to extend the patent 490 | license to downstream recipients. "Knowingly relying" means you have 491 | actual knowledge that, but for the patent license, your conveying the 492 | covered work in a country, or your recipient's use of the covered work 493 | in a country, would infringe one or more identifiable patents in that 494 | country that you have reason to believe are valid. 495 | 496 | If, pursuant to or in connection with a single transaction or 497 | arrangement, you convey, or propagate by procuring conveyance of, a 498 | covered work, and grant a patent license to some of the parties 499 | receiving the covered work authorizing them to use, propagate, modify 500 | or convey a specific copy of the covered work, then the patent license 501 | you grant is automatically extended to all recipients of the covered 502 | work and works based on it. 503 | 504 | A patent license is "discriminatory" if it does not include within the 505 | scope of its coverage, prohibits the exercise of, or is conditioned on 506 | the non-exercise of one or more of the rights that are specifically 507 | granted under this License. You may not convey a covered work if you 508 | are a party to an arrangement with a third party that is in the 509 | business of distributing software, under which you make payment to the 510 | third party based on the extent of your activity of conveying the 511 | work, and under which the third party grants, to any of the parties 512 | who would receive the covered work from you, a discriminatory patent 513 | license (a) in connection with copies of the covered work conveyed by 514 | you (or copies made from those copies), or (b) primarily for and in 515 | connection with specific products or compilations that contain the 516 | covered work, unless you entered into that arrangement, or that patent 517 | license was granted, prior to 28 March 2007. 518 | 519 | Nothing in this License shall be construed as excluding or limiting 520 | any implied license or other defenses to infringement that may 521 | otherwise be available to you under applicable patent law. 522 | 523 | #### 12. No Surrender of Others' Freedom. 524 | 525 | If conditions are imposed on you (whether by court order, agreement or 526 | otherwise) that contradict the conditions of this License, they do not 527 | excuse you from the conditions of this License. If you cannot convey a 528 | covered work so as to satisfy simultaneously your obligations under 529 | this License and any other pertinent obligations, then as a 530 | consequence you may not convey it at all. For example, if you agree to 531 | terms that obligate you to collect a royalty for further conveying 532 | from those to whom you convey the Program, the only way you could 533 | satisfy both those terms and this License would be to refrain entirely 534 | from conveying the Program. 535 | 536 | #### 13. Remote Network Interaction; Use with the GNU General Public License. 537 | 538 | Notwithstanding any other provision of this License, if you modify the 539 | Program, your modified version must prominently offer all users 540 | interacting with it remotely through a computer network (if your 541 | version supports such interaction) an opportunity to receive the 542 | Corresponding Source of your version by providing access to the 543 | Corresponding Source from a network server at no charge, through some 544 | standard or customary means of facilitating copying of software. This 545 | Corresponding Source shall include the Corresponding Source for any 546 | work covered by version 3 of the GNU General Public License that is 547 | incorporated pursuant to the following paragraph. 548 | 549 | Notwithstanding any other provision of this License, you have 550 | permission to link or combine any covered work with a work licensed 551 | under version 3 of the GNU General Public License into a single 552 | combined work, and to convey the resulting work. The terms of this 553 | License will continue to apply to the part which is the covered work, 554 | but the work with which it is combined will remain governed by version 555 | 3 of the GNU General Public License. 556 | 557 | #### 14. Revised Versions of this License. 558 | 559 | The Free Software Foundation may publish revised and/or new versions 560 | of the GNU Affero General Public License from time to time. Such new 561 | versions will be similar in spirit to the present version, but may 562 | differ in detail to address new problems or concerns. 563 | 564 | Each version is given a distinguishing version number. If the Program 565 | specifies that a certain numbered version of the GNU Affero General 566 | Public License "or any later version" applies to it, you have the 567 | option of following the terms and conditions either of that numbered 568 | version or of any later version published by the Free Software 569 | Foundation. If the Program does not specify a version number of the 570 | GNU Affero General Public License, you may choose any version ever 571 | published by the Free Software Foundation. 572 | 573 | If the Program specifies that a proxy can decide which future versions 574 | of the GNU Affero General Public License can be used, that proxy's 575 | public statement of acceptance of a version permanently authorizes you 576 | to choose that version for the Program. 577 | 578 | Later license versions may give you additional or different 579 | permissions. However, no additional obligations are imposed on any 580 | author or copyright holder as a result of your choosing to follow a 581 | later version. 582 | 583 | #### 15. Disclaimer of Warranty. 584 | 585 | THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY 586 | APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT 587 | HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT 588 | WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT 589 | LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 590 | A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND 591 | PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE 592 | DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR 593 | CORRECTION. 594 | 595 | #### 16. Limitation of Liability. 596 | 597 | IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING 598 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR 599 | CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, 600 | INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES 601 | ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT 602 | NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR 603 | LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM 604 | TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER 605 | PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. 606 | 607 | #### 17. Interpretation of Sections 15 and 16. 608 | 609 | If the disclaimer of warranty and limitation of liability provided 610 | above cannot be given local legal effect according to their terms, 611 | reviewing courts shall apply local law that most closely approximates 612 | an absolute waiver of all civil liability in connection with the 613 | Program, unless a warranty or assumption of liability accompanies a 614 | copy of the Program in return for a fee. 615 | 616 | END OF TERMS AND CONDITIONS 617 | 618 | ### How to Apply These Terms to Your New Programs 619 | 620 | If you develop a new program, and you want it to be of the greatest 621 | possible use to the public, the best way to achieve this is to make it 622 | free software which everyone can redistribute and change under these 623 | terms. 624 | 625 | To do so, attach the following notices to the program. It is safest to 626 | attach them to the start of each source file to most effectively state 627 | the exclusion of warranty; and each file should have at least the 628 | "copyright" line and a pointer to where the full notice is found. 629 | 630 | 631 | Copyright (C) 632 | 633 | This program is free software: you can redistribute it and/or modify 634 | it under the terms of the GNU Affero General Public License as 635 | published by the Free Software Foundation, either version 3 of the 636 | License, or (at your option) any later version. 637 | 638 | This program is distributed in the hope that it will be useful, 639 | but WITHOUT ANY WARRANTY; without even the implied warranty of 640 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 641 | GNU Affero General Public License for more details. 642 | 643 | You should have received a copy of the GNU Affero General Public License 644 | along with this program. If not, see . 645 | 646 | Also add information on how to contact you by electronic and paper 647 | mail. 648 | 649 | If your software can interact with users remotely through a computer 650 | network, you should also make sure that it provides a way for users to 651 | get its source. For example, if your program is a web application, its 652 | interface could display a "Source" link that leads users to an archive 653 | of the code. There are many ways you could offer source, and different 654 | solutions will be better for different programs; see section 13 for 655 | the specific requirements. 656 | 657 | You should also get your employer (if you work as a programmer) or 658 | school, if any, to sign a "copyright disclaimer" for the program, if 659 | necessary. For more information on this, and how to apply and follow 660 | the GNU AGPL, see . 661 | --------------------------------------------------------------------------------