{"id":963,"date":"2018-06-24T14:24:09","date_gmt":"2018-06-24T08:54:09","guid":{"rendered":"http:\/\/www.rangakrish.com\/?p=963"},"modified":"2018-06-24T14:32:17","modified_gmt":"2018-06-24T09:02:17","slug":"calling-go-functions-from-lisp-part-2","status":"publish","type":"post","link":"https:\/\/www.rangakrish.com\/index.php\/2018\/06\/24\/calling-go-functions-from-lisp-part-2\/","title":{"rendered":"Calling Go Functions from Lisp – Part 2"},"content":{"rendered":"

In my earlier article Calling Go Functions from Lisp<\/strong><\/em><\/a>, I explained the steps for making calls to Go<\/strong><\/em> functions from another language, specifically LispWorks<\/strong><\/a> Lisp<\/strong><\/em>. Today, I want to give a slightly more\u00a0 <\/span>interesting example showing the use of Go<\/strong> channels<\/strong><\/a><\/em>\u00a0through exported functions.<\/p>\n

Go<\/strong><\/em> is widely admired for its native support for concurrency via Goroutines<\/strong><\/em><\/a>. Synchronization without explcit locks or condition variables is facilitated by Channels<\/strong><\/em><\/a>. This greatly simplifies concurrent programming. So, why can’t we take advantage of this powerful feature of Go<\/strong><\/em> and use it in another language environment? I am not saying that this alone is sufficient reason for integrating Go<\/strong><\/em> runtime with another language program, but it is an appealing reason!<\/p>\n

Anyway, without getting into a debate on this topic, let me show you how easy it is to do this.<\/p>\n

The following figure shows three Go<\/strong><\/em> functions that I have defined for working with a Go<\/strong><\/em> Channel.\u00a0<\/span><\/p>\n

\"Go<\/a>
Go Functions<\/strong><\/figcaption><\/figure>\n

For simplicity, I am using a single channel of type int. The function createChannel<\/strong><\/em> is used to initialize this\u00a0<\/span>global channel. The function writeToChannel<\/strong><\/em> writes an integer value to the channel and the third function readFromChannel<\/strong><\/em> reads an integer from the channel. All three functions are exported<\/strong><\/em>.<\/p>\n

The next step is to create a LIB file and Header file from the Go<\/strong><\/em> source.<\/p>\n

> go build -o GoFunctions.lib -buildmode=c-shared GoFunctions.go<\/span><\/p><\/blockquote>\n

As discussed in the article<\/a>, we need to write appropriate C<\/strong><\/em> wrapper functions that get compiled into a DLL<\/strong><\/em>. See the following figure.<\/p>\n

\"Wrapper<\/a>
Wrapper Functions<\/strong><\/figcaption><\/figure>\n

Building the DLL is a two-step process:<\/p>\n

> gcc -c GoFunctionsWrapper.c<\/span><\/p>\n

> gcc -shared -o GoFunctionsWrapper.dll GoFunctionsWrapper.o GoFunctions.lib<\/span><\/p><\/blockquote>\n

We have to copy GoFunctionsWrapper.dll<\/strong><\/em> and GoFunctions.lib<\/strong><\/em> to our Lisp project directory (or make sure they are in executable path).<\/p>\n

Lisp Layer:<\/strong><\/em><\/h2>\n

Now we are ready to write our LispWorks Lisp<\/strong><\/em> code. As discussed in the earlier article, we have to declare the DLL<\/strong><\/em> functions in Lisp and ensure that the DLL<\/strong><\/em> is registered properly.<\/p>\n

\"Declaring<\/a>
Declaring the DLL Functions<\/strong><\/figcaption><\/figure>\n

Now comes the interesting part. Since channels are meaningful only in concurrent programs, in order to use and test them, we have to write a multi-threaded Lisp program. Here is the simplest one that uses the Go<\/strong><\/em> functions we have implemented:<\/p>\n

\"Multi-threaded<\/a>
Multi-threaded Access<\/strong><\/figcaption><\/figure>\n

I am writing to the channel in a separate thread (similar to goroutines<\/strong><\/em>), while reading from the same channel in the main thread.<\/p>\n

Here is the output when I run the function:<\/p>\n

\"Testing<\/a>
Testing Channel<\/strong><\/figcaption><\/figure>\n

Super. What will happen if we write to the channel (unbuffered) and read from it in the same thread? Deadlock, right? Here is the version I wrote to test that behavior:<\/p>\n

\"Deadlock<\/a>
Deadlock Version<\/strong><\/figcaption><\/figure>\n

And here is output:<\/p>\n

\"Testing<\/a>
Testing Deadlock<\/strong><\/figcaption><\/figure>\n

As expected, the program is deadlocked because after the first element is written, it cannot be consumed by another thread!<\/p>\n

So there we are. This example shows that we are able to use Go’s channels<\/strong> <\/em>via exported functions in a foreign language, in this case Lisp<\/strong><\/em>.<\/p>\n

As I mentioned in the beginning of this article, before using Go<\/strong><\/em> functions in a foreign language, we have to convince ourselves that this has definite advantages. Remember we now have two runtimes in our code, one from Go<\/strong><\/em> and another from Lisp<\/strong><\/em>. This can cause subtle problems in a large program, so we have to be careful, especially when passing objects around the two different runtimes.<\/p>\n

Download the sources from here<\/a>. Have a great weekend!<\/p>\n","protected":false},"excerpt":{"rendered":"

In my earlier article Calling Go Functions from Lisp, I explained the steps for making calls to Go functions from another language, specifically LispWorks Lisp. Today, I want to give a slightly more\u00a0 interesting example showing the use of Go channels\u00a0through exported functions. Go is widely admired for its native support for concurrency via Goroutines. […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"advanced_seo_description":"","jetpack_seo_html_title":"","jetpack_seo_noindex":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[141,18,17],"tags":[110,142,99],"class_list":["post-963","post","type-post","status-publish","format-standard","hentry","category-golang","category-lisp","category-programming","tag-common-lisp","tag-go-language","tag-lispworks"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p9OLnF-fx","jetpack-related-posts":[{"id":944,"url":"https:\/\/www.rangakrish.com\/index.php\/2018\/06\/10\/calling-lisp-functions-from-go-language\/","url_meta":{"origin":963,"position":0},"title":"Calling Lisp Functions from Go Language","author":"admin","date":"June 10, 2018","format":false,"excerpt":"In the previous post, we saw how to invoke a Go function from Lisp. In today's post, I would like to explain how to go in the other direction, namely, how to call Lisp functins from Go. There are two ways to do this. The first approach is to load\u2026","rel":"","context":"In "Golang"","block_context":{"text":"Golang","link":"https:\/\/www.rangakrish.com\/index.php\/category\/golang\/"},"img":{"alt_text":"Direct DLL Call","src":"https:\/\/i0.wp.com\/www.rangakrish.com\/wp-content\/uploads\/2018\/06\/LispCall.png?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.rangakrish.com\/wp-content\/uploads\/2018\/06\/LispCall.png?resize=350%2C200 1x, https:\/\/i0.wp.com\/www.rangakrish.com\/wp-content\/uploads\/2018\/06\/LispCall.png?resize=525%2C300 1.5x"},"classes":[]},{"id":928,"url":"https:\/\/www.rangakrish.com\/index.php\/2018\/05\/27\/calling-go-functions-from-lisp\/","url_meta":{"origin":963,"position":1},"title":"Calling Go Functions from Lisp","author":"admin","date":"May 27, 2018","format":false,"excerpt":"For the past few weeks I was travelling in the USA and had the pleasure of meeting several friends, some of whom are senior developers and architects. It was interesting to learn that many of them were either using Go language in their daily work, or were passionately endorsing the\u2026","rel":"","context":"In "Golang"","block_context":{"text":"Golang","link":"https:\/\/www.rangakrish.com\/index.php\/category\/golang\/"},"img":{"alt_text":"Part of Header File","src":"https:\/\/i0.wp.com\/www.rangakrish.com\/wp-content\/uploads\/2018\/05\/Header-file.png?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.rangakrish.com\/wp-content\/uploads\/2018\/05\/Header-file.png?resize=350%2C200 1x, https:\/\/i0.wp.com\/www.rangakrish.com\/wp-content\/uploads\/2018\/05\/Header-file.png?resize=525%2C300 1.5x"},"classes":[]},{"id":2645,"url":"https:\/\/www.rangakrish.com\/index.php\/2021\/12\/25\/calling-lisp-functions-from-d-language\/","url_meta":{"origin":963,"position":2},"title":"Calling Lisp Functions from D Language","author":"admin","date":"December 25, 2021","format":false,"excerpt":"After exploring \"newLisp\" in the past few posts, I would like to start looking at the \"D Programming Language\"\u00a0(DLang). DLang\u00a0has been around since 2001. It was originally created by Walter Bright and later Andrei Alexandrescu joined the team in 2007. The main inspiration for DLang was C++, although it uses\u2026","rel":"","context":"In "D Language"","block_context":{"text":"D Language","link":"https:\/\/www.rangakrish.com\/index.php\/category\/d-language\/"},"img":{"alt_text":"Lisp Function Called from D","src":"https:\/\/i0.wp.com\/www.rangakrish.com\/wp-content\/uploads\/2021\/12\/Lisp-300x107.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.rangakrish.com\/wp-content\/uploads\/2021\/12\/Lisp-300x107.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/www.rangakrish.com\/wp-content\/uploads\/2021\/12\/Lisp-300x107.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":2057,"url":"https:\/\/www.rangakrish.com\/index.php\/2020\/07\/19\/calling-lisp-functions-from-elixir\/","url_meta":{"origin":963,"position":3},"title":"Calling Lisp Functions from Elixir","author":"admin","date":"July 19, 2020","format":false,"excerpt":"In the last article\u00a0I showed how we can simulate the idea of Lisp's \"closure\" in Elixir. Today, I would like to demonstrate how we can call Lisp functions from Elixir using the NIF interface. What is the need to integrate Elixir with another language? 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As Julia documentation says, such calls do not involve any \u201cboilerplate\u201d code and hence are efficient. In today\u2019s article, I am going to show how to call functions defined in a DLL (Windows 64 bit). Instead of using direct\u2026","rel":"","context":"In "Julia"","block_context":{"text":"Julia","link":"https:\/\/www.rangakrish.com\/index.php\/category\/julia\/"},"img":{"alt_text":"The \"lispEval\" Function","src":"https:\/\/i0.wp.com\/www.rangakrish.com\/wp-content\/uploads\/2023\/02\/code-300x117.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.rangakrish.com\/wp-content\/uploads\/2023\/02\/code-300x117.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/www.rangakrish.com\/wp-content\/uploads\/2023\/02\/code-300x117.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":2334,"url":"https:\/\/www.rangakrish.com\/index.php\/2021\/02\/28\/calling-c-methods-from-lispworks-lisp-through-com-interface\/","url_meta":{"origin":963,"position":5},"title":"Calling C# Methods from LispWorks Lisp through COM Interface","author":"admin","date":"February 28, 2021","format":false,"excerpt":"In an earlier article, I showed how to invoke C# methods from Sicstus Prolog. Today, I would like to detail the steps for doing the same from LispWorks Lisp. LispWorks Enterprise Edition comes budled with support for COM and Automation. This is what we will be using. What this means\u2026","rel":"","context":"In "LISP"","block_context":{"text":"LISP","link":"https:\/\/www.rangakrish.com\/index.php\/category\/lisp\/"},"img":{"alt_text":"The COM Server in C#","src":"https:\/\/i0.wp.com\/www.rangakrish.com\/wp-content\/uploads\/2021\/02\/C-Code-300x267.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]}],"_links":{"self":[{"href":"https:\/\/www.rangakrish.com\/index.php\/wp-json\/wp\/v2\/posts\/963","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.rangakrish.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.rangakrish.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.rangakrish.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.rangakrish.com\/index.php\/wp-json\/wp\/v2\/comments?post=963"}],"version-history":[{"count":0,"href":"https:\/\/www.rangakrish.com\/index.php\/wp-json\/wp\/v2\/posts\/963\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.rangakrish.com\/index.php\/wp-json\/wp\/v2\/media?parent=963"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.rangakrish.com\/index.php\/wp-json\/wp\/v2\/categories?post=963"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.rangakrish.com\/index.php\/wp-json\/wp\/v2\/tags?post=963"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}