{"id":2942,"date":"2021-10-27T22:23:39","date_gmt":"2021-10-28T06:23:39","guid":{"rendered":"https:\/\/wonghoi.humgar.com\/blog\/?p=2942"},"modified":"2021-10-28T00:08:10","modified_gmt":"2021-10-28T08:08:10","slug":"styles-for-lambda-anonymous-function-named-or-unnamed-in-dart-language","status":"publish","type":"post","link":"https:\/\/wonghoi.humgar.com\/blog\/2021\/10\/27\/styles-for-lambda-anonymous-function-named-or-unnamed-in-dart-language\/","title":{"rendered":"Styles for (Lambda) anonymous function (named or unnamed) in Dart Language"},"content":{"rendered":"\n

Official Dart docs<\/a> is sometimes too simple to provide ultimate answers for various language questions. I discoverd an alternative syntax for named lambda here<\/a> and here<\/a>. In Dart,<\/p>\n\n\n\n

(args) => expr<\/pre>\n\n\n\n
is the shorthand for<\/p>\n\n\n\n
(args) { \n  return expr \n}<\/pre>\n\n\n\n
So the Lambda-style (C++11) names variable by assigning it to a messy functor type (inferred with var<\/code> in Dart and auto<\/code> in C++11):<\/p>\n\n\n\n
var f = (args) => expr<\/pre>\n\n\n\n
Which can also be rewritten using C-style function pointer-like declaration except <\/p>\n\n\n\n
  1. the body expr<\/code> is included (which is not allowed in C), <\/li>
  2. return<\/code> must be explicit<\/span> in curly braces block. <\/li>
  3. arrow notation =><\/code> takes whatever the expr evaluates to (which can be null for statements like print)<\/li>
  4. it’s simply the function name f<\/code> in Dart instead of pointer (*f)<\/code> in C<\/li><\/ol>\n\n\n\n
    [optional return type] f(args) { \n  return expr;\n}<\/pre>\n\n\n\n
    which can be simplified with the arrow operator<\/p>\n\n\n\n
    [optional return type] f(args) => { expr }<\/pre>\n\n\n\n
    <\/p>\n
    <\/div>
    <\/path><\/svg><\/i> \"Loading\"<\/p>
    <\/div>","protected":false},"excerpt":{"rendered":"
    Official Dart docs is sometimes too simple to provide ultimate answers for various language questions. I discoverd an alternative syntax for named lambda here and here. In Dart, is the shorthand for So the Lambda-style (C++11) names variable by assigning … Continue reading →<\/span><\/a><\/p>\n
    <\/div>\n
    <\/path><\/svg><\/i> \"Loading\"<\/p>\n
    <\/div>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false,"footnotes":""},"categories":[62,61],"tags":[],"class_list":["post-2942","post","type-post","status-publish","format-standard","hentry","category-dart","category-functional-programming"],"_links":{"self":[{"href":"https:\/\/wonghoi.humgar.com\/blog\/wp-json\/wp\/v2\/posts\/2942","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wonghoi.humgar.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wonghoi.humgar.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wonghoi.humgar.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/wonghoi.humgar.com\/blog\/wp-json\/wp\/v2\/comments?post=2942"}],"version-history":[{"count":5,"href":"https:\/\/wonghoi.humgar.com\/blog\/wp-json\/wp\/v2\/posts\/2942\/revisions"}],"predecessor-version":[{"id":2950,"href":"https:\/\/wonghoi.humgar.com\/blog\/wp-json\/wp\/v2\/posts\/2942\/revisions\/2950"}],"wp:attachment":[{"href":"https:\/\/wonghoi.humgar.com\/blog\/wp-json\/wp\/v2\/media?parent=2942"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wonghoi.humgar.com\/blog\/wp-json\/wp\/v2\/categories?post=2942"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wonghoi.humgar.com\/blog\/wp-json\/wp\/v2\/tags?post=2942"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}