Showing 612 of 612 total issues
Line length Open
Мы не можем работать с функцией, которая ничего не вычисляет. То есть аналога C-функции `void f(int i)` в Haskell быть не может, так как это противоречит математической природе. Однако мы можем работать с функцией, которая ничего не принимает, то есть с аналогом C-функции `int f(void)`. С такими функциями мы познакомимся в следующих главах.- Read upRead up
- Exclude checks
MD013 - Line length
Tags: line_length
Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)
This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.
This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.
You also have the option to exclude this rule for code blocks and tables. To
do this, set the code_blocks and/or tables parameters to false.
Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.
Line length Open
Функция `+` записана в инфиксной (англ. infix) форме, то есть между своими аргументами. Такая запись выглядит естественнее, нежели обычная:- Read upRead up
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MD013 - Line length
Tags: line_length
Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)
This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.
This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.
You also have the option to exclude this rule for code blocks and tables. To
do this, set the code_blocks and/or tables parameters to false.
Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.
Line length Open
Круглые скобки и значения, разделённые запятыми. Этот кортеж содержит значение типа `String` и ещё одно, типа `Int`. Вот ещё пример:- Read upRead up
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MD013 - Line length
Tags: line_length
Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)
This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.
This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.
You also have the option to exclude this rule for code blocks and tables. To
do this, set the code_blocks and/or tables parameters to false.
Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.
Line length Open
При энергичной модели (называемой ещё «жадной» или «строгой») выражение, являющееся аргументом функции, будет вычислено ещё до того, как попадёт в тело функции. На фоне определения функции `square` будет яснее:- Read upRead up
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MD013 - Line length
Tags: line_length
Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)
This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.
This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.
You also have the option to exclude this rule for code blocks and tables. To
do this, set the code_blocks and/or tables parameters to false.
Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.
Line length Open
Список `evens`, формируемый через арифметическую последовательность, содержит в себе чётные числа от `2` до `100` включительно. Используется этот список в качестве второго аргумента стандартной функции `take`, которая даёт нам N первых элементов из переданного ей списка:- Read upRead up
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MD013 - Line length
Tags: line_length
Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)
This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.
This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.
You also have the option to exclude this rule for code blocks and tables. To
do this, set the code_blocks and/or tables parameters to false.
Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.
Line length Open
Проблема space leak вытекает из самой природы ленивых вычислений. Многие программисты, узнав об этой проблеме, отворачиваются от Haskell. Мол, если в этом языке можно легко написать код, сжирающий уймищу памяти, значит этот язык точно не подходит для серьёзного использования. Но не так страшен чёрт, как его малюют. Я расскажу о двух способах борьбы со space leak.- Read upRead up
- Exclude checks
MD013 - Line length
Tags: line_length
Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)
This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.
This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.
You also have the option to exclude this rule for code blocks and tables. To
do this, set the code_blocks and/or tables parameters to false.
Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.
Line length Open
Haskell — не первый язык с ленивой стратегией вычислений. Открою вам исторический факт: у языка Haskell был предшественник, язык программирования с красивым женским именем [Miranda](https://en.wikipedia.org/wiki/Miranda_(programming_language)). Лень и чистая функциональность пришли в Haskell именно из Miranda, и лишь в этих двух языках ленивая стратегия вычисления аргументов используется по умолчанию. На сегодняшний день, насколько мне известно, язык Miranda мёртв. Впрочем, как сугубо исследовательский язык он, может быть, кем-то и используется.- Read upRead up
- Exclude checks
MD013 - Line length
Tags: line_length
Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)
This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.
This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.
You also have the option to exclude this rule for code blocks and tables. To
do this, set the code_blocks and/or tables parameters to false.
Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.
Dollar signs used before commands without showing output Open
```bash- Read upRead up
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MD014 - Dollar signs used before commands without showing output
Tags: code
Aliases: commands-show-output
This rule is triggered when there are code blocks showing shell commands to be typed, and the shell commands are preceded by dollar signs ($):
$ ls
$ cat foo
$ less barThe dollar signs are unnecessary in the above situation, and should not be included:
ls
cat foo
less barHowever, an exception is made when there is a need to distinguish between typed commands and command output, as in the following example:
$ ls
foo bar
$ cat foo
Hello world
$ cat bar
bazRationale: it is easier to copy and paste and less noisy if the dollar signs are omitted when they are not needed. See http://www.cirosantilli.com/markdown-styleguide/#dollar-signs-in-shell-code for more information.
Line length Open
Это канонический пример проблемы, обусловленной слабой (англ. weak) системой типов. Функция `coeff` возвращает значение типа `double`, однако вызывающая сторона ожидает почему-то целое число. Ну вот ошиблись мы, криво скопировали. В этом случае произойдёт жульничество, называемое скрытым приведением типов (англ. implicit type casting): число с плавающей точкой, возвращённое функцией `coeff`, будет грубо сломано путём приведения его к типу `int`, в результате чего дробная часть будет отброшена и мы получим не `608.4426`, а `608`. Подобная ошибка, кстати, приводила к серьёзным последствиям, таким как уничтожение космических аппаратов. Нет, это вовсе не означает, что слабая типизация ужасна сама по себе, просто есть иной путь.- Read upRead up
- Exclude checks
MD013 - Line length
Tags: line_length
Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)
This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.
This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.
You also have the option to exclude this rule for code blocks and tables. To
do this, set the code_blocks and/or tables parameters to false.
Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.
Line length Open
Ещё одно замечание про оператор применения функции. Он весьма гибок, и мы можем написать так:- Read upRead up
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MD013 - Line length
Tags: line_length
Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)
This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.
This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.
You also have the option to exclude this rule for code blocks and tables. To
do this, set the code_blocks and/or tables parameters to false.
Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.
Line length Open
С модулями — файлами, содержащими Haskell-код, — мы уже знакомы, они являются основным кирпичом любого Haskell-проекта. Библиотека, также являясь Haskell-проектом, тоже состоит из модулей (не важно, из одного или из сотен). Поэтому использование библиотеки сводится к использованию входящих в неё модулей. И мы уже неоднократно делали это в предыдущих главах.- Read upRead up
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MD013 - Line length
Tags: line_length
Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)
This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.
This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.
You also have the option to exclude this rule for code blocks and tables. To
do this, set the code_blocks and/or tables parameters to false.
Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.
Line length Open
Файл с расширением `.cabal` — это обязательный сборочный файл Haskell-проекта. Он содержит главные инструкции, касающиеся сборки проекта. С синтаксисом сборочного файла мы будем постепенно знакомиться в следующих главах.- Read upRead up
- Exclude checks
MD013 - Line length
Tags: line_length
Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)
This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.
This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.
You also have the option to exclude this rule for code blocks and tables. To
do this, set the code_blocks and/or tables parameters to false.
Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.
Line length Open
Впрочем, некоторым Haskell-программистам любое указание принадлежности к модулю кажется избыточным. Поэтому они идут по другому пути: выборочное включение/выключение. Например:- Read upRead up
- Exclude checks
MD013 - Line length
Tags: line_length
Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)
This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.
This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.
You also have the option to exclude this rule for code blocks and tables. To
do this, set the code_blocks and/or tables parameters to false.
Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.
Line length Open
Пришло время познакомиться с важной концепцией — лямбда-функцией. Именно с неё всё и началось. Приготовьтесь: в этой главе нас ждут новые открытия.- Read upRead up
- Exclude checks
MD013 - Line length
Tags: line_length
Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)
This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.
This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.
You also have the option to exclude this rule for code blocks and tables. To
do this, set the code_blocks and/or tables parameters to false.
Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.
Line length Open
Что это за буква `a`? Во-первых, мы не встречали такой тип ранее, а во-вторых, разве имя типа в Haskell не обязано начинаться с большой буквы? Обязано. А всё дело в том, что буква `a` в данном случае — это не совсем имя типа. А вот что это такое, мы узнаем в одной из ближайших глав.- Read upRead up
- Exclude checks
MD013 - Line length
Tags: line_length
Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)
This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.
This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.
You also have the option to exclude this rule for code blocks and tables. To
do this, set the code_blocks and/or tables parameters to false.
Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.
Line length Open
Вспомним, что присваивание (англ. assignment) пришло к нам из императивных языков. Императивное программирование (англ. imperative programming) — это направление в разработке, объединяющее несколько парадигм программирования, одной из которых является знаменитая объектно-ориентированная парадигма. В рамках этого направления программа воспринимается как набор инструкций, выполнение которых неразрывно связано с изменением состояния (англ. state) этой программы. Вот почему в императивных языках обязательно присутствует понятие «переменная» (англ. variable). А раз есть переменные — должен быть и оператор присваивания. Когда мы пишем:- Read upRead up
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MD013 - Line length
Tags: line_length
Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)
This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.
This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.
You also have the option to exclude this rule for code blocks and tables. To
do this, set the code_blocks and/or tables parameters to false.
Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.
Line length Open
Обратите внимание, объявление функции отформатировано чуток иначе: типы выстроены друг под другом через выравнивание стрелок под двоеточием. Вы часто встретите такой стиль в Haskell-проектах.- Read upRead up
- Exclude checks
MD013 - Line length
Tags: line_length
Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)
This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.
This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.
You also have the option to exclude this rule for code blocks and tables. To
do this, set the code_blocks and/or tables parameters to false.
Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.
Line length Open
Функция говорит нам: «Да, я знаю, что мой аргумент — это четырёхэлементный кортеж, но меня в нём интересует исключительно третий по счёту элемент, соответствующий адресу почты, его я и верну». Универсальный образец `_` делает наш код лаконичнее и понятнее, ведь он помогает нам игнорировать то, что нам неинтересно. Строго говоря, мы не обязаны использовать `_`, но с ним будет лучше.- Read upRead up
- Exclude checks
MD013 - Line length
Tags: line_length
Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)
This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.
This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.
You also have the option to exclude this rule for code blocks and tables. To
do this, set the code_blocks and/or tables parameters to false.
Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.
Line length Open
Естественно, по причине неизменности кортежа, никакого обновления тут не происходит, но выглядит симпатично. При запуске получаем результат:- Read upRead up
- Exclude checks
MD013 - Line length
Tags: line_length
Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)
This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.
This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.
You also have the option to exclude this rule for code blocks and tables. To
do this, set the code_blocks and/or tables parameters to false.
Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.
Trailing punctuation in header Open
## А если ошиблись?- Read upRead up
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MD026 - Trailing punctuation in header
Tags: headers
Aliases: no-trailing-punctuation
Parameters: punctuation (string; default ".,;:!?")
This rule is triggered on any header that has a punctuation character as the last character in the line:
# This is a header.To fix this, remove any trailing punctuation:
# This is a headerNote: The punctuation parameter can be used to specify what characters class
as punctuation at the end of the header. For example, you can set it to
'.,;:!' to allow headers with question marks in them, such as might be used
in an FAQ.