Showing 612 of 612 total issues
Line length Open
Вычисленным до конца называют такое выражение, которое вычислено до своей окончательной, нередуцируемой формы. О таком выражении говорят как о выражении в «нормальной форме» (англ. normal form).- 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 `fakeSum` строга по своему первому аргументу и ленива по своему второму аргументу. Первый аргумент `x` непременно будет вычислен, ведь он передаётся оператору сложения. Второй же аргумент игнорируется, оставшись невычисленным. И кстати, существует простой способ проверить, строга ли функция по некоторому аргументу или ленива.- 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
Как мы помним, деления на ноль так и не произошло за ненадобностью его результата. В этом случае выражение осталось в виде thunk. Возникает вопрос: что же с ним стало? У нас есть функция `div` и есть два значения типа `Int`, `2` и `0`. Если функция `div` так и не была применена к ним, где же всё это хозяйство находилось в процессе работы нашей программы? Оно находилось в памяти, в виде особого графа, который можно изобразить так:- 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
В чём же здесь рациональность, спросите вы? А в том, что список `evens` в итоге содержал в себе лишь 5 элементов. Да, но ведь чётных чисел от `2` до `100` куда больше, нежели пять! Совершенно верно, но лень позволяет нам сделать лишь столько работы, сколько реально требуется. Раз уж список `evens` нужен лишь функции `take`, которая, в свою очередь, хочет только пять первых его элементов — зачем же создавать оставшиеся элементы? Нужно первые пять — получи пять. Если же напишем так:- 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
Эта строка содержит различные опции компилятора GHC, и оптимизационный флаг дописывается именно сюда. Попробуем подставить туда сначала флаг `-O0`, а затем `-O2`. Результаты запуска программы будут такими:- 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
То есть сама функция и два значения, которые должны были занять место двух её аргументов. И вот этот граф в памяти так и остался невостребованным. Казалось бы, ну и в чём проблема? А проблема в количестве. Если мы смогли написать код, при работе которого в память отложился один thunk, значит теоретически мы можем написать и такой код, количество thunk-ов при работе которого будет исчисляться миллионами. А учитывая тот факт, что каждый thunk занимает в памяти хотя бы несколько байт, вы можете себе представить масштаб проблемы.- 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
Статическая проверка типов (англ. static type checking) — это проверка типов всех данных в программе, осуществляемая на этапе компиляции. Haskell-компилятор упрям: когда ему что-либо не нравится в типах, он громко ругается. Поэтому если функция работает с целыми числами, применить её к строкам никак не получится. Так что если компиляция нашей программы завершилась успешно, мы точно знаем, что с типами у нас всё в порядке. Преимущества статической проверки невозможно переоценить, ведь она гарантирует отсутствие в наших программах целого ряда ошибок. Мы уже не сможем спутать числа со строками или вычесть метры из рублей.- 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
Не сомневайтесь: программа спокойно вернёт нам `23`, ведь функция `head` строга лишь по первому элементу переданного ей списка, остальное содержимое оного её абсолютно не интересует. Но если попробуете вытащить второй или третий элемент из подобного списка — крах неминуем.- 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
К предыдущему выражению вновь прибавляется единица — и мы опять входим в очередную итерацию, так и не выполнив сложения:- 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
Первый способа самый простой — оптимизация. Когда компилятор превращает наш код в программу, его можно попросить оптимизировать наш код, сделав его более эффективным, по тем или иным критериям. Чтобы попросить компилятор провести оптимизацию, мы должны использовать специальный флаг. Откроем сборочный файл нашего проекта `real.cabal`, найдём секцию `executable real-exe`, в которой есть строка:- 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
> Вычислить выражение — это значит применить какие-то функции (одну или более) к каким-то аргументам (одному или более).- 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
Если применение функции представляет собой выражение, не можем ли мы как-нибудь компоновать их друг с другом? Конечно можем, мы уже делали это много раз, вспомните:- 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
Вместо привычного оператора применения `$` мы видим оператор строго применения `$!` (англ. strict application operator). Этот оператор говорит аргументу: «Забудь о лени, я приказываю тебе немедленно вычислиться до слабой головной формы»:- 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
Выглядит необычно, но работать будет так, как и ожидается: мы определили собственный оператор `<+>` с тем же функционалом, что и стандартный оператор композиции. Поэтому можно написать ещё проще:- 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
Благодаря сильной типизации в Haskell подобный код не имеет ни малейших шансов пройти компиляцию. Мы всегда получаем то, что ожидаем, и если должно быть число с плавающей точкой — расшибись, но предоставь именно его. Компилятор скрупулёзно отслеживает соответствие ожидаемого типа фактическому, поэтому когда компиляция завершается успешно, мы абсолютно уверены в гармонии между типами всех наших данных.- 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
программа, попытавшись передать `undefined` оператору сложения, аварийно остановится. Или вот другой пример:- 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
Теперь мы видим, что в композиции функций нет ничего сверхъестественного. Эту мысль я подчёркиваю на протяжении всей книги: в Haskell нет никакой магии, он логичен и последователен.- 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
И всё работает! В мире Haskell принято именно так: если что-то может быть упрощено — мы это упрощаем.- 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
Полезный результат мы получаем в результате вычисления (англ. evaluation) выражения. Все выражения можно вычислить, однако одни выражения в результате вычисления уменьшаются (англ. reduce), а другие — нет. Первые иногда называют редуцируемыми выражениями, а вторые — нередуцируемые. Так, выражение:- 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
Справедливости ради следует заметить, что не все Haskell-разработчики любят избавляться от круглых скобок, некоторые предпочитают использовать именно их. Что ж, это лишь вопрос стиля и привычек.- 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.