File 1374-Formatting-don-t-nest-code-inside-p-tag.patch of Package erlang

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File 1374-Formatting-don-t-nest-code-inside-p-tag.patch of Package erlang (Revision a2c746346df91f7eba485155dba10e85)

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From 6d1152bcd592586bfc2d2cbee4b2a23e3a964378 Mon Sep 17 00:00:00 2001
From: Maxwell Elliot Heiber <mheiber@fb.com>
Date: Wed, 22 Dec 2021 19:06:44 +0000
Subject: [PATCH 3/3] Formatting, don't nest code inside p tag

---
 system/doc/reference_manual/opaques.xml | 122 +++++++++++++++++++-----
 1 file changed, 98 insertions(+), 24 deletions(-)

diff --git a/system/doc/reference_manual/opaques.xml b/system/doc/reference_manual/opaques.xml
index b14042cb19..8fa3bae3e5 100644
--- a/system/doc/reference_manual/opaques.xml
+++ b/system/doc/reference_manual/opaques.xml
@@ -1,10 +1,11 @@
-<?xml version="1.0" encoding="utf-8" ?>
+<?xml version="1.0" encoding="utf-8"?>
 <!DOCTYPE chapter SYSTEM "chapter.dtd">
 
 <chapter>
 <header>
 <copyright>
- <year>2021</year><year>2022</year>
+ <year>2021</year>
+ <year>2022</year>
 <holder>Ericsson AB. All Rights Reserved.</holder>
 </copyright>
 <legalnotice>
@@ -30,38 +31,111 @@
 <file>opaques.xml</file>
 </header>
 
- <section><title>Opaque Type Aliases</title>
+ <section>
+ <title>Opaque Type Aliases</title>
 The main use case for opacity in Erlang is to hide the implementation of a data type, enabling evolving the API while minimizing the risk of breaking consumers. The runtime does not check opacity. Dialyzer provides some opacity-checking, but the rest is up to convention.
 
 
-This document explains what Erlang opacity is (and the trade-offs involved) via the example of OTP's <c>sets:set()</c> data type. This type was defined in `sets` module like this:
+ This document explains what Erlang opacity is (and the trade-offs involved) via the example of OTP's
+ <c>sets:set()</c>
+ data type. This type
+ was
+ defined in `sets` module like this:
+ 
+ <code type="erl">-opaque set(Element) :: #set{segs :: segs(Element)}.</code>
+ OTP 24 changed the definition to the following, in
+ <url href="https://github.com/erlang/otp/commit/e66941e8d7c47b973dff94c0308ea85a6be1958e">this commit</url>
+ 
+ <code type="erl">-opaque set(Element) :: #set{segs :: segs(Element)} | #{Element => ?VALUE}.</code>
+ 
+ And this change was safer and more backwards-compatible than if the type had been defined with
+ <c>-type</c>
+ instead of
+ <c>-opaque</c>
+ . Here's why: when a module defines an
+ <c>-opaque</c>
+ , the contract is that only the defining module should rely on the definition of the type: no other modules should rely on the definition.
 
 
- <code type="erl">-opaque set(Element) :: #set{segs :: segs(Element)}.</code>
- OTP 24 changed the definition to the following, in <url href="https://github.com/erlang/otp/commit/e66941e8d7c47b973dff94c0308ea85a6be1958e">this commit</url>.
- <code type="erl">-opaque set(Element) :: #set{segs :: segs(Element)} | #{Element => ?VALUE}.</code>
-And this change was safer and more backwards-compatible than if the type had been defined with <c>-type</c> instead of <c>-opaque</c>. Here's why: when a module defines an <c>-opaque</c>, the contract is that only the defining module should rely on the definition of the type: no other modules should rely on the definition.
-This means that code that pattern-matched on <c>set</c> as a record/tuple technically broke the contract, and opted in to being potentially broken when the definition of <c>set()</c> changed. Before OTP 24, this code printed <c>ok</c>. In OTP 24 it may error:
+ This means that code that pattern-matched on
+ <c>set</c>
+ as a record/tuple technically broke the contract, and opted in to being potentially broken when the definition of
+ <c>set()</c>
+ changed. Before OTP 24, this code printed
+ <c>ok</c>
+ . In OTP 24 it may error:
+ 
 <code type="erl">
 case sets:new() of
 Set when is_tuple(Set) -&gt;
 io:format(&quot;ok&quot;)
 end.
 </code>
-
-When working with an opaque defined in another module, here are some recommendations:
+ 
+ When working with an opaque defined in another module, here are some recommendations:
+ 
 
-<list type="bulleted">
-<item>Don't examine the underlying type using pattern-matching, guards, or functions that reveal the type, such as <c>tuple_size/1</c>.</item>
-<item>Instead, use functions provided by the module for working with the type. For example, <c>sets</c> module provides <c>sets:new/0</c>, <c>sets:add/2</c>, <c>sets:is_element/2</c>, etc.</item>
-<item><c>sets:set(a)</c> is a subtype of <c>sets:set(a | b)</c> and not the other way around. Generally, you can rely on the property that <c>the_opaque(T)</c> is a subtype of <c>the_opaque(U)</c> when T is a subtype of U.</item>
-</list>
-When defining your own opaques, here are some recommendations:
-<list type="bulleted">
-<item>Since consumers are expected to not rely on the definition of the opaque type, you must provide functions for constructing and querying/deconstructing intances of your opaque type. For example, sets can be constructed with <c>sets:new/0</c>, <c>sets:from_list/1</c>, <c>sets:add/2</c>, queried with <c>sets:is_element/2</c>, and deconstructed with <c>sets:to_list/1</c>.</item>
-<item>Don't define an opaque with a type variable in parameter position. This breaks the normal and expected behavior that (for example) <c>my_type(a)</c> is a subtype of <c>my_type(a | b)</c></item>
-<item>Add <seealso marker="typespec">specs</seealso> to exported functions that use the opaque type</item>
-</list>
-Note that opaques can be harder to work with for consumers, since the consumer is expected not to pattern-match and must instead use functions that the author of the opaque type provides to use instances of the type.
-Also, opacity in Erlang is skin-deep: the runtime does not enforce opacity-checking. So now that sets are implemented in terms of maps, an <c>is_map</c> check on a set will pass. The opacity rules are only enforced by convention and by additional tooling such as Dialyzer. And this enforcement is not total: For example, determined consumer of <c>sets</c> can still do things that reveal the structure of the set, such as by printing, serializing, or using a set as <c>term()</c> and then inspecting via functions like <c>is_map</c> or <c>maps:get/2</c>. And Dialyzer must make some <url href="https://github.com/erlang/otp/issues/5118">approximations</url>. Opacity checking has limitations, but is still a vital tool in scalable Erlang development.</section>
+ <list type="bulleted">
+ <item>
+ Don't examine the underlying type using pattern-matching, guards, or functions that reveal the type, such as
+ <c>tuple_size/1</c>
+ .
+ </item>
+ <item>
+ Instead, use functions provided by the module for working with the type. For example,
+ <c>sets</c>
+ module provides
+ <c>sets:new/0</c>
+ ,
+ <c>sets:add/2</c>
+ ,
+ <c>sets:is_element/2</c>
+ , etc.
+ </item>
+ <item>
+ <c>sets:set(a)</c>
+ is a subtype of
+ <c>sets:set(a | b)</c>
+ and not the other way around. Generally, you can rely on the property that
+ <c>the_opaque(T)</c>
+ is a subtype of
+ <c>the_opaque(U)</c>
+ when T is a subtype of U.
+ </item>
+ </list>
+ 
+ When defining your own opaques, here are some recommendations:
+ 
+ <list type="bulleted">
+ <item>
+ Since consumers are expected to not rely on the definition of the opaque type, you must provide functions for constructing and querying/deconstructing intances of your opaque type. For example, sets can be constructed with
+ <c>sets:new/0</c>, <c>sets:from_list/1</c>, <c>sets:add/2</c>, queried with <c>sets:is_element/2</c>, and deconstructed with<c>sets:to_list/1</c>.
+ </item>
+ <item>
+ Don't define an opaque with a type variable in parameter position. This breaks the normal and expected behavior that (for example)
+ <c>my_type(a)</c> is a subtype of <c>my_type(a | b)</c>
+ </item>
+ <item>
+ Add <seealso marker="typespec">specs</seealso> to exported functions that use the opaque type
+ </item>
+ </list>
+ Note that opaques can be harder to work with for consumers, since the consumer is expected not to pattern-match and must instead use functions that the author of the opaque type provides to use instances of the type.
+ 
+ Also, opacity in Erlang is skin-deep: the runtime does not enforce opacity-checking. So now that sets are implemented in terms of maps, an
+ <c>is_map</c>
+ check on a set
+ will
+ pass. The opacity rules are only enforced by convention and by additional tooling such as Dialyzer. And this enforcement is not total: For example, determined consumer of
+ <c>sets</c>
+ can still do things that reveal the structure of the set, such as by printing, serializing, or using a set as
+ <c>term()</c>
+ and then inspecting via functions like
+ <c>is_map</c>
+ or
+ <c>maps:get/2</c>
+ . And Dialyzer must make some
+ <url href="https://github.com/erlang/otp/issues/5118">approximations</url>
+ . Opacity checking has limitations, but is still a vital tool in scalable Erlang development.
+ 
+ </section>
 </chapter>
-- 
2.31.1

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File 1374-Formatting-don-t-nest-code-inside-p-tag.patch of Package erlang (Revision a2c746346df91f7eba485155dba10e85)

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