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-rw-r--r--lib/stdlib/doc/src/proplists.xml303
1 files changed, 183 insertions, 120 deletions
diff --git a/lib/stdlib/doc/src/proplists.xml b/lib/stdlib/doc/src/proplists.xml
index a0063a58d3..fe6b8cc3bf 100644
--- a/lib/stdlib/doc/src/proplists.xml
+++ b/lib/stdlib/doc/src/proplists.xml
@@ -1,23 +1,24 @@
-<?xml version="1.0" encoding="latin1" ?>
+<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE erlref SYSTEM "erlref.dtd">
<erlref>
<header>
<copyright>
- <year>2002</year><year>2013</year>
+ <year>2002</year><year>2016</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
- The contents of this file are subject to the Erlang Public License,
- Version 1.1, (the "License"); you may not use this file except in
- compliance with the License. You should have received a copy of the
- Erlang Public License along with this software. If not, it can be
- retrieved online at http://www.erlang.org/.
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
- Software distributed under the License is distributed on an "AS IS"
- basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
- the License for the specific language governing rights and limitations
- under the License.
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
</legalnotice>
@@ -29,51 +30,66 @@
<checked></checked>
<date>2002-09-28</date>
<rev>A</rev>
- <file>proplists.sgml</file>
+ <file>proplists.xml</file>
</header>
<module>proplists</module>
- <modulesummary>Support functions for property lists</modulesummary>
+ <modulesummary>Support functions for property lists.</modulesummary>
<description>
<p>Property lists are ordinary lists containing entries in the form
of either tuples, whose first elements are keys used for lookup and
- insertion, or atoms, which work as shorthand for tuples <c>{Atom, true}</c>. (Other terms are allowed in the lists, but are ignored
- by this module.) If there is more than one entry in a list for a
+ insertion, or atoms, which work as shorthand for tuples
+ <c>{Atom, true}</c>. (Other terms are allowed in the lists, but are
+ ignored by this module.) If there is more than one entry in a list for a
certain key, the first occurrence normally overrides any later
(irrespective of the arity of the tuples).</p>
+
<p>Property lists are useful for representing inherited properties,
- such as options passed to a function where a user may specify options
+ such as options passed to a function where a user can specify options
overriding the default settings, object properties, annotations,
- etc.</p>
- <p>Two keys are considered equal if they match (<c>=:=</c>). In other
- words, numbers are compared literally rather than by value, so that,
- for instance, <c>1</c> and <c>1.0</c> are different keys.</p>
+ and so on.</p>
+
+ <p>Two keys are considered equal if they match (<c>=:=</c>). That is,
+ numbers are compared literally rather than by value, so that,
+ for example, <c>1</c> and <c>1.0</c> are different keys.</p>
</description>
+
<datatypes>
<datatype>
<name name="property"/>
</datatype>
</datatypes>
+
<funcs>
<func>
<name name="append_values" arity="2"/>
<fsummary></fsummary>
<desc>
- <p>Similar to <c>get_all_values/2</c>, but each value is
- wrapped in a list unless it is already itself a list, and the
- resulting list of lists is concatenated. This is often useful for
- "incremental" options; e.g., <c>append_values(a, [{a, [1,2]}, {b, 0}, {a, 3}, {c, -1}, {a, [4]}])</c> will return the list
- <c>[1,2,3,4]</c>.</p>
+ <p>Similar to
+ <seealso marker="#get_all_values/2"><c>get_all_values/2</c></seealso>,
+ but each value is wrapped in a list unless it is already itself a
+ list. The resulting list of lists is concatenated. This is often
+ useful for "incremental" options.</p>
+ <p><em>Example:</em></p>
+ <code type="none">
+append_values(a, [{a, [1,2]}, {b, 0}, {a, 3}, {c, -1}, {a, [4]}])</code>
+ <p>returns:</p>
+ <code type="none">
+[1,2,3,4]</code>
</desc>
</func>
+
<func>
<name name="compact" arity="1"/>
<fsummary></fsummary>
<desc>
<p>Minimizes the representation of all entries in the list. This is
equivalent to <c><![CDATA[[property(P) || P <- ListIn]]]></c>.</p>
- <p>See also: <c>property/1</c>, <c>unfold/1</c>.</p>
+ <p>See also
+ <seealso marker="#property/1"><c>property/1</c></seealso>,
+ <seealso marker="#unfold/1"><c>unfold/1</c></seealso>.</p>
</desc>
</func>
+
<func>
<name name="delete" arity="2"/>
<fsummary></fsummary>
@@ -82,96 +98,111 @@
<c><anno>List</anno></c>.</p>
</desc>
</func>
+
<func>
<name name="expand" arity="2"/>
<fsummary></fsummary>
<desc>
<p>Expands particular properties to corresponding sets of
- properties (or other terms). For each pair <c>{<anno>Property</anno>, <anno>Expansion</anno>}</c> in <c><anno>Expansions</anno></c>, if <c>E</c> is
- the first entry in <c><anno>ListIn</anno></c> with the same key as
- <c><anno>Property</anno></c>, and <c>E</c> and <c><anno>Property</anno></c>
- have equivalent normal forms, then <c>E</c> is replaced with
- the terms in <c><anno>Expansion</anno></c>, and any following entries with
- the same key are deleted from <c><anno>ListIn</anno></c>.</p>
- <p>For example, the following expressions all return <c>[fie, bar, baz, fum]</c>:</p>
+ properties (or other terms). For each pair <c>{<anno>Property</anno>,
+ <anno>Expansion</anno>}</c> in <c><anno>Expansions</anno></c>: if
+ <c>E</c> is the first entry in <c><anno>ListIn</anno></c> with the
+ same key as <c><anno>Property</anno></c>, and <c>E</c> and
+ <c><anno>Property</anno></c> have equivalent normal forms, then
+ <c>E</c> is replaced with the terms in <c><anno>Expansion</anno></c>,
+ and any following entries with the same key are deleted from
+ <c><anno>ListIn</anno></c>.</p>
+ <p>For example, the following expressions all return
+ <c>[fie, bar, baz, fum]</c>:</p>
<code type="none">
- expand([{foo, [bar, baz]}],
- [fie, foo, fum])
- expand([{{foo, true}, [bar, baz]}],
- [fie, foo, fum])
- expand([{{foo, false}, [bar, baz]}],
- [fie, {foo, false}, fum])</code>
- <p>However, no expansion is done in the following call:</p>
+expand([{foo, [bar, baz]}], [fie, foo, fum])
+expand([{{foo, true}, [bar, baz]}], [fie, foo, fum])
+expand([{{foo, false}, [bar, baz]}], [fie, {foo, false}, fum])</code>
+ <p>However, no expansion is done in the following call
+ because <c>{foo, false}</c> shadows <c>foo</c>:</p>
<code type="none">
- expand([{{foo, true}, [bar, baz]}],
- [{foo, false}, fie, foo, fum])</code>
- <p>because <c>{foo, false}</c> shadows <c>foo</c>.</p>
- <p>Note that if the original property term is to be preserved in the
+expand([{{foo, true}, [bar, baz]}], [{foo, false}, fie, foo, fum])</code>
+ <p>Notice that if the original property term is to be preserved in the
result when expanded, it must be included in the expansion list. The
inserted terms are not expanded recursively. If
- <c><anno>Expansions</anno></c> contains more than one property with the same
- key, only the first occurrence is used.</p>
- <p>See also: <c>normalize/2</c>.</p>
+ <c><anno>Expansions</anno></c> contains more than one property with
+ the same key, only the first occurrence is used.</p>
+ <p>See also
+ <seealso marker="#normalize/2"><c>normalize/2</c></seealso>.</p>
</desc>
</func>
+
<func>
<name name="get_all_values" arity="2"/>
<fsummary></fsummary>
<desc>
- <p>Similar to <c>get_value/2</c>, but returns the list of
- values for <em>all</em> entries <c>{Key, Value}</c> in
- <c><anno>List</anno></c>. If no such entry exists, the result is the empty
- list.</p>
- <p>See also: <c>get_value/2</c>.</p>
+ <p>Similar to
+ <seealso marker="#get_value/2"><c>get_value/2</c></seealso>,
+ but returns the list of values for <em>all</em> entries
+ <c>{Key, Value}</c> in <c><anno>List</anno></c>. If no such entry
+ exists, the result is the empty list.</p>
</desc>
</func>
+
<func>
<name name="get_bool" arity="2"/>
<fsummary></fsummary>
<desc>
<p>Returns the value of a boolean key/value option. If
- <c>lookup(<anno>Key</anno>, <anno>List</anno>)</c> would yield <c>{<anno>Key</anno>, true}</c>,
- this function returns <c>true</c>; otherwise <c>false</c>
- is returned.</p>
- <p>See also: <c>get_value/2</c>, <c>lookup/2</c>.</p>
+ <c>lookup(<anno>Key</anno>, <anno>List</anno>)</c> would yield
+ <c>{<anno>Key</anno>, true}</c>, this function returns <c>true</c>,
+ otherwise <c>false</c>.</p>
+ <p>See also
+ <seealso marker="#get_value/2"><c>get_value/2</c></seealso>,
+ <seealso marker="#lookup/2"><c>lookup/2</c></seealso>.</p>
</desc>
</func>
+
<func>
<name name="get_keys" arity="1"/>
<fsummary></fsummary>
<desc>
- <p>Returns an unordered list of the keys used in <c><anno>List</anno></c>,
- not containing duplicates.</p>
+ <p>Returns an unordered list of the keys used in
+ <c><anno>List</anno></c>, not containing duplicates.</p>
</desc>
</func>
+
<func>
<name name="get_value" arity="2"/>
<fsummary></fsummary>
<desc>
- <p>Equivalent to <c>get_value(<anno>Key</anno>, <anno>List</anno>, undefined)</c>.</p>
+ <p>Equivalent to
+ <c>get_value(<anno>Key</anno>, <anno>List</anno>, undefined)</c>.</p>
</desc>
</func>
+
<func>
<name name="get_value" arity="3"/>
<fsummary></fsummary>
<desc>
<p>Returns the value of a simple key/value property in
- <c><anno>List</anno></c>. If <c>lookup(<anno>Key</anno>, <anno>List</anno>)</c> would yield
- <c>{<anno>Key</anno>, Value}</c>, this function returns the corresponding
- <c>Value</c>, otherwise <c><anno>Default</anno></c> is returned.</p>
- <p>See also: <c>get_all_values/2</c>, <c>get_bool/2</c>,
- <c>get_value/2</c>, <c>lookup/2</c>.</p>
+ <c><anno>List</anno></c>. If <c>lookup(<anno>Key</anno>,
+ <anno>List</anno>)</c> would yield <c>{<anno>Key</anno>, Value}</c>,
+ this function returns the corresponding <c>Value</c>, otherwise
+ <c><anno>Default</anno></c>.</p>
+ <p>See also
+ <seealso marker="#get_all_values/2"><c>get_all_values/2</c></seealso>,
+ <seealso marker="#get_bool/2"><c>get_bool/2</c></seealso>,
+ <seealso marker="#get_value/2"><c>get_value/2</c></seealso>,
+ <seealso marker="#lookup/2"><c>lookup/2</c></seealso>.</p>
</desc>
</func>
+
<func>
<name name="is_defined" arity="2"/>
<fsummary></fsummary>
<desc>
<p>Returns <c>true</c> if <c><anno>List</anno></c> contains at least
one entry associated with <c><anno>Key</anno></c>, otherwise
- <c>false</c> is returned.</p>
+ <c>false</c>.</p>
</desc>
</func>
+
<func>
<name name="lookup" arity="2"/>
<fsummary></fsummary>
@@ -180,128 +211,160 @@
<c><anno>List</anno></c>, if one exists, otherwise returns
<c>none</c>. For an atom <c>A</c> in the list, the tuple
<c>{A, true}</c> is the entry associated with <c>A</c>.</p>
- <p>See also: <c>get_bool/2</c>, <c>get_value/2</c>,
- <c>lookup_all/2</c>.</p>
+ <p>See also
+ <seealso marker="#get_bool/2"><c>get_bool/2</c></seealso>,
+ <seealso marker="#get_value/2"><c>get_value/2</c></seealso>,
+ <seealso marker="#lookup_all/2"><c>lookup_all/2</c></seealso>.</p>
</desc>
</func>
+
<func>
<name name="lookup_all" arity="2"/>
<fsummary></fsummary>
<desc>
- <p>Returns the list of all entries associated with <c><anno>Key</anno></c>
- in <c><anno>List</anno></c>. If no such entry exists, the result is the
- empty list.</p>
- <p>See also: <c>lookup/2</c>.</p>
+ <p>Returns the list of all entries associated with
+ <c><anno>Key</anno></c> in <c><anno>List</anno></c>. If no such entry
+ exists, the result is the empty list.</p>
+ <p>See also
+ <seealso marker="#lookup/2"><c>lookup/2</c></seealso>.</p>
</desc>
</func>
+
<func>
<name name="normalize" arity="2"/>
<fsummary></fsummary>
<desc>
<p>Passes <c><anno>ListIn</anno></c> through a sequence of
substitution/expansion stages. For an <c>aliases</c> operation,
- the function <c>substitute_aliases/2</c> is applied using the
- given list of aliases; for a <c>negations</c> operation,
- <c>substitute_negations/2</c> is applied using the given
- negation list; for an <c>expand</c> operation, the function
- <c>expand/2</c> is applied using the given list of expansions.
- The final result is automatically compacted (cf.
- <c>compact/1</c>).</p>
+ function <seealso marker="#substitute_aliases/2">
+ <c>substitute_aliases/2</c></seealso> is applied using the
+ specified list of aliases:</p>
+ <list type="bulleted">
+ <item>
+ <p>For a <c>negations</c> operation, <c>substitute_negations/2</c>
+ is applied using the specified negation list.</p>
+ </item>
+ <item>
+ <p>For an <c>expand</c> operation, function
+ <seealso marker="#expand/2"><c>expand/2</c></seealso>
+ is applied using the specified list of expansions.</p>
+ </item>
+ </list>
+ <p>The final result is automatically compacted (compare
+ <seealso marker="#compact/1"><c>compact/1</c></seealso>).</p>
<p>Typically you want to substitute negations first, then aliases,
then perform one or more expansions (sometimes you want to pre-expand
particular entries before doing the main expansion). You might want
to substitute negations and/or aliases repeatedly, to allow such
forms in the right-hand side of aliases and expansion lists.</p>
- <p>See also: <c>compact/1</c>, <c>expand/2</c>,
- <c>substitute_aliases/2</c>, <c>substitute_negations/2</c>.</p>
+ <p>See also <seealso marker="#substitute_negations/2">
+ <c>substitute_negations/2</c></seealso>.</p>
</desc>
</func>
+
<func>
<name name="property" arity="1"/>
<fsummary></fsummary>
<desc>
<p>Creates a normal form (minimal) representation of a property. If
- <c><anno>PropertyIn</anno></c> is <c>{Key, true}</c> where
- <c>Key</c> is an atom, this returns <c>Key</c>, otherwise
- the whole term <c><anno>PropertyIn</anno></c> is returned.</p>
- <p>See also: <c>property/2</c>.</p>
+ <c><anno>PropertyIn</anno></c> is <c>{Key, true}</c>, where
+ <c>Key</c> is an atom, <c>Key</c> is returned, otherwise
+ the whole term <c><anno>PropertyIn</anno></c> is returned.</p>
+ <p>See also
+ <seealso marker="#property/2"><c>property/2</c></seealso>.</p>
</desc>
</func>
+
<func>
<name name="property" arity="2"/>
<fsummary></fsummary>
<desc>
- <p>Creates a normal form (minimal) representation of a simple
- key/value property. Returns <c><anno>Key</anno></c> if <c><anno>Value</anno></c> is
- <c>true</c> and <c><anno>Key</anno></c> is an atom, otherwise a tuple
- <c>{<anno>Key</anno>, <anno>Value</anno>}</c> is returned.</p>
- <p>See also: <c>property/1</c>.</p>
+ <p>Creates a normal form (minimal) representation of a simple key/value
+ property. Returns <c><anno>Key</anno></c> if <c><anno>Value</anno></c>
+ is <c>true</c> and <c><anno>Key</anno></c> is an atom, otherwise a
+ tuple <c>{<anno>Key</anno>, <anno>Value</anno>}</c> is returned.</p>
+ <p>See also
+ <seealso marker="#property/1"><c>property/1</c></seealso>.</p>
</desc>
</func>
+
<func>
<name name="split" arity="2"/>
<fsummary></fsummary>
<desc>
<p>Partitions <c><anno>List</anno></c> into a list of sublists and a
- remainder. <c><anno>Lists</anno></c> contains one sublist for each key in
- <c><anno>Keys</anno></c>, in the corresponding order. The relative order of
- the elements in each sublist is preserved from the original
- <c><anno>List</anno></c>. <c><anno>Rest</anno></c> contains the elements in
- <c><anno>List</anno></c> that are not associated with any of the given keys,
+ remainder. <c><anno>Lists</anno></c> contains one sublist for each key
+ in <c><anno>Keys</anno></c>, in the corresponding order. The relative
+ order of the elements in each sublist is preserved from the original
+ <c><anno>List</anno></c>. <c><anno>Rest</anno></c> contains the
+ elements in <c><anno>List</anno></c> that are not associated with any
+ of the specified keys,
also with their original relative order preserved.</p>
- <p>Example:
- split([{c, 2}, {e, 1}, a, {c, 3, 4}, d, {b, 5}, b], [a, b, c])</p>
- <p>returns</p>
- <p>{[[a], [{b, 5}, b],[{c, 2}, {c, 3, 4}]], [{e, 1}, d]}</p>
+ <p><em>Example:</em></p>
+ <code type="none">
+split([{c, 2}, {e, 1}, a, {c, 3, 4}, d, {b, 5}, b], [a, b, c])</code>
+ <p>returns:</p>
+ <code type="none">
+{[[a], [{b, 5}, b],[{c, 2}, {c, 3, 4}]], [{e, 1}, d]}</code>
</desc>
</func>
+
<func>
<name name="substitute_aliases" arity="2"/>
<fsummary></fsummary>
<desc>
<p>Substitutes keys of properties. For each entry in
- <c><anno>ListIn</anno></c>, if it is associated with some key <c>K1</c>
- such that <c>{K1, K2}</c> occurs in <c><anno>Aliases</anno></c>, the
+ <c><anno>ListIn</anno></c>, if it is associated with some key
+ <c>K1</c> such that <c>{K1, K2}</c> occurs in
+ <c><anno>Aliases</anno></c>, the
key of the entry is changed to <c>K2</c>. If the same
<c>K1</c> occurs more than once in <c><anno>Aliases</anno></c>, only
the first occurrence is used.</p>
- <p>Example: <c>substitute_aliases([{color, colour}], L)</c>
- will replace all tuples <c>{color, ...}</c> in <c>L</c>
+ <p>For example, <c>substitute_aliases([{color, colour}], L)</c>
+ replaces all tuples <c>{color, ...}</c> in <c>L</c>
with <c>{colour, ...}</c>, and all atoms <c>color</c>
with <c>colour</c>.</p>
- <p>See also: <c>normalize/2</c>, <c>substitute_negations/2</c>.</p>
+ <p>See also
+ <seealso marker="#normalize/2"><c>normalize/2</c></seealso>,
+ <seealso marker="#substitute_negations/2">
+ <c>substitute_negations/2</c></seealso>.</p>
</desc>
</func>
+
<func>
<name name="substitute_negations" arity="2"/>
<fsummary></fsummary>
<desc>
<p>Substitutes keys of boolean-valued properties and
simultaneously negates their values. For each entry in
- <c><anno>ListIn</anno></c>, if it is associated with some key <c>K1</c>
- such that <c>{K1, K2}</c> occurs in <c><anno>Negations</anno></c>, then
- if the entry was <c>{K1, true}</c> it will be replaced with
- <c>{K2, false}</c>, otherwise it will be replaced with
- <c>{K2, true}</c>, thus changing the name of the option and
- simultaneously negating the value given by
- <c>get_bool(ListIn)</c>. If the same <c>K1</c> occurs more
- than once in <c><anno>Negations</anno></c>, only the first occurrence is
- used.</p>
- <p>Example: <c>substitute_negations([{no_foo, foo}], L)</c>
- will replace any atom <c>no_foo</c> or tuple
+ <c><anno>ListIn</anno></c>, if it is associated with some key
+ <c>K1</c> such that <c>{K1, K2}</c> occurs in
+ <c><anno>Negations</anno></c>: if the entry was
+ <c>{K1, true}</c>, it is replaced with <c>{K2, false}</c>, otherwise
+ with <c>{K2, true}</c>, thus changing the name of the option and
+ simultaneously negating the value specified by
+ <seealso marker="#get_bool/2">
+ <c>get_bool(Key, <anno>ListIn</anno></c></seealso>.
+ If the same <c>K1</c> occurs more than once in
+ <c><anno>Negations</anno></c>, only the first occurrence is used.</p>
+ <p>For example, <c>substitute_negations([{no_foo, foo}], L)</c>
+ replaces any atom <c>no_foo</c> or tuple
<c>{no_foo, true}</c> in <c>L</c> with <c>{foo, false}</c>,
- and any other tuple <c>{no_foo, ...}</c> with
- <c>{foo, true}</c>.</p>
- <p>See also: <c>get_bool/2</c>, <c>normalize/2</c>,
- <c>substitute_aliases/2</c>.</p>
+ and any other tuple <c>{no_foo, ...}</c> with <c>{foo, true}</c>.</p>
+ <p>See also
+ <seealso marker="#get_bool/2"><c>get_bool/2</c></seealso>,
+ <seealso marker="#normalize/2"><c>normalize/2</c></seealso>,
+ <seealso marker="#substitute_aliases/2">
+ <c>substitute_aliases/2</c></seealso>.</p>
</desc>
</func>
+
<func>
<name name="unfold" arity="1"/>
<fsummary></fsummary>
<desc>
- <p>Unfolds all occurrences of atoms in <c><anno>ListIn</anno></c> to tuples
- <c>{Atom, true}</c>.</p>
+ <p>Unfolds all occurrences of atoms in <c><anno>ListIn</anno></c> to
+ tuples <c>{Atom, true}</c>.</p>
</desc>
</func>
</funcs>
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-12 03:43:04 +0000