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3481-Add-lists-enumerate-3.patch
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File 3481-Add-lists-enumerate-3.patch of Package erlang
From 54456030a9a1bea26786d8eb888061951111a413 Mon Sep 17 00:00:00 2001 From: Maria Scott <maria-12648430@hnc-agency.org> Date: Wed, 1 Mar 2023 07:45:02 +0100 Subject: [PATCH] Add lists:enumerate/3 --- lib/stdlib/doc/src/lists.xml | 42 +++++++------------ lib/stdlib/src/lists.erl | 25 +++++++---- lib/stdlib/test/lists_SUITE.erl | 24 +++++++++++ lib/stdlib/test/lists_property_test_SUITE.erl | 4 ++ lib/stdlib/test/property_test/lists_prop.erl | 22 ++++++++++ 5 files changed, 83 insertions(+), 34 deletions(-) diff --git a/lib/stdlib/doc/src/lists.xml b/lib/stdlib/doc/src/lists.xml index 00caf89d23..f6f329bf85 100644 --- a/lib/stdlib/doc/src/lists.xml +++ b/lib/stdlib/doc/src/lists.xml @@ -176,43 +176,33 @@ <func> <name name="enumerate" arity="1" since="OTP 25.0"/> + <name name="enumerate" arity="2" since="OTP 25.0"/> + <name name="enumerate" arity="3" since="OTP 26.0"/> <fsummary>Annotates elements with their index.</fsummary> <desc> <p>Returns <c><anno>List1</anno></c> with each element - <c>H</c> replaced by a tuple of form <c>{I, H}</c> where - <c>I</c> is the position of <c>H</c> in - <c><anno>List1</anno></c>. The enumeration starts with 1 and - increases by 1 in each step.</p> - <p>That is, <c>enumerate/1</c> behaves as if it had been defined as follows:</p> + <c>H</c> replaced by a tuple of form <c>{I, H}</c> where + <c>I</c> is the position of <c>H</c> in + <c><anno>List1</anno></c>. The enumeration starts with + <c><anno>Index</anno></c> and increases by <c><anno>Step</anno></c> + in each step.</p> + <p>That is, <c>enumerate/3</c> behaves as if it had been defined as follows:</p> <code type="erl"> -enumerate(List) -> - {List1, _ } = lists:mapfoldl(fun(T, Acc) -> {{Acc, T}, Acc+1} end, 1, List), +enumerate(I, S, List) -> + {List1, _ } = lists:mapfoldl(fun(T, Acc) -> {{Acc, T}, Acc+S} end, I, List), List1.</code> - <p><em>Example:</em></p> + <p>The default values for <c><anno>Index</anno></c> and + <c><anno>Step</anno></c> are both <c>1</c>.</p> + <p><em>Examples:</em></p> <pre> > <input>lists:enumerate([a,b,c]).</input> [{1,a},{2,b},{3,c}]</pre> - </desc> - </func> - - <func> - <name name="enumerate" arity="2" since="OTP 25.0"/> - <fsummary>Annotates elements with their index.</fsummary> - <desc> - <p>Returns <c><anno>List1</anno></c> with each element - <c>H</c> replaced by a tuple of form <c>{I, H}</c> where - <c>I</c> is the position of <c>H</c> in - <c><anno>List1</anno></c>. The enumeration starts with - <c><anno>Index</anno></c> and increases by 1 in each step.</p> - <p>That is, <c>enumerate/2</c> behaves as if it had been defined as follows:</p> - <code type="erl"> -enumerate(I, List) -> - {List1, _ } = lists:mapfoldl(fun(T, Acc) -> {{Acc, T}, Acc+1} end, I, List), - List1.</code> - <p><em>Example:</em></p> <pre> > <input>lists:enumerate(10, [a,b,c]).</input> [{10,a},{11,b},{12,c}]</pre> + <pre> +> <input>lists:enumerate(0, -2, [a,b,c]).</input> +[{0,a},{-2,b},{-4,c}]</pre> </desc> </func> diff --git a/lib/stdlib/src/lists.erl b/lib/stdlib/src/lists.erl index b1be8e1c2d..15bed9e292 100644 --- a/lib/stdlib/src/lists.erl +++ b/lib/stdlib/src/lists.erl @@ -29,7 +29,7 @@ %% arguments. Please keep in alphabetical order. -export([append/1, append/2, concat/1, delete/2, droplast/1, duplicate/2, - enumerate/1, enumerate/2, + enumerate/1, enumerate/2, enumerate/3, flatlength/1, flatten/1, flatten/2, join/2, last/1, min/1, max/1, nth/2, nthtail/2, @@ -1160,20 +1160,29 @@ keymap(Fun, Index, []) when is_integer(Index), Index >= 1, List2 :: [{Index, T}], Index :: integer(), T :: term(). -enumerate(List1) when is_list(List1) -> - enumerate_1(1, List1). +enumerate(List1) -> + enumerate(1, 1, List1). -spec enumerate(Index, List1) -> List2 when List1 :: [T], List2 :: [{Index, T}], Index :: integer(), T :: term(). -enumerate(Index, List1) when is_integer(Index), is_list(List1) -> - enumerate_1(Index, List1). +enumerate(Index, List1) -> + enumerate(Index, 1, List1). -enumerate_1(Index, [H|T]) -> - [{Index, H}|enumerate_1(Index + 1, T)]; -enumerate_1(_Index, []) -> +-spec enumerate(Index, Step, List1) -> List2 when + List1 :: [T], + List2 :: [{Index, T}], + Index :: integer(), + Step :: integer(), + T :: term(). +enumerate(Index, Step, List1) when is_integer(Index), is_integer(Step) -> + enumerate_1(Index, Step, List1). + +enumerate_1(Index, Step, [H|T]) -> + [{Index, H}|enumerate_1(Index + Step, Step, T)]; +enumerate_1(_Index, _Step, []) -> []. %%% Suggestion from OTP-2948: sort and merge with Fun. diff --git a/lib/stdlib/test/lists_SUITE.erl b/lib/stdlib/test/lists_SUITE.erl index 792a94702a..1ab4458a5a 100644 --- a/lib/stdlib/test/lists_SUITE.erl +++ b/lib/stdlib/test/lists_SUITE.erl @@ -3198,15 +3198,39 @@ hof(Config) when is_list(Config) -> enumerate(Config) when is_list(Config) -> [] = lists:enumerate([]), [] = lists:enumerate(10, []), + [] = lists:enumerate(-10, []), + [] = lists:enumerate(10, 2, []), + [] = lists:enumerate(10, -2, []), + [] = lists:enumerate(-10, 2, []), + [] = lists:enumerate(-10, -2, []), [{1,a},{2,b},{3,c}] = lists:enumerate([a,b,c]), [{10,a},{11,b},{12,c}] = lists:enumerate(10, [a,b,c]), + [{-10,a},{-9,b},{-8,c}] = lists:enumerate(-10, [a,b,c]), + [{10,a},{12,b},{14,c}] = lists:enumerate(10, 2, [a,b,c]), + [{10,a},{8,b},{6,c}] = lists:enumerate(10, -2, [a,b,c]), + [{-10,a},{-12,b},{-14,c}] = lists:enumerate(-10, -2, [a,b,c]), {'EXIT', {function_clause, _}} = catch lists:enumerate(0), {'EXIT', {function_clause, _}} = catch lists:enumerate(0, 10), + {'EXIT', {function_clause, _}} = catch lists:enumerate(0, 10, 20), {'EXIT', {function_clause, _}} = catch lists:enumerate(1.0, []), {'EXIT', {function_clause, _}} = catch lists:enumerate(1.0, [a,b,c]), + {'EXIT', {function_clause, _}} = catch lists:enumerate(1.0, 2, []), + {'EXIT', {function_clause, _}} = catch lists:enumerate(1.0, 2, [a,b,c]), + {'EXIT', {function_clause, _}} = catch lists:enumerate(1, 2.0, []), + {'EXIT', {function_clause, _}} = catch lists:enumerate(1, 2.0, [a,b,c]), + {'EXIT', {function_clause, _}} = catch lists:enumerate(1.0, 2.0, []), + {'EXIT', {function_clause, _}} = catch lists:enumerate(1.0, 2.0, [a,b,c]), {'EXIT', {function_clause, _}} = catch lists:enumerate(<<1>>, []), {'EXIT', {function_clause, _}} = catch lists:enumerate(<<1>>, [a,b,c]), + {'EXIT', {function_clause, _}} = catch lists:enumerate(<<1>>, 2, []), + {'EXIT', {function_clause, _}} = catch lists:enumerate(<<1>>, 2, [a,b,c]), + {'EXIT', {function_clause, _}} = catch lists:enumerate(1, <<2>>, []), + {'EXIT', {function_clause, _}} = catch lists:enumerate(1, <<2>>, [a,b,c]), + {'EXIT', {function_clause, _}} = catch lists:enumerate(<<1>>, <<2>>, []), + {'EXIT', {function_clause, _}} = catch lists:enumerate(<<1>>, <<2>>, [a,b,c]), + {'EXIT', {function_clause, _}} = catch lists:enumerate(<<1,2,3>>), {'EXIT', {function_clause, _}} = catch lists:enumerate(1, <<1,2,3>>), + {'EXIT', {function_clause, _}} = catch lists:enumerate(1, 2, <<1,2,3>>), ok. diff --git a/lib/stdlib/test/lists_property_test_SUITE.erl b/lib/stdlib/test/lists_property_test_SUITE.erl index 4b366d730a..ecbf14309e 100644 --- a/lib/stdlib/test/lists_property_test_SUITE.erl +++ b/lib/stdlib/test/lists_property_test_SUITE.erl @@ -35,6 +35,7 @@ all() -> duplicate_case, enumerate_1_case, enumerate_2_case, + enumerate_3_case, filter_case, filtermap_case, flatlength_case, @@ -159,6 +160,9 @@ enumerate_1_case(Config) -> enumerate_2_case(Config) -> do_proptest(prop_enumerate_2, Config). +enumerate_3_case(Config) -> + do_proptest(prop_enumerate_3, Config). + filter_case(Config) -> do_proptest(prop_filter, Config). diff --git a/lib/stdlib/test/property_test/lists_prop.erl b/lib/stdlib/test/property_test/lists_prop.erl index 00b518ff83..68c087b76d 100644 --- a/lib/stdlib/test/property_test/lists_prop.erl +++ b/lib/stdlib/test/property_test/lists_prop.erl @@ -240,6 +240,28 @@ prop_enumerate_2() -> lists:enumerate(StartIndex, InList) =:= ExpList ). +%% enumerate/3 +prop_enumerate_3() -> + ?FORALL( + {StartIndex, Step, InList, ExpList}, + ?LET( + {N, S}, + {integer(), integer()}, + ?LET( + {L, {_, EL}}, + gen_list_fold( + gen_any(), + fun(T, {I, Acc}) -> + {I + S, Acc ++ [{I, T}]} + end, + {N, []} + ), + {N, S, L, EL} + ) + ), + lists:enumerate(StartIndex, Step, InList) =:= ExpList + ). + %% filter/2 prop_filter() -> ?FORALL( -- 2.35.3
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