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Use lexemes so that list can be empty #5

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Merged
martinsumner merged 5 commits into from
Dec 4, 2025
Merged

Use lexemes so that list can be empty #5

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ac97f4d
Use lexemes so that list can be empty
martinsumner Nov 14, 2025
bdc9304
Need to cover to_string
martinsumner Nov 14, 2025
80223b8
Test to_string, and handle empty string
martinsumner Nov 14, 2025
4391524
The use of to_string/1 for string
martinsumner Nov 14, 2025
54ea797
Add test of to_string of empty list
martinsumner Nov 16, 2025
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42 changes: 37 additions & 5 deletions src/cuttlefish_datatypes.erl
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Original file line number Diff line number Diff line change
Expand Up @@ -92,6 +92,9 @@ is_supported(float) -> true;
is_supported({list, {list, _}}) ->
% lists of lists are not supported
false;
is_supported({list, {integer, _}}) ->
% lists of integers are not supported due to issues with to_string/1
false;
is_supported({list, ListDatatype}) ->
is_supported(ListDatatype);
is_supported(_) -> false.
Expand Down Expand Up @@ -197,6 +200,21 @@ to_string(Float, float) when is_float(Float) ->
float_to_list(Float, [{decimals, 6}, compact]);
to_string(Float, float) when is_list(Float) -> Float;

to_string([], {list, _}) -> "";
to_string(List, {list, DT}) when is_list(List) ->
case lists:all(fun erlang:is_integer/1, List) of
true ->
% is already a string
List;
false ->
lists:flatten(
lists:join(
",",
lists:map(fun(E) -> to_string(E, DT) end, List)
)
)
end;

%% The Pokemon Clause: Gotta Catch 'em all!
to_string(Value, MaybeExtendedDatatype) ->
case is_extended(MaybeExtendedDatatype) of
Expand Down Expand Up @@ -277,7 +295,7 @@ from_string(List, {list, DataType}) when is_list(List) ->
lists:map(fun(El) ->
from_string(string:trim(El), DataType)
end,
string:split(List, ",", all));
string:lexemes(List, ","));

from_string(Thing, InvalidDatatype) ->
{error, {type, {Thing, InvalidDatatype}}}.
Expand Down Expand Up @@ -382,6 +400,16 @@ to_string_float_test() ->
?assertEqual("0.1", to_string("0.1", float)),
ok.

to_string_list_test() ->
?assertEqual("", to_string([], {list, {enum, [crash, error]}})),
?assertEqual(
"crash,error",
to_string([crash, error], {list, {enum, [crash, error]}})
),
?assertEqual("none", to_string([none], {list, {enum, [none, error]}})),
?assertEqual("none", to_string("none", {list, {enum, [crash, none]}})),
?assertEqual("", to_string("", {list, {enum, [crash, error]}})).

to_string_extended_type_test() ->
?assertEqual("split_the", to_string(split_the, {atom, split_the})),
?assertEqual("split_the", to_string("split_the", {atom, split_the})),
Expand Down Expand Up @@ -527,22 +555,26 @@ from_string_string_test() ->
?assertEqual("string", from_string("string", string)).

from_string_string_list_test() ->
%% more examples in the the cuttlefish_duration tests
?assertEqual(["v1", "v2", "v3"], from_string("v1, v2,v3", {list, string})),
ok.

from_string_integer_list_test() ->
%% more examples in the the cuttlefish_duration tests
?assertEqual([1, 2, 3], from_string("1, 2,3", {list, integer})),
ok.

from_string_atom_list_test() ->
%% more examples in the the cuttlefish_duration tests
?assertEqual([a, b, c], from_string("a, b,c", {list, atom})),
ok.

from_string_singleatom_list_test() ->
?assertEqual([a], from_string("a ", {list, atom})),
ok.

from_emptystring_atom_list_test() ->
?assertEqual([], from_string("", {list, atom})),
ok.

from_string_string_in_integer_list_test() ->
%% more examples in the the cuttlefish_duration tests
?assertEqual([{error, {conversion, {"a", integer}}}, 1, 2],
from_string("a, 1,2", {list, integer})),
ok.
Expand Down