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authorSerge Aleynikov <[email protected]>2013-01-21 15:36:43 +0100
committerBjörn-Egil Dahlberg <[email protected]>2013-01-21 15:36:43 +0100
commitab27e8699ef2a2bafe574158200993f184de3dc2 (patch)
treea4365e182109d25ce049244b220844705b7d2a25 /erts/preloaded
parent9f461fbaf0be7aba7c0b8b89be1f0b6f1141b7a5 (diff)
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Text representation of a float formatted using given options.
This BIF solves a problem of float_to_list/1 that doesn't allow specifying the number of digits after the decimal point when formatting floats. float_to_list(Float, Options) -> string() Float = float() Options = [Option] Option = {decimals, Decimals::0..249} | {scientific, Decimals::0..249} | compact Returns a string which corresponds to the text representation of a `Float` formatted using given options. When decimals option is specified the returned value will contain at most `Decimals` number of digits past the decimal point. When `compact` option is provided the trailing zeros at the end of the list are truncated (this option is only meaningful together with the `decimals` option). When `scientific` option is provided, the float will be formatted using scientific notation with `Decimals` digits of precision. If `Options` is `[]` the function behaves like `float_to_list/1`. When using `decimals` option and the number doesn't fit in the static internal buffer of 256 bytes the function throws `badarg`.
Diffstat (limited to 'erts/preloaded')
-rw-r--r--erts/preloaded/src/erlang.erl13
1 files changed, 12 insertions, 1 deletions
diff --git a/erts/preloaded/src/erlang.erl b/erts/preloaded/src/erlang.erl
index 061db72dd8..3a40a6f97d 100644
--- a/erts/preloaded/src/erlang.erl
+++ b/erts/preloaded/src/erlang.erl
@@ -84,7 +84,8 @@
-export([display_nl/0, display_string/1, dist_exit/3, erase/0, erase/1]).
-export([error/1, error/2, exit/1, exit/2, external_size/1]).
-export([external_size/2, finish_after_on_load/2, finish_loading/1, float/1]).
--export([float_to_list/1, fun_info/2, fun_to_list/1, function_exported/3]).
+-export([float_to_list/1, float_to_list/2]).
+-export([fun_info/2, fun_to_list/1, function_exported/3]).
-export([garbage_collect/0, garbage_collect/1]).
-export([garbage_collect_message_area/0, get/0, get/1, get_keys/1]).
-export([get_module_info/1, get_stacktrace/0, group_leader/0]).
@@ -711,6 +712,16 @@ float(_Number) ->
float_to_list(_Float) ->
erlang:nif_error(undefined).
+%% float_to_list/2
+-spec float_to_list(Float, Options) -> string() when
+ Float :: float(),
+ Options :: [Option],
+ Option :: {decimals, non_neg_integer()} |
+ {scientific, non_neg_integer()} |
+ compact.
+float_to_list(_Float, _Options) ->
+ erlang:nif_error(undefined).
+
%% fun_info/2
-spec erlang:fun_info(Fun, Item) -> {Item, Info} when
Fun :: function(),