aboutsummaryrefslogtreecommitdiffstats
path: root/erts/emulator/test
diff options
context:
space:
mode:
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/emulator/test
parent9f461fbaf0be7aba7c0b8b89be1f0b6f1141b7a5 (diff)
downloadotp-ab27e8699ef2a2bafe574158200993f184de3dc2.tar.gz
otp-ab27e8699ef2a2bafe574158200993f184de3dc2.tar.bz2
otp-ab27e8699ef2a2bafe574158200993f184de3dc2.zip
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/emulator/test')
-rw-r--r--erts/emulator/test/num_bif_SUITE.erl45
1 files changed, 39 insertions, 6 deletions
diff --git a/erts/emulator/test/num_bif_SUITE.erl b/erts/emulator/test/num_bif_SUITE.erl
index 4459732257..7a045484cf 100644
--- a/erts/emulator/test/num_bif_SUITE.erl
+++ b/erts/emulator/test/num_bif_SUITE.erl
@@ -25,6 +25,7 @@
%% abs/1
%% float/1
%% float_to_list/1
+%% float_to_list/2
%% integer_to_list/1
%% list_to_float/1
%% list_to_integer/1
@@ -114,14 +115,46 @@ t_float(Config) when is_list(Config) ->
ok.
-%% Tests float_to_list/1.
+%% Tests float_to_list/1, float_to_list/2.
t_float_to_list(Config) when is_list(Config) ->
- ?line test_ftl("0.0e+0", 0.0),
- ?line test_ftl("2.5e+1", 25.0),
- ?line test_ftl("2.5e+0", 2.5),
- ?line test_ftl("2.5e-1", 0.25),
- ?line test_ftl("-3.5e+17", -350.0e15),
+ test_ftl("0.0e+0", 0.0),
+ test_ftl("2.5e+1", 25.0),
+ test_ftl("2.5e+0", 2.5),
+ test_ftl("2.5e-1", 0.25),
+ test_ftl("-3.5e+17", -350.0e15),
+ "1.00000000000000000000e+00" = float_to_list(1.0),
+ "1.00000000000000000000e+00" = float_to_list(1.0, []),
+ "-1.00000000000000000000e+00" = float_to_list(-1.0, []),
+ "-1.00000000000000000000" = float_to_list(-1.0, [{decimals, 20}]),
+ {'EXIT', {badarg, _}} = (catch float_to_list(1.0, [{decimals, -1}])),
+ {'EXIT', {badarg, _}} = (catch float_to_list(1.0, [{decimals, 250}])),
+ {'EXIT', {badarg, _}} = (catch float_to_list(1.0e+300, [{decimals, 1}])),
+ "1.0e+300" = float_to_list(1.0e+300, [{scientific, 1}]),
+ "1.0" = float_to_list(1.0, [{decimals, 249}, compact]),
+ Expected = "1." ++ string:copies("0", 249) ++ "e+00",
+ Expected = float_to_list(1.0, [{scientific, 249}, compact]),
+
+ X1 = float_to_list(1.0),
+ X2 = float_to_list(1.0, [{scientific, 20}]),
+ X1 = X2,
+ "1.000e+00" = float_to_list(1.0, [{scientific, 3}]),
+ "1.000" = float_to_list(1.0, [{decimals, 3}]),
+ "1.0" = float_to_list(1.0, [{decimals, 3}, compact]),
+ "1.12" = float_to_list(1.123, [{decimals, 2}]),
+ "1.123" = float_to_list(1.123, [{decimals, 3}]),
+ "1.123" = float_to_list(1.123, [{decimals, 3}, compact]),
+ "1.1230" = float_to_list(1.123, [{decimals, 4}]),
+ "1.12300" = float_to_list(1.123, [{decimals, 5}]),
+ "1.123" = float_to_list(1.123, [{decimals, 5}, compact]),
+ "1.1234" = float_to_list(1.1234,[{decimals, 6}, compact]),
+ "2.333333" = erlang:float_to_list(7/3, [{decimals, 6}, compact]),
+ "2.333333" = erlang:float_to_list(7/3, [{decimals, 6}]),
+ "0.00000000000000000000e+00" = float_to_list(0.0, [compact]),
+ "0.0" = float_to_list(0.0, [{decimals, 10}, compact]),
+ "123000000000000000000.0" = float_to_list(1.23e20, [{decimals, 10}, compact]),
+ "1.2300000000e+20" = float_to_list(1.23e20, [{scientific, 10}, compact]),
+ "1.23000000000000000000e+20" = float_to_list(1.23e20, []),
ok.
test_ftl(Expect, Float) ->