From 8f9cca0e5c170ba60c79f6926b1eb580caa846c0 Mon Sep 17 00:00:00 2001 From: Philipp Hausmann Date: Thu, 9 Apr 2020 09:26:09 +0200 Subject: [PATCH] Print float values with full precision. Instead of printing at most 6 digits, print as many digits as are necessary to preserve float values exactly. See also http://www2.open-std.org/JTC1/SC22/WG21/docs/papers/2005/n1822.pdf --- src/libexpr/eval.cc | 3 ++- src/libexpr/nixexpr.cc | 3 ++- src/libutil/json.cc | 4 ++-- tests/lang/eval-okay-float.exp | 2 +- tests/lang/eval-okay-fromTOML.exp | 2 +- tests/lang/eval-okay-tojson.exp | 2 +- tests/lang/eval-okay-tojson.nix | 1 + 7 files changed, 10 insertions(+), 7 deletions(-) diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc index dac32b6f563..3b22d94d143 100644 --- a/src/libexpr/eval.cc +++ b/src/libexpr/eval.cc @@ -16,6 +16,7 @@ #include #include #include +#include #include #include @@ -125,7 +126,7 @@ static void printValue(std::ostream & str, std::set & active, con str << *v.external; break; case tFloat: - str << v.fpoint; + str << std::setprecision(std::numeric_limits::max_digits10) << v.fpoint; break; default: throw Error("invalid value"); diff --git a/src/libexpr/nixexpr.cc b/src/libexpr/nixexpr.cc index 63cbef1ddf8..7b55ba0e5bf 100644 --- a/src/libexpr/nixexpr.cc +++ b/src/libexpr/nixexpr.cc @@ -3,6 +3,7 @@ #include "util.hh" #include +#include namespace nix { @@ -70,7 +71,7 @@ void ExprInt::show(std::ostream & str) const void ExprFloat::show(std::ostream & str) const { - str << nf; + str << std::setprecision(std::numeric_limits::max_digits10) << nf; } void ExprString::show(std::ostream & str) const diff --git a/src/libutil/json.cc b/src/libutil/json.cc index 74e37b4c442..dd55cae0b19 100644 --- a/src/libutil/json.cc +++ b/src/libutil/json.cc @@ -30,8 +30,8 @@ template<> void toJSON(std::ostream & str, const long & n) { str << n; } template<> void toJSON(std::ostream & str, const unsigned long & n) { str << n; } template<> void toJSON(std::ostream & str, const long long & n) { str << n; } template<> void toJSON(std::ostream & str, const unsigned long long & n) { str << n; } -template<> void toJSON(std::ostream & str, const float & n) { str << n; } -template<> void toJSON(std::ostream & str, const double & n) { str << n; } +template<> void toJSON(std::ostream & str, const float & n) { str << std::setprecision(std::numeric_limits::max_digits10) << n; } +template<> void toJSON(std::ostream & str, const double & n) { str << std::setprecision(std::numeric_limits::max_digits10) << n; } template<> void toJSON(std::ostream & str, const std::string & s) { diff --git a/tests/lang/eval-okay-float.exp b/tests/lang/eval-okay-float.exp index 3c50a8adce8..05a38bc6085 100644 --- a/tests/lang/eval-okay-float.exp +++ b/tests/lang/eval-okay-float.exp @@ -1 +1 @@ -[ 3.4 3.5 2.5 1.5 ] +[ 3.3999999999999999 3.5 2.5 1.5 ] diff --git a/tests/lang/eval-okay-fromTOML.exp b/tests/lang/eval-okay-fromTOML.exp index d0dd3af2c81..1b6947c648d 100644 --- a/tests/lang/eval-okay-fromTOML.exp +++ b/tests/lang/eval-okay-fromTOML.exp @@ -1 +1 @@ -[ { clients = { data = [ [ "gamma" "delta" ] [ 1 2 ] ]; hosts = [ "alpha" "omega" ]; }; database = { connection_max = 5000; enabled = true; ports = [ 8001 8001 8002 ]; server = "192.168.1.1"; }; owner = { name = "Tom Preston-Werner"; }; servers = { alpha = { dc = "eqdc10"; ip = "10.0.0.1"; }; beta = { dc = "eqdc10"; ip = "10.0.0.2"; }; }; title = "TOML Example"; } { "1234" = "value"; "127.0.0.1" = "value"; a = { b = { c = { }; }; }; arr1 = [ 1 2 3 ]; arr2 = [ "red" "yellow" "green" ]; arr3 = [ [ 1 2 ] [ 3 4 5 ] ]; arr4 = [ "all" "strings" "are the same" "type" ]; arr5 = [ [ 1 2 ] [ "a" "b" "c" ] ]; arr7 = [ 1 2 3 ]; arr8 = [ 1 2 ]; bare-key = "value"; bare_key = "value"; bin1 = 214; bool1 = true; bool2 = false; "character encoding" = "value"; d = { e = { f = { }; }; }; dog = { "tater.man" = { type = { name = "pug"; }; }; }; flt1 = 1; flt2 = 3.1415; flt3 = -0.01; flt4 = 5e+22; flt5 = 1e+06; flt6 = -0.02; flt7 = 6.626e-34; flt8 = 9.22462e+06; fruit = [ { name = "apple"; physical = { color = "red"; shape = "round"; }; variety = [ { name = "red delicious"; } { name = "granny smith"; } ]; } { name = "banana"; variety = [ { name = "plantain"; } ]; } ]; g = { h = { i = { }; }; }; hex1 = 3735928559; hex2 = 3735928559; hex3 = 3735928559; int1 = 99; int2 = 42; int3 = 0; int4 = -17; int5 = 1000; int6 = 5349221; int7 = 12345; j = { "ʞ" = { l = { }; }; }; key = "value"; key2 = "value"; name = "Orange"; oct1 = 342391; oct2 = 493; physical = { color = "orange"; shape = "round"; }; products = [ { name = "Hammer"; sku = 738594937; } { } { color = "gray"; name = "Nail"; sku = 284758393; } ]; "quoted \"value\"" = "value"; site = { "google.com" = true; }; str = "I'm a string. \"You can quote me\". Name\tJosé\nLocation\tSF."; table-1 = { key1 = "some string"; key2 = 123; }; table-2 = { key1 = "another string"; key2 = 456; }; x = { y = { z = { w = { animal = { type = { name = "pug"; }; }; name = { first = "Tom"; last = "Preston-Werner"; }; point = { x = 1; y = 2; }; }; }; }; }; "ʎǝʞ" = "value"; } { metadata = { "checksum aho-corasick 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)" = "d6531d44de723825aa81398a6415283229725a00fa30713812ab9323faa82fc4"; "checksum ansi_term 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ee49baf6cb617b853aa8d93bf420db2383fab46d314482ca2803b40d5fde979b"; "checksum ansi_term 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "23ac7c30002a5accbf7e8987d0632fa6de155b7c3d39d0067317a391e00a2ef6"; "checksum arrayvec 0.4.7 (registry+https://github.com/rust-lang/crates.io-index)" = "a1e964f9e24d588183fcb43503abda40d288c8657dfc27311516ce2f05675aef"; }; package = [ { dependencies = [ "memchr 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)" ]; name = "aho-corasick"; source = "registry+https://github.com/rust-lang/crates.io-index"; version = "0.6.4"; } { name = "ansi_term"; source = "registry+https://github.com/rust-lang/crates.io-index"; version = "0.9.0"; } { dependencies = [ "libc 0.2.42 (registry+https://github.com/rust-lang/crates.io-index)" "termion 1.5.1 (registry+https://github.com/rust-lang/crates.io-index)" "winapi 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" ]; name = "atty"; source = "registry+https://github.com/rust-lang/crates.io-index"; version = "0.2.10"; } ]; } { a = [ [ { b = true; } ] ]; c = [ [ { d = true; } ] ]; e = [ [ 123 ] ]; } ] +[ { clients = { data = [ [ "gamma" "delta" ] [ 1 2 ] ]; hosts = [ "alpha" "omega" ]; }; database = { connection_max = 5000; enabled = true; ports = [ 8001 8001 8002 ]; server = "192.168.1.1"; }; owner = { name = "Tom Preston-Werner"; }; servers = { alpha = { dc = "eqdc10"; ip = "10.0.0.1"; }; beta = { dc = "eqdc10"; ip = "10.0.0.2"; }; }; title = "TOML Example"; } { "1234" = "value"; "127.0.0.1" = "value"; a = { b = { c = { }; }; }; arr1 = [ 1 2 3 ]; arr2 = [ "red" "yellow" "green" ]; arr3 = [ [ 1 2 ] [ 3 4 5 ] ]; arr4 = [ "all" "strings" "are the same" "type" ]; arr5 = [ [ 1 2 ] [ "a" "b" "c" ] ]; arr7 = [ 1 2 3 ]; arr8 = [ 1 2 ]; bare-key = "value"; bare_key = "value"; bin1 = 214; bool1 = true; bool2 = false; "character encoding" = "value"; d = { e = { f = { }; }; }; dog = { "tater.man" = { type = { name = "pug"; }; }; }; flt1 = 1; flt2 = 3.1415000000000002; flt3 = -0.01; flt4 = 4.9999999999999996e+22; flt5 = 1000000; flt6 = -0.02; flt7 = 6.6259999999999998e-34; flt8 = 9224617.4459912274; fruit = [ { name = "apple"; physical = { color = "red"; shape = "round"; }; variety = [ { name = "red delicious"; } { name = "granny smith"; } ]; } { name = "banana"; variety = [ { name = "plantain"; } ]; } ]; g = { h = { i = { }; }; }; hex1 = 3735928559; hex2 = 3735928559; hex3 = 3735928559; int1 = 99; int2 = 42; int3 = 0; int4 = -17; int5 = 1000; int6 = 5349221; int7 = 12345; j = { "ʞ" = { l = { }; }; }; key = "value"; key2 = "value"; name = "Orange"; oct1 = 342391; oct2 = 493; physical = { color = "orange"; shape = "round"; }; products = [ { name = "Hammer"; sku = 738594937; } { } { color = "gray"; name = "Nail"; sku = 284758393; } ]; "quoted \"value\"" = "value"; site = { "google.com" = true; }; str = "I'm a string. \"You can quote me\". Name\tJosé\nLocation\tSF."; table-1 = { key1 = "some string"; key2 = 123; }; table-2 = { key1 = "another string"; key2 = 456; }; x = { y = { z = { w = { animal = { type = { name = "pug"; }; }; name = { first = "Tom"; last = "Preston-Werner"; }; point = { x = 1; y = 2; }; }; }; }; }; "ʎǝʞ" = "value"; } { metadata = { "checksum aho-corasick 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)" = "d6531d44de723825aa81398a6415283229725a00fa30713812ab9323faa82fc4"; "checksum ansi_term 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ee49baf6cb617b853aa8d93bf420db2383fab46d314482ca2803b40d5fde979b"; "checksum ansi_term 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "23ac7c30002a5accbf7e8987d0632fa6de155b7c3d39d0067317a391e00a2ef6"; "checksum arrayvec 0.4.7 (registry+https://github.com/rust-lang/crates.io-index)" = "a1e964f9e24d588183fcb43503abda40d288c8657dfc27311516ce2f05675aef"; }; package = [ { dependencies = [ "memchr 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)" ]; name = "aho-corasick"; source = "registry+https://github.com/rust-lang/crates.io-index"; version = "0.6.4"; } { name = "ansi_term"; source = "registry+https://github.com/rust-lang/crates.io-index"; version = "0.9.0"; } { dependencies = [ "libc 0.2.42 (registry+https://github.com/rust-lang/crates.io-index)" "termion 1.5.1 (registry+https://github.com/rust-lang/crates.io-index)" "winapi 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" ]; name = "atty"; source = "registry+https://github.com/rust-lang/crates.io-index"; version = "0.2.10"; } ]; } { a = [ [ { b = true; } ] ]; c = [ [ { d = true; } ] ]; e = [ [ 123 ] ]; } ] diff --git a/tests/lang/eval-okay-tojson.exp b/tests/lang/eval-okay-tojson.exp index e92aae3235f..8a4a37c66f1 100644 --- a/tests/lang/eval-okay-tojson.exp +++ b/tests/lang/eval-okay-tojson.exp @@ -1 +1 @@ -"{\"a\":123,\"b\":-456,\"c\":\"foo\",\"d\":\"foo\\n\\\"bar\\\"\",\"e\":true,\"f\":false,\"g\":[1,2,3],\"h\":[\"a\",[\"b\",{\"foo\\nbar\":{}}]],\"i\":3,\"j\":1.44,\"k\":\"foo\"}" +"{\"a\":123,\"b\":-456,\"c\":\"foo\",\"d\":\"foo\\n\\\"bar\\\"\",\"e\":true,\"f\":false,\"g\":[1,2,3],\"h\":[\"a\",[\"b\",{\"foo\\nbar\":{}}]],\"i\":3,\"j\":1.4399999999999999,\"k\":\"foo\",\"l\":50.03125}" diff --git a/tests/lang/eval-okay-tojson.nix b/tests/lang/eval-okay-tojson.nix index ce67943bead..304bf9a7947 100644 --- a/tests/lang/eval-okay-tojson.nix +++ b/tests/lang/eval-okay-tojson.nix @@ -10,4 +10,5 @@ builtins.toJSON i = 1 + 2; j = 1.44; k = { __toString = self: self.a; a = "foo"; }; + l = 50.03125; }