From cea2a9087d44378802c77ba041a4f54cd7b6087d Mon Sep 17 00:00:00 2001
From: katlogic <kat@lua.cz>
Date: Sun, 15 Jun 2014 01:49:14 +0200
Subject: [PATCH 1/2] More human readable `$`(float)

The output matches that of Python (eg 1e100, not 1.0e100), but also
reflects locale (assuming it was set using setlocale() before).
---
 lib/system/ansi_c.nim |  5 ++++-
 lib/system/repr.nim   |  4 ++--
 lib/system/sysstr.nim | 14 ++++++++++----
 3 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/lib/system/ansi_c.nim b/lib/system/ansi_c.nim
index 5111bc3cf5..da101cc2c6 100644
--- a/lib/system/ansi_c.nim
+++ b/lib/system/ansi_c.nim
@@ -106,10 +106,13 @@ proc c_fopen(filename, mode: cstring): C_TextFileStar {.
   importc: "fopen", header: "<stdio.h>".}
 proc c_fclose(f: C_TextFileStar) {.importc: "fclose", header: "<stdio.h>".}
 
-proc c_sprintf(buf, frmt: cstring) {.header: "<stdio.h>", 
+proc c_sprintf(buf, frmt: cstring): int {.header: "<stdio.h>", 
   importc: "sprintf", varargs, noSideEffect.}
   # we use it only in a way that cannot lead to security issues
 
+proc c_localeconv():ptr cstring {.header: "<locale.h>",
+  importc: "localeconv", noSideEffect.}
+
 proc c_fread(buf: pointer, size, n: int, f: C_BinaryFileStar): int {.
   importc: "fread", header: "<stdio.h>".}
 proc c_fseek(f: C_BinaryFileStar, offset: clong, whence: int): int {.
diff --git a/lib/system/repr.nim b/lib/system/repr.nim
index 487bac0527..f8f9496680 100644
--- a/lib/system/repr.nim
+++ b/lib/system/repr.nim
@@ -17,12 +17,12 @@ proc reprFloat(x: float): string {.compilerproc.} = return $x
 
 proc reprPointer(x: pointer): string {.compilerproc.} =
   var buf: array [0..59, char]
-  c_sprintf(buf, "%p", x)
+  discard c_sprintf(buf, "%p", x)
   return $buf
 
 proc `$`(x: uint64): string =
   var buf: array [0..59, char]
-  c_sprintf(buf, "%llu", x)
+  discard c_sprintf(buf, "%llu", x)
   return $buf
 
 proc reprStrAux(result: var string, s: string) =
diff --git a/lib/system/sysstr.nim b/lib/system/sysstr.nim
index 4244bae4cb..183ea0c8d1 100644
--- a/lib/system/sysstr.nim
+++ b/lib/system/sysstr.nim
@@ -250,10 +250,16 @@ proc nimIntToStr(x: int): string {.compilerRtl.} =
   for j in 0..i div 2 - 1:
     swap(result[j], result[i-j-1])
 
-proc nimFloatToStr(x: float): string {.compilerproc.} =
-  var buf: array [0..59, char]
-  c_sprintf(buf, "%#.16e", x)
-  return $buf
+proc nimFloatToStr(f: float): string {.compilerproc.} =
+  var buf: array [0..64, char]
+  var n:int = c_sprintf(buf, "%.16g", f)
+  for i in 0..n-1:
+    if buf[i] notin {'0'..'9','-'}:
+      return $buf
+  buf[n] = c_localeconv()[0]
+  buf[n+1] = '0'
+  buf[n+2] = '\0'
+  result = $buf
 
 proc nimInt64ToStr(x: int64): string {.compilerRtl.} =
   result = newString(sizeof(x)*4)

From 9532951cfc4280d815160a4c86c7fec60d2a2001 Mon Sep 17 00:00:00 2001
From: katlogic <kat@lua.cz>
Date: Sun, 15 Jun 2014 01:53:09 +0200
Subject: [PATCH 2/2] Tests for `$`(float)

---
 tests/matrix/tmatrix2.nim           |  2 +-
 tests/showoff/tdrdobbs_examples.nim |  2 +-
 tests/system/tfloatToString.nim     | 22 ++++++++++++++++++++++
 3 files changed, 24 insertions(+), 2 deletions(-)
 create mode 100644 tests/system/tfloatToString.nim

diff --git a/tests/matrix/tmatrix2.nim b/tests/matrix/tmatrix2.nim
index 442096e93a..82990f1a59 100644
--- a/tests/matrix/tmatrix2.nim
+++ b/tests/matrix/tmatrix2.nim
@@ -1,5 +1,5 @@
 discard """
-  output: "5.0000000000000000e+00"
+  output: "5.0"
 """
 
 type
diff --git a/tests/showoff/tdrdobbs_examples.nim b/tests/showoff/tdrdobbs_examples.nim
index 8a39990ba5..13a685950e 100644
--- a/tests/showoff/tdrdobbs_examples.nim
+++ b/tests/showoff/tdrdobbs_examples.nim
@@ -1,7 +1,7 @@
 discard """
   output: '''108
 11 -1 1936
-4.0000000000000002e-01
+0.4
 true
 truefalse'''
 """
diff --git a/tests/system/tfloatToString.nim b/tests/system/tfloatToString.nim
new file mode 100644
index 0000000000..bb45a91d70
--- /dev/null
+++ b/tests/system/tfloatToString.nim
@@ -0,0 +1,22 @@
+discard """
+  output:'''2.3242
+2.982
+123912.1
+123912.1823
+5.0
+1e+100
+inf
+-inf
+nan
+'''
+"""
+
+echo($(2.3242))
+echo($(2.982))
+echo($(123912.1))
+echo($(123912.1823))
+echo($(5.0))
+echo($(1e100))
+echo($(1e1000000))
+echo($(-1e1000000))
+echo($(0.0/0.0))