From 5d7d8816e527155aa2a4845dfce6507df872eb92 Mon Sep 17 00:00:00 2001
From: Parashurama <Rhagdamaziel@ymail.com>
Date: Thu, 19 May 2016 21:03:22 +0200
Subject: [PATCH] fixes some issues with underscores in float literals. add
 more tests.

fixes some potential issues with underscores in float literals.
adds more checks for badly positionned underscores in float literals.
adds more test files.
---
 lib/system/sysstr.nim   | 12 +++++++-----
 tests/float/tfloat6.nim | 21 +++++++++++++++++++++
 tests/float/tfloat7.nim | 26 ++++++++++++++++++++++++++
 3 files changed, 54 insertions(+), 5 deletions(-)
 create mode 100644 tests/float/tfloat6.nim
 create mode 100644 tests/float/tfloat7.nim

diff --git a/lib/system/sysstr.nim b/lib/system/sysstr.nim
index 3177d05bdc..64d6634d26 100644
--- a/lib/system/sysstr.nim
+++ b/lib/system/sysstr.nim
@@ -328,7 +328,7 @@ proc nimParseBiggestFloat(s: string, number: var BiggestFloat,
     fraction: uint64
     frac_exponent= 0
     exp_sign = 1
-    first_digit = 0
+    first_digit = -1
     has_sign = false
 
   # Sign?
@@ -359,6 +359,7 @@ proc nimParseBiggestFloat(s: string, number: var BiggestFloat,
   # Skip leading zero
   while s[i] == '0':
     inc(i)
+    while s[i] == '_': inc(i)
 
   if s[i] in {'0'..'9'}:
       first_digit = (s[i].ord - '0'.ord)
@@ -366,7 +367,7 @@ proc nimParseBiggestFloat(s: string, number: var BiggestFloat,
   while s[i] in {'0'..'9'}:
     inc(kdigits)
     integer = integer * 10'u64 + (s[i].ord - '0'.ord).uint64
-    inc(i);
+    inc(i)
     while s[i] == '_': inc(i)
 
   # Fractional part?
@@ -374,11 +375,12 @@ proc nimParseBiggestFloat(s: string, number: var BiggestFloat,
     inc(i)
     # if no integer part, Skip leading zeros
     if kdigits <= 0:
-      while s[i] in {'_','0'}:
-        inc(i)
+      while s[i] == '0':
         inc(frac_exponent)
+        inc(i)
+        while s[i] == '_': inc(i)
 
-    if s[i] in {'0'..'9'}:
+    if first_digit == -1 and s[i] in {'0'..'9'}:
       first_digit = (s[i].ord - '0'.ord)
     # get fractional part
     while s[i] in {'0'..'9'}:
diff --git a/tests/float/tfloat6.nim b/tests/float/tfloat6.nim
new file mode 100644
index 0000000000..721abd7219
--- /dev/null
+++ b/tests/float/tfloat6.nim
@@ -0,0 +1,21 @@
+discard """
+  file: "tfloat6.nim"
+  output: '''1e-06 : 1e-06
+1e-06 : 1e-06
+0.001 : 0.001
+1e-06 : 1e-06
+1e-06 : 1e-06
+10.000001 : 10.000001
+100.000001 : 100.000001'''
+"""
+
+import strutils
+
+echo "0.00_0001".parseFloat(), " : ", 1E-6
+echo "0.00__00_01".parseFloat(), " : ", 1E-6
+echo "0.0_01".parseFloat(), " : ", 0.001
+echo "0.00_000_1".parseFloat(), " : ", 1E-6
+echo "0.00000_1".parseFloat(), " : ", 1E-6
+
+echo "1_0.00_0001".parseFloat(), " : ", 10.000001
+echo "1__00.00_0001".parseFloat(), " : ", 1_00.000001
diff --git a/tests/float/tfloat7.nim b/tests/float/tfloat7.nim
new file mode 100644
index 0000000000..2337d1dd4e
--- /dev/null
+++ b/tests/float/tfloat7.nim
@@ -0,0 +1,26 @@
+discard """
+  file: "tfloat6.nim"
+  output: '''passed.
+passed.
+passed.
+passed.
+passed.
+passed.
+passed.'''
+"""
+
+import strutils
+template expect_fail(x: expr) =
+  try:
+    discard x
+    echo("expected to fail!")
+  except ValueError:
+    echo("passed.")
+
+expect_fail("1_0._00_0001".parseFloat())
+expect_fail("_1_0_00.0001".parseFloat())
+expect_fail("10.00.01".parseFloat())
+expect_fail("10.00E_01".parseFloat())
+expect_fail("10.00E_01".parseFloat())
+expect_fail("10.00E".parseFloat())
+expect_fail("10.00A".parseFloat())