fixes #21847; let parseFloat behave like strtod (#21854)

nim-lang · May 16, 2023 · f22e506 · f22e506
1 parent eecf12c
commit f22e506
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Showing 2 changed files with 11 additions and 3 deletions.
diff --git a/lib/system/strmantle.nim b/lib/system/strmantle.nim
@@ -178,7 +178,9 @@ proc nimParseBiggestFloat(s: openArray[char], number: var BiggestFloat,
 
   # if exponent greater than can be represented: +/- zero or infinity
   if absExponent > 999:
-    if expNegative:
+    if integer == 0:
+      number = 0.0
+    elif expNegative:
       number = 0.0*sign
     else:
       number = Inf*sign

diff --git a/tests/float/tfloat4.nim b/tests/float/tfloat4.nim
@@ -56,8 +56,14 @@ doAssert 0.9999999999999999 == ".9999999999999999".parseFloat
 
 # bug #18400
 var s = [-13.888888'f32]
-assert $s[0] == "-13.888888"
+doAssert $s[0] == "-13.888888"
 var x = 1.23456789012345'f32
-assert $x == "1.2345679"
+doAssert $x == "1.2345679"
+
+# bug #21847
+doAssert parseFloat"0e+42" == 0.0
+doAssert parseFloat"0e+42949672969" == 0.0
+doAssert parseFloat"0e+42949672970" == 0.0
+doAssert parseFloat"0e+42949623223346323563272970" == 0.0
 
 echo("passed all tests.")