objfloat: Try to achieve the same float printing format as CPython does.

pfalcon · pfalcon · commit 7de5377ca7ee · 2014-04-18T21:21:59.000+03:00
Test usecase I used is print(time.time()) and print(time.time() - time.time()).
On Linux/Glibc they now give the same output as CPython 3.3. Specifically,
time.time() gives non-exponential output with 7 decimal digits, and subtraction
gives exponential output e-06/e-07.
diff --git a/py/objfloat.c b/py/objfloat.c
@@ -30,7 +30,7 @@ STATIC void float_print(void (*print)(void *env, const char *fmt, ...), void *en
     }
 #else
     char buf[32];
-    sprintf(buf, "%.8g", (double) o->value);
+    sprintf(buf, "%.17g", (double) o->value);
     print(env, buf);
     if (strchr(buf, '.') == NULL) {
         // Python floats always have decimal point

Original file line number	Diff line number	Diff line change
`@@ -30,7 +30,7 @@ STATIC void float_print(void (print)(void env, const char fmt, ...), void en`
`30`	`30`	`}`
`31`	`31`	`#else`
`32`	`32`	`char buf[32];`
`33`		`- sprintf(buf, "%.8g", (double) o->value);`
	`33`	`+ sprintf(buf, "%.17g", (double) o->value);`
`34`	`34`	`print(env, buf);`
`35`	`35`	`if (strchr(buf, '.') == NULL) {`
`36`	`36`	`// Python floats always have decimal point`