formatting: don't force the presence of ".0" for %f and %e when precision is 0

It's misleading because you can think you have more precision than you really
do when looking at the output. So instead of "1.0", we can format it as "1" or
"1.".  And instead of "1.0e+00" we can format "1e+00" or "1.e+00".  In C,
printf does not print the radix character, it's prettier. But since the factor
parser accepts both styles, and keeping the radix character gives a stronger sense
that the number is approximate, I prefer to keep the radix character..

diff --git a/basis/formatting/formatting-tests.factor b/basis/formatting/formatting-tests.factor
index b3e503fd3aae96ab1638c84087b87d18c0385918..d01b4f6336a645990532805b7fbb3c7cedb11bde 100755 (executable)
--- a/basis/formatting/formatting-tests.factor
+++ b/basis/formatting/formatting-tests.factor
@@ -35,8 +35,10 @@ IN: formatting.tests
 { "100000000000000000000000.000000" } [ 23 10^ "%f" sprintf ] unit-test
 { "1.2" } [ 125/100 "%.1f" sprintf ] unit-test
 { "1.4" } [ 135/100 "%.1f" sprintf ] unit-test
-{ "2.0" } [ 5/2 "%.0f" sprintf ] unit-test
-{ "4.0" } [ 7/2 "%.0f" sprintf ] unit-test
+{ "2." } [ 5/2 "%.0f" sprintf ] unit-test
+{ "4." } [ 7/2 "%.0f" sprintf ] unit-test
+{ "2.e+00" } [ 5/2 "%.0e" sprintf ] unit-test
+{ "4.e+00" } [ 7/2 "%.0e" sprintf ] unit-test
 { "  1.23" } [ 1.23456789 "%6.2f" sprintf ] unit-test
 { "001100" } [ 12 "%06b" sprintf ] unit-test
 { "==14" } [ 12 "%'=4o" sprintf ] unit-test
@@ -85,6 +87,30 @@ IN: formatting.tests
 { "-9007199254740992.0" } [ 53 2^ neg "%.1f" sprintf ] unit-test
 { "-9007199254740993.0" } [ 53 2^ 1 + neg "%.1f" sprintf ] unit-test
 
+{ "987654321098765432" } [ 987654321098765432 "%d" sprintf ] unit-test
+{ "987654321098765432.0" } [ 987654321098765432 "%.1f" sprintf ] unit-test
+{ "987654321098765432." } [ 987654321098765432 "%.0f" sprintf ] unit-test
+{ "9.8765432109876543200e+17" } [ 987654321098765432 "%.19e" sprintf ] unit-test
+{ "9.876543210987654320e+17" } [ 987654321098765432 "%.18e" sprintf ] unit-test
+{ "9.87654321098765432e+17" } [ 987654321098765432 "%.17e" sprintf ] unit-test
+{ "9.8765432109876543e+17" } [ 987654321098765432 "%.16e" sprintf ] unit-test
+{ "9.876543210987654e+17" } [ 987654321098765432 "%.15e" sprintf ] unit-test
+{ "9.87654321098765e+17" } [ 987654321098765432 "%.14e" sprintf ] unit-test
+{ "9.8765432109877e+17" } [ 987654321098765432 "%.13e" sprintf ] unit-test
+{ "9.876543210988e+17" } [ 987654321098765432 "%.12e" sprintf ] unit-test
+{ "9.87654321099e+17" } [ 987654321098765432 "%.11e" sprintf ] unit-test
+{ "9.8765432110e+17" } [ 987654321098765432 "%.10e" sprintf ] unit-test
+{ "9.876543211e+17" } [ 987654321098765432 "%.9e" sprintf ] unit-test
+{ "9.87654321e+17" } [ 987654321098765432 "%.8e" sprintf ] unit-test
+{ "9.8765432e+17" } [ 987654321098765432 "%.7e" sprintf ] unit-test
+{ "9.876543e+17" } [ 987654321098765432 "%.6e" sprintf ] unit-test
+{ "9.87654e+17" } [ 987654321098765432 "%.5e" sprintf ] unit-test
+{ "9.8765e+17" } [ 987654321098765432 "%.4e" sprintf ] unit-test
+{ "9.877e+17" } [ 987654321098765432 "%.3e" sprintf ] unit-test
+{ "9.88e+17" } [ 987654321098765432 "%.2e" sprintf ] unit-test
+{ "9.9e+17" } [ 987654321098765432 "%.1e" sprintf ] unit-test
+{ "1.e+18" } [ 987654321098765432 "%.0e" sprintf ] unit-test
+
 { "1.5625" } [ 1.5625 "%d" sprintf ] unit-test
 { "1.9p0" } [ 1.5625 "%x" sprintf ] unit-test
 { "1.9P0" } [ 1.5625 "%X" sprintf ] unit-test

diff --git a/basis/formatting/formatting.factor b/basis/formatting/formatting.factor
index 19bff37899df96d2e4b610a03b1e9d2001189002..344a29c4508844f7c834f4e83fd5f93695f7bb7e 100644 (file)
--- a/basis/formatting/formatting.factor
+++ b/basis/formatting/formatting.factor
@@ -5,7 +5,7 @@ combinators.smart fry generalizations io io.streams.string
 kernel macros math math.functions math.parser namespaces
 peg.ebnf present prettyprint quotations sequences
 sequences.generalizations strings unicode vectors
-math.functions.integer-logs math.order ;
+math.functions.integer-logs splitting ;
 FROM: math.parser.private => format-float ;
 IN: formatting
 
@@ -33,8 +33,8 @@ IN: formatting
     [
         [ abs ] dip
         [ 10^ * round-to-even >integer number>string ]
-        [ 1 + CHAR: 0 pad-head 2 CHAR: 0 pad-tail ]
-        [ 1 max cut* ] tri "." glue
+        [ 1 + CHAR: 0 pad-head ]
+        [ cut* ] tri "." glue
     ] curry keep neg? [ CHAR: - prefix ] when ;
 
 : format-scientific-mantissa ( x log10x digits -- string )
@@ -63,10 +63,14 @@ IN: formatting
         [ [ [ >float ] dip ] when ] keep
     ] if ;
 
+: ?fix-nonsignificant-zero ( string digits -- string )
+    [ ".0" "." replace ] [ drop ] if-zero ;
+
 : format-scientific ( x digits -- string )
-    format-fast-scientific?
-    [ "e" format-float-fast ]
-    [ format-scientific-simple ] if ;
+    format-fast-scientific?  [
+        [ "e" format-float-fast ]
+        [ ?fix-nonsignificant-zero ] bi
+    ] [ format-scientific-simple ] if ;
 
 : format-fast-decimal? ( x digits -- x' digits ? )
     over float? [ t ]
@@ -82,9 +86,10 @@ IN: formatting
     ] if ; inline
 
 : format-decimal ( x digits -- string )
-    format-fast-decimal?
-    [ "f" format-float-fast ]
-    [ format-decimal-simple ] if ;
+    format-fast-decimal? [
+        [ "f" format-float-fast ]
+        [ ?fix-nonsignificant-zero ] bi
+    ] [ format-decimal-simple ] if ;
 
 ERROR: unknown-printf-directive ;