fennel: Make best effort at keeping the number format when compiling ints v1 PROPOSED

: 1
 Make best effort at keeping the number format when compiling ints

 5 files changed, 52 insertions(+), 8 deletions(-)

[PATCH fennel] Make best effort at keeping the number format when compiling ints Export this patch

From: Andrey Listopadov <andreyorst@gmail.com>

---
 changelog.md            |  1 +
 src/fennel/compiler.fnl | 19 ++++++++++++++++---
 src/fennel/view.fnl     | 21 ++++++++++++++++++---
 test/core.fnl           |  9 ++++++++-
 test/parser.fnl         | 10 +++++++++-
 5 files changed, 52 insertions(+), 8 deletions(-)

diff --git a/changelog.md b/changelog.md
index 560fcf3..398af18 100644
--- a/changelog.md
+++ b/changelog.md
@@ -15,6 +15,7 @@ deprecated forms.
 * Macro quote expansion no longer breaks when `sym`, `list` or `sequence` is shadowed
 * Bring `fennel.traceback` behavior closer to Lua's `traceback` by
   not modifying non-string and non-`nil` values.
+* Avoid losing precision when compiling large numbers on LuaJIT.
 
 ## 1.5.0 / 2024-06-23
 
diff --git a/src/fennel/compiler.fnl b/src/fennel/compiler.fnl
index 0faf74b..e3e3774 100644
--- a/src/fennel/compiler.fnl
+++ b/src/fennel/compiler.fnl
@@ -533,10 +533,23 @@ (fn compile-sym
 
 ;; We do gsub transformation because some locales use , for
 ;; decimal separators, which will not be accepted by Lua.
+;; Makes best effort to keep the original notation of the number.
 (fn serialize-number [n]
-  (if (= (math.floor n) n)
-      (string.format "%d" n)
-      (string.gsub (tostring n) "," ".")))
+  (let [val (if (= (math.floor n) n)
+                (let [s1 (string.format "%.f" n)]
+                  (if (= s1 (tostring n)) s1
+                      (faccumulate [s nil i 0 99 :until s]
+                        (let [s (string.format (.. "%." i "e") n)
+                              n* (tonumber s)]
+                          (when (= n n*)
+                            (let [exp (s:match "e%+?(%d+)$")]
+                              ;; Lua stops transforming numbers from
+                              ;; e-notation to integers at e+14
+                              (if (and exp (> (tonumber exp) 14))
+                                  s
+                                  s1)))))))
+                (tostring n))]
+    (pick-values 1 (string.gsub val "," "."))))
 
 (fn compile-scalar [ast _scope parent opts]
   (let [serialize (match (type ast)
diff --git a/src/fennel/view.fnl b/src/fennel/view.fnl
index 08ef7f8..781d827 100644
--- a/src/fennel/view.fnl
+++ b/src/fennel/view.fnl
@@ -282,11 +282,26 @@ (fn pp-table
     (set options.level (- options.level 1))
     x))
 
+;; A copy of compiler.serialize-number because fennel.view can't have
+;; dependencies
 (fn number->string [n]
   ;; Transform number to a string without depending on correct `os.locale`
-  (if (= (math.floor n) n)
-      (string.format "%d" n)
-      (pick-values 1 (string.gsub (tostring n) "," "."))))
+  ;; Makes best effort to keep the original notation of the number.
+  (let [val (if (= (math.floor n) n)
+                (let [s1 (string.format "%.f" n)]
+                  (if (= s1 (tostring n)) s1
+                      (faccumulate [s nil i 0 99 :until s]
+                        (let [s (string.format (.. "%." i "e") n)
+                              n* (tonumber s)]
+                          (when (= n n*)
+                            (let [exp (s:match "e%+?(%d+)$")]
+                              ;; Lua stops transforming numbers from
+                              ;; e-notation to integers at e+14
+                              (if (and exp (> (tonumber exp) 14))
+                                  s
+                                  s1)))))))
+                (tostring n))]
+    (pick-values 1 (string.gsub val "," "."))))
 
 (fn colon-string? [s]
   ;; Test if given string is valid colon string.
diff --git a/test/core.fnl b/test/core.fnl
index 4b138b5..4b9ed83 100644
--- a/test/core.fnl
+++ b/test/core.fnl
@@ -561,7 +561,14 @@ (fn test-with-open
       ["asdf" "closed file" "closed file"])
   (== [(with-open [proc1 (io.popen "echo hi") proc2 (io.popen "echo bye")]
          (values (proc1:read) (proc2:read)))]
-      ["hi" "bye"]))
+      ["hi" "bye"])
+  (== (do
+        (var fh nil)
+        (local (ok msg) (pcall #(with-open [f (io.tmpfile)]
+                                  (set fh f)
+                                  (error {:bork! :bark!}))))
+        [(io.type fh) ok (case msg {:bork! :bark!} msg _ "didn't match")])
+      ["closed file" false {:bork! :bark!}]))
 
 (fn test-comment []
   (t.= "--[[ hello world ]]\nreturn nil"
diff --git a/test/parser.fnl b/test/parser.fnl
index 57df216..ac62cb6 100644
--- a/test/parser.fnl
+++ b/test/parser.fnl
@@ -20,8 +20,16 @@ (fn test-basics
        [((fennel.parser (fennel.string-stream "&abc ")))])
   (t.= "141791343654238"
        (fennel.view (fennel.eval "141791343654238")))
+  (t.= "141791343654238"
+       (fennel.view (fennel.eval "1.41791343654238e+14")))
+  (t.= "1.41791343654238e+15"
+       (fennel.view (fennel.eval "1.41791343654238e+15")))
   (t.= "14179134365.125"
-       (fennel.view (fennel.eval "14179134365.125"))))
+       (fennel.view (fennel.eval "14179134365.125")))
+  (t.= "2.3456789012e+76"
+       (fennel.view (fennel.eval "2.3456789012e+76")))
+  (t.= "1.23456789e-13"
+       (fennel.view (fennel.eval "1.23456789e-13"))))
 
 (fn test-comments []
   (let [(ok? ast) ((fennel.parser (fennel.string-stream ";; abc")
-- 
2.45.0

builds.sr.ht <builds@sr.ht>

a month ago

fennel/patches/.build.yml: SUCCESS in 32s

[Make best effort at keeping the number format when compiling ints][0] from [][1]

[0]: https://lists.sr.ht/~technomancy/fennel/patches/54442
[1]: mailto:andreyorst@gmail.com

✓ #1301751 SUCCESS fennel/patches/.build.yml https://builds.sr.ht/~technomancy/job/1301751