From 3af41a1290e9db0feb2fcec9d860942ef34eba64 Mon Sep 17 00:00:00 2001
From: Jay Hemnani <193022578+jayhemnani9910@users.noreply.github.com>
Date: Mon, 26 Oct 2026 15:10:52 +0530
Subject: [PATCH] interpreter: print integral numbers as integers

A float went through the shortest round-trip formatter, so integral
values from 1e16 up came out in exponent form (print 2^64 gave
1.8446744073709552e+19) and -0 printed as -0. POSIX converts an integer
value as if by %d, and gawk prints 18446744073709551616 and 0. Write
finite integral values with all their digits.
---
 interpreter/src/vm/types.rs |  6 ++++++
 tests/by-util/test_awk.rs   | 15 +++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/interpreter/src/vm/types.rs b/interpreter/src/vm/types.rs
index 19cf257..df210b4 100644
--- a/interpreter/src/vm/types.rs
+++ b/interpreter/src/vm/types.rs
@@ -376,6 +376,12 @@ impl<'a> AwkValue<'a> {
         }
         match self {
             // TODO: NaN and infinities.
+            // An integral value is written as an integer, as by "%d" (POSIX),
+            // so 2^64 and 1e16 keep all their digits and -0 is "0".
+            Self::Float(f) if f.0.is_finite() && f.0.fract() == 0.0 => {
+                let n = if f.0 == 0.0 { 0.0 } else { f.0 };
+                out.extend_from_slice(format!("{n:.0}").as_bytes());
+            }
             Self::Float(f) => {
                 let mut buf = zmij::Buffer::new();
                 let s = buf.format(f.0);
diff --git a/tests/by-util/test_awk.rs b/tests/by-util/test_awk.rs
index 9819842..10a115c 100644
--- a/tests/by-util/test_awk.rs
+++ b/tests/by-util/test_awk.rs
@@ -1005,3 +1005,18 @@ fn test_referencing_an_element_creates_it() {
         .succeeds()
         .stdout_only("1 1 2 0\n");
 }
+
+#[test]
+fn integral_numbers_print_as_integers() {
+    ucmd()
+        .arg("BEGIN { print 2^64, 1e16, -1e16, -0; x = 1e16 \"\"; print x }")
+        .succeeds()
+        .stdout_only(
+            "18446744073709551616 10000000000000000 -10000000000000000 0\n10000000000000000\n",
+        );
+    ucmd()
+        .arg("{ print $1 * 1 }")
+        .pipe_in("5e20\n")
+        .succeeds()
+        .stdout_only("500000000000000000000\n");
+}