Address Copilot review: remove unused printer field and add cross-platform fallback

Author: dlevy-msft-sql

pkg/sqlcmd/regional.go

@@ -9,13 +9,11 @@ import (
 	"time"
 
 	"golang.org/x/text/language"
-	"golang.org/x/text/message"
 )
 
 // RegionalSettings provides locale-aware formatting for output when -R is used
 type RegionalSettings struct {
 	enabled bool
-	printer *message.Printer
 	tag     language.Tag
 	dateFmt string
 	timeFmt string
@@ -27,7 +25,6 @@ func NewRegionalSettings(enabled bool) *RegionalSettings {
 	r := &RegionalSettings{enabled: enabled}
 	if enabled {
 		r.tag = detectUserLocale()
-		r.printer = message.NewPrinter(r.tag)
 		r.dateFmt, r.timeFmt = getLocaleDateTimeFormats(r.tag)
 	}
 	return r

pkg/sqlcmd/regional_other.go

@@ -0,0 +1,64 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+//go:build !windows && !linux && !darwin
+
+package sqlcmd
+
+import (
+	"os"
+	"strings"
+
+	"golang.org/x/text/language"
+)
+
+// detectUserLocale returns the user's locale from environment variables.
+// This is a fallback implementation for platforms other than Windows, Linux, and Darwin.
+// It uses the same environment variable approach as Linux.
+func detectUserLocale() language.Tag {
+	// Check standard locale environment variables in order of precedence
+	for _, envVar := range []string{"LC_ALL", "LC_MESSAGES", "LANG"} {
+		if locale := os.Getenv(envVar); locale != "" {
+			tag := parseUnixLocale(locale)
+			if tag != language.Und {
+				return tag
+			}
+		}
+	}
+	return language.English
+}
+
+// parseUnixLocale converts a Unix locale string to a language.Tag
+// Examples: "en_US.UTF-8", "de_DE", "fr_FR.utf8", "C", "POSIX"
+func parseUnixLocale(locale string) language.Tag {
+	// Handle special cases
+	if locale == "C" || locale == "POSIX" || locale == "" {
+		return language.English
+	}
+
+	// Remove encoding suffix (e.g., ".UTF-8")
+	if idx := strings.Index(locale, "."); idx != -1 {
+		locale = locale[:idx]
+	}
+
+	// Remove modifier (e.g., "@euro")
+	if idx := strings.Index(locale, "@"); idx != -1 {
+		locale = locale[:idx]
+	}
+
+	// Convert underscore to hyphen for BCP 47 format
+	locale = strings.Replace(locale, "_", "-", -1)
+
+	if tag, err := language.Parse(locale); err == nil {
+		return tag
+	}
+
+	// Try with just the language part
+	if idx := strings.Index(locale, "-"); idx != -1 {
+		if tag, err := language.Parse(locale[:idx]); err == nil {
+			return tag
+		}
+	}
+
+	return language.Und
+}