diff --git a/hall.scm b/hall.scm
index 1ada03c..3cfe209 100644
--- a/hall.scm
+++ b/hall.scm
@@ -22,10 +22,14 @@
            ((directory
               "runewidth"
               ((scheme-file "emoji")
+               (directory "eastasian"
+                          ((scheme-file "locale")))
                (scheme-file "eastasian")
                (scheme-file "internal")))
             (scheme-file "runewidth")))
-         (tests ((directory "tests" ((scheme-file "test-posix")))))
+         (tests ((directory
+                  "tests"
+                  ((scheme-file "test-eastasian-locale")))))
          (programs
            ((directory
               "scripts"
@@ -40,5 +44,4 @@
          (infrastructure
            ((scheme-file "guix")
             (text-file ".gitignore")
-            (scheme-file "hall")
-            (directory "tests" ((scheme-file "test-posix")))))))
+            (scheme-file "hall")))))
diff --git a/runewidth/posix.scm b/runewidth/eastasian/locale.scm
similarity index 86%
rename from runewidth/posix.scm
rename to runewidth/eastasian/locale.scm
index 89f4fc2..4eb0c1e 100644
--- a/runewidth/posix.scm
+++ b/runewidth/eastasian/locale.scm
@@ -1,6 +1,6 @@
-(define-module (runewidth posix)
+(define-module (runewidth eastasian locale)
   #:use-module (ice-9 regex)
-  #:export (east-asian?))
+  #:export (eastasian-locale?))
 
 (define wide-locales
   (list
@@ -36,7 +36,7 @@
       (getenv "LANG")
       ""))
 
-(define* (east-asian? #:optional (locale (get-env-locale)))
+(define* (eastasian-locale? #:optional (locale (get-env-locale)))
   "Check if a given locale (or the currently installed locale from the environment) is considered an east asian locale"
   (unless (string? locale)
     (error "`locale' must be a string"))
@@ -52,13 +52,19 @@
          (match:substring locale-match 2)))
       locale)))
 
+  (pk locale)
+  (pk charset)
+
   (and
    (not (regexp-exec c-or-posix-regexp locale))
    (not (string-suffix? "@cjk_narrow" charset))
    (let ((index-@ (string-index charset #\@)))
      ;; strip @foo from the end of the charset
      (when index-@
-       (set! charset (substring/shared charset 0 index-@)))
+       (set! charset (substring charset 0 index-@)))
+
+     (pk charset)
+     (pk locale)
 
      (and (member charset wide-locales)
           (or
diff --git a/tests/test-posix.scm b/tests/test-eastasian-locale.scm
similarity index 55%
rename from tests/test-posix.scm
rename to tests/test-eastasian-locale.scm
index efc1d68..0872005 100644
--- a/tests/test-posix.scm
+++ b/tests/test-eastasian-locale.scm
@@ -1,11 +1,14 @@
-(define-module (tests test-posix)
-  #:use-module (runewidth posix)
+(define-module (tests test-eastasian-locale)
+  #:use-module (runewidth eastasian locale)
   #:use-module (srfi srfi-64))
 
-(test-begin "test-posix")
+(test-begin "test-eastasian-locale")
 
 (define (test-east expected charset)
-  (test-equal expected (east-asian? charset)))
+  (test-equal
+      (format #f "check ~a" charset)
+    expected
+    (eastasian-locale? charset)))
 
 (define data
   '((#f "foo@cjk_narrow")
@@ -20,4 +23,4 @@
 
 (for-each (λ (p) (apply test-east p)) data)
 
-(test-end "test-posix")
+(test-end "test-eastasian-locale")