diff --git a/docs/install.rst b/docs/install.rst
index bb4ce1a..4cd2561 100644
--- a/docs/install.rst
+++ b/docs/install.rst
@@ -61,7 +61,7 @@ __ http://www.quicklisp.org/beta/
 
 When building from sources, you should always build from the current git
 HEAD as it's basically the only source that is managed in a way to ensure it
-builds aginst current set of dependencies versions.
+builds against current set of dependencies versions.
 
 The build system for pgloader uses a Makefile and the Quicklisp Common Lisp
 packages distribution system.
diff --git a/src/parsers/command-db-uri.lisp b/src/parsers/command-db-uri.lisp
index edb8190..1421583 100644
--- a/src/parsers/command-db-uri.lisp
+++ b/src/parsers/command-db-uri.lisp
@@ -44,9 +44,6 @@
       ;; password looks like '(":" "password")
       (list :user username :password (cadr password)))))
 
-(defun hexdigit-char-p (character)
-  (member character #. (quote (coerce "0123456789abcdefABCDEF" 'list))))
-
 (defrule ipv4-part (and (digit-char-p character)
 			(? (digit-char-p character))
 			(? (digit-char-p character))))
@@ -55,13 +52,13 @@
   (:lambda (ipv4)
     (list :ipv4 (text ipv4))))
 
-(defrule ipv6 (and #\[ (+ (or (digit-char-p character) ":")) #\])
+(defrule ipv6 (and #\[ (+ (or (hexdigit-char-p character) ":")) #\])
   (:lambda (ipv6)
     (list :ipv6 (text ipv6))))
 
-;;; socket directory is unix only, so we can forbid ":" on the parsing
+;; socket directory is unix only, so we can forbid ":" on the parsing
 (defun socket-directory-character-p (char)
-  (or (member char #.(quote (coerce "/.-_" 'list)))
+  (or (find char "/.-_")
       (alphanumericp char)))
 
 (defrule socket-directory (and "unix:"
diff --git a/src/parsers/command-utils.lisp b/src/parsers/command-utils.lisp
index 4ad3a63..a2639a9 100644
--- a/src/parsers/command-utils.lisp
+++ b/src/parsers/command-utils.lisp
@@ -65,3 +65,7 @@
 
 (defrule comma-separator (and ignore-whitespace #\, ignore-whitespace)
   (:constant ","))
+
+;; Predicates for use in rules can only be called with arity 1.
+(defun hexdigit-char-p (character)
+  (digit-char-p character 16))
diff --git a/src/parsers/parse-pgpass.lisp b/src/parsers/parse-pgpass.lisp
index 5f62aba..84a6d37 100644
--- a/src/parsers/parse-pgpass.lisp
+++ b/src/parsers/parse-pgpass.lisp
@@ -15,7 +15,7 @@
   (:lambda (c) (second c)))
 
 (defrule pgpass-ipv6-hostname (and #\[
-                                   (+ (or (digit-char-p character) ":"))
+                                   (+ (or (hexdigit-char-p character) ":"))
                                    #\])
   (:lambda (ipv6) (text (second ipv6))))