From 234a14fc013422dba8a05e7cda262672f9cfc499 Mon Sep 17 00:00:00 2001
From: Francois-Rene Rideau <tunes@google.com>
Date: Wed, 9 Oct 2013 13:11:27 -0400
Subject: [PATCH] More docstrings for UIOP.

---
 uiop/configuration.lisp | 30 +++++++++++++++---
 uiop/filesystem.lisp    |  9 +++++-
 uiop/image.lisp         | 16 +++++++++-
 uiop/lisp-build.lisp    | 45 +++++++++++++++++++++------
 uiop/os.lisp            | 28 ++++++++++++++---
 uiop/pathname.lisp      | 69 ++++++++++++++++++++++++++++++++---------
 uiop/run-program.lisp   | 12 +++++--
 7 files changed, 172 insertions(+), 37 deletions(-)

diff --git a/uiop/configuration.lisp b/uiop/configuration.lisp
index d064c688..ba770783 100644
--- a/uiop/configuration.lisp
+++ b/uiop/configuration.lisp
@@ -32,8 +32,10 @@
                               (condition-arguments c))))))
 
   (defun get-folder-path (folder)
-    (or ;; this semi-portably implements a subset of the functionality of lispworks' sys:get-folder-path
-        #+(and lispworks mswindows) (sys:get-folder-path folder)
+    "Semi-portable implementation of a subset of LispWorks' sys:get-folder-path,
+this function tries to locate the Windows FOLDER for one of
+:LOCAL-APPDATA, :APPDATA or :COMMON-APPDATA."
+    (or #+(and lispworks mswindows) (sys:get-folder-path folder)
         ;; read-windows-registry HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders\AppData
         (ecase folder
           (:local-appdata (getenv-absolute-directory "LOCALAPPDATA"))
@@ -42,6 +44,7 @@
                                (subpathname* (getenv-absolute-directory "ALLUSERSPROFILE") "Application Data/"))))))
 
   (defun user-configuration-directories ()
+    "Determine user configuration directories"
     (let ((dirs
             `(,@(when (os-unix-p)
                   (cons
@@ -56,6 +59,7 @@
                          :from-end t :test 'equal)))
 
   (defun system-configuration-directories ()
+    "Determine system user configuration directories"
     (cond
       ((os-unix-p) '(#p"/etc/common-lisp/"))
       ((os-windows-p)
@@ -63,23 +67,28 @@
          (list it)))))
 
   (defun in-first-directory (dirs x &key (direction :input))
+    "Determine system user configuration directories"
     (loop :with fun = (ecase direction
                         ((nil :input :probe) 'probe-file*)
                         ((:output :io) 'identity))
           :for dir :in dirs
-          :thereis (and dir (funcall fun (merge-pathnames* x (ensure-directory-pathname dir))))))
+          :thereis (and dir (funcall fun (subpathname (ensure-directory-pathname dir) x)))))
 
   (defun in-user-configuration-directory (x &key (direction :input))
+    "return pathname under user configuration directory, subpathname X"
     (in-first-directory (user-configuration-directories) x :direction direction))
   (defun in-system-configuration-directory (x &key (direction :input))
+    "return pathname under system configuration directory, subpathname X"
     (in-first-directory (system-configuration-directories) x :direction direction))
 
   (defun configuration-inheritance-directive-p (x)
+    "Is X a configuration inheritance directive?"
     (let ((kw '(:inherit-configuration :ignore-inherited-configuration)))
       (or (member x kw)
           (and (length=n-p x 1) (member (car x) kw)))))
 
   (defun report-invalid-form (reporter &rest args)
+    "Report an invalid form according to REPORTER and various ARGS"
     (etypecase reporter
       (null
        (apply 'error 'invalid-configuration args))
@@ -90,10 +99,12 @@
       (cons
        (apply 'apply (append reporter args)))))
 
-  (defvar *ignored-configuration-form* nil)
+  (defvar *ignored-configuration-form* nil
+    "Have configuration forms been ignored while parsing the configuration?")
 
   (defun validate-configuration-form (form tag directive-validator
                                             &key location invalid-form-reporter)
+    "Validate a configuration FORM"
     (unless (and (consp form) (eq (car form) tag))
       (setf *ignored-configuration-form* t)
       (report-invalid-form invalid-form-reporter :form form :location location)
@@ -122,6 +133,7 @@
              (return (nreverse x))))
 
   (defun validate-configuration-file (file validator &key description)
+    "Validate a configuration file for conformance of its form with the validator function"
     (let ((forms (read-file-forms file)))
       (unless (length=n-p forms 1)
         (error (compatfmt "~@<One and only one form allowed for ~A. Got: ~3i~_~S~@:>~%")
@@ -154,6 +166,7 @@ values of TAG include :source-registry and :output-translations."
         :inherit-configuration)))
 
   (defun resolve-relative-location (x &key ensure-directory wilden)
+    "Given a designator X for an relative location, resolve it to a pathname"
     (ensure-pathname
      (etypecase x
        (pathname x)
@@ -192,6 +205,7 @@ directive.")
     "A specification as per RESOLVE-LOCATION of where the user keeps his FASL cache")
 
   (defun compute-user-cache ()
+    "Compute the location of the default user-cache for translate-output objects"
     (setf *user-cache*
           (flet ((try (x &rest sub) (and x `(,x ,@sub))))
             (or
@@ -204,6 +218,7 @@ directive.")
   (register-image-restore-hook 'compute-user-cache)
 
   (defun resolve-absolute-location (x &key ensure-directory wilden)
+    "Given a designator X for an absolute location, resolve it to a pathname"
     (ensure-pathname
      (etypecase x
        (pathname x)
@@ -244,6 +259,7 @@ directive.")
                                (:ensure-directory boolean)) t) resolve-location))
 
   (defun* (resolve-location) (x &key ensure-directory wilden directory)
+    "Resolve location designator X into a PATHNAME"
     ;; :directory backward compatibility, until 2014-01-16: accept directory as well as ensure-directory
     (loop* :with dirp = (or directory ensure-directory)
            :with (first . rest) = (if (atom x) (list x) x)
@@ -261,6 +277,7 @@ directive.")
            :finally (return path)))
 
   (defun location-designator-p (x)
+    "Is X a designator for a location?"
     (flet ((absolute-component-p (c)
              (typep c '(or string pathname
                         (member :root :home :here :user-cache))))
@@ -272,6 +289,7 @@ directive.")
           (and (consp x) (absolute-component-p (first x)) (every #'relative-component-p (rest x))))))
 
   (defun location-function-p (x)
+    "Is X the specification of a location function?"
     (and
      (length=n-p x 2)
      (eq (car x) :function)))
@@ -279,15 +297,17 @@ directive.")
   (defvar *clear-configuration-hook* '())
 
   (defun register-clear-configuration-hook (hook-function &optional call-now-p)
+    "Register a function to be called when clearing configuration"
     (register-hook-function '*clear-configuration-hook* hook-function call-now-p))
 
   (defun clear-configuration ()
+    "Call the functions in *CLEAR-CONFIGURATION-HOOK*"
     (call-functions *clear-configuration-hook*))
 
   (register-image-dump-hook 'clear-configuration)
 
-  ;; If a previous version of ASDF failed to read some configuration, try again.
   (defun upgrade-configuration ()
+    "If a previous version of ASDF failed to read some configuration, try again now."
     (when *ignored-configuration-form*
       (clear-configuration)
       (setf *ignored-configuration-form* nil))))
diff --git a/uiop/filesystem.lisp b/uiop/filesystem.lisp
index 1c762ab5..555e7503 100644
--- a/uiop/filesystem.lisp
+++ b/uiop/filesystem.lisp
@@ -157,6 +157,9 @@ Try to override the defaults to not resolving symlinks, if implementation allows
                                         '(:resolve-symlinks nil))))))
 
   (defun filter-logical-directory-results (directory entries merger)
+    "Given ENTRIES in a DIRECTORY, remove if the directory is logical
+the entries which are physical yet when transformed by MERGER have a different TRUENAME.
+This function is used as a helper to DIRECTORY-FILES to avoid invalid entries when using logical-pathnames."
     (if (logical-pathname-p directory)
         ;; Try hard to not resolve logical-pathname into physical pathnames;
         ;; otherwise logical-pathname users/lovers will be disappointed.
@@ -166,7 +169,7 @@ Try to override the defaults to not resolving symlinks, if implementation allows
         ;; translating the LPN commute.
         (loop :for f :in entries
               :for p = (or (and (logical-pathname-p f) f)
-                           (let* ((u (ignore-errors (funcall merger f))))
+                           (let* ((u (ignore-errors (call-function merger f))))
                              ;; The first u avoids a cumbersome (truename u) error.
                              ;; At this point f should already be a truename,
                              ;; but isn't quite in CLISP, for it doesn't have :version :newest
@@ -201,6 +204,7 @@ which is not very portable to override. Try not resolve symlinks if implementati
                             :version (make-pathname-component-logical (pathname-version f))))))))
 
   (defun subdirectories (directory)
+    "Given a DIRECTORY pathname designator, return a list of the subdirectories under it."
     (let* ((directory (ensure-directory-pathname directory))
            #-(or abcl cormanlisp genera xcl)
            (wild (merge-pathnames*
@@ -238,6 +242,9 @@ which is not very portable to override. Try not resolve symlinks if implementati
                      :directory (append prefix (make-pathname-component-logical (last dir)))))))))))
 
   (defun collect-sub*directories (directory collectp recursep collector)
+    "Given a DIRECTORY, call-function the COLLECTOR function designator
+on the directory if COLLECTP returns true when CALL-FUNCTION'ed with the directory,
+and recurse each of its subdirectories on which the RECURSEP returns true when CALL-FUNCTION'ed with them."
     (when (call-function collectp directory)
       (call-function collector directory))
     (dolist (subdir (subdirectories directory))
diff --git a/uiop/image.lisp b/uiop/image.lisp
index bbe7840d..33415432 100644
--- a/uiop/image.lisp
+++ b/uiop/image.lisp
@@ -131,6 +131,7 @@ This is designed to abstract away the implementation specific quit forms."
      stream))
 
   (defun print-backtrace (&rest keys &key stream count)
+    "Print a backtrace"
     (declare (ignore stream count))
     (with-safe-io-syntax (:package :cl)
       (let ((*print-readably* nil)
@@ -142,6 +143,7 @@ This is designed to abstract away the implementation specific quit forms."
         (ignore-errors (apply 'raw-print-backtrace keys)))))
 
   (defun print-condition-backtrace (condition &key (stream *stderr*) count)
+    "Print a condition after a backtrace triggered by that condition"
     ;; We print the condition *after* the backtrace,
     ;; for the sake of who sees the backtrace at a terminal.
     ;; It is up to the caller to print the condition *before*, with some context.
@@ -151,10 +153,12 @@ This is designed to abstract away the implementation specific quit forms."
                     condition)))
 
   (defun fatal-condition-p (condition)
+    "Is the CONDITION fatal? It is if it matches any in *FATAL-CONDITIONS*"
     (match-any-condition-p condition *fatal-conditions*))
 
   (defun handle-fatal-condition (condition)
-    "Depending on whether *LISP-INTERACTION* is set, enter debugger or die"
+    "Handle a fatal CONDITION:
+depending on whether *LISP-INTERACTION* is set, enter debugger or die"
     (cond
       (*lisp-interaction*
        (invoke-debugger condition))
@@ -164,10 +168,12 @@ This is designed to abstract away the implementation specific quit forms."
        (die 99 "~A" condition))))
 
   (defun call-with-fatal-condition-handler (thunk)
+    "Call THUNK in a context where fatal conditions are appropriately handled"
     (handler-bind (((satisfies fatal-condition-p) #'handle-fatal-condition))
       (funcall thunk)))
 
   (defmacro with-fatal-condition-handler ((&optional) &body body)
+    "Execute BODY in a context where fatal conditions are appropriately handled"
     `(call-with-fatal-condition-handler #'(lambda () ,@body)))
 
   (defun shell-boolean-exit (x)
@@ -178,15 +184,19 @@ This is designed to abstract away the implementation specific quit forms."
 ;;; Using image hooks
 (with-upgradability ()
   (defun register-image-restore-hook (hook &optional (call-now-p t))
+    "Regiter a hook function to be run when restoring a dumped image"
     (register-hook-function '*image-restore-hook* hook call-now-p))
 
   (defun register-image-dump-hook (hook &optional (call-now-p nil))
+    "Register a the hook function to be run before to dump an image"
     (register-hook-function '*image-dump-hook* hook call-now-p))
 
   (defun call-image-restore-hook ()
+    "Call the hook functions registered to be run when restoring a dumped image"
     (call-functions (reverse *image-restore-hook*)))
 
   (defun call-image-dump-hook ()
+    "Call the hook functions registered to be run before to dump an image"
     (call-functions *image-dump-hook*)))
 
 
@@ -230,6 +240,8 @@ if we are not called from a directly executable image."
                           ((:prelude *image-prelude*) *image-prelude*)
                           ((:entry-point *image-entry-point*) *image-entry-point*)
                           (if-already-restored '(cerror "RUN RESTORE-IMAGE ANYWAY")))
+    "From a freshly restarted Lisp image, restore the saved Lisp environment
+by setting appropriate variables, running various hooks, and calling any specified entry point."
     (when *image-restored-p*
       (if if-already-restored
           (call-function if-already-restored "Image already ~:[being ~;~]restored" (eq *image-restored-p* t))
@@ -255,6 +267,7 @@ if we are not called from a directly executable image."
                                 ((:postlude *image-postlude*) *image-postlude*)
                                 ((:dump-hook *image-dump-hook*) *image-dump-hook*)
                                 #+clozure prepend-symbols #+clozure (purify t))
+    "Dump an image of the current Lisp environment at pathname FILENAME, with various options"
     (declare (ignorable filename output-name executable))
     (setf *image-dumped-p* (if executable :executable t))
     (setf *image-restored-p* :in-regress)
@@ -321,6 +334,7 @@ if we are not called from a directly executable image."
                          (entry-point () entry-point-p) build-args)
     (declare (ignorable destination object-files kind output-name prologue-code epilogue-code
                         prelude preludep postlude postludep entry-point entry-point-p build-args))
+    "On ECL, create an executable at pathname DESTINATION from the specified OBJECT-FILES and options"
     ;; Is it meaningful to run these in the current environment?
     ;; only if we also track the object files that constitute the "current" image,
     ;; and otherwise simulate dump-image, including quitting at the end.
diff --git a/uiop/lisp-build.lisp b/uiop/lisp-build.lisp
index a22946b6..65d55402 100644
--- a/uiop/lisp-build.lisp
+++ b/uiop/lisp-build.lisp
@@ -49,8 +49,10 @@ Note that ASDF ALWAYS raises an error if it fails to create an output file when
 
 ;;; Optimization settings
 (with-upgradability ()
-  (defvar *optimization-settings* nil)
-  (defvar *previous-optimization-settings* nil)
+  (defvar *optimization-settings* nil
+    "Optimization settings to be used by PROCLAIM-OPTIMIZATION-SETTINGS")
+  (defvar *previous-optimization-settings* nil
+    "Optimization settings saved by PROCLAIM-OPTIMIZATION-SETTINGS")
   (defun get-optimization-settings ()
     "Get current compiler optimization settings, ready to PROCLAIM again"
     #-(or clisp clozure cmu ecl sbcl scl)
@@ -79,6 +81,7 @@ Note that ASDF ALWAYS raises an error if it fails to create an output file when
   #+sbcl
   (progn
     (defun sb-grovel-unknown-constant-condition-p (c)
+      "Detect SB-GROVEL unknown-constant conditions on older versions of SBCL"
       (and (typep c 'sb-int:simple-style-warning)
            (string-enclosed-p
             "Couldn't grovel for "
@@ -124,16 +127,18 @@ Note that ASDF ALWAYS raises an error if it fails to create an output file when
 ;;;; ----- Filtering conditions while building -----
 (with-upgradability ()
   (defun call-with-muffled-compiler-conditions (thunk)
+    "Call given THUNK in a context where uninteresting conditions and compiler conditions are muffled"
     (call-with-muffled-conditions
      thunk (append *uninteresting-conditions* *uninteresting-compiler-conditions*)))
   (defmacro with-muffled-compiler-conditions ((&optional) &body body)
-    "Run BODY where uninteresting compiler conditions are muffled"
+    "Trivial syntax for CALL-WITH-MUFFLED-COMPILER-CONDITIONS"
     `(call-with-muffled-compiler-conditions #'(lambda () ,@body)))
   (defun call-with-muffled-loader-conditions (thunk)
+    "Call given THUNK in a context where uninteresting conditions and loader conditions are muffled"
     (call-with-muffled-conditions
      thunk (append *uninteresting-conditions* *uninteresting-loader-conditions*)))
   (defmacro with-muffled-loader-conditions ((&optional) &body body)
-    "Run BODY where uninteresting compiler and additional loader conditions are muffled"
+    "Trivial syntax for CALL-WITH-MUFFLED-LOADER-CONDITIONS"
     `(call-with-muffled-loader-conditions #'(lambda () ,@body))))
 
 
@@ -159,6 +164,8 @@ Note that ASDF ALWAYS raises an error if it fails to create an output file when
 
   (defun check-lisp-compile-warnings (warnings-p failure-p
                                                   &optional context-format context-arguments)
+    "Given the warnings or failures as resulted from COMPILE-FILE or checking deferred warnings,
+raise an error or warning as appropriate"
     (when failure-p
       (case *compile-file-failure-behaviour*
         (:warn (warn 'compile-failed-warning
@@ -184,6 +191,7 @@ Note that ASDF ALWAYS raises an error if it fails to create an output file when
 
   (defun check-lisp-compile-results (output warnings-p failure-p
                                              &optional context-format context-arguments)
+    "Given the results of COMPILE-FILE, raise an error or warning as appropriate"
     (unless output
       (error 'compile-file-error :context-format context-format :context-arguments context-arguments))
     (check-lisp-compile-warnings warnings-p failure-p context-format context-arguments)))
@@ -196,6 +204,8 @@ Note that ASDF ALWAYS raises an error if it fails to create an output file when
 ;;; See their respective docstrings.
 (with-upgradability ()
   (defun reify-simple-sexp (sexp)
+    "Given a simple SEXP, return a representation of it as a portable SEXP.
+Simple means made of symbols, numbers, characters, simple-strings, pathnames, cons cells."
     (etypecase sexp
       (symbol (reify-symbol sexp))
       ((or number character simple-string pathname) sexp)
@@ -203,6 +213,7 @@ Note that ASDF ALWAYS raises an error if it fails to create an output file when
       (simple-vector (vector (mapcar 'reify-simple-sexp (coerce sexp 'list))))))
 
   (defun unreify-simple-sexp (sexp)
+    "Given the portable output of REIFY-SIMPLE-SEXP, return the simple SEXP it represents"
     (etypecase sexp
       ((or symbol number character simple-string pathname) sexp)
       (cons (cons (unreify-simple-sexp (car sexp)) (unreify-simple-sexp (cdr sexp))))
@@ -454,6 +465,8 @@ possibly in a different process."
         (terpri s))))
 
   (defun warnings-file-type (&optional implementation-type)
+    "The pathname type for warnings files on given IMPLEMENTATION-TYPE,
+where NIL designates the current one"
     (case (or implementation-type *implementation-type*)
       ((:acl :allegro) "allegro-warnings")
       ;;((:clisp) "clisp-warnings")
@@ -463,21 +476,27 @@ possibly in a different process."
       ((:scl) "scl-warnings")))
 
   (defvar *warnings-file-type* nil
-    "Type for warnings files")
+    "Pathname type for warnings files, or NIL if disabled")
 
   (defun enable-deferred-warnings-check ()
+    "Enable the saving of deferred warnings"
     (setf *warnings-file-type* (warnings-file-type)))
 
   (defun disable-deferred-warnings-check ()
+    "Disable the saving of deferred warnings"
     (setf *warnings-file-type* nil))
 
   (defun warnings-file-p (file &optional implementation-type)
+    "Is FILE a saved warnings file for the given IMPLEMENTATION-TYPE?
+If that given type is NIL, use the currently configured *WARNINGS-FILE-TYPE* instead."
     (if-let (type (if implementation-type
                       (warnings-file-type implementation-type)
                       *warnings-file-type*))
       (equal (pathname-type file) type)))
 
   (defun check-deferred-warnings (files &optional context-format context-arguments)
+    "Given a list of FILES in which deferred warnings were saved by CALL-WITH-DEFERRED-WARNINGS,
+re-intern and raise any warnings that are still meaningful."
     (let ((file-errors nil)
           (failure-p nil)
           (warnings-p nil))
@@ -518,6 +537,9 @@ possibly in a different process."
   |#
 
   (defun call-with-saved-deferred-warnings (thunk warnings-file)
+    "If WARNINGS-FILE is not nil, record the deferred-warnings around a call to THUNK
+and save those warnings to the given file for latter use,
+possibly in a different process. Otherwise just call THUNK."
     (if warnings-file
         (with-compilation-unit (:override t)
           (unwind-protect
@@ -529,21 +551,22 @@ possibly in a different process."
         (funcall thunk)))
 
   (defmacro with-saved-deferred-warnings ((warnings-file) &body body)
-    "If WARNINGS-FILE is not nil, records the deferred-warnings around the BODY
-and saves those warnings to the given file for latter use,
-possibly in a different process. Otherwise just run the BODY."
+    "Trivial syntax for CALL-WITH-SAVED-DEFERRED-WARNINGS" 
     `(call-with-saved-deferred-warnings #'(lambda () ,@body) ,warnings-file)))
 
 
 ;;; from ASDF
 (with-upgradability ()
   (defun current-lisp-file-pathname ()
+    "Portably return the PATHNAME of the current Lisp source file being compiled or loaded"
     (or *compile-file-pathname* *load-pathname*))
 
   (defun load-pathname ()
-    *load-pathname*)
+    "Portably return the LOAD-PATHNAME of the current source file or fasl"
+    *load-pathname*) ;; see magic for GCL in uiop/common-lisp 
 
   (defun lispize-pathname (input-file)
+    "From a INPUT-FILE pathname, return a corresponding .lisp source pathname"
     (make-pathname :type "lisp" :defaults input-file))
 
   (defun compile-file-type (&rest keys)
@@ -553,9 +576,11 @@ possibly in a different process. Otherwise just run the BODY."
     #+(or ecl mkcl) (pathname-type (apply 'compile-file-pathname "foo" keys)))
 
   (defun call-around-hook (hook function)
+    "Call a HOOK around the execution of FUNCTION"
     (call-function (or hook 'funcall) function))
 
   (defun compile-file-pathname* (input-file &rest keys &key output-file &allow-other-keys)
+    "Variant of COMPILE-FILE-PATHNAME that works well with COMPILE-FILE*"
     (let* ((keys
              (remove-plist-keys `(#+(and allegro (not (version>= 8 2))) :external-format
                                     ,@(unless output-file '(:output-file))) keys)))
@@ -664,6 +689,7 @@ it will filter them appropriately."
         (values output-truename warnings-p failure-p))))
 
   (defun load* (x &rest keys &key &allow-other-keys)
+    "Portable wrapper around LOAD that properly handles loading from a stream."
     (etypecase x
       ((or pathname string #-(or allegro clozure gcl2.6 genera) stream)
        (apply 'load x
@@ -686,6 +712,7 @@ it will filter them appropriately."
 ;;; Links FASLs together
 (with-upgradability ()
   (defun combine-fasls (inputs output)
+    "Combine a list of FASLs INPUTS into a single FASL OUTPUT"
     #-(or abcl allegro clisp clozure cmu lispworks sbcl scl xcl)
     (error "~A does not support ~S~%inputs ~S~%output  ~S"
            (implementation-type) 'combine-fasls inputs output)
diff --git a/uiop/os.lisp b/uiop/os.lisp
index 84c3180e..20294283 100644
--- a/uiop/os.lisp
+++ b/uiop/os.lisp
@@ -33,25 +33,30 @@ keywords explicitly."
       (t (error "Malformed feature specification ~S" x))))
 
   (defun os-unix-p ()
+    "Is the underlying operating system some Unix variant?"
     (or #+abcl (featurep :unix)
         #+(and (not abcl) (or unix cygwin darwin)) t))
 
   (defun os-macosx-p ()
-    ;; OS-MACOSX is not mutually exclusive with OS-UNIX, in fact the
-    ;;former implies the latter.
+    "Is the underlying operating system MacOS X?"
+    ;; OS-MACOSX is not mutually exclusive with OS-UNIX,
+    ;; in fact the former implies the latter.
     (or
      #+allegro (featurep :macosx)
      #+clisp (featurep :macos)
      (featurep :darwin)))
 
   (defun os-windows-p ()
+    "Is the underlying operating system Microsoft Windows?"
     (or #+abcl (featurep :windows)
         #+(and (not (or abcl unix cygwin darwin)) (or win32 windows mswindows mingw32)) t))
 
   (defun os-genera-p ()
+    "Is the underlying operating system Genera (running on a Symbolics Lisp Machine)?"
     (or #+genera t))
 
   (defun os-oldmac-p ()
+    "Is the underlying operating system an (emulated?) MacOS 9 or earlier?"
     (or #+mcl t))
 
   (defun detect-os ()
@@ -117,6 +122,7 @@ then returning the non-empty string value of the variable"
 
 (with-upgradability ()
   (defun first-feature (feature-sets)
+    "A helper for various feature detection functions"
     (dolist (x feature-sets)
       (multiple-value-bind (short long feature-expr)
           (if (consp x)
@@ -126,15 +132,18 @@ then returning the non-empty string value of the variable"
           (return (values short long))))))
 
   (defun implementation-type ()
+    "The type of Lisp implementation used, as a short UIOP-standardized keyword"
     (first-feature
      '(:abcl (:acl :allegro) (:ccl :clozure) :clisp (:corman :cormanlisp)
        (:cmu :cmucl :cmu) :ecl :gcl
        (:lwpe :lispworks-personal-edition) (:lw :lispworks)
        :mcl :mkcl :sbcl :scl (:smbx :symbolics) :xcl)))
 
-  (defvar *implementation-type* (implementation-type))
+  (defvar *implementation-type* (implementation-type)
+    "The type of Lisp implementation used, as a short UIOP-standardized keyword")
 
   (defun operating-system ()
+    "The operating system of the current host"
     (first-feature
      '(:cygwin (:win :windows :mswindows :win32 :mingw32) ;; try cygwin first!
        (:linux :linux :linux-target) ;; for GCL at least, must appear before :bsd
@@ -143,6 +152,7 @@ then returning the non-empty string value of the variable"
        :genera)))
 
   (defun architecture ()
+    "The CPU architecture of the current host"
     (first-feature
      '((:x64 :x86-64 :x86_64 :x8664-target :amd64 (:and :word-size=64 :pc386))
        (:x86 :x86 :i386 :i486 :i586 :i686 :pentium3 :pentium4 :pc386 :iapx386 :x8632-target)
@@ -163,6 +173,7 @@ then returning the non-empty string value of the variable"
         (error "Can't determine fasl version.")))
 
   (defun lisp-version-string ()
+    "return a string that identifies the current Lisp implementation version"
     (let ((s (lisp-implementation-version)))
       (car ; as opposed to OR, this idiom prevents some unreachable code warning
        (list
@@ -213,6 +224,7 @@ suitable for use as a directory name to segregate Lisp FASLs, C dynamic librarie
 
 (with-upgradability ()
   (defun hostname ()
+    "return the hostname of the current host"
     ;; Note: untested on RMCL
     #+(or abcl clozure cmu ecl genera lispworks mcl mkcl sbcl scl xcl) (machine-instance)
     #+cormanlisp "localhost" ;; is there a better way? Does it matter?
@@ -226,6 +238,7 @@ suitable for use as a directory name to segregate Lisp FASLs, C dynamic librarie
 
   #+cmu
   (defun parse-unix-namestring* (unix-namestring)
+    "variant of LISP::PARSE-UNIX-NAMESTRING that returns a pathname object"
     (multiple-value-bind (host device directory name type version)
         (lisp::parse-unix-namestring unix-namestring 0 (length unix-namestring))
       (make-pathname :host (or host lisp::*unix-host*) :device device
@@ -275,22 +288,27 @@ suitable for use as a directory name to segregate Lisp FASLs, C dynamic librarie
 ;;;; Jesse Hager: The Windows Shortcut File Format.
 ;;;; http://www.wotsit.org/list.asp?fc=13
 
-#-(or clisp genera) ; CLISP doesn't need it, and READ-SEQUENCE annoys old Genera.
+#-(or clisp genera) ; CLISP doesn't need it, and READ-SEQUENCE annoys old Genera that doesn't need it
 (with-upgradability ()
   (defparameter *link-initial-dword* 76)
   (defparameter *link-guid* #(1 20 2 0 0 0 0 0 192 0 0 0 0 0 0 70))
 
   (defun read-null-terminated-string (s)
+    "Read a null-terminated string from an octet stream S"
+    ;; note: doesn't play well with UNICODE
     (with-output-to-string (out)
       (loop :for code = (read-byte s)
             :until (zerop code)
             :do (write-char (code-char code) out))))
 
   (defun read-little-endian (s &optional (bytes 4))
+    "Read a number in little-endian format from an byte (octet) stream S,
+the number having BYTES octets (defaulting to 4)."
     (loop :for i :from 0 :below bytes
           :sum (ash (read-byte s) (* 8 i))))
 
   (defun parse-file-location-info (s)
+    "helper to parse-windows-shortcut"
     (let ((start (file-position s))
           (total-length (read-little-endian s))
           (end-of-header (read-little-endian s))
@@ -314,6 +332,8 @@ suitable for use as a directory name to segregate Lisp FASLs, C dynamic librarie
                   (read-null-terminated-string s))))))
 
   (defun parse-windows-shortcut (pathname)
+    "From a .lnk windows shortcut, extract the pathname linked to"
+    ;; NB: doesn't do much checking & doesn't look like it will work well with UNICODE.
     (with-open-file (s pathname :element-type '(unsigned-byte 8))
       (handler-case
           (when (and (= (read-little-endian s) *link-initial-dword*)
diff --git a/uiop/pathname.lisp b/uiop/pathname.lisp
index 963b6f74..17971d17 100644
--- a/uiop/pathname.lisp
+++ b/uiop/pathname.lisp
@@ -44,7 +44,9 @@
 
 (with-upgradability ()
   (defun normalize-pathname-directory-component (directory)
-    "Given a pathname directory component, return an equivalent form that is a list"
+    "Convert the DIRECTORY component from a format usable by the underlying
+implementation's MAKE-PATHNAME and other primitives to a CLHS-standard format
+that is a list and not a string."
     #+gcl2.6 (setf directory (substitute :back :parent directory))
     (cond
       #-(or cmu sbcl scl) ;; these implementations already normalize directory components.
@@ -62,6 +64,8 @@
        (error (compatfmt "~@<Unrecognized pathname directory component ~S~@:>") directory))))
 
   (defun denormalize-pathname-directory-component (directory-component)
+    "Convert the DIRECTORY-COMPONENT from a CLHS-standard format to a format usable
+by the underlying implementation's MAKE-PATHNAME and other primitives"
     #-gcl2.6 directory-component
     #+gcl2.6
     (let ((d (substitute-if :parent (lambda (x) (member x '(:up :back)))
@@ -72,7 +76,7 @@
         (t d))))
 
   (defun merge-pathname-directory-components (specified defaults)
-    ;; Helper for merge-pathnames* that handles directory components.
+    "Helper for MERGE-PATHNAMES* that handles directory components"
     (let ((directory (normalize-pathname-directory-component specified)))
       (ecase (first directory)
         ((nil) defaults)
@@ -99,7 +103,8 @@
   ;; This will be :unspecific if supported, or NIL if not.
   (defparameter *unspecific-pathname-type*
     #+(or abcl allegro clozure cmu gcl genera lispworks mkcl sbcl scl xcl) :unspecific
-    #+(or clisp ecl #|These haven't been tested:|# cormanlisp mcl) nil)
+    #+(or clisp ecl #|These haven't been tested:|# cormanlisp mcl) nil
+    "Unspecific type component to use with the underlying implementation's MAKE-PATHNAME")
 
   (defun make-pathname* (&rest keys &key (directory nil #+gcl2.6 directoryp)
                                       host (device () #+allegro devicep) name type version defaults
@@ -140,11 +145,11 @@ and make a new pathname with corresponding components and specified logical HOST
 if the SPECIFIED pathname does not have an absolute directory,
 then the HOST and DEVICE both come from the DEFAULTS, whereas
 if the SPECIFIED pathname does have an absolute directory,
-then the HOST and DEVICE both come from the SPECIFIED.
+then the HOST and DEVICE both come from the SPECIFIED pathname.
 This is what users want on a modern Unix or Windows operating system,
-unlike the MERGE-PATHNAME behavior.
+unlike the MERGE-PATHNAMES behavior.
 Also, if either argument is NIL, then the other argument is returned unmodified;
-this is unlike MERGE-PATHNAME which always merges with a pathname,
+this is unlike MERGE-PATHNAMES which always merges with a pathname,
 by default *DEFAULT-PATHNAME-DEFAULTS*, which cannot be NIL."
     (when (null specified) (return-from merge-pathnames* defaults))
     (when (null defaults) (return-from merge-pathnames* specified))
@@ -178,7 +183,7 @@ by default *DEFAULT-PATHNAME-DEFAULTS*, which cannot be NIL."
 
   (defun nil-pathname (&optional (defaults *default-pathname-defaults*))
     "A pathname that is as neutral as possible for use as defaults
-   when merging, making or parsing pathnames"
+when merging, making or parsing pathnames"
     ;; 19.2.2.2.1 says a NIL host can mean a default host;
     ;; see also "valid physical pathname host" in the CLHS glossary, that suggests
     ;; strings and lists of strings or :unspecific
@@ -192,15 +197,20 @@ by default *DEFAULT-PATHNAME-DEFAULTS*, which cannot be NIL."
                        ;; the default shouldn't matter, but we really want something physical
                        #-mcl ,@'(:defaults defaults)))
 
-  (defvar *nil-pathname* (nil-pathname (translate-logical-pathname (user-homedir-pathname))))
+  (defvar *nil-pathname* (nil-pathname (translate-logical-pathname (user-homedir-pathname)))
+    "A pathname that is as neutral as possible for use as defaults
+when merging, making or parsing pathnames")
 
   (defmacro with-pathname-defaults ((&optional defaults) &body body)
+    "Execute BODY in a context where the *DEFAULT-PATHNAME-DEFAULTS* are as neutral as possible
+when merging, making or parsing pathnames"
     `(let ((*default-pathname-defaults* ,(or defaults '*nil-pathname*))) ,@body)))
 
 
 ;;; Some pathname predicates
 (with-upgradability ()
   (defun pathname-equal (p1 p2)
+    "Are the two pathnames P1 and P2 reasonably equal in the paths they denote?"
     (when (stringp p1) (setf p1 (pathname p1)))
     (when (stringp p2) (setf p2 (pathname p2)))
     (flet ((normalize-component (x)
@@ -221,9 +231,11 @@ by default *DEFAULT-PATHNAME-DEFAULTS*, which cannot be NIL."
                       (=? pathname-version)))))))
 
   (defun logical-pathname-p (x)
+    "is X a logical-pathname?"
     (typep x 'logical-pathname))
 
   (defun physical-pathname-p (x)
+    "is X a pathname that is not a logical-pathname?"
     (and (pathnamep x) (not (logical-pathname-p x))))
 
   (defun absolute-pathname-p (pathspec)
@@ -522,6 +534,7 @@ then it is merged with the PATHNAME-DIRECTORY-PATHNAME of PATHNAME."
          (subpathname (ensure-directory-pathname pathname) subpath :type type)))
 
   (defun pathname-root (pathname)
+    "return the root directory for the host and device of given PATHNAME"
     (make-pathname* :directory '(:absolute)
                     :name nil :type nil :version nil
                     :defaults pathname ;; host device, and on scl, *some*
@@ -529,6 +542,7 @@ then it is merged with the PATHNAME-DIRECTORY-PATHNAME of PATHNAME."
                     . #.(or #+scl '(:parameters nil :query nil :fragment nil))))
 
   (defun pathname-host-pathname (pathname)
+    "return a pathname with the same host as given PATHNAME, and all other fields NIL"
     (make-pathname* :directory nil
                     :name nil :type nil :version nil :device nil
                     :defaults pathname ;; host device, and on scl, *some*
@@ -536,6 +550,8 @@ then it is merged with the PATHNAME-DIRECTORY-PATHNAME of PATHNAME."
                     . #.(or #+scl '(:parameters nil :query nil :fragment nil))))
 
   (defun subpathp (maybe-subpath base-pathname)
+    "if MAYBE-SUBPATH is a pathname that is under BASE-PATHNAME, return a pathname object that
+when used with MERGE-PATHNAMES* with defaults BASE-PATHNAME, returns MAYBE-SUBPATH."
     (and (pathnamep maybe-subpath) (pathnamep base-pathname)
          (absolute-pathname-p maybe-subpath) (absolute-pathname-p base-pathname)
          (directory-pathname-p base-pathname) (not (wild-pathname-p base-pathname))
@@ -545,6 +561,9 @@ then it is merged with the PATHNAME-DIRECTORY-PATHNAME of PATHNAME."
              (and (relative-pathname-p enough) (pathname enough))))))
 
   (defun ensure-absolute-pathname (path &optional defaults (on-error 'error))
+    "Given a pathname designator PATH, return an absolute pathname as specified by PATH
+considering the DEFAULTS, or, if not possible, use CALL-FUNCTION on the specified ON-ERROR behavior,
+with a format control-string and other arguments as arguments"
     (cond
       ((absolute-pathname-p path))
       ((stringp path) (ensure-absolute-pathname (pathname path) defaults on-error))
@@ -563,28 +582,37 @@ then it is merged with the PATHNAME-DIRECTORY-PATHNAME of PATHNAME."
 
 ;;; Wildcard pathnames
 (with-upgradability ()
-  (defparameter *wild* (or #+cormanlisp "*" :wild))
-  (defparameter *wild-directory-component* (or #+gcl2.6 "*" :wild))
-  (defparameter *wild-inferiors-component* (or #+gcl2.6 "**" :wild-inferiors))
+  (defparameter *wild* (or #+cormanlisp "*" :wild)
+    "Wild component for use with MAKE-PATHNAME")
+  (defparameter *wild-directory-component* (or #+gcl2.6 "*" :wild)
+    "Wild directory component for use with MAKE-PATHNAME")
+  (defparameter *wild-inferiors-component* (or #+gcl2.6 "**" :wild-inferiors)
+    "Wild-inferiors directory component for use with MAKE-PATHNAME")
   (defparameter *wild-file*
     (make-pathname :directory nil :name *wild* :type *wild*
-                   :version (or #-(or allegro abcl xcl) *wild*)))
+                   :version (or #-(or allegro abcl xcl) *wild*))
+    "A pathname object with wildcards for matching any file in a given directory")
   (defparameter *wild-directory*
     (make-pathname* :directory `(:relative ,*wild-directory-component*)
-                    :name nil :type nil :version nil))
+                    :name nil :type nil :version nil)
+    "A pathname object with wildcards for matching any subdirectory")
   (defparameter *wild-inferiors*
     (make-pathname* :directory `(:relative ,*wild-inferiors-component*)
-                    :name nil :type nil :version nil))
+                    :name nil :type nil :version nil)
+    "A pathname object with wildcards for matching any recursive subdirectory")
   (defparameter *wild-path*
-    (merge-pathnames* *wild-file* *wild-inferiors*))
+    (merge-pathnames* *wild-file* *wild-inferiors*)
+    "A pathname object with wildcards for matching any file in any recursive subdirectory")
 
   (defun wilden (path)
+    "From a pathname, return a wildcard pathname matching any file in any subdirectory of given pathname's directory"
     (merge-pathnames* *wild-path* path)))
 
 
 ;;; Translate a pathname
 (with-upgradability ()
   (defun relativize-directory-component (directory-component)
+    "Given the DIRECTORY-COMPONENT of a pathname, return an otherwise similar relative directory component"
     (let ((directory (normalize-pathname-directory-component directory-component)))
       (cond
         ((stringp directory)
@@ -595,17 +623,21 @@ then it is merged with the PATHNAME-DIRECTORY-PATHNAME of PATHNAME."
          directory))))
 
   (defun relativize-pathname-directory (pathspec)
+    "Given a PATHNAME, return a relative pathname with otherwise the same components"
     (let ((p (pathname pathspec)))
       (make-pathname*
        :directory (relativize-directory-component (pathname-directory p))
        :defaults p)))
 
   (defun directory-separator-for-host (&optional (pathname *default-pathname-defaults*))
+    "Given a PATHNAME, return the character used to delimit directory names on this host and device."
     (let ((foo (make-pathname* :directory '(:absolute "FOO") :defaults pathname)))
       (last-char (namestring foo))))
 
   #-scl
   (defun directorize-pathname-host-device (pathname)
+    "Given a PATHNAME, return a pathname that has representations of its HOST and DEVICE components
+added to its DIRECTORY component. This is useful for output translations."
     #+(or unix abcl)
     (when (and #+abcl (os-unix-p) (physical-pathname-p pathname))
       (return-from directorize-pathname-host-device pathname))
@@ -650,6 +682,13 @@ then it is merged with the PATHNAME-DIRECTORY-PATHNAME of PATHNAME."
         pathname)))
 
   (defun* (translate-pathname*) (path absolute-source destination &optional root source)
+    "A wrapper around TRANSLATE-PATHNAME to be used by the ASDF output-translations facility.
+PATH is the pathname to be translated.
+ABSOLUTE-SOURCE is an absolute pathname to use as source for translate-pathname,
+DESTINATION is either a function, to be called with PATH and ABSOLUTE-SOURCE,
+or a relative pathname, to be merged with ROOT and used as destination for translate-pathname
+or an absolute pathname, to be used as destination for translate-pathname.
+In that last case, if ROOT is non-NIL, PATH is first transformated by DIRECTORIZE-PATHNAME-HOST-DEVICE."
     (declare (ignore source))
     (cond
       ((functionp destination)
diff --git a/uiop/run-program.lisp b/uiop/run-program.lisp
index 37f20116..b75ed11f 100644
--- a/uiop/run-program.lisp
+++ b/uiop/run-program.lisp
@@ -92,6 +92,7 @@ omit the outer double-quotes if key argument :QUOTE is NIL"
     (when quote (princ #\" s)))
 
   (defun easy-sh-character-p (x)
+    "Is X an \"easy\" character that does not require quoting by the shell?"
     (or (alphanumericp x) (find x "+-_.,%@:/")))
 
   (defun escape-sh-token (token &optional s)
@@ -101,6 +102,7 @@ for use within a POSIX Bourne shell, outputing to S."
                         :escaper 'escape-sh-token-within-double-quotes))
 
   (defun escape-shell-token (token &optional s)
+    "Escape a token for the current operating system shell"
     (cond
       ((os-unix-p) (escape-sh-token token s))
       ((os-windows-p) (escape-windows-token token s))))
@@ -136,6 +138,10 @@ by /bin/sh in POSIX"
 ;;;; Slurping a stream, typically the output of another program
 (with-upgradability ()
   (defun call-stream-processor (fun processor stream)
+    "Given FUN (typically SLURP-INPUT-STREAM or VOMIT-OUTPUT-STREAM,
+a PROCESSOR specification which is either an atom or a list specifying
+a processor an keyword arguments, call the specified processor with
+the given STREAM as input"
     (if (consp processor)
         (apply fun (first processor) stream (rest processor))
         (funcall fun processor stream)))
@@ -664,6 +670,7 @@ It returns a process-info plist with possible keys:
 
   (defun %use-run-program (command &rest keys
                            &key input output error-output ignore-error-status &allow-other-keys)
+    ;; helper for RUN-PROGRAM when using %run-program
     #+(or abcl cormanlisp gcl (and lispworks os-windows) mcl mkcl xcl)
     (error "Not implemented on this platform")
     (assert (not (member :stream (list input output error-output))))
@@ -716,13 +723,13 @@ It returns a process-info plist with possible keys:
                                        :ignore-error-status ignore-error-status))))))))
       (values output-result error-output-result exit-code)))
 
-  (defun %normalize-system-command (command)
+  (defun %normalize-system-command (command) ;; helper for %USE-SYSTEM
     (etypecase command
       (string command)
       (list (escape-shell-command
              (if (os-unix-p) (cons "exec" command) command)))))
 
-  (defun %redirected-system-command (command in out err directory)
+  (defun %redirected-system-command (command in out err directory) ;; helper for %USE-SYSTEM
     (flet ((redirect (spec operator)
              (let ((pathname
                      (typecase spec
@@ -776,6 +783,7 @@ It returns a process-info plist with possible keys:
 
   (defun %use-system (command &rest keys
                       &key input output error-output ignore-error-status &allow-other-keys)
+    ;; helper for RUN-PROGRAM when using %system
     (let (output-result error-output-result exit-code)
       (with-program-output ((reduced-output)
                             output :keys keys :setf output-result)
-- 
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