Add defpackage macro.

* lisplib.c (package_set_entries, package_instantiate): New
static functions.
(lisplib_init): Register auto-loading for new package.tl
file using new functions.

* share/txr/stdlib/package.tl: New file.

* txr.1: Documented.

3 files changed, 152 insertions, 0 deletions

diff --git a/lisplib.c b/lisplib.c
index 97cdedb9..06178383 100644
--- a/lisplib.c
+++ b/lisplib.c
@@ -407,6 +407,24 @@ static val getopts_instantiate(val set_fun)
   return nil;
 }
 
+static val package_set_entries(val dlt, val fun)
+{
+  val name[] = {
+    lit("defpackage"),
+    nil
+  };
+  set_dlt_entries(dlt, name, fun);
+  return nil;
+}
+
+static val package_instantiate(val set_fun)
+{
+  funcall1(set_fun, nil);
+  load(format(nil, lit("~apackage.tl"), stdlib_path, nao));
+  return nil;
+}
+
+
 val dlt_register(val dlt,
                  val (*instantiate)(val),
                  val (*set_entries)(val, val))
@@ -440,6 +458,7 @@ void lisplib_init(void)
   dlt_register(dl_table, build_instantiate, build_set_entries);
   dlt_register(dl_table, trace_instantiate, trace_set_entries);
   dlt_register(dl_table, getopts_instantiate, getopts_set_entries);
+  dlt_register(dl_table, package_instantiate, package_set_entries);
 }
 
 val lisplib_try_load(val sym)
diff --git a/share/txr/stdlib/package.tl b/share/txr/stdlib/package.tl
new file mode 100644
index 00000000..4c423145
--- /dev/null
+++ b/share/txr/stdlib/package.tl
@@ -0,0 +1,61 @@
+;; Copyright 2016
+;; Kaz Kylheku <kaz@kylheku.com>
+;; Vancouver, Canada
+;; All rights reserved.
+;;
+;; Redistribution and use in source and binary forms, with or without
+;; modification, are permitted provided that the following conditions are met:
+;;
+;; 1. Redistributions of source code must retain the above copyright notice, this
+;;    list of conditions and the following disclaimer.
+;;
+;; 2. Redistributions in binary form must reproduce the above copyright notice,
+;;    this list of conditions and the following disclaimer in the documentation
+;;    and/or other materials provided with the distribution.
+;;
+;; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+;; ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+;; WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+;; DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+;; FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+;; DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+;; SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+;; CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+;; OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+;; OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+(macro-time
+  (defun sys:name-str (kind sym-or-string)
+    (cond
+      ((symbolp sym-or-string) (symbol-name sym-or-string))
+      ((stringp sym-or-string) sym-or-string)
+      (t (throw 'eval-error "~s: ~s isn't a valid ~a name"
+                'defpackage sym-or-string kind)))))
+
+(defmacro defpackage (name . clauses)
+  (let* ((pkg (gensym "pkg-"))
+         (name-str (sys:name-str 'package name))
+         (exp-clauses (append-each ((c clauses))
+                        (tree-case c
+                          ((keyword . rest)
+                            (caseql keyword
+                              (:use
+                                (if rest ^((use-package ',rest ,pkg))))
+                              (:use-syms
+                                ^((each ((s ',rest))
+                                    (use-sym s ,pkg))))
+                              (:local
+                                ^((each ((n ',(mapcar (op sys:name-str 'symbol)
+                                                      rest)))
+                                    (let ((s (intern n ,pkg)))
+                                      (unless (eq (symbol-package s) ,pkg)
+                                        (unuse-sym s ,pkg)
+                                        (intern n ,pkg))))))))
+                          (atom
+                            (throwf 'eval-error "~s: invalid clause: ~s"
+                                    'defpackage atom))))))
+    ^(let ((,pkg (or (find-package ,name-str)
+                     (make-package ,name-str))))
+       ,*(unless (assoc :use clauses) ^((use-package "usr" ,pkg)))
+       ,*exp-clauses
+       ,pkg)))
diff --git a/txr.1 b/txr.1
index 0c53c117..39be55b9 100644
--- a/txr.1
+++ b/txr.1
@@ -38955,6 +38955,11 @@ function creates and returns a package named
 where
 .meta name
 is a string. It is an error if a package by that name exists already.
+Note: ordinary creation of packages for everyday program modularization
+should be performed with the
+.code defpackage
+macro rather than by direct use of
+.codn make-package .
 
 .coNP Function @ delete-package
 .synb
@@ -39429,6 +39434,73 @@ of the
 .cble
 expression.
 
+.coNP Macro @ defpackage
+.synb
+.mets (defpackage < name << clause *)
+.syne
+.desc
+The
+.code defpackage
+macro provides a convenient means to create a package and establish its
+properties in a single construct. It is intended for the ordinary situations
+in which packages support the organization of programs into modules.
+
+The
+.code name
+argument, giving the package name, may be a symbol or a character string.
+If it is a symbol, then the symbol's name is taken to be name for the
+package.
+
+If a package called
+.code name
+already exists, then
+.code defpackage
+selects that package for further operations. Otherwise, a new,
+empty package is created.
+
+The
+.code name
+may be optionally followed by one or more clauses, which are processed
+in the order that they appear. Each clause is a compound form headed
+by a keyword. If no
+.code :use
+clauses are present, then an implicit
+.code "(:use \(dqusr\(dq)"
+clause is inserted ahead of all other clauses.
+
+The supported clauses are as follows:
+.RS
+.meIP (:use << package-name *)
+The
+.code :use
+clause specifies packages whose local symbols are to be interned
+into the package as foreign symbols. Each
+.meta package-name
+may be a string or symbol naming an existing package.
+The list of package names is processed as if by a call to
+.codn use-package .
+.meIP (:use-syms << symbol *)
+The
+.code :use-syms
+clause specifies individual symbols to be interned in the new package.
+The arguments are symbols.
+.meIP (:local << symbol-name *)
+The
+.code :local
+clause specifies the names of symbols to be interned in the new package
+as local symbols. Each
+.meta symbol-name
+argument must be either a character string or a symbol. If it is a symbol, its
+name is taken, thereby reducing the argument to a character string.
+The arguments are processed in the order in which they appear. Each name is
+first interned in the newly created package using the
+.code intern
+function. Then, if the resulting symbol is foreign to the package, it is
+removed with
+.code unuse-sym
+and the name is interned again.
+.RE
+
 .SS* Pseudo-random Numbers
 .coNP Special variable @ *random-state*
 .desc