From 71cc1d5902abb8cc005114f28a5cea8d766a4b05 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Mon, 7 Jul 2014 20:29:43 -0700
Subject: * Makefile: install the LICENSE and METALICENSE files into the data
 directory.

* txr.c (help): Help text updated to document --license option.
(license): New function.
(txr_main): Implement --license option.

* unwind.h (uw_catch): Add cast to suppress warning about unused symbol.

* txr.1: Document --license option.
---
 ChangeLog | 13 +++++++++++++
 Makefile  |  2 ++
 txr.1     |  5 +++++
 txr.c     | 39 +++++++++++++++++++++++++++++++++++++++
 unwind.h  |  1 +
 5 files changed, 60 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index a6a1c27c..58abab14 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2014-07-07  Kaz Kylheku  <kaz@kylheku.com>
+
+	* Makefile: install the LICENSE and METALICENSE files into the data
+	directory.
+
+	* txr.c (help): Help text updated to document --license option.
+	(license): New function.
+	(txr_main): Implement --license option.
+
+	* unwind.h (uw_catch): Add cast to suppress warning about unused symbol.
+
+	* txr.1: Document --license option.
+
 2014-07-07  Kaz Kylheku  <kaz@kylheku.com>
 
 	* lib.c (replace_list, sel): fix use of unused variable.
diff --git a/Makefile b/Makefile
index 1dbc87fa..0f5b4d39 100644
--- a/Makefile
+++ b/Makefile
@@ -167,6 +167,8 @@ PREINSTALL := :
 install: $(PROG)
 	$(PREINSTALL)
 	$(call INSTALL,0755,txr$(EXE),$(DESTDIR)$(bindir))
+	$(call INSTALL,0444,$(top_srcdir)/LICENSE,$(DESTDIR)$(datadir))
+	$(call INSTALL,0444,$(top_srcdir)/METALICENSE,$(DESTDIR)$(datadir))
 	$(call INSTALL,0444,$(top_srcdir)/txr.1,$(DESTDIR)$(mandir)/man1)
 	$(call INSTALL,0444,$(top_srcdir)/share/txr/stdlib/*.txr,$(DESTDIR)$(datadir)/stdlib)
 
diff --git a/txr.1 b/txr.1
index ec6174ff..42b01bdc 100644
--- a/txr.1
+++ b/txr.1
@@ -194,6 +194,11 @@ once.
 .IP --help
 Prints usage summary on standard output, and terminates successfully.
 
+.IP --license
+Prints the software license. This depends on the software being
+installed such that the LICENSE file is in the data directory.
+Use of txr implies agreement with the liability disclaimer in the license.
+
 .IP --version
 Prints program version standard output, and terminates successfully.
 
diff --git a/txr.c b/txr.c
index aa3ab885..4d666635 100644
--- a/txr.c
+++ b/txr.c
@@ -121,6 +121,9 @@ static void help(void)
 "                       to the utility.\n"
 "--help                 You already know!\n"
 "--version              Display program version\n"
+"--license              Display software license\n"
+"                       Use of txr implies agreement with the disclaimer\n"
+"                       section at the bottom of the license.\n"
 "--lisp-bindings        Synonym for -l\n"
 "--debugger             Synonym for -d\n"
 "\n"
@@ -240,6 +243,39 @@ static void sysroot_init(void)
           toint(lit(TXR_VER), nil));
 }
 
+static int license(void)
+{
+  int retval = EXIT_SUCCESS;
+
+  uw_catch_begin(cons(error_s, nil), esym, eobj);
+
+  {
+    val path = sysroot(lit("share/txr/LICENSE"));
+    val lic = open_file(path, lit("r"));
+    val line;
+
+    put_char(chr('\n'), std_output);
+
+    while ((line = get_line(lic)))
+      put_line(line, std_output);
+
+    put_char(chr('\n'), std_output);
+
+    close_stream(lic, nil);
+  }
+
+  uw_catch (esym, eobj) {
+    format(std_output, lit("~a:\nThis TXR installation might be unlicensed.\n"), eobj, nao);
+    retval = EXIT_FAILURE;
+  }
+
+  uw_unwind { }
+
+  uw_catch_end;
+
+  return retval;
+}
+
 int txr_main(int argc, char **argv);
 
 int main(int argc, char **argv)
@@ -331,6 +367,9 @@ int txr_main(int argc, char **argv)
       return 0;
     }
 
+    if (equal(arg, lit("--license")))
+      return license();
+
     if (memqual(arg, list(lit("-a"), lit("-c"), lit("-f"),
                           lit("-e"), lit("-p"), nao)))
     {
diff --git a/unwind.h b/unwind.h
index ea92e9b1..4e42eecc 100644
--- a/unwind.h
+++ b/unwind.h
@@ -173,6 +173,7 @@ noreturn val type_mismatch(val, ...);
     case 2:                             \
       EXCVAR = uw_catch.ca.exception;   \
       SYMVAR = uw_catch.ca.sym;         \
+      (void) SYMVAR;                    \
       /* prevent looping */             \
       uw_catch.ca.matches = nil;
 
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