From 4abffc416e2bc48547e7b8753643abce063dc729 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Wed, 8 Mar 2017 19:54:35 -0800
Subject: Drop the annoying need for - for standard input.

* match.c (open_data_source): If there is nothing
in the files array and data is t (indicating a request
to open a data source), then use standard input.
Subject to the compatibility option.

* Makefile (txr-manpage.html): Drop use of
the txr - argument in rule recipe.

* txr.1: Document that - isn't necessary.
Added to compatibility notes.
---
 Makefile |  2 +-
 match.c  | 10 +++++++++-
 txr.1    | 18 ++++++++++++++++++
 3 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index 1024cf04..deef23f8 100644
--- a/Makefile
+++ b/Makefile
@@ -443,7 +443,7 @@ install-tests:
 # Generate web page from man page
 #
 txr-manpage.html: txr.1 genman.txr
-	man2html $< | $(TXR) genman.txr - > $@
+	man2html $< | $(TXR) genman.txr > $@
 
 txr-manpage.pdf: txr.1 checkman.txr
 	$(TXR) checkman.txr $<
diff --git a/match.c b/match.c
index ef758580..f183c509 100644
--- a/match.c
+++ b/match.c
@@ -4427,7 +4427,15 @@ static void open_data_source(match_files_ctx *c)
       c->data = nil;
     }
   } else if (c->data == t && c->files == nil) {
-    c->data = nil;
+    if (opt_compat && opt_compat <= 170) {
+      c->data = nil;
+    } else {
+      spec_bind (specline, first_spec, c->spec);
+      debuglf(first_spec, lit("opening standard input as data source"), nao);
+      c->curfile = lit("-");
+      c->data = lazy_stream_cons(std_input);
+      c->data_lineno = one;
+    }
   }
 }
 
diff --git a/txr.1 b/txr.1
index 02961abe..e1894f19 100644
--- a/txr.1
+++ b/txr.1
@@ -864,6 +864,12 @@ or one of the related options.  A file argument consisting of a single
 .code -
 means to read the standard input instead of opening a file.
 
+Specifying standard input as a source with an explicit
+.code -
+argument is unnecessary. If no data source arguments are present, then
+\*(TX scans standard input by default. This was not true in versions of \*(TX
+prior to 171; see the COMPATIBILITY section.
+
 .PP
 \*(TX begins by reading the script. In the case of the \*(TX pattern language,
 the entire query is scanned, internalized and then begins executing, if it is
@@ -52657,6 +52663,18 @@ of these version values, the described behaviors are provided if
 is given an argument which is equal or lower. For instance
 .code "-C 103"
 selects the behaviors described below for version 105, but not those for 102.
+.IP 170
+A value of 170 or lower disables the behavior that \*(TX scans standard input
+when no input sources are specified on the command line. Standard input must
+be requested explicitly using the
+.code -
+argument. This is how it was in all versions of \*(TX up to 170.
+Some programs may behave differently because of this. Specifically, programs
+which do not take any arguments, and do not select an input source using the
+.code @(next)
+directive, or suppress the use of an input source using
+.codn "@(next nil)" ,
+may now accidentally read from standard input.
 .IP 165
 A value of 165 restores the following behaviors, which changed starting in 166.
 There was a in Lisp evaluation support of the \*(TX pattern language.
-- 
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