From f5865550be77b5346adcea1a31c8d329f6b8a184 Mon Sep 17 00:00:00 2001
From: Jean Privat <jean@pryen.org>
Date: Wed, 1 Oct 2014 09:07:08 -0400
Subject: [PATCH] niti: add -n to run the program for each line in file-name
 arguments

Signed-off-by: Jean Privat <jean@pryen.org>
---
 lib/niti_runtime.nit |   53 ++++++++++++++++++++++++++++++++++++++++++++++++++
 src/nit.nit          |   11 ++++++++++-
 2 files changed, 63 insertions(+), 1 deletion(-)
 create mode 100644 lib/niti_runtime.nit

diff --git a/lib/niti_runtime.nit b/lib/niti_runtime.nit
new file mode 100644
index 0000000..a618fba
--- /dev/null
+++ b/lib/niti_runtime.nit
@@ -0,0 +1,53 @@
+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# This file is free software, which comes along with NIT.  This software is
+# distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+# without  even  the implied warranty of  MERCHANTABILITY or  FITNESS FOR A
+# PARTICULAR PURPOSE.  You can modify it is you want,  provided this header
+# is kept unaltered, and a notification of the changes is added.
+# You  are  allowed  to  redistribute it and sell it, alone or is a part of
+# another product.
+
+# Runtime library to loop around the main program for each line in file-name arguments
+#
+# Used by the interpreter when `-n` is used
+module niti_runtime
+
+redef class Sys
+	redef fun run do
+		if not args.is_empty then
+			open_next_stream
+		end
+		loop
+			read_next_line
+			main
+		end
+	end
+
+	# Read the next useful line from file-name arguments
+	private fun read_next_line
+	do
+		if stdin.eof then
+			open_next_stream
+		end
+		var line = stdin.read_line
+		loop
+			if not stdin.eof then break
+			open_next_stream
+			if not line.is_empty then break
+			line = stdin.read_line
+		end
+		self.line = line
+	end
+
+	# Open the next file until there is no more arguments
+	private fun open_next_stream
+	do
+		if args.is_empty then exit(0)
+		stdin.close
+		stdin = new IFStream.open(args.shift)
+	end
+
+	# The next line to process by the main program
+	var line: String
+end
diff --git a/src/nit.nit b/src/nit.nit
index 7ed1528..24bb00e 100644
--- a/src/nit.nit
+++ b/src/nit.nit
@@ -29,7 +29,8 @@ var opt = new OptionString("compatibility (does noting)", "-o")
 toolcontext.option_context.add_option(opt)
 var opt_mixins = new OptionArray("Additionals module to min-in", "-m")
 var opt_eval = new OptionBool("Specifies the program from command-line", "-e")
-toolcontext.option_context.add_option(opt_mixins, opt_eval)
+var opt_loop = new OptionBool("Repeatedly run the program for each line in file-name arguments", "-n")
+toolcontext.option_context.add_option(opt_mixins, opt_eval, opt_loop)
 # We do not add other options, so process them now!
 toolcontext.process_options(args)
 
@@ -49,6 +50,14 @@ if opt_eval.value then
 	toolcontext.check_errors
 
 	var parent = null
+	if opt_loop.value then
+		var nruntime = modelbuilder.load_module("niti_runtime")
+		if nruntime == null then
+			toolcontext.check_errors
+			abort
+		end
+		parent = nruntime.mmodule
+	end
 
 	modelbuilder.load_rt_module(parent, amodule, "-")
 
-- 
1.7.9.5