# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1486751466 -3600
# Node ID 37cb73adc7c209b7f52b06e9c1d4522e3529144a
# Parent  6d14963cce30db5ce642dd04d9368c2802a9ed69
Added module search path configuration using LICHENPATH and related options.
Added extra convenience options for help and version text viewing.

diff -r 6d14963cce30 -r 37cb73adc7c2 docs/lplc.1
--- a/docs/lplc.1	Fri Feb 10 17:52:47 2017 +0100
+++ b/docs/lplc.1	Fri Feb 10 19:31:06 2017 +0100
@@ -12,8 +12,14 @@
 .B lplc
 .I --version
 .SH DESCRIPTION
-Compile the program whose principal file is given in place of
-.IR file .
+.B lplc
+compiles programs written in the Lichen language, taking the indicated
+.I file
+representing the principal source file of a program, compiling the program to an
+intermediate representation, and then building the result using a C compiler and
+.B make
+to produce an executable. Other source files need not be specified: they will be
+identified by the compiler and loaded as required.
 .SH OPTIONS
 The following options may be specified:
 .PP
@@ -21,9 +27,15 @@
 .B \-c
 Only partially compile the program; do not attempt to build or link it
 .TP
+.B \-E
+Ignore environment variables affecting the module search path
+.TP
 .B \-g
 Generate debugging information for the built executable
 .TP
+.B \-P
+Show the module search path
+.TP
 .B \-q
 Silence messages produced when building an executable
 .TP
@@ -62,11 +74,31 @@
 of compiling a program:
 .PP
 .TP
-.B \-\-help
+.BR \-h ", " \-? ", " \-\-help
 Show a summary of the command syntax and options
 .TP
-.B \-\-version
+.BR \-V ", " \-\-version
 Show version information for this tool
+.SH ENVIRONMENT VARIABLES
+.TP
+ARCH
+Indicates a prefix to be used with tool names when building an executable. This
+permits things like cross-compilation where tools have been provided with names
+featuring architecture- and system-specific prefixes. For example,
+.I mipsel-linux-gnu
+may be used to indicate the use of tools for the MIPS architecture running
+GNU/Linux in little-endian mode.
+.TP
+LICHENPATH
+A collection of directories that are searched before those in the collection
+comprising the default "module search path". This collection, if already defined
+in the environment, may be excluded by specifying the
+.B \-E
+option.
+.SH AUTHOR
+Paul Boddie <paul@boddie.org.uk>
+.SH RESOURCES
+The project Web site: http://projects.boddie.org.uk/Lichen
 .SH COPYRIGHT
 Copyright \(co 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013,
 2014, 2015, 2016, 2017 Paul Boddie <paul@boddie.org.uk>
@@ -77,5 +109,3 @@
 .SH SEE ALSO
 .BR cc (1),
 .BR make (1).
-.SH RESOURCES
-The project Web site: http://projects.boddie.org.uk/Lichen
diff -r 6d14963cce30 -r 37cb73adc7c2 lplc
--- a/lplc	Fri Feb 10 17:52:47 2017 +0100
+++ b/lplc	Fri Feb 10 19:31:06 2017 +0100
@@ -22,7 +22,7 @@
 VERSION = "0.1"
 
 from errors import *
-from os import rename
+from os import environ, rename
 from os.path import abspath, exists, isfile, join, split
 from pyparser import error
 from subprocess import Popen, PIPE
@@ -32,6 +32,7 @@
 
 libdirs = [
     join(split(__file__)[0], "lib"),
+    split(__file__)[0],
     "/usr/share/lichen/lib"
     ]
 
@@ -90,7 +91,7 @@
 
     # Show help text if requested or if no arguments are given.
 
-    if "--help" in args or not args:
+    if "--help" in args or "-h" in args or "-?" in args or not args:
         print >>sys.stderr, """\
 Usage: %s [ <options> ] <filename>
 
@@ -98,7 +99,9 @@
 The following options may be specified:
 
 -c   Only partially compile the program; do not attempt to build or link it
+-E   Ignore environment variables affecting the module search path
 -g   Generate debugging information for the built executable
+-P   Show the module search path
 -q   Silence messages produced when building an executable
 -r   Reset (discard) cached program information; inspect the whole program again
 -t   Silence timing messages
@@ -122,13 +125,16 @@
 of compiling a program:
 
 --help      Show a summary of the command syntax and options
+-h          Equivalent to --help
+-?          Equivalent to --help
 --version   Show version information for this tool
+-V          Equivalent to --version
 """ % basename
         sys.exit(1)
 
     # Show the version information if requested.
 
-    elif "--version" in args:
+    elif "--version" in args or "-V" in args:
         print >>sys.stderr, """\
 lplc %s
 Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013,
@@ -142,6 +148,7 @@
     # Determine the options and arguments.
 
     debug = False
+    ignore_env = False
     make = True
     make_verbose = True
     reset = False
@@ -160,6 +167,7 @@
 
     for arg in args:
         if arg == "-c": make = False
+        elif arg == "-E": ignore_env = True
         elif arg == "-g": debug = True
         elif arg == "-q": make_verbose = False
         elif arg == "-r": reset = True
@@ -176,6 +184,20 @@
         if needed == 0:
             l = filenames
 
+    # Add extra components to the module search path from the environment.
+
+    if not ignore_env:
+        extra = environ.get("LICHENPATH")
+        if extra:
+            libdirs = extra.split(":") + libdirs
+
+    # Show the module search path if requested.
+
+    if "-P" in args:
+        for libdir in libdirs:
+            print libdir
+        sys.exit(0)
+
     # Obtain the program filename.
 
     if len(filenames) != 1: