add irep and lua-lang virtual dependency (#22492)

This adds a package for `irep`, a tool for reading `lua` input decks from 
Fortran, C, and C++.

`irep` can be built with either `lua` or `luajit`.  To address this, we also add
a virtual package for lua called `lua-lang`.  `luajit` isn't, by default, a drop-in
replacement for `lua`, but we add a `+lualinks` variant to it that adds symlinks
that make it behave like `lua@5.1`.  With this variant enabled, it provides the
`lua-lang` virtual.  `lua` always provides `lua-lang`.

- [x] add `irep` package
- [x] add `+lualinks` variant to `lua-luajit`
- [x] create `lua-lang` virtual, provided by `lua` and `luajit+lualinks`

Co-authored-by: Kayla Richarda Butler <butler59@quartz1148.llnl.gov>
Co-authored-by: Todd Gamblin <tgamblin@llnl.gov>

etc/spack/defaults/packages.yaml

@@ -34,6 +34,7 @@ packages:
       java: [openjdk, jdk, ibm-java]
       jpeg: [libjpeg-turbo, libjpeg]
       lapack: [openblas, amdlibflame]
+      lua-lang: [lua, lua-luajit]
       mariadb-client: [mariadb-c-client, mariadb]
       mkl: [intel-mkl]
       mpe: [mpe2]

var/spack/repos/builtin/packages/irep/package.py

@@ -0,0 +1,18 @@
+# Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+class Irep(CMakePackage):
+    """IREP is a tool that enables mixed-language simulation codes to use a
+    common, Lua-based format for their input decks. Essentially, the input
+    format is a set of tables -- Lua's one (and only?) data structure."""
+
+    homepage = "https://irep.readthedocs.io/"
+    url      = "https://github.com/LLNL/irep/archive/refs/tags/v1.0.0.tar.gz"
+
+    maintainers = ['tomstitt', 'kennyweiss']
+
+    version('1.0.0', 'b84203ac92de824dbdc672de45cfdb9609373791c4ee84a5201fa6e4ccecc1a4')
+
+    depends_on('lua-lang')

var/spack/repos/builtin/packages/lua-luajit/package.py

@@ -3,6 +3,7 @@
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
+import glob
 import os
 from spack import *
 
@@ -18,6 +19,34 @@ class LuaLuajit(MakefilePackage):
 
     conflicts('@:2.0.5', when='target=aarch64:')
 
+    variant('lualinks', default=False, description="add symlinks to make lua-luajit a drop-in lua replacement")
+
+    provides("lua-lang", when="+lualinks")
+
+    @run_after("install")
+    def install_links(self):
+        if not self.spec.satisfies("+lualinks"):
+            return
+
+        with working_dir(self.prefix.bin):
+            luajit = os.readlink(self.prefix.bin.luajit)
+            symlink(luajit, "lua")
+
+        with working_dir(self.prefix.include):
+            luajit_include_subdirs = glob.glob(
+                os.path.join(self.prefix.include, "luajit*"))
+            assert len(luajit_include_subdirs) == 1
+            symlink(luajit_include_subdirs[0], "lua")
+
+        with working_dir(self.prefix.lib):
+            luajit_libnames = glob.glob(
+                os.path.join(self.prefix.lib, "libluajit*.so*"))
+            real_lib = next(
+                lib for lib in luajit_libnames
+                if os.path.isfile(lib) and not os.path.islink(lib)
+            )
+            symlink(real_lib, "liblua.so")
+
     @property
     def headers(self):
         hdrs = find_headers('luajit', self.prefix.include, recursive=True)

var/spack/repos/builtin/packages/lua/package.py

@@ -34,6 +34,8 @@ class Lua(Package):
 
     extendable = True
 
+    provides('lua-lang')
+
     depends_on('ncurses+termlib')
     depends_on('readline')
     # luarocks needs unzip for some packages (e.g. lua-luaposix)