X-Git-Url: http://nitlanguage.org

diff --git a/src/loader.nit b/src/loader.nit
index 3bd8404..56b7058 100644
--- a/src/loader.nit
+++ b/src/loader.nit
@@ -18,6 +18,7 @@
 module loader
 
 import modelbuilder_base
+import ini
 
 redef class ToolContext
 	# Option --path
@@ -50,7 +51,9 @@ redef class ModelBuilder
 		end
 
 		var nit_dir = toolcontext.nit_dir
-		var libname = "{nit_dir}/lib"
+		var libname = nit_dir/"lib"
+		if libname.file_exists then paths.add(libname)
+		libname = nit_dir/"contrib"
 		if libname.file_exists then paths.add(libname)
 	end
 
@@ -70,10 +73,9 @@ redef class ModelBuilder
 		for a in modules do
 			var nmodule = self.load_module(a)
 			if nmodule == null then continue # Skip error
-			# Load imported module
-			build_module_importation(nmodule)
-
-			mmodules.add(nmodule.mmodule.as(not null))
+			var mmodule = nmodule.mmodule
+			if mmodule == null then continue # skip error
+			mmodules.add mmodule
 		end
 		var time1 = get_time
 		self.toolcontext.info("*** END PARSE: {time1-time0} ***", 2)
@@ -88,28 +90,69 @@ redef class ModelBuilder
 		return mmodules.to_a
 	end
 
-	# Load recursively all modules of the group `mgroup`.
-	# See `parse` for details.
-	fun parse_group(mgroup: MGroup): Array[MModule]
+	# Identify a bunch of modules and groups.
+	#
+	# This does the same as `parse_full` but does only the identification (cf. `identify_module`)
+	fun scan_full(names: Sequence[String]): Array[MModule]
 	do
-		var res = new Array[MModule]
-		visit_group(mgroup)
-		for mg in mgroup.in_nesting.smallers do
-			for mp in mg.module_paths do
-				var nmodule = self.load_module(mp.filepath)
-				if nmodule == null then continue # Skip error
-				# Load imported module
-				build_module_importation(nmodule)
+		var mmodules = new Array[MModule]
+		for a in names do
+			# Case of a group (root or sub-directory)
+			var mgroup = self.identify_group(a)
+			if mgroup != null then
+				scan_group(mgroup)
+				for mg in mgroup.in_nesting.smallers do mmodules.add_all mg.mmodules
+				continue
+			end
+
+			# Case of a directory that is not a group
+			var stat = a.to_path.stat
+			if stat != null and stat.is_dir then
+				self.toolcontext.info("look in directory {a}", 2)
+				var fs = a.files
+				# Try each entry as a group or a module
+				for f in fs do
+					var af = a/f
+					mgroup = identify_group(af)
+					if mgroup != null then
+						scan_group(mgroup)
+						for mg in mgroup.in_nesting.smallers do mmodules.add_all mg.mmodules
+						continue
+					end
+					var mmodule = identify_module(af)
+					if mmodule != null then
+						mmodules.add mmodule
+					else
+						self.toolcontext.info("ignore file {af}", 2)
+					end
+				end
+				continue
+			end
 
-				res.add(nmodule.mmodule.as(not null))
+			var mmodule = identify_module(a)
+			if mmodule == null then
+				continue
 			end
+
+			mmodules.add mmodule
 		end
-		return res
+		return mmodules
 	end
 
 	# Load a bunch of modules and groups.
-	# Each name can be a module or a group.
-	# If it is a group then recursively all its modules are parsed.
+	#
+	# Each name can be:
+	#
+	# * a path to a module, a group or a directory of packages.
+	# * a short name of a module or a group that are looked in the `paths` (-I)
+	#
+	# Then, for each entry, if it is:
+	#
+	# * a module, then is it parsed and returned.
+	# * a group then recursively all its modules are parsed.
+	# * a directory of packages then all the modules of all packages are parsed.
+	# * else an error is displayed.
+	#
 	# See `parse` for details.
 	fun parse_full(names: Sequence[String]): Array[MModule]
 	do
@@ -117,18 +160,11 @@ redef class ModelBuilder
 		# Parse and recursively load
 		self.toolcontext.info("*** PARSE ***", 1)
 		var mmodules = new ArraySet[MModule]
-		for a in names do
-			var mgroup = self.get_mgroup(a)
-			if mgroup != null then
-				mmodules.add_all parse_group(mgroup)
-				continue
-			end
-			var nmodule = self.load_module(a)
-			if nmodule == null then continue # Skip error
-			# Load imported module
-			build_module_importation(nmodule)
-
-			mmodules.add(nmodule.mmodule.as(not null))
+		var scans = scan_full(names)
+		for mmodule in scans do
+			var ast = mmodule.load(self)
+			if ast == null then continue # Skip error
+			mmodules.add mmodule
 		end
 		var time1 = get_time
 		self.toolcontext.info("*** END PARSE: {time1-time0} ***", 2)
@@ -152,42 +188,26 @@ redef class ModelBuilder
 	# Path can be added (or removed) by the client
 	var paths = new Array[String]
 
-	# Like (and used by) `get_mmodule_by_name` but just return the ModulePath
-	fun search_mmodule_by_name(anode: nullable ANode, mgroup: nullable MGroup, name: String): nullable ModulePath
+	# Like (and used by) `get_mmodule_by_name` but does not force the parsing of the MModule (cf. `identify_module`)
+	fun search_mmodule_by_name(anode: nullable ANode, mgroup: nullable MGroup, name: String): nullable MModule
 	do
 		# First, look in groups
 		var c = mgroup
-		while c != null do
-			var dirname = c.filepath
-			if dirname == null then break # virtual group
-			if dirname.has_suffix(".nit") then break # singleton project
-
-			# Second, try the directory to find a file
-			var try_file = dirname + "/" + name + ".nit"
-			if try_file.file_exists then
-				var res = self.identify_file(try_file.simplify_path)
-				assert res != null
-				return res
-			end
-
-			# Third, try if the requested module is itself a group
-			try_file = dirname + "/" + name + "/" + name + ".nit"
-			if try_file.file_exists then
-				var res = self.identify_file(try_file.simplify_path)
-				assert res != null
-				return res
-			end
-
-			c = c.parent
+		if c != null then
+			var r = c.mpackage.root
+			assert r != null
+			scan_group(r)
+			var res = r.mmodules_by_name(name)
+			if res.not_empty then return res.first
 		end
 
 		# Look at some known directories
 		var lookpaths = self.paths
 
-		# Look in the directory of the group project also (even if not explicitly in the path)
+		# Look in the directory of the group package also (even if not explicitly in the path)
 		if mgroup != null then
 			# path of the root group
-			var dirname = mgroup.mproject.root.filepath
+			var dirname = mgroup.mpackage.root.filepath
 			if dirname != null then
 				dirname = dirname.join_path("..").simplify_path
 				if not lookpaths.has(dirname) and dirname.file_exists then
@@ -201,9 +221,9 @@ redef class ModelBuilder
 
 		if candidate == null then
 			if mgroup != null then
-				error(anode, "Error: cannot find module {name} from {mgroup.name}. tried {lookpaths.join(", ")}")
+				error(anode, "Error: cannot find module `{name}` from `{mgroup.name}`. Tried: {lookpaths.join(", ")}.")
 			else
-				error(anode, "Error: cannot find module {name}. tried {lookpaths.join(", ")}")
+				error(anode, "Error: cannot find module `{name}`. Tried: {lookpaths.join(", ")}.")
 			end
 			return null
 		end
@@ -216,69 +236,85 @@ redef class ModelBuilder
 	# If no module exists or there is a name conflict, then an error on `anode` is displayed and null is returned.
 	fun get_mmodule_by_name(anode: nullable ANode, mgroup: nullable MGroup, name: String): nullable MModule
 	do
-		var path = search_mmodule_by_name(anode, mgroup, name)
-		if path == null then return null # Forward error
-		var res = self.load_module(path.filepath)
-		if res == null then return null # Forward error
-		# Load imported module
-		build_module_importation(res)
-		return res.mmodule.as(not null)
+		var mmodule = search_mmodule_by_name(anode, mgroup, name)
+		if mmodule == null then return null # Forward error
+		var ast = mmodule.load(self)
+		if ast == null then return null # Forward error
+		return mmodule
 	end
 
 	# Search a module `name` from path `lookpaths`.
-	# If found, the path of the file is returned
-	private fun search_module_in_paths(location: nullable Location, name: String, lookpaths: Collection[String]): nullable ModulePath
+	# If found, the module is returned.
+	private fun search_module_in_paths(location: nullable Location, name: String, lookpaths: Collection[String]): nullable MModule
 	do
-		var candidate: nullable String = null
+		var res = new ArraySet[MModule]
 		for dirname in lookpaths do
-			var try_file = (dirname + "/" + name + ".nit").simplify_path
-			if try_file.file_exists then
-				if candidate == null then
-					candidate = try_file
-				else if candidate != try_file then
-					# try to disambiguate conflicting modules
-					var abs_candidate = module_absolute_path(candidate)
-					var abs_try_file = module_absolute_path(try_file)
-					if abs_candidate != abs_try_file then
-						toolcontext.error(location, "Error: conflicting module file for {name}: {candidate} {try_file}")
-					end
-				end
+			# Try a single module file
+			var mp = identify_module((dirname/"{name}.nit").simplify_path)
+			if mp != null then res.add mp
+			# Try the default module of a group
+			var g = identify_group((dirname/name).simplify_path)
+			if g != null then
+				scan_group(g)
+				res.add_all g.mmodules_by_name(name)
 			end
-			try_file = (dirname + "/" + name + "/" + name + ".nit").simplify_path
-			if try_file.file_exists then
-				if candidate == null then
-					candidate = try_file
-				else if candidate != try_file then
-					# try to disambiguate conflicting modules
-					var abs_candidate = module_absolute_path(candidate)
-					var abs_try_file = module_absolute_path(try_file)
-					if abs_candidate != abs_try_file then
-						toolcontext.error(location, "Error: conflicting module file for {name}: {candidate} {try_file}")
-					end
-				end
+		end
+		if res.is_empty then return null
+		if res.length > 1 then
+			toolcontext.error(location, "Error: conflicting module files for `{name}`: `{[for x in res do x.filepath or else x.full_name].join("`, `")}`")
+		end
+		return res.first
+	end
+
+	# Search groups named `name` from paths `lookpaths`.
+	private fun search_group_in_paths(name: String, lookpaths: Collection[String]): ArraySet[MGroup]
+	do
+		var res = new ArraySet[MGroup]
+		for dirname in lookpaths do
+			# try a single group directory
+			var mg = identify_group(dirname/name)
+			if mg != null then
+				res.add mg
 			end
 		end
-		if candidate == null then return null
-		return identify_file(candidate)
+		return res
 	end
 
-	# Cache for `identify_file` by realpath
-	private var identified_files_by_path = new HashMap[String, nullable ModulePath]
+	# Cache for `identify_module` by relative and real paths
+	private var identified_modules_by_path = new HashMap[String, nullable MModule]
 
 	# All the currently identified modules.
-	# See `identify_file`.
-	var identified_files = new Array[ModulePath]
+	# See `identify_module`.
+	#
+	# An identified module exists in the model but might be not yet parsed (no AST), or not yet analysed (no importation).
+	var identified_modules = new Array[MModule]
+
+	# All the currently parsed modules.
+	#
+	# A parsed module exists in the model but might be not yet analysed (no importation).
+	var parsed_modules = new Array[MModule]
 
-	# Identify a source file
-	# Load the associated project and groups if required
+	# Identify a source file and load the associated package and groups if required.
 	#
-	# Silently return `null` if `path` is not a valid module path.
-	fun identify_file(path: String): nullable ModulePath
+	# This method does what the user expects when giving an argument to a Nit tool.
+	#
+	# * If `path` is an existing Nit source file (with the `.nit` extension),
+	#   then the associated MModule is returned
+	# * If `path` is a directory (with a `/`),
+	#   then the MModule of its default module is returned (if any)
+	# * If `path` is a simple identifier (eg. `digraph`),
+	#   then the main module of the package `digraph` is searched in `paths` and returned.
+	#
+	# Silently return `null` if `path` does not exists or cannot be identified.
+	#
+	# On success, it returns a module that is possibly not yet parsed (no AST), or not yet analysed (no importation).
+	# If the module was already identified, or loaded, it is returned.
+	fun identify_module(path: String): nullable MModule
 	do
 		# special case for not a nit file
-		if path.file_extension != "nit" then
+		if not path.has_suffix(".nit") then
 			# search dirless files in known -I paths
-			if path.dirname == "" then
+			if not path.chars.has('/') then
 				var res = search_module_in_paths(null, path, self.paths)
 				if res != null then return res
 			end
@@ -286,7 +322,7 @@ redef class ModelBuilder
 			# Found nothing? maybe it is a group...
 			var candidate = null
 			if path.file_exists then
-				var mgroup = get_mgroup(path)
+				var mgroup = identify_group(path)
 				if mgroup != null then
 					var owner_path = mgroup.filepath.join_path(mgroup.name + ".nit")
 					if owner_path.file_exists then candidate = owner_path
@@ -299,29 +335,46 @@ redef class ModelBuilder
 			path = candidate
 		end
 
+		# Does the file exists?
+		if not path.file_exists then
+			return null
+		end
+
 		# Fast track, the path is already known
-		var pn = path.basename(".nit")
+		if identified_modules_by_path.has_key(path) then return identified_modules_by_path[path]
 		var rp = module_absolute_path(path)
-		if identified_files_by_path.has_key(rp) then return identified_files_by_path[rp]
+		if identified_modules_by_path.has_key(rp) then return identified_modules_by_path[rp]
+
+		var pn = path.basename(".nit")
 
 		# Search for a group
 		var mgrouppath = path.join_path("..").simplify_path
-		var mgroup = get_mgroup(mgrouppath)
+		var mgroup = identify_group(mgrouppath)
 
 		if mgroup == null then
-			# singleton project
-			var mproject = new MProject(pn, model)
-			mgroup = new MGroup(pn, mproject, null) # same name for the root group
+			# singleton package
+			var mpackage = new MPackage(pn, model)
+			mgroup = new MGroup(pn, mpackage, null) # same name for the root group
 			mgroup.filepath = path
-			mproject.root = mgroup
-			toolcontext.info("found project `{pn}` at {path}", 2)
+			mpackage.root = mgroup
+			toolcontext.info("found singleton package `{pn}` at {path}", 2)
+
+			# Attach homonymous `ini` file to the package
+			var inipath = path.dirname / "{pn}.ini"
+			if inipath.file_exists then
+				var ini = new ConfigTree(inipath)
+				mpackage.ini = ini
+			end
 		end
 
-		var res = new ModulePath(pn, path, mgroup)
-		mgroup.module_paths.add(res)
+		var src = new SourceFile.from_string(path, "")
+		var loc = new Location(src, 0, 0, 0, 0)
+		var res = new MModule(model, mgroup, pn, loc)
+		res.filepath = path
 
-		identified_files_by_path[rp] = res
-		identified_files.add(res)
+		identified_modules_by_path[rp] = res
+		identified_modules_by_path[path] = res
+		identified_modules.add(res)
 		return res
 	end
 
@@ -332,12 +385,17 @@ redef class ModelBuilder
 	# If the directory is not a group null is returned.
 	#
 	# Note: `paths` is also used to look for mgroups
-	fun get_mgroup(dirpath: String): nullable MGroup
+	fun identify_group(dirpath: String): nullable MGroup
 	do
-		if not dirpath.file_exists then do
+		var stat = dirpath.file_stat
+
+		if stat == null then do
+			# search dirless directories in known -I paths
+			if dirpath.chars.has('/') then return null
 			for p in paths do
 				var try = p / dirpath
-				if try.file_exists then
+				stat = try.file_stat
+				if stat != null then
 					dirpath = try
 					break label
 				end
@@ -345,85 +403,149 @@ redef class ModelBuilder
 			return null
 		end label
 
+		# Filter out non-directories
+		if not stat.is_dir then
+			return null
+		end
+
+		# Fast track, the path is already known
 		var rdp = module_absolute_path(dirpath)
 		if mgroups.has_key(rdp) then
 			return mgroups[rdp]
 		end
 
-		# Hack, a group is determined by:
-		# * the presence of a honomymous nit file
-		# * the fact that the directory is named `src`
-		var pn = rdp.basename(".nit")
-		var mp = dirpath.join_path(pn + ".nit").simplify_path
+		# By default, the name of the package or group is the base_name of the directory
+		var pn = rdp.basename
 
-		var dirpath2 = dirpath
-		if not mp.file_exists then
-			if pn == "src" then
-				# With a src directory, the group name is the name of the parent directory
-				dirpath2 = rdp.dirname
-				pn = dirpath2.basename("")
-			else
+		# Check `package.ini` that indicate a package
+		var ini = null
+		var parent = null
+		var inipath = dirpath / "package.ini"
+		if inipath.file_exists then
+			ini = new ConfigTree(inipath)
+		end
+
+		if ini == null then
+			# No ini, multiple course of action
+
+			# The root of the directory hierarchy in the file system.
+			if rdp == "/" then
+				mgroups[rdp] = null
 				return null
 			end
-		end
 
-		# check parent directory
-		var parentpath = dirpath.join_path("..").simplify_path
-		var parent = get_mgroup(parentpath)
+			# Special stopper `packages.ini`
+			if (dirpath/"packages.ini").file_exists then
+				# dirpath cannot be a package since it is a package directory
+				mgroups[rdp] = null
+				return null
+			end
+
+			# check the parent directory (if it does not contain the stopper file)
+			var parentpath = dirpath.join_path("..").simplify_path
+			var stopper = parentpath / "packages.ini"
+			if not stopper.file_exists then
+				# Recursively get the parent group
+				parent = identify_group(parentpath)
+				if parent == null then
+					# Parent is not a group, thus we are not a group either
+					mgroups[rdp] = null
+					return null
+				end
+			end
+		end
 
 		var mgroup
 		if parent == null then
-			# no parent, thus new project
-			var mproject = new MProject(pn, model)
-			mgroup = new MGroup(pn, mproject, null) # same name for the root group
-			mproject.root = mgroup
-			toolcontext.info("found project `{mproject}` at {dirpath}", 2)
+			# no parent, thus new package
+			if ini != null then pn = ini["package.name"] or else pn
+			var mpackage = new MPackage(pn, model)
+			mgroup = new MGroup(pn, mpackage, null) # same name for the root group
+			mpackage.root = mgroup
+			toolcontext.info("found package `{mpackage}` at {dirpath}", 2)
+			mpackage.ini = ini
 		else
-			mgroup = new MGroup(pn, parent.mproject, parent)
+			mgroup = new MGroup(pn, parent.mpackage, parent)
 			toolcontext.info("found sub group `{mgroup.full_name}` at {dirpath}", 2)
 		end
-		var readme = dirpath2.join_path("README.md")
-		if not readme.file_exists then readme = dirpath2.join_path("README")
+
+		# search documentation
+		# in src first so the documentation of the package code can be distinct for the documentation of the package usage
+		var readme = dirpath.join_path("README.md")
+		if not readme.file_exists then readme = dirpath.join_path("README")
 		if readme.file_exists then
-			var mdoc = new MDoc(new Location(new SourceFile.from_string(readme, ""),0,0,0,0))
-			var s = new FileReader.open(readme)
-			while not s.eof do
-				mdoc.content.add(s.read_line)
-			end
+			var mdoc = load_markdown(readme)
 			mgroup.mdoc = mdoc
 			mdoc.original_mentity = mgroup
 		end
+
 		mgroup.filepath = dirpath
 		mgroups[rdp] = mgroup
 		return mgroup
 	end
 
-	# Force the identification of all ModulePath of the group and sub-groups.
-	fun visit_group(mgroup: MGroup) do
+	# Load a markdown file as a documentation object
+	fun load_markdown(filepath: String): MDoc
+	do
+		var s = new FileReader.open(filepath)
+		var lines = new Array[String]
+		var line_starts = new Array[Int]
+		var len = 1
+		while not s.eof do
+			var line = s.read_line
+			lines.add(line)
+			line_starts.add(len)
+			len += line.length + 1
+		end
+		s.close
+		var source = new SourceFile.from_string(filepath, lines.join("\n"))
+		source.line_starts.add_all line_starts
+		var mdoc = new MDoc(new Location(source, 1, lines.length, 0, 0))
+		mdoc.content.add_all(lines)
+		return mdoc
+	end
+
+	# Force the identification of all ModulePath of the group and sub-groups in the file system.
+	#
+	# When a group is scanned, its sub-groups hierarchy is filled (see `MGroup::in_nesting`)
+	# and the potential modules (and nested modules) are identified (see `MGroup::module_paths`).
+	#
+	# Basically, this recursively call `get_mgroup` and `identify_file` on each directory entry.
+	#
+	# No-op if the group was already scanned (see `MGroup::scanned`).
+	fun scan_group(mgroup: MGroup) do
+		if mgroup.scanned then return
+		mgroup.scanned = true
 		var p = mgroup.filepath
+		# a virtual group has nothing to scan
+		if p == null then return
 		for f in p.files do
 			var fp = p/f
-			var g = get_mgroup(fp)
-			if g != null then visit_group(g)
-			identify_file(fp)
+			var g = identify_group(fp)
+			# Recursively scan for groups of the same package
+			if g == null then
+				identify_module(fp)
+			else if g.mpackage == mgroup.mpackage then
+				scan_group(g)
+			end
 		end
 	end
 
 	# Transform relative paths (starting with '../') into absolute paths
 	private fun module_absolute_path(path: String): String do
-		return getcwd.join_path(path).simplify_path
+		return path.realpath
 	end
 
 	# Try to load a module AST using a path.
 	# Display an error if there is a problem (IO / lexer / parser) and return null
 	fun load_module_ast(filename: String): nullable AModule
 	do
-		if filename.file_extension != "nit" then
-			self.toolcontext.error(null, "Error: file {filename} is not a valid nit module.")
+		if not filename.has_suffix(".nit") then
+			self.toolcontext.error(null, "Error: file `{filename}` is not a valid nit module.")
 			return null
 		end
 		if not filename.file_exists then
-			self.toolcontext.error(null, "Error: file {filename} not found.")
+			self.toolcontext.error(null, "Error: file `{filename}` not found.")
 			return null
 		end
 
@@ -448,40 +570,46 @@ redef class ModelBuilder
 		return nmodule
 	end
 
+	# Remove Nit source files from a list of arguments.
+	#
+	# Items of `args` that can be loaded as a nit file will be removed from `args` and returned.
+	fun filter_nit_source(args: Array[String]): Array[String]
+	do
+		var keep = new Array[String]
+		var res = new Array[String]
+		for a in args do
+			var l = identify_module(a)
+			if l == null then
+				keep.add a
+			else
+				res.add a
+			end
+		end
+		args.clear
+		args.add_all(keep)
+		return res
+	end
+
 	# Try to load a module using a path.
 	# Display an error if there is a problem (IO / lexer / parser) and return null.
 	# Note: usually, you do not need this method, use `get_mmodule_by_name` instead.
 	#
-	# The MModule is created however, the importation is not performed,
-	# therefore you should call `build_module_importation`.
+	# The MModule is located, created, parsed and the importation is performed.
 	fun load_module(filename: String): nullable AModule
 	do
 		# Look for the module
-		var file = identify_file(filename)
-		if file == null then
-			toolcontext.error(null, "Error: cannot find module `{filename}`.")
+		var mmodule = identify_module(filename)
+		if mmodule == null then
+			if filename.file_exists then
+				toolcontext.error(null, "Error: `{filename}` is not a Nit source file.")
+			else
+				toolcontext.error(null, "Error: cannot find module `{filename}`.")
+			end
 			return null
 		end
 
-		# Already known and loaded? then return it
-		var mmodule = file.mmodule
-		if mmodule != null then
-			return mmodule2nmodule[mmodule]
-		end
-
-		# Load it manually
-		var nmodule = load_module_ast(file.filepath)
-		if nmodule == null then return null # forward error
-
-		# build the mmodule and load imported modules
-		mmodule = build_a_mmodule(file.mgroup, file.name, nmodule)
-
-		if mmodule == null then return null # forward error
-
-		# Update the file information
-		file.mmodule = mmodule
-
-		return nmodule
+		# Load it
+		return mmodule.load(self)
 	end
 
 	# Injection of a new module without source.
@@ -510,33 +638,33 @@ redef class ModelBuilder
 	end
 
 	# Visit the AST and create the `MModule` object
-	private fun build_a_mmodule(mgroup: nullable MGroup, mod_name: String, nmodule: AModule): nullable MModule
+	private fun build_a_mmodule(mgroup: nullable MGroup, nmodule: AModule)
 	do
+		var mmodule = nmodule.mmodule
+		assert mmodule != null
+
 		# Check the module name
 		var decl = nmodule.n_moduledecl
 		if decl != null then
 			var decl_name = decl.n_name.n_id.text
-			if decl_name != mod_name then
-				error(decl.n_name, "Error: module name missmatch; declared {decl_name} file named {mod_name}")
+			if decl_name != mmodule.name then
+				error(decl.n_name, "Error: module name mismatch; declared {decl_name} file named {mmodule.name}.")
 			end
 		end
 
-		# Check for conflicting module names in the project
+		# Check for conflicting module names in the package
 		if mgroup != null then
-			var others = model.get_mmodules_by_name(mod_name)
+			var others = model.get_mmodules_by_name(mmodule.name)
 			if others != null then for other in others do
-				if other.mgroup!= null and other.mgroup.mproject == mgroup.mproject then
+				if other != mmodule and mmodule2nmodule.has_key(mmodule) and other.mgroup!= null and other.mgroup.mpackage == mgroup.mpackage then
 					var node: ANode
 					if decl == null then node = nmodule else node = decl.n_name
-					error(node, "Error: A module named `{other.full_name}` already exists at {other.location}")
+					error(node, "Error: a module named `{other.full_name}` already exists at {other.location}.")
 					break
 				end
 			end
 		end
 
-		# Create the module
-		var mmodule = new MModule(model, mgroup, mod_name, nmodule.location)
-		nmodule.mmodule = mmodule
 		nmodules.add(nmodule)
 		self.mmodule2nmodule[mmodule] = nmodule
 
@@ -559,8 +687,84 @@ redef class ModelBuilder
 			# Is the module a test suite?
 			mmodule.is_test_suite = not decl.get_annotations("test_suite").is_empty
 		end
+	end
 
-		return mmodule
+	# Resolve the module identification for a given `AModuleName`.
+	#
+	# This method handles qualified names as used in `AModuleName`.
+	fun seach_module_by_amodule_name(n_name: AModuleName, mgroup: nullable MGroup): nullable MModule
+	do
+		var mod_name = n_name.n_id.text
+
+		# If a quad is given, we ignore the starting group (go from path)
+		if n_name.n_quad != null then mgroup = null
+
+		# If name not qualified, just search the name
+		if n_name.n_path.is_empty then
+			# Fast search if no n_path
+			return search_mmodule_by_name(n_name, mgroup, mod_name)
+		end
+
+		# If qualified and in a group
+		if mgroup != null then
+			# First search in the package
+			var r = mgroup.mpackage.root
+			assert r != null
+			scan_group(r)
+			# Get all modules with the final name
+			var res = r.mmodules_by_name(mod_name)
+			# Filter out the name that does not match the qualifiers
+			res = [for x in res do if match_amodulename(n_name, x) then x]
+			if res.not_empty then
+				if res.length > 1 then
+					error(n_name, "Error: conflicting module files for `{mod_name}`: `{[for x in res do x.filepath or else x.full_name].join("`, `")}`")
+				end
+				return res.first
+			end
+		end
+
+		# If no module yet, then assume that the first element of the path
+		# Is to be searched in the path.
+		var root_name = n_name.n_path.first.text
+		var roots = search_group_in_paths(root_name, paths)
+		if roots.is_empty then
+			error(n_name, "Error: cannot find `{root_name}`. Tried: {paths.join(", ")}.")
+			return null
+		end
+
+		var res = new ArraySet[MModule]
+		for r in roots do
+			# Then, for each root, collect modules that matches the qualifiers
+			scan_group(r)
+			var root_res = r.mmodules_by_name(mod_name)
+			for x in root_res do if match_amodulename(n_name, x) then res.add x
+		end
+		if res.not_empty then
+			if res.length > 1 then
+				error(n_name, "Error: conflicting module files for `{mod_name}`: `{[for x in res do x.filepath or else x.full_name].join("`, `")}`")
+			end
+			return res.first
+		end
+		# If still nothing, just call a basic search that will fail and will produce an error message
+		error(n_name, "Error: cannot find module `{mod_name}` from `{root_name}`. Tried: {paths.join(", ")}.")
+		return null
+	end
+
+	# Is elements of `n_name` correspond to the group nesting of `m`?
+	#
+	# Basically it check that `bar::foo` matches `bar/foo.nit` and `bar/baz/foo.nit`
+	# but not `baz/foo.nit` nor `foo/bar.nit`
+	#
+	# Is used by `seach_module_by_amodule_name` to validate qualified names.
+	private fun match_amodulename(n_name: AModuleName, m: MModule): Bool
+	do
+		var g: nullable MGroup = m.mgroup
+		for grp in n_name.n_path.reverse_iterator do
+			while g != null and grp.text != g.name do
+				g = g.parent
+			end
+		end
+		return g != null
 	end
 
 	# Analyze the module importation and fill the module_importation_hierarchy
@@ -574,50 +778,116 @@ redef class ModelBuilder
 		var stdimport = true
 		var imported_modules = new Array[MModule]
 		for aimport in nmodule.n_imports do
+			# Do not imports conditional
+			var atconditionals = aimport.get_annotations("conditional")
+			if atconditionals.not_empty then continue
+
 			stdimport = false
 			if not aimport isa AStdImport then
 				continue
 			end
-			var mgroup = mmodule.mgroup
-			if aimport.n_name.n_quad != null then mgroup = null # Start from top level
-			for grp in aimport.n_name.n_path do
-				var path = search_mmodule_by_name(grp, mgroup, grp.text)
-				if path == null then return # Skip error
-				mgroup = path.mgroup
+
+			# Load the imported module
+			var sup = seach_module_by_amodule_name(aimport.n_name, mmodule.mgroup)
+			if sup == null then
+				mmodule.is_broken = true
+				nmodule.mmodule = null # invalidate the module
+				continue # Skip error
+			end
+			var ast = sup.load(self)
+			if ast == null then
+				mmodule.is_broken = true
+				nmodule.mmodule = null # invalidate the module
+				continue # Skip error
 			end
-			var mod_name = aimport.n_name.n_id.text
-			var sup = self.get_mmodule_by_name(aimport.n_name, mgroup, mod_name)
-			if sup == null then continue # Skip error
+
 			aimport.mmodule = sup
 			imported_modules.add(sup)
 			var mvisibility = aimport.n_visibility.mvisibility
 			if mvisibility == protected_visibility then
+				mmodule.is_broken = true
 				error(aimport.n_visibility, "Error: only properties can be protected.")
+				mmodule.is_broken = true
+				nmodule.mmodule = null # invalidate the module
 				return
 			end
 			if sup == mmodule then
-				error(aimport.n_name, "Error: Dependency loop in module {mmodule}.")
+				error(aimport.n_name, "Error: dependency loop in module {mmodule}.")
+				mmodule.is_broken = true
+				nmodule.mmodule = null # invalidate the module
 			end
 			if sup.in_importation < mmodule then
-				error(aimport.n_name, "Error: Dependency loop between modules {mmodule} and {sup}.")
+				error(aimport.n_name, "Error: dependency loop between modules {mmodule} and {sup}.")
+				mmodule.is_broken = true
+				nmodule.mmodule = null # invalidate the module
 				return
 			end
 			mmodule.set_visibility_for(sup, mvisibility)
 		end
 		if stdimport then
-			var mod_name = "standard"
+			var mod_name = "core"
 			var sup = self.get_mmodule_by_name(nmodule, null, mod_name)
-			if sup != null then # Skip error
+			if sup == null then
+				mmodule.is_broken = true
+				nmodule.mmodule = null # invalidate the module
+			else # Skip error
 				imported_modules.add(sup)
 				mmodule.set_visibility_for(sup, public_visibility)
 			end
 		end
-		self.toolcontext.info("{mmodule} imports {imported_modules.join(", ")}", 3)
+
+		# Declare conditional importation
+		for aimport in nmodule.n_imports do
+			if not aimport isa AStdImport then continue
+			var atconditionals = aimport.get_annotations("conditional")
+			if atconditionals.is_empty then continue
+
+			var suppath = seach_module_by_amodule_name(aimport.n_name, mmodule.mgroup)
+			if suppath == null then continue # skip error
+
+			for atconditional in atconditionals do
+				var nargs = atconditional.n_args
+				if nargs.is_empty then
+					error(atconditional, "Syntax Error: `conditional` expects module identifiers as arguments.")
+					continue
+				end
+
+				# The rule
+				var rule = new Array[MModule]
+
+				# First element is the goal, thus
+				rule.add suppath
+
+				# Second element is the first condition, that is to be a client of the current module
+				rule.add mmodule
+
+				# Other condition are to be also a client of each modules indicated as arguments of the annotation
+				for narg in nargs do
+					var id = narg.as_id
+					if id == null then
+						error(narg, "Syntax Error: `conditional` expects module identifier as arguments.")
+						continue
+					end
+
+					var mp = search_mmodule_by_name(narg, mmodule.mgroup, id)
+					if mp == null then continue
+
+					rule.add mp
+				end
+
+				conditional_importations.add rule
+			end
+		end
+
 		mmodule.set_imported_mmodules(imported_modules)
 
-		# Force standard to be public if imported
+		apply_conditional_importations(mmodule)
+
+		self.toolcontext.info("{mmodule} imports {mmodule.in_importation.direct_greaters.join(", ")}", 3)
+
+		# Force `core` to be public if imported
 		for sup in mmodule.in_importation.greaters do
-			if sup.name == "standard" then
+			if sup.name == "core" then
 				mmodule.set_visibility_for(sup, public_visibility)
 			end
 		end
@@ -635,6 +905,57 @@ redef class ModelBuilder
 		end
 	end
 
+	# Global list of conditional importation rules.
+	#
+	# Each rule is a "Horn clause"-like sequence of modules.
+	# It means that the first module is the module to automatically import.
+	# The remaining modules are the conditions of the rule.
+	#
+	# Rules are declared by `build_module_importation` and are applied by `apply_conditional_importations`
+	# (and `build_module_importation` that calls it).
+	#
+	# TODO (when the loader will be rewritten): use a better representation and move up rules in the model.
+	private var conditional_importations = new Array[SequenceRead[MModule]]
+
+	# Extends the current importations according to imported rules about conditional importation
+	fun apply_conditional_importations(mmodule: MModule)
+	do
+		# Because a conditional importation may cause additional conditional importation, use a fixed point
+		# The rules are checked naively because we assume that it does not worth to be optimized
+		var check_conditional_importations = true
+		while check_conditional_importations do
+			check_conditional_importations = false
+
+			for ci in conditional_importations do
+				# Check conditions
+				for i in [1..ci.length[ do
+					var m = ci[i]
+					# Is imported?
+					if not mmodule.in_importation.greaters.has(m) then continue label
+				end
+				# Still here? It means that all conditions modules are loaded and imported
+
+				# Identify the module to automatically import
+				var sup = ci.first
+				var ast = sup.load(self)
+				if ast == null then continue
+
+				# Do nothing if already imported
+				if mmodule.in_importation.greaters.has(sup) then continue label
+
+				# Import it
+				self.toolcontext.info("{mmodule} conditionally imports {sup}", 3)
+				# TODO visibility rules (currently always public)
+				mmodule.set_visibility_for(sup, public_visibility)
+				# TODO linearization rules (currently added at the end in the order of the rules)
+				mmodule.set_imported_mmodules([sup])
+
+				# Prepare to reapply the rules
+				check_conditional_importations = true
+			end label
+		end
+	end
+
 	# All the loaded modules
 	var nmodules = new Array[AModule]
 
@@ -653,31 +974,65 @@ redef class ModelBuilder
 	end
 end
 
-# File-system location of a module (file) that is identified but not always loaded.
-class ModulePath
-	# The name of the module
-	# (it's the basename of the filepath)
-	var name: String
+redef class MModule
+	# The path of the module source
+	var filepath: nullable String = null
 
-	# The human path of the module
-	var filepath: String
+	# Force the parsing of the module using `modelbuilder`.
+	#
+	# If the module was already parsed, the existing ASI is returned.
+	# Else the source file is loaded, and parsed and some
+	#
+	# The importation is not done by this
+	#
+	# REQUIRE: `filepath != null`
+	# ENSURE: `modelbuilder.parsed_modules.has(self)`
+	fun parse(modelbuilder: ModelBuilder): nullable AModule
+	do
+		# Already known and loaded? then return it
+		var nmodule = modelbuilder.mmodule2nmodule.get_or_null(self)
+		if nmodule != null then return nmodule
 
-	# The group (and the project) of the possible module
-	var mgroup: MGroup
+		var filepath = self.filepath
+		assert filepath != null
+		# Load it manually
+		nmodule = modelbuilder.load_module_ast(filepath)
+		if nmodule == null then return null # forward error
 
-	# The loaded module (if any)
-	var mmodule: nullable MModule = null
+		# build the mmodule
+		nmodule.mmodule = self
+		modelbuilder.build_a_mmodule(mgroup, nmodule)
 
-	redef fun to_s do return filepath
+		modelbuilder.parsed_modules.add self
+		return nmodule
+	end
+
+	# Parse and process importation of a given MModule.
+	#
+	# Basically chains `parse` and `build_module_importation`.
+	fun load(modelbuilder: ModelBuilder): nullable AModule
+	do
+		var nmodule = parse(modelbuilder)
+		if nmodule == null then return null
+
+		modelbuilder.build_module_importation(nmodule)
+		return nmodule
+	end
 end
 
-redef class MGroup
-	# Modules paths associated with the group
-	var module_paths = new Array[ModulePath]
+redef class MPackage
+	# The associated `.ini` file, if any
+	#
+	# The `ini` file is given as is and might contain invalid or missing information.
+	#
+	# Some packages, like stand-alone packages or virtual packages have no `ini` file associated.
+	var ini: nullable ConfigTree = null
+end
 
+redef class MGroup
 	# Is the group interesting for a final user?
 	#
-	# Groups are mandatory in the model but for simple projects they are not
+	# Groups are mandatory in the model but for simple packages they are not
 	# always interesting.
 	#
 	# A interesting group has, at least, one of the following true:
@@ -687,9 +1042,33 @@ redef class MGroup
 	# * it has a documentation
 	fun is_interesting: Bool
 	do
-		return module_paths.length > 1 or mmodules.length > 1 or not in_nesting.direct_smallers.is_empty or mdoc != null
+		return mmodules.length > 1 or
+			not in_nesting.direct_smallers.is_empty or
+			mdoc != null or
+			(mmodules.length == 1 and default_mmodule == null)
 	end
 
+	# Are files and directories in self scanned?
+	#
+	# See `ModelBuilder::scan_group`.
+	var scanned = false
+
+	# Return the modules in self and subgroups named `name`.
+	#
+	# If `self` is not scanned (see `ModelBuilder::scan_group`) the
+	# results might be partial.
+	fun mmodules_by_name(name: String): Array[MModule]
+	do
+		var res = new Array[MModule]
+		for g in in_nesting.smallers do
+			for mp in g.mmodules do
+				if mp.name == name then
+					res.add mp
+				end
+			end
+		end
+		return res
+	end
 end
 
 redef class SourceFile
@@ -704,7 +1083,8 @@ end
 
 redef class AModule
 	# The associated MModule once build by a `ModelBuilder`
-	var mmodule: nullable MModule
+	var mmodule: nullable MModule = null
+
 	# Flag that indicate if the importation is already completed
 	var is_importation_done: Bool = false
 end