From 4762c92c7d68a12b091028dcea1076fe4e498068 Mon Sep 17 00:00:00 2001
From: Jean Privat <jean@pryen.org>
Date: Thu, 6 Aug 2015 14:32:14 -0400
Subject: [PATCH] typing: change specification about default arguments.
 everything is done here

Signed-off-by: Jean Privat <jean@pryen.org>
---
 src/semantize/typing.nit |   58 ++++++++++++++++++++++++++++------------------
 1 file changed, 35 insertions(+), 23 deletions(-)

diff --git a/src/semantize/typing.nit b/src/semantize/typing.nit
index 1b53f65..9b0d841 100644
--- a/src/semantize/typing.nit
+++ b/src/semantize/typing.nit
@@ -414,26 +414,30 @@ private class TypeVisitor
 				return null
 			end
 		else if args.length != msignature.arity then
-			if msignature.arity == msignature.min_arity then
-				modelbuilder.error(node, "Error: expected {msignature.arity} argument(s) for `{mproperty}{msignature}`; got {args.length}. See introduction at `{mproperty.full_name}`.")
-				return null
-			end
+			# Too much argument
 			if args.length > msignature.arity then
-				modelbuilder.error(node, "Error: expected at most {msignature.arity} argument(s) for `{mproperty}{msignature}`; got {args.length}. See introduction at `{mproperty.full_name}`.")
-				return null
-			end
-			if args.length < msignature.min_arity then
-				modelbuilder.error(node, "Error: expected at least {msignature.min_arity} argument(s) for `{mproperty}{msignature}`; got {args.length}. See introduction at `{mproperty.full_name}`.")
+				modelbuilder.error(node, "Error: expected {msignature.arity} argument(s) for `{mproperty}{msignature}`; got {args.length}. See introduction at `{mproperty.full_name}`.")
 				return null
 			end
+			# Other cases are managed later
 		end
 
+
 		#debug("CALL {unsafe_type}.{msignature}")
 
 		# Associate each parameter to a position in the arguments
 		var map = new SignatureMap
 
-		var setted = args.length - msignature.min_arity
+		# Special case for the isolated last argument
+		# TODO: reify this method characteristics (where? the param, the signature, the method?)
+		var last_is_padded = mproperty.name.chars.last == '='
+		var nbargs = args.length
+		if last_is_padded then
+			nbargs -= 1
+			assert not args.last isa ANamedargExpr
+			map.map[msignature.arity - 1] = args.length - 1
+			self.visit_expr_subtype(args.last, msignature.mparameters.last.mtype)
+		end
 
 		# First, handle named arguments
 		for i in [0..args.length[ do
@@ -445,10 +449,6 @@ private class TypeVisitor
 				modelbuilder.error(e.n_id, "Error: no parameter `{name}` for `{mproperty}{msignature}`.")
 				return null
 			end
-			if not param.is_default then
-				modelbuilder.error(e, "Error: parameter `{name}` is not optional for `{mproperty}{msignature}`.")
-				return null
-			end
 			var idx = msignature.mparameters.index_of(param)
 			var prev = map.map.get_or_null(idx)
 			if prev != null then
@@ -456,10 +456,12 @@ private class TypeVisitor
 				return null
 			end
 			map.map[idx] = i
-			setted -= 1
 			e.mtype = self.visit_expr_subtype(e.n_expr, param.mtype)
 		end
 
+		# Number of minimum mandatory remaining parameters
+		var min_arity = 0
+
 		# Second, associate remaining parameters
 		var vararg_decl = args.length - msignature.arity
 		var j = 0
@@ -468,16 +470,16 @@ private class TypeVisitor
 			if map.map.has_key(i) then continue
 
 			var param = msignature.mparameters[i]
-			if param.is_default then
-				if setted > 0 then
-					setted -= 1
-				else
-					continue
-				end
-			end
 
 			# Search the next free argument: skip named arguments since they are already associated
-			while args[j] isa ANamedargExpr do j += 1
+			while j < nbargs and args[j] isa ANamedargExpr do j += 1
+			if j >= nbargs then
+				if not param.mtype isa MNullableType then
+					min_arity = j + 1
+				end
+				j += 1
+				continue
+			end
 			var arg = args[j]
 			map.map[i] = j
 			j += 1
@@ -491,6 +493,16 @@ private class TypeVisitor
 			self.visit_expr_subtype(arg, paramtype)
 		end
 
+		if min_arity > 0 then
+			if last_is_padded then min_arity += 1
+			if min_arity < msignature.arity then
+				modelbuilder.error(node, "Error: expected at least {min_arity} argument(s) for `{mproperty}{msignature}`; got {args.length}. See introduction at `{mproperty.full_name}`.")
+			else
+				modelbuilder.error(node, "Error: expected {min_arity} argument(s) for `{mproperty}{msignature}`; got {args.length}. See introduction at `{mproperty.full_name}`.")
+			end
+			return null
+		end
+
 		# Third, check varargs
 		if vararg_rank >= 0 then
 			var paramtype = msignature.mparameters[vararg_rank].mtype
-- 
1.7.9.5