From 33c49ff171540f9a97c105970f00103173afbe7e Mon Sep 17 00:00:00 2001
From: Jean Privat <jean@pryen.org>
Date: Tue, 6 Oct 2015 21:30:20 -0400
Subject: [PATCH] grammar: add `for_group` in `for` for multi-iterators

Signed-off-by: Jean Privat <jean@pryen.org>
---
 src/parser/nit.sablecc3xx   |   19 +++++++++++++++----
 src/parser/parser_nodes.nit |   23 +++++++++++++++++------
 2 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/src/parser/nit.sablecc3xx b/src/parser/nit.sablecc3xx
index ef6260d..694da7b 100644
--- a/src/parser/nit.sablecc3xx
+++ b/src/parser/nit.sablecc3xx
@@ -511,8 +511,16 @@ while~withelse {-> expr}
 	;
 
 for~withelse {-> expr}
-	= kwfor no [ids]:idlist [n2]:no kwin [n3]:no expr [n4]:no kwdo stmtso_withend label {-> New expr.for(kwfor, [ids.id], kwin, expr, kwdo, stmtso_withend.expr, label)}
-	| {nolabel} kwfor no [ids]:idlist [n2]:no kwin [n3]:no expr [n4]:no kwdo stmtso~withelse {-> New expr.for(kwfor, [ids.id], kwin, expr, kwdo, stmtso~withelse.expr, Null)}
+	= kwfor no for_groups [n4]:no kwdo stmtso_withend label {-> New expr.for(kwfor, [for_groups.for_group], kwdo, stmtso_withend.expr, label)}
+	| {nolabel} kwfor no for_groups [n4]:no kwdo stmtso~withelse {-> New expr.for(kwfor, [for_groups.for_group], kwdo, stmtso~withelse.expr, Null)}
+	;
+
+for_groups {-> for_group*}
+	= {one} for_group {-> [for_group]}
+	| {many} for_groups no comma [n2]:no for_group {-> [for_groups.for_group, for_group] }
+	;
+for_group
+	= [ids]:idlist [n2]:no kwin [n3]:no expr {-> New for_group([ids.id], kwin, expr)}
 	;
 
 with~withelse {-> expr}
@@ -673,7 +681,7 @@ array_items_tail {-> expr}
 	;
 array_item {-> expr}
 	= expr no {-> expr}
-	| {for} kwfor no [ids]:idlist [n2]:no kwin [n3]:no expr [n4]:no kwdo [block]:array_item {-> New expr.for(kwfor, [ids.id], kwin, expr, kwdo, block.expr, Null)}
+	| {for} kwfor no for_groups [n4]:no kwdo [block]:array_item {-> New expr.for(kwfor, [for_groups.for_group], kwdo, block.expr, Null)}
 	| {if} kwif [n1]:no expr [n2]:no kwthen [n3]:no [then]:array_item {-> New expr.if(kwif, expr, kwthen, then.expr, Null, Null)}
 	;
 
@@ -951,7 +959,7 @@ expr	= {block} expr* kwend?
 	| {ifexpr} kwif expr kwthen [then]:expr kwelse [else]:expr
 	| {while} kwwhile expr kwdo [block]:expr? label?
 	| {loop} kwloop [block]:expr? label?
-	| {for} kwfor [ids]:id* kwin expr kwdo [block]:expr? label?
+	| {for} kwfor [groups]:for_group* kwdo [block]:expr? label?
 	| {with} kwwith expr kwdo [block]:expr? label?
 	| {assert} kwassert id? expr kwelse? [else]:expr?
 	| {once} kwonce expr 
@@ -1046,6 +1054,9 @@ assign_op
 	| {ll} [op]:lleq
 	| {gg} [op]:ggeq
 	;
+for_group
+	= [ids]:id* kwin expr
+	;
 
 module_name = quad? [path]:id* id;
 extern_calls = kwimport [extern_calls]:extern_call*
diff --git a/src/parser/parser_nodes.nit b/src/parser/parser_nodes.nit
index 5204376..df01109 100644
--- a/src/parser/parser_nodes.nit
+++ b/src/parser/parser_nodes.nit
@@ -1907,6 +1907,23 @@ class AForExpr
 	# The `for` keyword
 	var n_kwfor: TKwfor is writable, noinit
 
+	# The list of groups to iterate
+	var n_groups = new ANodes[AForGroup](self)
+
+	# The `do` keyword
+	var n_kwdo: TKwdo is writable, noinit
+
+	# The body of the loop
+	var n_block: nullable AExpr = null is writable
+end
+
+# A collection iterated by a for, its automatic variables and its implicit iterator.
+#
+# Standard `for` iterate on a single collection.
+# Multiple `for` can iterate on more than one collection at once.
+class AForGroup
+	super Prod
+
 	# The list of name of the automatic variables
 	var n_ids = new ANodes[TId](self)
 
@@ -1915,12 +1932,6 @@ class AForExpr
 
 	# The expression used as the collection to iterate on
 	var n_expr: AExpr is writable, noinit
-
-	# The `do` keyword
-	var n_kwdo: TKwdo is writable, noinit
-
-	# The body of the loop
-	var n_block: nullable AExpr = null is writable
 end
 
 # A `with` statement
-- 
1.7.9.5