interpreter: implements array comprehensions

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/src/interpreter/naive_interpreter.nit b/src/interpreter/naive_interpreter.nit
index a12657e..4bbe635 100644 (file)
--- a/src/interpreter/naive_interpreter.nit
+++ b/src/interpreter/naive_interpreter.nit
@@ -173,14 +173,20 @@ class NaiveInterpreter
        # If `n` cannot be evaluated, then aborts.
        fun stmt(n: nullable AExpr)
        do
-               if n != null then
-                       var frame = self.frame
-                       var old = frame.current_node
-                       frame.current_node = n
-                       #n.debug("Execute stmt")
-                       n.stmt(self)
-                       frame.current_node = old
+               if n == null then return
+
+               if n.comprehension != null then
+                       var comprehension = frame.comprehension.as(not null)
+                       var i = expr(n)
+                       if i != null then comprehension.add(i)
+                       return
                end
+
+               var frame = self.frame
+               var old = frame.current_node
+               frame.current_node = n
+               n.stmt(self)
+               frame.current_node = old
        end
 
        # Map used to store values of nodes that must be evaluated once in the system (`AOnceExpr`)
@@ -664,6 +670,7 @@ class Frame
        var arguments: Array[Instance]
        # Mapping between a variable and the current value
        private var map: Map[Variable, Instance] = new HashMap[Variable, Instance]
+       var comprehension: nullable Array[Instance] = null
 end
 
 redef class ANode
@@ -1532,11 +1539,18 @@ redef class AArrayExpr
        redef fun expr(v)
        do
                var val = new Array[Instance]
+               var old_comprehension = v.frame.comprehension
+               v.frame.comprehension = val
                for nexpr in self.n_exprs do
-                       var i = v.expr(nexpr)
-                       if i == null then return null
-                       val.add(i)
+                       if nexpr isa AForExpr then
+                               v.stmt(nexpr)
+                       else
+                               var i = v.expr(nexpr)
+                               if i == null then return null
+                               val.add(i)
+                       end
                end
+               v.frame.comprehension = old_comprehension
                var mtype = v.unanchor_type(self.mtype.as(not null)).as(MClassType)
                var elttype = mtype.arguments.first
                return v.array_instance(val, elttype)