compile: implement for loop

Author: ncw

compile/compile.go

@@ -236,7 +236,7 @@ func (c *compiler) NewLabel() *Label {
 // Compiles a jump instruction
 func (c *compiler) Jump(Op byte, Dest *Label) {
 	switch Op {
-	case vm.JUMP_IF_FALSE_OR_POP, vm.JUMP_IF_TRUE_OR_POP, vm.JUMP_ABSOLUTE, vm.POP_JUMP_IF_FALSE, vm.POP_JUMP_IF_TRUE: // Absolute
+	case vm.JUMP_IF_FALSE_OR_POP, vm.JUMP_IF_TRUE_OR_POP, vm.JUMP_ABSOLUTE, vm.POP_JUMP_IF_FALSE, vm.POP_JUMP_IF_TRUE, vm.CONTINUE_LOOP: // Absolute
 		c.OpCodes.Add(&JumpAbs{OpArg: OpArg{Op: Op}, Dest: Dest})
 	case vm.JUMP_FORWARD, vm.SETUP_WITH, vm.FOR_ITER, vm.SETUP_LOOP, vm.SETUP_EXCEPT, vm.SETUP_FINALLY:
 		c.OpCodes.Add(&JumpRel{OpArg: OpArg{Op: Op}, Dest: Dest})
@@ -338,7 +338,26 @@ func (c *compiler) Stmt(stmt ast.Stmt) {
 		// Iter   Expr
 		// Body   []Stmt
 		// Orelse []Stmt
-		panic("FIXME compile: For not implemented")
+		endfor := new(Label)
+		endpopblock := new(Label)
+		c.Jump(vm.SETUP_LOOP, endpopblock)
+		c.Expr(node.Iter)
+		c.Op(vm.GET_ITER)
+		forloop := c.NewLabel()
+		c.loops.Push(loop{Start: forloop, End: endpopblock, IsForLoop: true})
+		c.Jump(vm.FOR_ITER, endfor)
+		c.Expr(node.Target)
+		for _, stmt := range node.Body {
+			c.Stmt(stmt)
+		}
+		c.Jump(vm.JUMP_ABSOLUTE, forloop)
+		c.Label(endfor)
+		c.Op(vm.POP_BLOCK)
+		c.loops.Pop()
+		for _, stmt := range node.Orelse {
+			c.Stmt(stmt)
+		}
+		c.Label(endpopblock)
 	case *ast.While:
 		// Test   Expr
 		// Body   []Stmt
@@ -449,8 +468,9 @@ func (c *compiler) Stmt(stmt ast.Stmt) {
 			panic(py.ExceptionNewf(py.SyntaxError, "'continue' not properly in loop"))
 		}
 		if l.IsForLoop {
-			panic(py.ExceptionNewf(py.SyntaxError, "FIXME continue in for loop not implemented", stmt))
-			c.OpArg(vm.CONTINUE_LOOP, 0)
+			// FIXME when do we use CONTINUE_LOOP?
+			c.Jump(vm.JUMP_ABSOLUTE, l.Start)
+			//c.Jump(vm.CONTINUE_LOOP, l.Start)
 		} else {
 			c.Jump(vm.JUMP_ABSOLUTE, l.Start)
 		}

compile/compile_data_test.go

@@ -1151,7 +1151,7 @@ var compileTestData = []struct {
 		Name:        "<module>",
 		Firstlineno: 1,
 		Lnotab:      "",
-	}, "  1           0 LOAD_CONST               0 (<code object <lambda> at 0x7f3037488db0, file \"<string>\", line 1>)\n              3 LOAD_CONST               1 ('<lambda>')\n              6 MAKE_FUNCTION            0\n              9 RETURN_VALUE\n", nil, ""},
+	}, "  1           0 LOAD_CONST               0 (<code object <lambda> at 0x7f37b1535db0, file \"<string>\", line 1>)\n              3 LOAD_CONST               1 ('<lambda>')\n              6 MAKE_FUNCTION            0\n              9 RETURN_VALUE\n", nil, ""},
 	{"pass", "exec", &py.Code{
 		Argcount:       0,
 		Kwonlyargcount: 0,
@@ -1681,4 +1681,55 @@ var compileTestData = []struct {
 	}, "  1           0 SETUP_LOOP              28 (to 31)\n        >>    3 LOAD_NAME                0 (a)\n              6 POP_JUMP_IF_FALSE       30\n\n  2           9 LOAD_NAME                1 (b)\n             12 POP_JUMP_IF_FALSE       21\n             15 JUMP_ABSOLUTE            3\n             18 JUMP_FORWARD             0 (to 21)\n\n  3     >>   21 LOAD_NAME                2 (c)\n             24 STORE_NAME               1 (b)\n             27 JUMP_ABSOLUTE            3\n        >>   30 POP_BLOCK\n        >>   31 LOAD_CONST               0 (None)\n             34 RETURN_VALUE\n", nil, ""},
 	{"continue", "exec", nil, "", py.SyntaxError, "'continue' not properly in loop"},
 	{"break", "exec", nil, "", py.SyntaxError, "'break' outside loop"},
+	{"for a in b: pass", "exec", &py.Code{
+		Argcount:       0,
+		Kwonlyargcount: 0,
+		Nlocals:        0,
+		Stacksize:      2,
+		Flags:          64,
+		Code:           "\x78\x0e\x00\x65\x00\x00\x44\x5d\x06\x00\x5a\x01\x00\x71\x07\x00\x57\x64\x00\x00\x53",
+		Consts:         []py.Object{py.None},
+		Names:          []string{"b", "a"},
+		Varnames:       []string{},
+		Freevars:       []string{},
+		Cellvars:       []string{},
+		Filename:       "<string>",
+		Name:           "<module>",
+		Firstlineno:    1,
+		Lnotab:         "\x0d\x00",
+	}, "  1           0 SETUP_LOOP              14 (to 17)\n              3 LOAD_NAME                0 (b)\n              6 GET_ITER\n        >>    7 FOR_ITER                 6 (to 16)\n             10 STORE_NAME               1 (a)\n             13 JUMP_ABSOLUTE            7\n        >>   16 POP_BLOCK\n        >>   17 LOAD_CONST               0 (None)\n             20 RETURN_VALUE\n", nil, ""},
+	{"for a in b:\n if a:\n  break\n c = e\nelse: c = d\n", "exec", &py.Code{
+		Argcount:       0,
+		Kwonlyargcount: 0,
+		Nlocals:        0,
+		Stacksize:      2,
+		Flags:          64,
+		Code:           "\x78\x24\x00\x65\x00\x00\x44\x5d\x16\x00\x5a\x01\x00\x65\x01\x00\x72\x17\x00\x50\x6e\x00\x00\x65\x02\x00\x5a\x03\x00\x71\x07\x00\x57\x65\x04\x00\x5a\x03\x00\x64\x00\x00\x53",
+		Consts:         []py.Object{py.None},
+		Names:          []string{"b", "a", "e", "c", "d"},
+		Varnames:       []string{},
+		Freevars:       []string{},
+		Cellvars:       []string{},
+		Filename:       "<string>",
+		Name:           "<module>",
+		Firstlineno:    1,
+		Lnotab:         "\x0d\x01\x06\x01\x04\x01\x0a\x01",
+	}, "  1           0 SETUP_LOOP              36 (to 39)\n              3 LOAD_NAME                0 (b)\n              6 GET_ITER\n        >>    7 FOR_ITER                22 (to 32)\n             10 STORE_NAME               1 (a)\n\n  2          13 LOAD_NAME                1 (a)\n             16 POP_JUMP_IF_FALSE       23\n\n  3          19 BREAK_LOOP\n             20 JUMP_FORWARD             0 (to 23)\n\n  4     >>   23 LOAD_NAME                2 (e)\n             26 STORE_NAME               3 (c)\n             29 JUMP_ABSOLUTE            7\n        >>   32 POP_BLOCK\n\n  5          33 LOAD_NAME                4 (d)\n             36 STORE_NAME               3 (c)\n        >>   39 LOAD_CONST               0 (None)\n             42 RETURN_VALUE\n", nil, ""},
+	{"for a in b:\n if a:\n  continue\n c = e\nelse: c = d\n", "exec", &py.Code{
+		Argcount:       0,
+		Kwonlyargcount: 0,
+		Nlocals:        0,
+		Stacksize:      2,
+		Flags:          64,
+		Code:           "\x78\x26\x00\x65\x00\x00\x44\x5d\x18\x00\x5a\x01\x00\x65\x01\x00\x72\x19\x00\x71\x07\x00\x6e\x00\x00\x65\x02\x00\x5a\x03\x00\x71\x07\x00\x57\x65\x04\x00\x5a\x03\x00\x64\x00\x00\x53",
+		Consts:         []py.Object{py.None},
+		Names:          []string{"b", "a", "e", "c", "d"},
+		Varnames:       []string{},
+		Freevars:       []string{},
+		Cellvars:       []string{},
+		Filename:       "<string>",
+		Name:           "<module>",
+		Firstlineno:    1,
+		Lnotab:         "\x0d\x01\x06\x01\x06\x01\x0a\x01",
+	}, "  1           0 SETUP_LOOP              38 (to 41)\n              3 LOAD_NAME                0 (b)\n              6 GET_ITER\n        >>    7 FOR_ITER                24 (to 34)\n             10 STORE_NAME               1 (a)\n\n  2          13 LOAD_NAME                1 (a)\n             16 POP_JUMP_IF_FALSE       25\n\n  3          19 JUMP_ABSOLUTE            7\n             22 JUMP_FORWARD             0 (to 25)\n\n  4     >>   25 LOAD_NAME                2 (e)\n             28 STORE_NAME               3 (c)\n             31 JUMP_ABSOLUTE            7\n        >>   34 POP_BLOCK\n\n  5          35 LOAD_NAME                4 (d)\n             38 STORE_NAME               3 (c)\n        >>   41 LOAD_CONST               0 (None)\n             44 RETURN_VALUE\n", nil, ""},
 }

compile/compile_test.go

@@ -89,7 +89,7 @@ func TestCompile(t *testing.T) {
 			defer func() {
 				if r := recover(); r != nil {
 					if test.exceptionType == nil {
-						t.Errorf("%s: Got exception %v when not expecting one", test.in)
+						t.Errorf("%s: Got exception %v when not expecting one", test.in, r)
 						return
 					}
 					exc, ok := r.(*py.Exception)

compile/make_compile_test.py

@@ -140,6 +140,10 @@
     ('''while a:\n if b: continue\n b = c\n''', "exec"),
     ('''continue''', "exec", SyntaxError),
     ('''break''', "exec", SyntaxError),
+    # for
+    ('''for a in b: pass''', "exec"),
+    ('''for a in b:\n if a:\n  break\n c = e\nelse: c = d\n''', "exec"),
+    ('''for a in b:\n if a:\n  continue\n c = e\nelse: c = d\n''', "exec"),
 
 ]