1isset() and empty()
2-----
3<?php
4isset($a);
5isset($a, $b, $c);
6
7empty($a);
8empty(foo());
9empty(array(1, 2, 3));
10-----
11array(
12    0: Stmt_Expression(
13        expr: Expr_Isset(
14            vars: array(
15                0: Expr_Variable(
16                    name: a
17                )
18            )
19        )
20    )
21    1: Stmt_Expression(
22        expr: Expr_Isset(
23            vars: array(
24                0: Expr_Variable(
25                    name: a
26                )
27                1: Expr_Variable(
28                    name: b
29                )
30                2: Expr_Variable(
31                    name: c
32                )
33            )
34        )
35    )
36    2: Stmt_Expression(
37        expr: Expr_Empty(
38            expr: Expr_Variable(
39                name: a
40            )
41        )
42    )
43    3: Stmt_Expression(
44        expr: Expr_Empty(
45            expr: Expr_FuncCall(
46                name: Name(
47                    name: foo
48                )
49                args: array(
50                )
51            )
52        )
53    )
54    4: Stmt_Expression(
55        expr: Expr_Empty(
56            expr: Expr_Array(
57                items: array(
58                    0: ArrayItem(
59                        key: null
60                        value: Scalar_Int(
61                            value: 1
62                        )
63                        byRef: false
64                        unpack: false
65                    )
66                    1: ArrayItem(
67                        key: null
68                        value: Scalar_Int(
69                            value: 2
70                        )
71                        byRef: false
72                        unpack: false
73                    )
74                    2: ArrayItem(
75                        key: null
76                        value: Scalar_Int(
77                            value: 3
78                        )
79                        byRef: false
80                        unpack: false
81                    )
82                )
83            )
84        )
85    )
86)
87