Function calls
-----
<?php

// function name variations
a();
$a();
${'a'}();
$$a();
$$$a();
$a['b']();
$a{'b'}();

// array dereferencing
a()['b'];
-----
array(
    0: Expr_FuncCall(
        name: Name(
            parts: array(
                0: a
            )
        )
        args: array(
        )
    )
    1: Expr_FuncCall(
        name: Expr_Variable(
            name: a
        )
        args: array(
        )
    )
    2: Expr_FuncCall(
        name: Expr_Variable(
            name: Scalar_String(
                value: a
            )
        )
        args: array(
        )
    )
    3: Expr_FuncCall(
        name: Expr_Variable(
            name: Expr_Variable(
                name: a
            )
        )
        args: array(
        )
    )
    4: Expr_FuncCall(
        name: Expr_Variable(
            name: Expr_Variable(
                name: Expr_Variable(
                    name: a
                )
            )
        )
        args: array(
        )
    )
    5: Expr_FuncCall(
        name: Expr_ArrayDimFetch(
            var: Expr_Variable(
                name: a
            )
            dim: Scalar_String(
                value: b
            )
        )
        args: array(
        )
    )
    6: Expr_FuncCall(
        name: Expr_ArrayDimFetch(
            var: Expr_Variable(
                name: a
            )
            dim: Scalar_String(
                value: b
            )
        )
        args: array(
        )
    )
    7: Expr_ArrayDimFetch(
        var: Expr_FuncCall(
            name: Name(
                parts: array(
                    0: a
                )
            )
            args: array(
            )
        )
        dim: Scalar_String(
            value: b
        )
    )
)