comment on

Problems:

Your code won't always compile. PPCODE cannot start with variable declarations as it can be preceded by non-declarations.

PPCODE:
    int i;
    f();
[download]

should be

PREINIT:
    int i;
PPCODE:
    f();
[download]

PPCODE:
    {
        int i;
        f();
    }
[download]

Your snippets don't handle magical variables (e.g. $1, %ENV) except sometimes by chance. e.g.
```
say lengths1(substr("abc", 0, 1));  # 0
[download]
```
lengths1 uses SvLEN when it should be usingSvCUR. e.g.
```
say lengths1("abc");  # 16
[download]
```

Your snippets suffer from The Unicode bug. e.g. After fixing the above problems,

$_="\x{A0}";               say lengths1($_), "=", length($_);  # 1=1
$_="\x{A0}\x{2660}"; chop; say lengths1($_), "=", length($_);  # 2=1
[download]

lengths1 uses type-based polymorphism —something which should be avoided in Perl— and does it "poorly". e.g. After fixing the above problems,
```
say lengths1(456), "=", length(456);  # 0=3
[download]
```

In reply to Re: Yet Another XS Tutorial by ikegami
in thread Yet Another XS Tutorial by cdybedahl

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