A talk about XS Fun, an easy-going tutorial to Perl XS: https://github.com/xsawyerx/xs-fun This talk was originally given at Cluj.pm, on November 7th, 2013.

1. XS Fun
Sawyer X ( @PerlSawyer)

2. XS is...
A glue layer between Perl and C/C++
Sections, macros, functions
Requires knowledge with C, Perl API, XS, typemaps
Written by our very best
Complex, difficult, strenuous, laborious, painful, formidable
(additional words can be found in thesaurus.com )
An impediment to Modern Perl

4. XS is
misunderstood
No need to be an expert
Basic Perl API is simple
XS is not too difficult
Lots of options
All documented

5. Except...
... except those that aren't documented
... except that the official tutorial sucks
... except that there's no better (or any other full) tutorial
(at least not one I could find)

6. I guess I'll write one then!

7. XS Fun
A tutorial making XS fun
Starts easy, progresses slowly
Split to chapters, each taking a small task
A lot of explanations for beginners
All examples work

8. Features
Already on Github
A few chapters already covered
Functions (XS, C)
Constructor
Simple methods

9. Missing
Complex methods
Converting objects with typemaps
Advanced XS

10. Quick glossary
SV = Scalar Value
Of:
IV = Integer Value (m $ = - 0
y i
3)
UV = Unsigned Integer Value (m $ = 3 0 . .
y u
00.)
NV = Double Value (m $ = 3 . 7 )
y d
071
PV = String Value (m $ = ' e l w r d )
y s
hlo ol'
SV = (another) Scalar Value
AH = Array Value (m @ = q < e l w r d )
y a
whlo ol>
HV = Hash Value (m % = ( h l o = ' o l ' )
y h
el > wrd )
RV = Reference Value (m $ a h e = h
y hsrf
%)
That's it for now

11. Examples

12. XSFun.pm
pcaeXFn
akg Su;
uesrc;
s tit
uewrig;
s anns
ueEpre;
s xotr
ueXLae;
s Sodr
uebs 'xotr;
s ae Epre'
or$ESO
u VRIN
='.0'
001;
or%XOTTG =('l'= [wgtvrin])
u EPR_AS
al > q<e_eso> ;
or@XOTO
u EPR_K =(@ $XOTTG{al}})
{ EPR_AS'l'
;
XLae:la('Su' $ESO )
Sodr:od XFn, VRIN ;
1
;

13. XSFun.xs
#nld "XENh
icue ETR."
#nld "elh
icue pr."
#nld "SBh
icue XU."
#nld "poth
icue ppr."
MDL =XFn
OUE
Su
PCAE=XFn
AKG
Su
dul
obe
adnmesdul a dul b
d_ubr(obe , obe )
CD:
OE
RTA =a+b
EVL
;
OTU:
UPT
RTA
EVL
S *
V
adnmespr(V*,S *)
d_ubr_elS a V b
CD:
OE
{
cntdul sm=SN()+SN()
os obe u
vVa
vVb;
RTA =nwVvsm;
EVL
eSn(u)
}
OTU:RTA
UPT EVL

14. XSFun.xs (more)
#nld <hoarn.>
icue crmpith
/ i tecd scin*
* n h oe eto /
cntca *
os hr
gtvrin)
e_eso(
CD:
OE
RTA =crmpitgtvrin)
EVL
hoarn_e_eso(;
OTU:RTA
UPT EVL
#i vrint
n eso.:
ueXFn'al;
s Su :l'
i(gtvrin) '..' 'hoarn vrini 600 )
s e_eso(, 600, crmpit eso s ..' ;
tvrint. o
/eso. . k
Altssscesu.
l et ucsfl
Fls1 Tss1 0wlcoksc (00 ur 00 ss+ 00 cs
ie=, et=,
allc es
.3 s
.1 y
.2 ur
00 cy = 00 CU
.0 ss
.6 P)
Rsl:PS
eut AS

15. Audio::Chromaprint
Interface to Chromaprint library

16. Audio/Chromaprint.pm
pcaeAdo:hoarn;
akg ui:Crmpit
uesrc;
s tit
uewrig;
s anns
ueXLae;
s Sodr
or$ESO ='.0'
u VRIN
001;
XLae:la('ui:Crmpit,$ESO )
Sodr:od Ado:hoarn' VRIN ;
1
;

17. Chromaprint.xs
#nld "XENh
icue ETR."
#nld "elh
icue pr."
#nld "SBh
icue XU."
#nld "poth
icue ppr."
#nld <hoarn.>
icue crmpith
MDL =Ado:hoarn
OUE
ui:Crmpit
PCAE=Ado:hoarn
AKG
ui:Crmpit

18. Chromaprint.xs
cntca *
os hr
vrinS *ef
eso(V sl)
CD:
OE
RTA =crmpitgtvrin)
EVL
hoarn_e_eso(;
OTU:RTA
UPT EVL

19. Constructor
#I Pr:
n el
sbnw{bes{,sit}
u e
ls } hf
#o..
r.
sbnw{
u e
m $ls =sit #o $[]
y cas
hf;
r _0
m %ah =(;
y hs
)
m $ef =hs;
y sl
%ah
rtr bes$ef $ls;
eun ls sl, cas
}

20. #Pr-el
uePr
sbnw{
u e
m $ls =sit #o $[]
y cas
hf;
r _0
m %ah =(;
y hs
)
m $ef =hs;
y sl
%ah
rtr bes$ef $ls;
eun ls sl, cas
}
/ i X *
* n S /
S *
V
nw cntca *ls )
e( os hr cas
CD:
OE
/ Cet ahs *
* rae
ah /
H*hs =nwV)
V ah
eH(;
/ Cet arfrnet tehs *
* rae
eeec o h ah /
S*cntsl =nwVnic (V*hs )
V os ef
eR_on( S )ah ;
/ besit tepoe pcae*
* ls no h rpr akg /
RTA =s_ls(sl,g_tsp(cas 0))
EVL
vbes ef vsahv ls,
;
OTU:RTA
UPT EVL

21. Conclusions
XS is not that complex
XS can be fun
You can do it!

22. Thank you
Homework:
github.com/xsawyerx/xs-fun
perldoc perlguts
perldoc perlapi
perldoc perlxs