Composing heterogeneous software with style

Transcription

1 Composing heterogeneous software with style Stephen Kell Composing... p.1/12

2 Software is heterogeneous When building software, we have a lot of choices. Composing... p.2/12

3 Heterogeneous software doesn t compose What if wedidn tchoosethesame x? x Isay... You say... language libraries GLib java.util conventions return EIO; throw new IOException(); patterns while (it!= end()) while (it.hasnext()) Let s call the whole thing off! Composing... p.3/12

4 Simple example struct wc; // opaque to client struct wc wc new(const char fname); // returns NULL and sets errno on error int wc get words(struct wc obj); int wc get characters(struct wc obj); int wc get lines(struct wc obj); int wc get all (struct wc obj, int words out, int chars out, int lines out ); void wc free(struct wc obj); Composing... p.4/12

5 Simple example struct wc; // opaque to client class WordCounter { / fields not shown... / struct wc wc new(const char fname); // returns NULL and sets errno on error public WordCounter(String filename) throws IOException { /... / } int wc get words(struct wc obj); int wc get characters(struct wc obj); int wc get lines(struct wc obj); int wc get all (struct wc obj, int words out, int chars out, int lines out ); void wc free(struct wc obj); public int getwords() { /... / } public int getcharacters() { /... / } public int getlines() { /... / } public Triple <Integer, Integer, Integer> getall () { /... / } }; // deallocation by + GC Goal: link an implementation with alternate client. Composing... p.4/12

6 Styles in one slide What is astyle? It sany set of interfaceconventions that recuracross many components Why do wecareabout styles? By describing them explicitly in someway wecan link componentsthat use different styles. How do we identify styles? Empirically! By looking at existing code throughaunifyinglens. Composing... p.5/12

7 Unifying lens Alot of codeis(orcan be) compiled down to object code. wc_new("readme") = 0x9cd6180[struct wc] wc_get_words(0x9cd6180[struct wc]) = 311 wc_get_characters(0x9cd6180[struct wc]) = 2275 wc_get_lines(0x9cd6180[struct wc]) = 59 wc_get_all(0x9cd6180[struct wc], 0xbffeed00[stack], 0xbffeecfc[stack], 0xbffeecf8[stack]) = 0 wc_free(0x9cd6180[struct wc]) = () Composing... p.6/12

8 Unifying lens Alot of codeis(orcan be) compiled down to object code. _Jv_InitClass(..., 0x6015e0[java::lang::Class],...) =... _Jv_AllocObjectNoFinalizer(..., 0x6015e0,...) = 0x9158d20 WordCounter::WordCounter(java::lang::String*)( 0x9158d20[WordCounter], 0x9ae3dc8[java::lang::String]) = WordCounter::getWords()(0x9158d20[WordCounter]) = 311 WordCounter::getCharacters()(0x9158d20[WordCounter]) = 2275 WordCounter::getLines()(0x9158d20[WordCounter]) = 59 WordCounter::getAll()(0x9158d20[WordCounter]) = 0x9f6093e8[Triple] Goal: abstract these tracesto bealike... Composing... p.6/12

9 Unifying lens Alot of codeis(orcan be) compiled down to object code. INITIALIZE STATIC WC STATE ALLOCATE WC OBJECT O INITIALIZE WC OBJECT(O) GET WORDS(O) W GET CHARACTERS(O) C GET LINES(O) L GET ALL(O) (AW, AC, AL) FINALIZE WC OBJECT(O)... so that they link directly! Composing... p.6/12

10 Cakein threeslides (1) To capture styles, we extend the Cake linking language: arule-basedlanguage fordescribing adapters declarative,black-box, convenient... Cake rules compile A.o generated adapter B.o Composing... p.7/12

11 Cakein twoslides (2) Cake code consists of rules which relate interface elements. foo() bar() A B foo (...) bar (...); Composing... p.8/12

12 Cakein twoslides (2) Cake code consists of rules which relate interface elements. foo() bar() baz(a,b) baz(b,a) A B foo (...) bar (...); baz(a, b) baz(b, a); Composing... p.8/12

13 Cakein twoslides (2) Cake code consists of rules which relate interface elements. foo() bar() baz(a,b) baz(b,a) A xyz(a) xyz(a,42) B foo (...) bar (...); baz(a, b) baz(b, a); xyz(a) xyz(a, 42); Composing... p.8/12

14 Cakein twoslides (2) Cake code consists of rules which relate interface elements. foo() bar() baz(a,b) baz(b,a) A xyz(a) xyz(a,42) struct Br struct Tr B foo (...) bar (...); baz(a, b) baz(b, a); xyz(a) xyz(a, 42); values Br Tr Composing... p.8/12

15 Cakein twoslides (2) Cake code consists of rules which relate interface elements. foo() bar() baz(a,b) baz(b,a) A xyz(a) xyz(a,42) struct Br struct Tr int sz;... int len;... B foo (...) bar (...); baz(a, b) baz(b, a); xyz(a) xyz(a, 42); values Br Tr { sz len; }; Not shown: many-to-many rules, context-sensitive rules... Composing... p.8/12

16 Cakein threeslides (3) Style rules relate concrete with abstracted interfaces. style name of style(parameter,...) { concrete form abstracted form /... / ; //... } Existing Cake compositions... A.o B.o Composing... p.9/12

17 Cakein threeslides (3) Style rules relate concrete with abstracted interfaces. style name of style(parameter,...) { concrete form abstracted form /... / ; //... } abstraction...cf. with styles: A.o B.o Composing... p.9/12

18 Style rules Styles relate more concrete with more abstract interfaces. style c89 style booleans(bool) { table BOOL bool { 0 false ; true; 1 true; } }; style shell style booleans(bool) { table BOOL bool { 0 true; false ; 1 false ; } }; Styles are applied when declaring a pre-existing component. exists c89 style booleans( elf reloc ( componenta.o )) componenta; exists shell style booleans( elf reloc ( componentb.o )) componentb; Composing... p.10/12

19 Howit works abstraction in style c89_style_booleans (BOOL) in empty style false 0 int style-enabled highlevel matching related vertically by style rules low-level conversion would ignore the latent boolean abstraction compiler chooses the most abstracting flow int false 1 in style shell_style_boolean (BOOL) in empty style Composing... p.11/12

20 Conclusions & work in progress Extra stuff in the paper: amorecomplex example (JNIdispatch) composition ofstyles preliminarystylessurvey (inappendix) moreneeded! No implementation yet! Cakecompilerincludes somefoundations backgroundproject forme(collaboratorswelcome!) Thanks for listening. Any questions? Composing... p.12/12