(x) => x + 1

Short talk about adding (x) => x + 1 anonymous functions to R

Transcript

1. (x) => x + 1 Andrew Craig Tokyo.R #87 2020/08/01
2. (x) => x + 1 Changing R to add new syntax
3. Me • Andrew Craig • Data Scientist • GitHub: @andycraig • Twitter: @andrew_cb2 • Professional: R, Python • Hobby: Clojure, APL
4. > sapply(c(1, 2), function(x) x + 1) [1] 2 3
5. > sapply(c(1, 2), function(x) x + 1) [1] 2 3
6. > sapply(c(1, 2), function(x) x + 1) [1] 2 3
7. > sapply(c(1, 2), function(x) x + 1) [1] 2 3 long!
8. Future R? useR! 2020 talk by Luke Tierney (Syntax Extensions starts at 1:07:00) https://www.youtube.com/watch?v=X_eDHNVceCU&feature=youtu.be
9. Future R? useR! 2020 talk by Luke Tierney (Syntax Extensions starts at 1:07:00) https://www.youtube.com/watch?v=X_eDHNVceCU&feature=youtu.be 1. \(x) x + 1 2. @(x) x + 1 3. (x) => x + 1
10. Future R? 1. \(x) x + 1 # Haskell style 2. @(x) x + 1 # Matlab style 3. (x) => x + 1 # JavaScript style
11. Future R? 1. \(x) x + 1 # EASY 2. @(x) x + 1 # EASY 3. (x) => x + 1 # DIFFICULT
12. Future R? 1. \(x) x + 1 # EASY 2. @(x) x + 1 # EASY 3. (x) => x + 1 # DIFFICULT
13. Future R? 1. \(x) x + 1 # EASY 2. @(x) x + 1 # EASY 3. (x) => x + 1 # DIFFICULT Let’s try it!
14. How?!?!
15. R source code doc etc m4 po share src tests tools ChangeLog config.site configure https://cran.rstudio.com/src/base/R-3/R-3.6.3.tar.gz
16. R source code appl extra gnuwin32 include library main modules nmath scripts unix Makefile.in https://cran.rstudio.com/src/base/R-3/R-3.6.3.tar.gz
17. R source code g_her_glyph.c g_her_metr.h g_jis.h gevents.c gram.c gram.y gram-ex.c graphics.c grep.c gzio.h identical.c https://cran.rstudio.com/src/base/R-3/R-3.6.3.tar.gz
18. R source code gram.y???
19. R source code gram.y??? grammar file
20. gram.y
21. gram.y | FUNCTION '(' formlist ')' cr expr_or_assign %prec { $$ = xxdefun($1,$3,$6,&@$); se | IF ifcond expr_or_assign ELSE expr_or_assign { | FOR forcond expr_or_assign %prec FOR { $$ = xxf | WHILE cond expr_or_assign { $$ = xxwhile($1,$2,$ | expr LBB sublist ']' ']' { $$ = xxsubscript($1,
22. gram.y: (x) => x + 1
23. gram.y: (x) => x + 1 "FUNCTION", "'function'", "EQ_ASSIGN", "'='", "RIGHT_ASSIGN", "'->'", "LBB", "'[['", "FOR", "'for'", "IN", "'in'",
24. gram.y: (x) => x + 1 "FUNCTION", "'function'", "EQ_ASSIGN", "'='", "RIGHT_ASSIGN", "'->'", "ANON", "'=>'", "LBB", "'[['", "FOR", "'for'", "IN", "'in'",
25. gram.y: (x) => x + 1 | '(' SYMBOL ')' ANON expr_or_assign { $$ = xxfirstformal0($2); mo $$ = xxdefunanon($$,$5,&@$); | '(' SYMBOL EQ_ASSIGN expr ')' ANON expr_or_assign { $$ = xxfirstformal1($2,$4); $$ = xxdefunanon($$,$7,&@$); | '(' formlist ')' ANON expr_or_assign { $$ = xxdefunanon($2,$5,&@$);
26. gram.y: (x) => x + 1 | '(' SYMBOL ')' ANON expr_or_assign { $$ = xxfirstformal0($2); mo $$ = xxdefunanon($$,$5,&@$); | '(' SYMBOL EQ_ASSIGN expr ')' ANON expr_or_assign { $$ = xxfirstformal1($2,$4); $$ = xxdefunanon($$,$7,&@$); | '(' formlist ')' ANON expr_or_assign { $$ = xxdefunanon($2,$5,&@$);
27. By the way … What is this? (y = 3)
28. By the way … What is this? (y = 3) => y + 1 It was a new function!
29. By the way … What is this? (y = 3) It was NOT a new function!
30. By the way … What is this? (y = 3) It was NOT a new function! DIFFICULT PART
31. By the way … What is this? (y = 3) It was NOT a new function! Needs grammar change too
32. gram.y: (x) => x + 1 gram.y → gram.c
33. gram.y: (x) => x + 1 gram.y → gram.c $ bison -d src/main/gram.y -o src/main/gram.c
34. gram.y: (x) => x + 1 gram.y → gram.c $ bison -d src/main/gram.y -o src/main/gram.c Compile $ make
35. gram.y: (x) => x + 1 gram.y → gram.c $ bison -d src/main/gram.y -o src/main/gram.c Compile $ make Creates R with (x) => x + 1!
36. Test > sapply(c(1, 2), function(x) x + 1) [1] 2 3
37. Test > sapply(c(1, 2), function(x) x + 1) [1] 2 3 > sapply(c(1, 2), (x) => x + 1)
38. Test > sapply(c(1, 2), function(x) x + 1) [1] 2 3 > sapply(c(1, 2), (x) => x + 1) [1] 2 3
39. Test > sapply(c(1, 2), function(x) x + 1) [1] 2 3 > sapply(c(1, 2), (x) => x + 1) [1] 2 3
40. Code https://github.com/andycraig/r-anonymous-functions gram.y: +38 lines -6 lines
41. You can program in R You can program R