3 ms·

> I would expect many languages to do something similar. Of the common dynamic languages I can think of, the only ones that do something similar are Perl/Perl6

> I would expect many languages to do something similar. Of the common dynamic languages I can think of, the only ones that do something similar are Perl/Perl6 and PHP, and even they are still saner than JS. $ $((1+\2)) bash: 1+\2: syntax error: operand expected (error token is "\2") $ $((1-\2)) bash: 1-\2: syntax error: operand expected (error token is "\2") $ ruby -e"1+'2'" -e:1:in `+': String can't be coerced into Integer (TypeError) from -e:1:in `<main>' $ ruby -e"1-'2'" -e:1:in `-': String can't be coerced into Integer (TypeError) from -e:1:in `<main>' $ python3 -c"1+'2'" Traceback (most recent call last): File "<string>", line 1, in <module> TypeError: unsupported operand type(s) for +: 'int' and 'str' $ python3 -c"1-'2'" Traceback (most recent call last): File "<string>", line 1, in <module> TypeError: unsupported operand type(s) for -: 'int' and 'str' >>> exit() $ python2 -c"1+'2'" Traceback (most recent call last): File "<string>", line 1, in <module> TypeError: unsupported operand type(s) for +: 'int' and 'str' $ python2 -c"1-'2'" Traceback (most recent call last): File "<string>", line 1, in <module> TypeError: unsupported operand type(s) for -: 'int' and 'str' $ perl -e'print 1+"2"."\n"' 3 $ perl -e'print 1-"2"."\n"' -1 $ perl6 -e"say 1+'2'" 3 $ perl6 -e"say 1-'2'" -1 $ php -r'echo 1+"2","\n";' 3 $ php -r'echo 1-"2","\n";' -1 $ racket -e '(+ 1 "2")' +: contract violation expected: number? given: "2" argument position: 2nd other arguments...: 1 $ racket -e '(- 1 "2")' -: contract violation expected: number? given: "2" argument position: 2nd other arguments...: 1 $ sbcl This is SBCL 1.3.18, an implementation of ANSI Common Lisp. More information about SBCL is available at <http://www.sbcl.org/>. SBCL is free software, provided as is, with absolutely no warranty. It is mostly in the public domain; some portions are provided under BSD-style licenses. See the CREDITS and COPYING files in the distribution for more information. * (+ 1 "2") debugger invoked on a TYPE-ERROR in thread #<THREAD "main thread" RUNNING {1001F0EC33}>: The value "2" is not of type NUMBER when binding SB-KERNEL::Y Type HELP for debugger help, or (SB-EXT:EXIT) to exit from SBCL. restarts (invokable by number or by possibly-abbreviated name): 0: [ABORT] Exit debugger, returning to top level. (SB-KERNEL:TWO-ARG-+ 1 "2") [external] 0] 0 * (- 1 "2") debugger invoked on a TYPE-ERROR in thread #<THREAD "main thread" RUNNING {1001F0EC33}>: The value "2" is not of type NUMBER when binding SB-KERNEL::Y Type HELP for debugger help, or (SB-EXT:EXIT) to exit from SBCL. restarts (invokable by number or by possibly-abbreviated name): 0: [ABORT] Exit debugger, returning to top level. (SB-KERNEL:TWO-ARG-- 1 "2") [external] 0] 0 * (exit) $ erl Erlang/OTP 19 [erts-8.3] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:10] [hipe] [kernel-poll:false] [dtrace] Eshell V8.3 (abort with ^G) 1> 1+"2". ** exception error: an error occurred when evaluating an arithmetic expression in operator +/2 called as 1 + "2" 2> 1-"2". ** exception error: an error occurred when evaluating an arithmetic expression in operator -/2 called as 1 - "2" 3> halt(). $ elixir -e '1+"2"' ** (ArithmeticError) bad argument in arithmetic expression :erlang.+(1, "2") (stdlib) erl_eval.erl:670: :erl_eval.do_apply/6 (elixir) lib/code.ex:170: Code.eval_string/3 $ elixir -e '1-"2"' ** (ArithmeticError) bad argument in arithmetic expression :erlang.-(1, "2") (stdlib) erl_eval.erl:670: :erl_eval.do_apply/6 (elixir) lib/code.ex:170: Code.eval_string/3

kazinator 9y ago
In the awk macro of TXR Lisp, I wanted to provide some of the convenience of the "duck typing" in Awk, whereby a string which looks like a number can be used like one. Instead of supporting such a thing directly (which I consider a computer science flunk job in language design) I came up with a field conversion facility that has a succinct syntax: clear and unobtrusive. http://www.nongnu.org/txr/txr-manpage.html#N-018CCE37 http://www.nongnu.org/txr/txr-manpage.html#N-018CCE37 This demonstrates some of it: 1> (awk (t (fconv i) (prinl f))) 1 2 3 4 5 (1 "2" "3" "4" "5") nil 2> (awk (t (fconv i : r) (prinl f))) 1 2 3 4 5 (1 2.0 3.0 4.0 5.0) nil 3> (awk (t (fconv : i : r) (prinl f))) 1 2 3 4 5 (1 2 3 4 5.0) nil 4> (awk (t (fconv i : r : i) (prinl f))) 1 2 3 4 5 (1 2.0 3.0 4.0 5) There are more conversion specifiers than just r and i. There can be any number in a row before the first colon, in the middle, or after the last colon. Conversions are matched with fields and applied. If a colon occurs, conversions after the colon are repeatedly applied to the remaining fields in cyclic repetition. If two colons occur, conversions after the second colon are applied to the trailing fields. There is intelligent prioritizing when these rules overlap. There are conversions with a z suffix which treat junk as zero: 8> (awk (t (fconv : iz) (prinl f))) a b c 1 2 3 (0 0 0 1 2 3) Without this, you get nil which will blow up if used as a number -- but you can test for it and handle the situation rather than getting a silent zero: 9> (awk (t (fconv : i) (prinl f))) a b c 1 2 3 (nil nil nil 1 2 3) Basically the whole "anything can be used as a number, and junk makes zero" nonsense can be avoided with only a small reduction in code golfing. Textual duck typing is a wrongheaded solution for an ergonomic problem, which sacrifices correctness and clarify of data representation for the sake of absolutely minimizing the program character count.

kazinator 9y ago

In the awk macro of TXR Lisp, I wanted to provide some of the convenience of the "duck typing" in Awk, whereby a string which looks like a number can be used like one. Instead of supporting such a thing directly (which I consider a computer science flunk job in language design) I came up with a field conversion facility that has a succinct syntax: clear and unobtrusive. http://www.nongnu.org/txr/txr-manpage.html#N-018CCE37 http://www.nongnu.org/txr/txr-manpage.html#N-018CCE37 This demonstrates some of it: 1> (awk (t (fconv i) (prinl f))) 1 2 3 4 5 (1 "2" "3" "4" "5") nil 2> (awk (t (fconv i : r) (prinl f))) 1 2 3 4 5 (1 2.0 3.0 4.0 5.0) nil 3> (awk (t (fconv : i : r) (prinl f))) 1 2 3 4 5 (1 2 3 4 5.0) nil 4> (awk (t (fconv i : r : i) (prinl f))) 1 2 3 4 5 (1 2.0 3.0 4.0 5) There are more conversion specifiers than just r and i. There can be any number in a row before the first colon, in the middle, or after the last colon. Conversions are matched with fields and applied. If a colon occurs, conversions after the colon are repeatedly applied to the remaining fields in cyclic repetition. If two colons occur, conversions after the second colon are applied to the trailing fields. There is intelligent prioritizing when these rules overlap. There are conversions with a z suffix which treat junk as zero: 8> (awk (t (fconv : iz) (prinl f))) a b c 1 2 3 (0 0 0 1 2 3) Without this, you get nil which will blow up if used as a number -- but you can test for it and handle the situation rather than getting a silent zero: 9> (awk (t (fconv : i) (prinl f))) a b c 1 2 3 (nil nil nil 1 2 3) Basically the whole "anything can be used as a number, and junk makes zero" nonsense can be avoided with only a small reduction in code golfing. Textual duck typing is a wrongheaded solution for an ergonomic problem, which sacrifices correctness and clarify of data representation for the sake of absolutely minimizing the program character count.