* Re: [9fans] rc: fn name @{block} [not found] <CAG3N4d81u5p-WVz5aXnjGE8ON5BMd-AEr0xRMjP+Ug4G9Db=UA@mail.gmail.c> @ 2012-03-30 12:52 ` erik quanstrom 2012-03-30 15:48 ` erik quanstrom 1 sibling, 0 replies; 8+ messages in thread From: erik quanstrom @ 2012-03-30 12:52 UTC (permalink / raw) To: 9fans On Fri Mar 30 07:43:57 EDT 2012, yarikos@gmail.com wrote: > "fn name @{block}" doesn't cause block to run in a sub-shell, although > it accepts the syntax. > Is it someting should not be tried, or something shoud be fixed? should be fixed. - erik ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [9fans] rc: fn name @{block} [not found] <CAG3N4d81u5p-WVz5aXnjGE8ON5BMd-AEr0xRMjP+Ug4G9Db=UA@mail.gmail.c> 2012-03-30 12:52 ` [9fans] rc: fn name @{block} erik quanstrom @ 2012-03-30 15:48 ` erik quanstrom 2012-03-30 15:56 ` Yaroslav [not found] ` <CAG3N4d_5f97O85mwGnrawwiGQAPN+K6CTQ0vbpk2EexkpbH0qg@mail.gmail.c> 1 sibling, 2 replies; 8+ messages in thread From: erik quanstrom @ 2012-03-30 15:48 UTC (permalink / raw) To: 9fans On Fri Mar 30 07:44:12 EDT 2012, yarikos@gmail.com wrote: > "fn name @{block}" doesn't cause block to run in a sub-shell, although > it accepts the syntax. > Is it someting should not be tried, or something shoud be fixed? you've misunderstood the current grammar. you have defined 2 functions name and '@' as {block}. the binding, illustrated with parens is fn (name @) {block} the production in the grammer is FN words brace but since once production for words is words -> keyword, a keyword is a valid function name. so if you have fn @{echo hi, mom} then ladd; fn @{echo hi, mom} # space makes no difference ladd; whatis @ fn @ {echo hi, mom} ladd; @ ladd; '@' hi, mom one could argue that this is a misfeature, since you can define a function named 'for' or 'if' or '~' or '!'. i don't currently see how disallowing keywords in function names would be a problem, but it would require at least 1 new production in the grammar. note that "fn {echo bar}" is also legal, but doesn't do anything. i've attached a change to the grammar that addresses this oddity. - erik ---- broken! diffy -c syn.y /n/dump/2012/0330/sys/src/cmd/rc/syn.y:29,35 - syn.y:29,35 struct tree *tree; }; %type<tree> line paren brace body cmdsa cmdsan assign epilog redir - %type<tree> cmd simple first word comword keyword words wordsnl + %type<tree> cmd simple first word nkword comword keyword nkwords words wordsnl %type<tree> NOT FOR IN WHILE IF TWIDDLE BANG SUBSHELL SWITCH FN BREAK %type<tree> WORD REDIR DUP PIPE %% /n/dump/2012/0330/sys/src/cmd/rc/syn.y:81,88 - syn.y:81,88 | assign cmd %prec BANG {$$=mung3($1, $1->child[0], $1->child[1], $2);} | BANG cmd {$$=mung1($1, $2);} | SUBSHELL cmd {$$=mung1($1, $2);} - | FN words brace {$$=tree2(FN, $2, $3);} - | FN words {$$=tree1(FN, $2);} + | FN nkwords brace {$$=tree2(FN, $2, $3);} + | FN nkwords {$$=tree1(FN, $2);} simple: first | simple word {$$=tree2(ARGLIST, $1, $2);} | simple redir {$$=tree2(ARGLIST, $1, $2);} /n/dump/2012/0330/sys/src/cmd/rc/syn.y:91,96 - syn.y:91,98 word: keyword {lastword=1; $1->type=WORD;} | comword | word '^' word {$$=tree2('^', $1, $3);} + nkword: comword + | word '^' word {$$=tree2('^', $1, $3);} comword: '$' word {$$=tree1('$', $2);} | '$' word SUB words ')' {$$=tree2(SUB, $2, $4);} | '"' word {$$=tree1('"', $2);} /n/dump/2012/0330/sys/src/cmd/rc/syn.y:107,109 - syn.y:109,113 | words: {$$=(struct tree*)0;} | words word {$$=tree2(WORDS, $1, $2);} + nkwords: {$$=(struct tree*)0;} + | nkwords nkword {$$=tree2(WORDS, $1, $2);} ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [9fans] rc: fn name @{block} 2012-03-30 15:48 ` erik quanstrom @ 2012-03-30 15:56 ` Yaroslav [not found] ` <CAG3N4d_5f97O85mwGnrawwiGQAPN+K6CTQ0vbpk2EexkpbH0qg@mail.gmail.c> 1 sibling, 0 replies; 8+ messages in thread From: Yaroslav @ 2012-03-30 15:56 UTC (permalink / raw) To: Fans of the OS Plan 9 from Bell Labs > you've misunderstood the current grammar. you have defined 2 functions > name and '@' as {block}. the binding, illustrated with parens is > fn (name @) {block} > the production in the grammer is > FN words brace > but since once production for words is words -> keyword, a keyword > is a valid function name. Then, how would you explain this: term% fn x @{x=y} term% whatis x fn x {x=y} term% fn 'x @'{x=y} term% whatis 'x @' fn 'x @' {x=y} ^ permalink raw reply [flat|nested] 8+ messages in thread
[parent not found: <CAG3N4d_5f97O85mwGnrawwiGQAPN+K6CTQ0vbpk2EexkpbH0qg@mail.gmail.c>]
* Re: [9fans] rc: fn name @{block} [not found] ` <CAG3N4d_5f97O85mwGnrawwiGQAPN+K6CTQ0vbpk2EexkpbH0qg@mail.gmail.c> @ 2012-03-30 16:01 ` erik quanstrom 2012-03-30 16:19 ` Yaroslav 0 siblings, 1 reply; 8+ messages in thread From: erik quanstrom @ 2012-03-30 16:01 UTC (permalink / raw) To: 9fans > Then, how would you explain this: it should be self-explanitory. > term% fn x @{x=y} > term% whatis x > fn x {x=y} creates to functions x and '@' definition {x=y}. > term% fn 'x @'{x=y} > term% whatis 'x @' > fn 'x @' {x=y} quoting disables any interpretation in rc; this isn't the bourne shell. what the parser sees is the following tokens. FN WORD '{' WORD '=' WORD '}' in this case 'x' for some x should be interpreted differently than for shell input. the *name* of the token is 'x', not its value. (such tokens typically have no value.) it does not matter that the first WORD is defined as 'x @'. - erik ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [9fans] rc: fn name @{block} 2012-03-30 16:01 ` erik quanstrom @ 2012-03-30 16:19 ` Yaroslav 2012-03-30 16:50 ` Anthony Sorace 0 siblings, 1 reply; 8+ messages in thread From: Yaroslav @ 2012-03-30 16:19 UTC (permalink / raw) To: Fans of the OS Plan 9 from Bell Labs >> term% fn x @{x=y} >> term% whatis x >> fn x {x=y} > > creates to functions x and '@' definition {x=y}. The question is why it discards @ here? ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [9fans] rc: fn name @{block} 2012-03-30 16:19 ` Yaroslav @ 2012-03-30 16:50 ` Anthony Sorace 2012-03-30 17:08 ` Yaroslav 0 siblings, 1 reply; 8+ messages in thread From: Anthony Sorace @ 2012-03-30 16:50 UTC (permalink / raw) To: Fans of the OS Plan 9 from Bell Labs [-- Attachment #1: Type: text/plain, Size: 501 bytes --] On Mar 30, 2012, at 12:19 , Yaroslav wrote: >>> term% fn x @{x=y} >>> term% whatis x >>> fn x {x=y} >> >> creates to functions x and '@' definition {x=y}. > > The question is why it discards @ here? Erik's point is that rc isn't discarding it. You have a list. It sets x equal to that function, then sets @ equal to that same function. : iota; fn x @{x=y} : iota; whatis x fn x {x=y} : iota; whatis '@' fn @ {x=y} When you quote the 'x @', that whole thing becomes one word. [-- Attachment #2: Message signed with OpenPGP using GPGMail --] [-- Type: application/pgp-signature, Size: 210 bytes --] ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [9fans] rc: fn name @{block} 2012-03-30 16:50 ` Anthony Sorace @ 2012-03-30 17:08 ` Yaroslav 0 siblings, 0 replies; 8+ messages in thread From: Yaroslav @ 2012-03-30 17:08 UTC (permalink / raw) To: Fans of the OS Plan 9 from Bell Labs I see now. Thank you guys! > Erik's point is that rc isn't discarding it. You have a list. It sets x > equal to that function, then sets @ equal to that same function. > > : iota; fn x @{x=y} > : iota; whatis x > fn x {x=y} > : iota; whatis '@' > fn @ {x=y} ^ permalink raw reply [flat|nested] 8+ messages in thread
* [9fans] rc: fn name @{block} @ 2012-03-30 11:43 Yaroslav 0 siblings, 0 replies; 8+ messages in thread From: Yaroslav @ 2012-03-30 11:43 UTC (permalink / raw) To: 9fans "fn name @{block}" doesn't cause block to run in a sub-shell, although it accepts the syntax. Is it someting should not be tried, or something shoud be fixed? ^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2012-03-30 17:08 UTC | newest] Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- [not found] <CAG3N4d81u5p-WVz5aXnjGE8ON5BMd-AEr0xRMjP+Ug4G9Db=UA@mail.gmail.c> 2012-03-30 12:52 ` [9fans] rc: fn name @{block} erik quanstrom 2012-03-30 15:48 ` erik quanstrom 2012-03-30 15:56 ` Yaroslav [not found] ` <CAG3N4d_5f97O85mwGnrawwiGQAPN+K6CTQ0vbpk2EexkpbH0qg@mail.gmail.c> 2012-03-30 16:01 ` erik quanstrom 2012-03-30 16:19 ` Yaroslav 2012-03-30 16:50 ` Anthony Sorace 2012-03-30 17:08 ` Yaroslav 2012-03-30 11:43 Yaroslav
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