arc> (defop hello req (pr "hello world"))
  #<procedure:gs1665>
  arc> (asv)
  The syntax of the command is incorrect.
  ready to serve port 8080

  open-output-file: cannot open output file: "C:\User\Programming\Arc\arc-wiki\arc
  /logs/srv-2008-02-26" (The system cannot find the path specified.; errno=3)
  
   === context ===
   srvlog
   gs1086
   handle-request-thread

It looks like (asv) calls (serve port), which calls (ensure-dir logdir* ), which would seem to be our culprit

  arc> (ensure-dir logdir* )
  The syntax of the command is incorrect.
  nil

  (system (string "mkdir -p " path))

  (mkdir path)

http://arclanguage.org/item?id=3442

  G:\Anarki\arc-wiki>mzscheme -m -f as.scm
  compile: bad yntax; function application is not allowed, because no %app syntax transformer is bound in: (quote nil)

   === context ===
  G:\Anarki\arc-wiki\ac.scm:978:0: aload1

  >

  arc> (load "news.arc")
  nil
  arc> (nsv)
  The syntax of the command is incorrect.

  The syntax of the command is incorrect.
 
  The syntax of the command is incorrect.

  The syntax of the command is incorrect.

  load items: Error: "directory-list: could not open \"G:\\Anarki\\arc-wiki\\arc\\news\\story\\\" (The system cannot find the path specified.; errno=3)"
  arc>

  (let pr [die]
    (prn 53)) ; doesn't die.

  Use (quit) to quit, (tl) to return here after an interrupt.
  arc> (defop hello req (pr "hello world"))
  #<procedure:gs1657>
  arc> (asv)
  The syntax of the command is incorrect.
  ready to serve port 8080

  'uname' is not recognized as an internal or external command,
  operable program or batch file.
  make-string: expects argument of type <non-negative exact integer>; given -1
  
   === context ===
   cut
   date
   memodate
   srvlog
   gs1078
   handle-request-thread

Second, in Lexicons.pdf, you write the following about hygiene:

"The solution, in a nutshell, is: Within a backquote, precede any function call that you want to be non-shadowable with a comma."

I find this rather ironic considering all the ado on the forum about hygienic macros. (If this works then why did people both writing all those posts about hygiene? Not that I'm saying it doesn't...)

http://arclanguage.org/item?id=3422 http://arclanguage.org/item?id=2962 http://arclanguage.org/item?id=886

So does it really work? (And if it works is it the Right Thing to do?) I suppose there is no possible way to shadow foo in

  (let foo (fn args (apply prs "foo:" args))
    (mac bar args `(,foo ,@args)))

  (mac baz args `(prs "baz:" ,@args)) ; would do this in a let if macros were first class
  (mac bad args `(,baz ,@args))

And if this is the Right Way to fix hygiene, should macro writers be expected to do this for every single macro they ever write?

Doesn't work in Arc2, but works in Anarki. Also doesn't work with macros, as you say. Macros aren't as big a deal however, because they cannot be shadowed by let or def, only by other macros with the same name.

While I find this an interesting approach, one problem I see is that this only works as long as Arc is an interpreter. Embedding foo into the s-expr mixes up runtime values (the function foo) and expand-time values (the s-expr).

In a compiler, you would have one runtime in which foo exists, and another runtime (the expand-time, at a higher "meta level") in which the s-expr exists, and the two runtimes can never meet -- they exist on different levels of the reflective tower.

(I am not entirely sure of this, and in any case it does not apply to Lexicons.)

It turns out that the current implementation has a serious bug, so at the moment the answer is no, it doesn't. But the situation appears to be salvageable.

> If this works then why did people both writing all those posts about hygiene?

  arc> (macex '(compose no litmatch))
  (fn gs1639 (no (apply litmatch gs1639)))
  arc> (macex '(complement litmatch))
  (fn gs1641 (no (apply litmatch gs1641)))
  arc> ((compose no litmatch) "a" "aston")
  nil
  arc> ((complement litmatch) "a" "aston")
  Error: "vector-ref: expects type <non-negative exact integer> as 2nd argument,
  given: \"a\"; other arguments were: #3(tagged mac #<procedure>)"

  (apply or args)

  (eval (cons or args))

http://arclanguage.org/item?id=2610

My solution calls the first parameter as a function when the object in the functional position is a number or symbol. The math operators are then overridden in infix.arc to do infix evaluation when they get a function in their parameter list.

This eliminates the need for explicit infix and prefix macros (the sqrt call below uses prefix notation in the middle of the infix expression):

  (3 + 4 * 5 - (sqrt 36))

I definitely think there is a lot to improve on, and your version of the infix macro has some features mine doesn't (e.g. associativity).

I don't know if my version would work for comparison logic... The program actually switches when the functional position is a number or symbol, and since t and nil are symbols, it would theoretically work.... But point is, my current version is not very extensible.

I'm trying to let the user specify what is/isn't infix, which is why I detect operators rather than numbers. I want the macro to have uses beyond infix arithmetic e.g. parsers expressed in BNF.

Also, mine is written entirely in Arc, so it's a good demonstration of what Arc can do, not to mention good practice for me.