Opened 3 years ago

Last modified 7 months ago

#349 new defect

ANSI lacuna: interaction between SHARPSIGN-LEFT-PARENTHENSIS and backquote splice operator

Reported by: mevenson Owned by:
Priority: major Milestone: 1.5.0
Component: interpreter Version: 1.3.0-dev
Keywords: ansi lacunae Cc:
Parent Tickets:

Description

Faré notes in <http://article.gmane.org/gmane.lisp.armedbear.devel/3101>:

What should this form read as?
`#5(1 , <at> `(2 3))

ECL, LispWorks and fare-quasiquote agree on #(1 2 3 2 3)
allegro, ccl, clisp, sbcl return the arguably conformant #(1 2 3 2 3 2 3 2 3)
abcl, cmucl, gcl, xcl all return the arguably completely buggy #(1 2 3)

Subtickets (add)

Change History (7)

comment:1 Changed 3 years ago by mevenson

  • Keywords ansi lacunae added
  • Summary changed from Incorret interaction between SHARPSIGN-LEFT-PARENTHENSIS and backquote splice operator to ANSI lacuna: interaction between SHARPSIGN-LEFT-PARENTHENSIS and backquote splice operator

comment:2 Changed 3 years ago by mevenson

Pascal notes

#5( anything ) should return a vector of dimension 5 in any case.

Furthermore,  

    "If the number of objects supplied before the closing ) is less than
     the unsigned decimal integer but greater than zero, the last object
     is used to fill all remaining elements of the  vector."

so they're all wrong, and expected result should be: #5(1 2 3 3 3)

Basically, 

            `#5(1 ,@`(2 3))

should take:

            `#(1 ,@`(2 3))

which all implementation agree that's read as:

            #(1 2 3)

and extends the last element to give:

            #5(1 2 3 3 3)


Now, since the reader macro is #\`, we should really apply #\` rules,
but the only rule for vectors is:

   * `#(x1 x2 x3 ... xn) may be interpreted to mean
     (apply #'vector `(x1 x2 x3 ... xn)).

so one could argue that there's no rule for `#n(…), and therefore it's
not a conforming form anyways.

If #n(…) is collapsed to #(…) then the abcl result is correct, as per
the above rule.

comment:3 Changed 3 years ago by mevenson

Try for sbcl

`#6(1 ,@`(2 3 4))
==>
#(1 2 3 4 2 3 4 2 3 4 2 3 4 2 3 4)

is surely bad…

Last edited 3 years ago by mevenson (previous) (diff)

comment:4 Changed 3 years ago by mevenson

  • Milestone changed from 1.3.0 to 2.0

Ticket retargeted after milestone closed

comment:5 Changed 3 years ago by mevenson

  • Milestone changed from 2.0 to 2.0.0

Milestone renamed

comment:6 Changed 3 years ago by mevenson

  • Milestone changed from 2.0.0 to 1.4.0

comment:7 Changed 7 months ago by mevenson

  • Milestone changed from 1.4.0 to 1.5.0

Ticket retargeted after milestone closed

Note: See TracTickets for help on using tickets.