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  2. Received: from kingfisher.CS.Arizona.EDU (kingfisher.CS.Arizona.EDU [192.12.69.239])
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  4.     for <icon-group-addresses@baskerville.CS.Arizona.EDU>; Wed, 27 May 1998 08:21:10 -0700 (MST)
  5. Received: by kingfisher.CS.Arizona.EDU (5.65v4.0/1.1.8.2/08Nov94-0446PM)
  6.     id AA01621; Wed, 27 May 1998 08:21:04 -0700
  7. Message-Id: <356B9C3B.15DA6101@charlie.cns.iit.edu>
  8. Date: Tue, 26 May 1998 23:53:15 -0500
  9. From: "Thomas W. Christopher" <tc@charlie.cns.iit.edu>
  10. Organization: Illinois Institute of Technology
  11. X-Mailer: Mozilla 4.05 [en] (WinNT; I)
  12. Mime-Version: 1.0
  13. To: Guy Laden <guy@math.tau.ac.il>
  14. Cc: icon-group@baskerville.CS.Arizona.EDU
  15. Subject: Re: Writing compilers in Icon
  16. References: <199805222014.XAA02171@orion.math.tau.ac.il>
  17. Content-Type: multipart/mixed; boundary="------------D07FD781A7537D236717351D"
  18. Errors-To: icon-group-errors@optima.CS.Arizona.EDU
  19. Status: RO
  20. Content-Length: 8242
  21.  
  22. This is a multi-part message in MIME format.
  23. --------------D07FD781A7537D236717351D
  24. Content-Type: text/plain; charset=us-ascii
  25. Content-Transfer-Encoding: 7bit
  26.  
  27. I have found Icon quite pleasant for compiler writing, although not for
  28. production quality compilers. I use them for teaching.
  29.  
  30. See:   http://www.iit.edu/~tc/toolsfor.htm
  31.  
  32. I found generators a lot more useful for writing my parser generator
  33. than for writing compilers themselves.
  34.  
  35. I have used coexpressions for scanners, but I don't currently due to the
  36. difficulty of explaining it to students.
  37.  
  38. My parser uses string invocation of procedures. All the grammar symbols,
  39. including action symbols, are represented by strings in my parse tables. The
  40.  
  41. action symbols are the names of the semantic routines to call.
  42.  
  43. I'll attach a grammar for Icon that my LL(k) parser generator, tcllk, can
  44. handle.
  45.  
  46. If you pass it through:
  47.         iconx tcllk -p icon.grm
  48. you might be able to use the after-translation version of the grammar for
  49. recursive
  50. descent, although it's a lot easier to use my parser generator and parser.
  51.  
  52. A few suggestions for scanning tokens in Icon and passing them on to the
  53. parser:
  54. 1) queue up the tokens leaving the scanner before the parser sees them, use
  55. the
  56. queue to do (2) and (3);
  57. 2) remove duplicate ";" and end-of-line symbols;
  58. 3) remove end-of-line symbols preceeding or following symbols like "do",
  59. "then", "else";
  60. 4) fix the panic-mode error recovery to respond to an unexpected end-of-line
  61.  
  62. symbol by throwing it away without comment.
  63.  
  64. Guy Laden wrote:
  65.  
  66. > I noticed the newly announced implementation of Jcon is written in Icon.
  67. > I was wondering whether anybody can comment on how suitable they
  68. > find Icon for writing compilers? Do any of Icon's unique features
  69. > prove especially useful for this task? I'm wondering more about
  70. > generators and goal-directed evaluation; the built-in data-structures
  71. > are obviously useful.
  72. >
  73. > btw, does anybody have an Icon grammar they are willing to share
  74. > that is suitable for recursive descent parsing?
  75. >
  76. > Regards,
  77. > Guy.
  78.  
  79.  
  80.  
  81. --
  82. Thomas W. Christopher --------------------- tc@charlie.cns.iit.edu
  83. Associate Prof., Illinois Inst. of Tech.--- http://www.iit.edu/~tc
  84. Principal, Tools of Computing LLC.--------- http://www.toc-press.com
  85.  
  86.  
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