compar.doc 1.8 KB

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  1. .sp 2
  2. .NH
  3. Comparison with the Pascal-VU compiler
  4. .nh
  5. .LP
  6. In this chapter, the differences with the Pascal-VU compiler [IM2] are listed.
  7. The points enumerated below can be used as improvements to the compiler (see
  8. also Chapter 11).
  9. .sp
  10. .NH 2
  11. Deviations
  12. .LP
  13. .sp
  14. - large labels
  15. .in +3m
  16. only labels in the closed interval 0..9999 are allowed, as opposed to the
  17. Pascal-VU compiler. The Pascal-VU compiler allows every unsigned integer
  18. as label.
  19. .in -3m
  20. - goto
  21. .in +3m
  22. the new compiler conforms to the standard as opposed to the old one. The
  23. following program, which contains an illegal jump to label 1, is accepted
  24. by the Pascal-VU compiler.
  25. .nf
  26. \fBprogram\fR illegal_goto(output);
  27. \fBlabel\fR 1;
  28. \fBvar\fR i : integer;
  29. \fBbegin\fR
  30. \fBgoto\fR 1;
  31. \fBfor\fR i := 1 \fBto\fR 10 \fBdo\fR
  32. \fBbegin\fR
  33. 1 : writeln(i);
  34. \fBend\fR;
  35. \fBend\fR.
  36. .fi
  37. This program is rejected by the new compiler.
  38. .in -3m
  39. .NH 2
  40. Extensions
  41. .LP
  42. .sp
  43. The extensions implemented by the Pascal-VU compiler are listed in
  44. Chapter 5 of [IM2].
  45. .sp
  46. - separate compilation
  47. .ti +3m
  48. the new compiler only accepts programs, not modules.
  49. - assertions
  50. .ti +3m
  51. not implemented.
  52. - additional procedures
  53. .ti +3m
  54. the procedures \fIhalt, mark\fR and \fIrelease\fR are not available.
  55. .bp
  56. - UNIX\(tm interfacing
  57. .ti +3m
  58. the \-c option is not implemented.
  59. .FS
  60. \(tm UNIX is a Trademark of Bell Laboratories.
  61. .FE
  62. - double length integers
  63. .ti +3m
  64. integer size can be set with the \-V option, so the additional type \fIlong\fR
  65. is not implemented.
  66. .NH 2
  67. Compiler options
  68. .LP
  69. .sp
  70. The options implemented by the Pascal-VU compiler are listed in
  71. Chapter 7 of [IM2].
  72. .sp
  73. The construction "{$....}" is not recognized.
  74. The options: \fIa, c, d, s\fR and \fIt\fR are not available.
  75. The \-l option has been changed into the \-L option.
  76. The size of reals can be set with the \-V option.