File-Format.html 6.6 KB

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  13. <title>avram - a virtual machine code interpreter: 2.3 File Format</title>
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  41. <tr><td valign="middle" align="left">[<a href="Blocking.html#Blocking" title="Previous section in reading order"> &lt; </a>]</td>
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  43. <td valign="middle" align="left"> &nbsp; </td>
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  54. <td valign="middle" align="left">[<a href="avram_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
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  57. <a name="File-Format-1"></a>
  58. <h2 class="section">2.3 File Format</h2>
  59. <a name="index-file-format"></a>
  60. <p>A virtual code file consists of an optional text preamble, followed by
  61. the concrete representation for a tree. The latter uses the
  62. syntax described in the previous section. The purpose of this section is
  63. to specify the remaining details of the file format.
  64. </p>
  65. <p>The format for virtual code files may also be used for other purposes
  66. by virtual code applications, as it is automatically detected and parsed
  67. by <code>avram</code> when used in an input file, and can be automatically
  68. written to output files at the discretion of the application.
  69. </p>
  70. <p>Other than virtual code files, input files not conforming to this format
  71. are not an error as far as <code>avram</code> is concerned, because they are
  72. <a name="index-text-files"></a>
  73. assumed to be text files. Applications can detect in virtual code
  74. the assumption that is made and report an error if appropriate.
  75. </p>
  76. <p>Although the data file format includes no checksums or other explicit
  77. <a name="index-checksums"></a>
  78. methods of error detection, the concrete syntax itself provides a
  79. good measure of protection against undetected errors. The probability is
  80. vanishingly small that a random alteration to any valid encoding leaves
  81. it intact, because every bit in the sequence either mandates or
  82. prohibits the occurrence of two more bits somewhere after it. Errors in
  83. different parts of the file would have to be consistent with one another
  84. to go unnoticed.
  85. </p>
  86. <table class="menu" border="0" cellspacing="0">
  87. <tr><td align="left" valign="top"><a href="Preamble-Section.html#Preamble-Section">2.3.1 Preamble Section</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
  88. </td></tr>
  89. <tr><td align="left" valign="top"><a href="Data-Section.html#Data-Section">2.3.2 Data Section</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
  90. </td></tr>
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  96. <td valign="middle" align="left"> &nbsp; </td>
  97. <td valign="middle" align="left">[<a href="Virtual-Machine-Specification.html#Virtual-Machine-Specification" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
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  104. <td valign="middle" align="left">[<a href="avram.html#Top" title="Cover (top) of document">Top</a>]</td>
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