Computer Science 301 - 2005 - Vacation Reading Test

1. What are your surname and student number? [2]

Pat Terry, 663T0184

2. What do you understand by the term "self-compiling compiler"? [2]

A compiler hosted in the language it is intended to compile, so that it can compile (regenerate) itself.

3. Suppose you have available a C compiler (BCC.EXE) for a Pentium computer. Complete the T diagrams below to show the steps you might follow in producing a self-compiling C# compiler for the same Pentium computer. [4]

       .--------------------------.          .--------------------------.
       |           CSC1.C         |          |          CSC1.EXE        |
       |   C#    -------->  M-code|          |  C#    --------->  M-code|
       |                          |          |                          |
       `-------.          .--------------------------.          .-------'
               |          |          BCC.EXE         |          |
               |     C    |   C     ------->  M-code |  M-Code  |
               |          |                          |          |
               `------------------.          .------------------'
                     |            |          |            |
                     |            |  M-code  |            |
                     |            |          |            |
                     |            `----------'            |
       Rewrite the   |                                    | Use this to
       compiler in   |                                    | compile it
       C#            |                                    |
                     |                  .-----------------'
                     v                  |
       .--------------------------.     |    .--------------------------.
       |           CSC.C#         |     |    |          CSC.EXE         |
       |   C#    --------> M-code |     |    |   C#   --------->  M-code|
       |                          |     v    |                          |
       `-------.          .--------------------------.          .-------'
               |          |         CSC1.EXE         |          |
               |    C#    |   C#    ------->   M-code|  M-Code  |
               |          |                          |          |
               `------------------.          .------------------'
                                  |          |
                                  |  M-Code  |
                                  |          |
                                  `----------'

4. Self-compiling compilers have to be able to pass a self consistency test. Depict this test by annotating the T diagram below. [2]

       .--------------------------.          .--------------------------.
       |           CSC.C#         |          |            CSC.EXE       |
       |   C#    --------> M-code |          |  C#    ---------> M-code |
       |                          |          |                          |
       `-------.          .--------------------------.          .-------'
               |          |          CSC.EXE         |          |
               |    C#    |   C#    ------->  M-code |  M-code  |
               |          |                          |          |
               `------------------.          .------------------'
                                  |          |            ^
                                  |  M-code  |            | should be
                                  |          |<-----------' identical
                                  `----------'



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