89 lines
1.8 KiB
Text
89 lines
1.8 KiB
Text
.sp 2
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.NH
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Comparison with the Pascal-VU compiler
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.nh
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.LP
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In this chapter, the differences with the Pascal-VU compiler [IM2] are listed.
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The points enumerated below can be used as improvements to the compiler (see
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also Chapter 11).
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.sp
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.NH 2
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Deviations
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.LP
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.sp
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- large labels
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.in +3m
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only labels in the closed interval 0..9999 are allowed, as opposed to the
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Pascal-VU compiler. The Pascal-VU compiler allows every unsigned integer
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as label.
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.in -3m
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- goto
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.in +3m
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the new compiler conforms to the standard as opposed to the old one. The
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following program, which contains an illegal jump to label 1, is accepted
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by the Pascal-VU compiler.
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.nf
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\fBprogram\fR illegal_goto(output);
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\fBlabel\fR 1;
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\fBvar\fR i : integer;
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\fBbegin\fR
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\fBgoto\fR 1;
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\fBfor\fR i := 1 \fBto\fR 10 \fBdo\fR
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\fBbegin\fR
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1 : writeln(i);
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\fBend\fR;
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\fBend\fR.
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.fi
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This program is rejected by the new compiler.
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.in -3m
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.NH 2
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Extensions
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.LP
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.sp
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The extensions implemented by the Pascal-VU compiler are listed in
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Chapter 5 of [IM2].
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.sp
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- separate compilation
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.ti +3m
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the new compiler only accepts programs, not modules.
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- assertions
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.ti +3m
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not implemented.
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- additional procedures
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.ti +3m
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the procedures \fIhalt, mark\fR and \fIrelease\fR are not available.
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.bp
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- UNIX\(tm interfacing
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.ti +3m
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the \-c option is not implemented.
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.FS
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\(tm UNIX is a Trademark of Bell Laboratories.
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.FE
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- double length integers
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.ti +3m
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integer size can be set with the \-V option, so the additional type \fIlong\fR
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is not implemented.
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.NH 2
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Compiler options
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.LP
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.sp
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The options implemented by the Pascal-VU compiler are listed in
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Chapter 7 of [IM2].
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.sp
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The construction "{$....}" is not recognized.
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The options: \fIa, c, d, s\fR and \fIt\fR are not available.
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The \-l option has been changed into the \-L option.
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The size of reals can be set with the \-V option.
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