git @ Cat's Eye Technologies SMETANA / be5f132
Initial import of SMETANA 2004.0227 sources. Cat's Eye Technologies 10 years ago
8 changed file(s) with 341 addition(s) and 0 deletion(s). Raw diff Collapse all Expand all
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doc/smetana.html less more
0 <html><head>
1 <meta http-equiv="Content-Type" content="text/html;CHARSET=iso-8859-1">
2 <title>Cat's Eye Technologies: The SMETANA Language</title>
3 </head>
4 <body bgcolor="#ffffff" text="#000000" link="#439773"
5 vlink="#ac9444" alink="#0cd490"
6 background="/img/sinewhite.gif" >
7 <h1>SMETANA</h1>
8 <P>Chris Pressey, 1994(ish)
9 <hr>
10
11 <p>A long time ago (about six years ago),
12 I was writing some amusing notes to
13 myself and among them was an "algorithm
14 that'll never fly," which went
15 something like:
16
17 <p>&nbsp;&nbsp;1. Swap steps one and two.
18 <br>&nbsp;&nbsp;2. Flap wings.
19 <br>&nbsp;&nbsp;3. Go back to step one.
20
21 <p>It then occurred to me that reducing
22 this form to the absurd (removing
23 the "Flap wings" instruction) just <i>might</i>
24 fail to yield a totally untractable language.
25
26 <p>I originally wrote the interpreter as a Visual Basic
27 application and named it SMETANA - both an acronym
28 for "Self-Modifying, Extremely Tiny AutomatoN
29 Application", and a reference to the composer of
30 the same name.
31
32 <ul><p><i>Turns out that the word</i> smetana <i>is
33 also Russian for</i> sour cream<i>. What do you know?
34 Finally, I join the all-too-exclusive club of people
35 who have invented a language
36 named after a foodstuff!</i></ul>
37
38 <p>The dsitribution available here is a much better
39 implementation of the SMETANA interpreter in
40 a much more device-independent and scalable form.
41 I have retained the English syntax exactly. The
42 program ends when it tries to peform step
43 number <i>n</i>, where <i>n</i> is one plus the number
44 of steps given in the source.
45
46 <!--
47 <p>Todo: mine information about SMETANA's Turing-Complete
48 status from the e-mail archives
49 -->
50
51 <p>Syntax of the SMETANA Language:
52
53 <pre> Smetana ::= Step {".\n" Step} ".".
54 Step ::= "Step" Integer "." (GoTo | Swap).
55 GoTo ::= "Go" "to" "step" Integer.
56 Swap ::= "Swap" "step" Integer "with" "step" Integer.
57 Integer ::= "0".."9" {"0".."9"}.</pre>
58
59 </body></html>
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eg/cool.bat less more
0 perl randsmet.pl 20 > cool2.sme
1 perl smetana.pl cool2.sme -d cls -m 500
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eg/cool.sme less more
0 Step 1. Swap step 1 with step 36.
1 Step 2. Go to step 1.
2 Step 3. Swap step 28 with step 33.
3 Step 4. Swap step 4 with step 13.
4 Step 5. Go to step 38.
5 Step 6. Swap step 16 with step 8.
6 Step 7. Go to step 22.
7 Step 8. Go to step 26.
8 Step 9. Swap step 30 with step 10.
9 Step 10. Go to step 12.
10 Step 11. Swap step 39 with step 8.
11 Step 12. Swap step 28 with step 5.
12 Step 13. Go to step 28.
13 Step 14. Swap step 35 with step 15.
14 Step 15. Swap step 12 with step 5.
15 Step 16. Swap step 4 with step 12.
16 Step 17. Swap step 33 with step 28.
17 Step 18. Go to step 13.
18 Step 19. Swap step 29 with step 18.
19 Step 20. Go to step 39.
20 Step 21. Go to step 22.
21 Step 22. Swap step 35 with step 4.
22 Step 23. Swap step 39 with step 38.
23 Step 24. Go to step 2.
24 Step 25. Swap step 25 with step 27.
25 Step 26. Swap step 3 with step 36.
26 Step 27. Swap step 22 with step 34.
27 Step 28. Swap step 10 with step 16.
28 Step 29. Go to step 3.
29 Step 30. Go to step 18.
30 Step 31. Swap step 2 with step 25.
31 Step 32. Swap step 33 with step 26.
32 Step 33. Go to step 4.
33 Step 34. Swap step 11 with step 22.
34 Step 35. Swap step 25 with step 27.
35 Step 36. Swap step 18 with step 10.
36 Step 37. Swap step 13 with step 25.
37 Step 38. Swap step 16 with step 15.
38 Step 39. Swap step 19 with step 8.
39 Step 40. Swap step 30 with step 34.
40 Step 41. Go to step 34.
41 Step 42. Swap step 29 with step 16.
42 Step 43. Go to step 11.
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eg/cool2.sme less more
0 Step 1. Go to step 4.
1 Step 2. Go to step 5.
2 Step 3. Go to step 17.
3 Step 4. Swap step 6 with step 12.
4 Step 5. Swap step 15 with step 1.
5 Step 6. Go to step 12.
6 Step 7. Go to step 2.
7 Step 8. Go to step 2.
8 Step 9. Go to step 1.
9 Step 10. Swap step 18 with step 12.
10 Step 11. Go to step 11.
11 Step 12. Swap step 14 with step 17.
12 Step 13. Swap step 9 with step 20.
13 Step 14. Go to step 9.
14 Step 15. Swap step 4 with step 6.
15 Step 16. Swap step 1 with step 20.
16 Step 17. Swap step 13 with step 8.
17 Step 18. Swap step 4 with step 13.
18 Step 19. Swap step 4 with step 4.
19 Step 20. Go to step 17.
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eg/decay.sme less more
0 Step 1. Swap step 1 with step 36.
1 Step 2. Go to step 1.
2 Step 3. Swap step 28 with step 33.
3 Step 4. Swap step 4 with step 13.
4 Step 5. Go to step 38.
5 Step 6. Swap step 16 with step 8.
6 Step 7. Go to step 22.
7 Step 8. Go to step 26.
8 Step 9. Swap step 30 with step 10.
9 Step 10. Go to step 12.
10 Step 11. Swap step 39 with step 8.
11 Step 12. Swap step 28 with step 5.
12 Step 13. Go to step 28.
13 Step 14. Swap step 35 with step 15.
14 Step 15. Swap step 12 with step 5.
15 Step 16. Swap step 4 with step 12.
16 Step 17. Swap step 33 with step 28.
17 Step 18. Go to step 13.
18 Step 19. Swap step 29 with step 18.
19 Step 20. Go to step 39.
20 Step 21. Go to step 22.
21 Step 22. Swap step 35 with step 4.
22 Step 23. Swap step 39 with step 38.
23 Step 24. Go to step 2.
24 Step 25. Swap step 25 with step 27.
25 Step 26. Swap step 3 with step 36.
26 Step 27. Swap step 22 with step 34.
27 Step 28. Swap step 10 with step 16.
28 Step 29. Go to step 3.
29 Step 30. Go to step 18.
30 Step 31. Swap step 2 with step 25.
31 Step 32. Swap step 33 with step 26.
32 Step 33. Go to step 4.
33 Step 34. Swap step 11 with step 22.
34 Step 35. Swap step 25 with step 27.
35 Step 36. Swap step 18 with step 10.
36 Step 37. Swap step 13 with step 25.
37 Step 38. Swap step 16 with step 15.
38 Step 39. Swap step 19 with step 8.
39 Step 40. Swap step 30 with step 34.
40 Step 41. Go to step 34.
41 Step 42. Swap step 29 with step 16.
42 Step 43. Go to step 11.
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eg/foo.sme less more
0 Step 1. Swap step 1 with step 2.
1 Step 2. Go to step 2.
2 Step 3. Go to step 1.
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eg/randsmet.pl less more
0 #!/usr/local/bin/perl -w
1
2 # randsmet[.pl] v2000.03.01 Cat's Eye Technologies
3 # Generate a random SMETANA program
4 # This work is part of the Public Domain.
5
6 ### MAIN ###
7
8 $| = 1;
9 if ($#ARGV == -1)
10 {
11 print "usage: randsmet <integer>\n";
12 exit(1);
13 }
14 $steps = shift @ARGV;
15 for($i=1;$i<=$steps;$i++)
16 {
17 print "Step $i. ";
18 if (rand > 0.5)
19 {
20 print "Go to step " . int(rand($steps)+1) . ".\n";
21 } else
22 {
23 print "Swap step " . int(rand($steps)+1) . " with step " .
24 int(rand($steps)+1) . ".\n";
25 }
26 }
27
28 ### END ###
29
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script/smetana.pl less more
0 #!/usr/bin/perl -w
1
2 ### BEGIN smetana.pl ###
3
4 # smetana[.pl] v2004.0227 Cat's Eye Technologies
5 # Interpreter/Debugger for the SMETANA language
6 # This work is part of the Public Domain.
7
8 ### GLOBALS ###
9
10 $[ = 1;
11 @step = ();
12 $cycle = 1;
13 $curstep = 1;
14 $maxcycle = 0;
15
16 ### SUBROUTINES ###
17
18 sub load_source_file # into global list variable @step
19 {
20 my $fn = shift @_;
21 my $rs = 1; my $x = '';
22
23 @step = ();
24 open FILE, "<$fn";
25 while(defined($x = <FILE>))
26 {
27 if ($x =~ /^\s*Step\s*(\d+)\s*\.\s*(.*?)$/io)
28 {
29 my $x = $2;
30 if ($1 == $rs)
31 {
32 if ($x =~ /^Go\s*to\s*step\s*(\d+)\s*\.\s*$/io)
33 {
34 push @step, [1, $1];
35 } elsif ($x =~ /^Swap\s*step\s*(\d+)\s*with\s*step\s*(\d+)\s*\.\s*$/io)
36 {
37 push @step, [0, $1, $2];
38 } else
39 {
40 print STDERR "SMETANA: Triple Boo! " .
41 "Insulting instruction in step $rs.\n";
42 return;
43 }
44 $rs++;
45 } else
46 {
47 print STDERR "SMETANA: Double Boo! " .
48 "Line $rs contains wrong step, step $1.\n";
49 return;
50 }
51 } else
52 {
53 print STDERR "SMETANA: Boo! Line $rs does not contain a step.\n";
54 return;
55 }
56 }
57 }
58
59 sub display_program
60 {
61 my $i = 1;
62 while (defined($step[$i]))
63 {
64 print "Step $i. ";
65 if ($step[$i][1])
66 {
67 print "Go to step " . $step[$i][2] . ".\n";
68 } else
69 {
70 print "Swap step " . $step[$i][2] . " with step " . $step[$i][3] . ".\n";
71 }
72 $i++;
73 }
74 print "\n";
75 }
76
77 ### MAIN ###
78
79 $| = 1;
80 if ($#ARGV == 0)
81 {
82 print <<'EOT';
83 smetana[.pl] v2004.0227 - Interpreter/Debugger for the SMETANA language
84 Chris Pressey, Cat's Eye Technologies.
85 This work is part of the Public Domain.
86
87 Usage:
88 [perl] smetana[.pl] inputfile {-d binfile | -m integer}
89 inputfile: text file to use as SMETANA source file.
90 -d binfile: optional program to shell between program states (e.g. cls)
91 -m integer: optional limit to number of states (to avoid infinite loops)
92 EOT
93 exit(1);
94 }
95
96 load_source_file shift @ARGV;
97
98 while (defined $ARGV[1])
99 {
100 $a = shift @ARGV;
101 if ($a eq '-d')
102 {
103 $xbefore = shift @ARGV;
104 } elsif ($a eq '-m')
105 {
106 $maxcycle += shift @ARGV;
107 } else
108 {
109 print STDERR "SMETANA: What the..? " .
110 "Unsupported command line option '$a'.\n";
111 }
112 }
113
114 while ($maxcycle == 0 or $cycle <= $maxcycle)
115 {
116 system $xbefore if $xbefore;
117 print "Current cycle: $cycle. Current step: $curstep.\n";
118 display_program();
119 if ($step[$curstep][1])
120 {
121 $curstep = $step[$curstep][2];
122 } else
123 {
124 my $a = $step[$curstep][2];
125 my $b = $step[$curstep][3];
126 my $temp = $step[$a];
127 $step[$a] = $step[$b];
128 $step[$b] = $temp;
129 $curstep++;
130 }
131 $cycle++;
132 last if $curstep > $#step;
133 }
134
135 system $xbefore if $xbefore;
136 print "Final cycle: $cycle. Final step: $curstep.\n";
137 display_program();
138
139 ### END of smetana.pl ###