First class environments: Difference between revisions
m (→{{header|REXX}}: changed indentation and whitespace, changed and added comments, changed pgm to handle larger intermediate Collatz numbers. -- ~~~~) |
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=={{header|REXX}}== |
=={{header|REXX}}== |
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The formatting is sensative to a terminating Collatz sequence and is shown as blanks. |
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<br>Column widths are automatically adjusted for their width (maximum number displayed in a column). |
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<lang rexx>/*REXX program illustrates first-class environments (using hailstone #s)*/ |
<lang rexx>/*REXX program illustrates first-class environments (using hailstone #s)*/ |
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parse arg |
parse arg N .; if N=='' then N=12 /*Was N defined? No, use default.*/ |
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w=length(N) /*the width (so far) for columns.*/ |
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@.= |
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do init=1 for N; @.init=init; end /*initialize all the environments*/ |
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do forever until @.0; @.0=1 /* ◄─── process all environments.*/ |
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/*═════════════════════════════════════initialize (twelve) environments.*/ |
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do |
do k=1 for N; x=hailstone(k); w=max(w,length(x)) |
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@.k=@.k x /*where the rubber meets the road*/ |
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end /*k*/ |
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end /*forever*/ |
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count=0 /* [↓] show tabular results. */ |
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/*═════════════════════════════════════process environments until done. */ |
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do lines=-1 until _==''; _= /*process each line for each env.*/ |
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do |
do j=1 for N /*process each environment. */ |
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select /*choose how to process the line.*/ |
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when count== 1 then _=_ right(words(@.j)-1, w) |
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end /*k*/ |
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when lines==-1 then _=_ right(j, w) /*hdr.*/ |
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when lines== 0 then _=_ right('', w, '─') /*sep.*/ |
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otherwise _=_ right(word(@.j, lines), w) |
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end /*select*/ |
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end /*j*/ |
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if count==1 then count=2 |
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/*═════════════════════════════════════show results in tabular form. */ |
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_=strip(_,'T'); if _=='' then count=count+1 /*if null, bump*/ |
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count=0; do lines=-1 until _==''; _= |
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if count==1 then _=copies(" "left('', w, "═"), N) /*foot sep*/ |
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if _\=='' then say substr(_,2) /*show the (foot) counts.*/ |
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end /*lines*/ |
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when lines==-1 then _=_ right(j,3) |
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when lines== 0 then _=_ right('',3,'─') |
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otherwise _=_ right(word(env_.j,lines),3) |
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end /*select*/ |
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end /*j*/ |
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if count==1 then count=2 |
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_=strip(_,'T') |
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if _=='' then count=count+1 |
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if count==1 then _=copies(' ═══',#envs) |
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if _\=='' then say substr(_,2) |
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end /*lines*/ |
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exit /*stick a fork in it, we're done.*/ |
exit /*stick a fork in it, we're done.*/ |
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/*─────────────────────────────────────HAILSTONE (Collatz) subroutine───*/ |
/*─────────────────────────────────────HAILSTONE (Collatz) subroutine───*/ |
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hailstone: procedure expose |
hailstone: procedure expose @.; parse arg y; _=word(@.y, words(@.y)) |
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if _==1 then return ''; |
if _==1 then return '' ; @.0=0; if _//2==0 then return _%2; return _*3+1</lang> |
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'''output''' using the default input: |
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{{out}} |
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<pre> |
<pre> |
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1 2 3 4 5 6 7 8 9 10 11 12 |
1 2 3 4 5 6 7 8 9 10 11 12 |
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| Line 997: | Line 996: | ||
═══ ═══ ═══ ═══ ═══ ═══ ═══ ═══ ═══ ═══ ═══ ═══ |
═══ ═══ ═══ ═══ ═══ ═══ ═══ ═══ ═══ ═══ ═══ ═══ |
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0 1 7 2 5 8 16 3 19 6 14 9 |
0 1 7 2 5 8 16 3 19 6 14 9 |
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</pre> |
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'''output''' when using the input of: <tt> 60 </tt> |
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<pre style="height:90ex;overflow:scroll"> |
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 |
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──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── |
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 |
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1 10 2 16 3 22 4 28 5 34 6 40 7 46 8 52 9 58 10 64 11 70 12 76 13 82 14 88 15 94 16 100 17 106 18 112 19 118 20 124 21 130 22 136 23 142 24 148 25 154 26 160 27 166 28 172 29 178 30 |
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5 1 8 10 11 2 14 16 17 3 20 22 23 4 26 28 29 5 32 34 35 6 38 40 41 7 44 46 47 8 50 52 53 9 56 58 59 10 62 64 65 11 68 70 71 12 74 76 77 13 80 82 83 14 86 88 89 15 |
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16 4 5 34 1 7 8 52 10 10 11 70 2 13 14 88 16 16 17 106 3 19 20 124 22 22 23 142 4 25 26 160 28 28 29 178 5 31 32 196 34 34 35 214 6 37 38 232 40 40 41 250 7 43 44 268 46 |
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8 2 16 17 22 4 26 5 5 34 35 1 40 7 44 8 8 52 53 10 58 10 62 11 11 70 71 2 76 13 80 14 14 88 89 16 94 16 98 17 17 106 107 3 112 19 116 20 20 124 125 22 130 22 134 23 |
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4 1 8 52 11 2 13 16 16 17 106 20 22 22 4 4 26 160 5 29 5 31 34 34 35 214 1 38 40 40 7 7 44 268 8 47 8 49 52 52 53 322 10 56 58 58 10 10 62 376 11 65 11 67 70 |
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2 4 26 34 1 40 8 8 52 53 10 11 11 2 2 13 80 16 88 16 94 17 17 106 107 19 20 20 22 22 22 134 4 142 4 148 26 26 160 161 5 28 29 29 5 5 31 188 34 196 34 202 35 |
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1 2 13 17 20 4 4 26 160 5 34 34 1 1 40 40 8 44 8 47 52 52 53 322 58 10 10 11 11 11 67 2 71 2 74 13 13 80 484 16 14 88 88 16 16 94 94 17 98 17 101 106 |
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1 40 52 10 2 2 13 80 16 17 17 20 20 4 22 4 142 26 26 160 161 29 5 5 34 34 34 202 1 214 1 37 40 40 40 242 8 7 44 44 8 8 47 47 52 49 52 304 53 |
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20 26 5 1 1 40 40 8 52 52 10 10 2 11 2 71 13 13 80 484 88 16 16 17 17 17 101 107 112 20 20 20 121 4 22 22 22 4 4 142 142 26 148 26 152 160 |
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10 13 16 20 20 4 26 26 5 5 1 34 1 214 40 40 40 242 44 8 8 52 52 52 304 322 56 10 10 10 364 2 11 11 11 2 2 71 71 13 74 13 76 80 |
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5 40 8 10 10 2 13 13 16 16 17 107 20 20 20 121 22 4 4 26 26 26 152 161 28 5 5 5 182 1 34 34 34 1 1 214 214 40 37 40 38 40 |
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16 20 4 5 5 1 40 40 8 8 52 322 10 10 10 364 11 2 2 13 13 13 76 484 14 16 16 16 91 17 17 17 107 107 20 112 20 19 20 |
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8 10 2 16 16 20 20 4 4 26 161 5 5 5 182 34 1 1 40 40 40 38 242 7 8 8 8 274 52 52 52 322 322 10 56 10 58 10 |
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4 5 1 8 8 10 10 2 2 13 484 16 16 16 91 17 20 20 20 19 121 22 4 4 4 137 26 26 26 161 161 5 28 5 29 5 |
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2 16 4 4 5 5 1 1 40 242 8 8 8 274 52 10 10 10 58 364 11 2 2 2 412 13 13 13 484 484 16 14 16 88 16 |
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1 8 2 2 16 16 20 121 4 4 4 137 26 5 5 5 29 182 34 1 1 1 206 40 40 40 242 242 8 7 8 44 8 |
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4 1 1 8 8 10 364 2 2 2 412 13 16 16 16 88 91 17 103 20 20 20 121 121 4 22 4 22 4 |
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2 4 4 5 182 1 1 1 206 40 8 8 8 44 274 52 310 10 10 10 364 364 2 11 2 11 2 |
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1 2 2 16 91 103 20 4 4 4 22 137 26 155 5 5 5 182 182 1 34 1 34 1 |
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1 1 8 274 310 10 2 2 2 11 412 13 466 16 16 16 91 91 17 17 |
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4 137 155 5 1 1 1 34 206 40 233 8 8 8 274 274 52 52 |
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2 412 466 16 17 103 20 700 4 4 4 137 137 26 26 |
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1 206 233 8 52 310 10 350 2 2 2 412 412 13 13 |
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103 700 4 26 155 5 175 1 1 1 206 206 40 40 |
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310 350 2 13 466 16 526 103 103 20 20 |
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155 175 1 40 233 8 263 310 310 10 10 |
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466 526 20 700 4 790 155 155 5 5 |
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233 263 10 350 2 395 466 466 16 16 |
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700 790 5 175 1 1186 233 233 8 8 |
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350 395 16 526 593 700 700 4 4 |
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175 1186 8 263 1780 350 350 2 2 |
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526 593 4 790 890 175 175 1 1 |
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263 1780 2 395 445 526 526 |
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790 890 1 1186 1336 263 263 |
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395 445 593 668 790 790 |
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1186 1336 1780 334 395 395 |
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593 668 890 167 1186 1186 |
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1780 334 445 502 593 593 |
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890 167 1336 251 1780 1780 |
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445 502 668 754 890 890 |
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1336 251 334 377 445 445 |
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668 754 167 1132 1336 1336 |
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334 377 502 566 668 668 |
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167 1132 251 283 334 334 |
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502 566 754 850 167 167 |
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251 283 377 425 502 502 |
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754 850 1132 1276 251 251 |
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377 425 566 638 754 754 |
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1132 1276 283 319 377 377 |
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566 638 850 958 1132 1132 |
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283 319 425 479 566 566 |
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850 958 1276 1438 283 283 |
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425 479 638 719 850 850 |
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1276 1438 319 2158 425 425 |
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638 719 958 1079 1276 1276 |
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319 2158 479 3238 638 638 |
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958 1079 1438 1619 319 319 |
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479 3238 719 4858 958 958 |
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1438 1619 2158 2429 479 479 |
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719 4858 1079 7288 1438 1438 |
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2158 2429 3238 3644 719 719 |
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1079 7288 1619 1822 2158 2158 |
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3238 3644 4858 911 1079 1079 |
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1619 1822 2429 2734 3238 3238 |
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4858 911 7288 1367 1619 1619 |
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2429 2734 3644 4102 4858 4858 |
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7288 1367 1822 2051 2429 2429 |
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3644 4102 911 6154 7288 7288 |
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1822 2051 2734 3077 3644 3644 |
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911 6154 1367 9232 1822 1822 |
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2734 3077 4102 4616 911 911 |
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1367 9232 2051 2308 2734 2734 |
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4102 4616 6154 1154 1367 1367 |
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2051 2308 3077 577 4102 4102 |
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6154 1154 9232 1732 2051 2051 |
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3077 577 4616 866 6154 6154 |
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9232 1732 2308 433 3077 3077 |
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4616 866 1154 1300 9232 9232 |
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2308 433 577 650 4616 4616 |
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1154 1300 1732 325 2308 2308 |
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577 650 866 976 1154 1154 |
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1732 325 433 488 577 577 |
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866 976 1300 244 1732 1732 |
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433 488 650 122 866 866 |
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1300 244 325 61 433 433 |
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650 122 976 184 1300 1300 |
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325 61 488 92 650 650 |
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976 184 244 46 325 325 |
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488 92 122 23 976 976 |
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244 46 61 70 488 488 |
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122 23 184 35 244 244 |
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61 70 92 106 122 122 |
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184 35 46 53 61 61 |
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92 106 23 160 184 184 |
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46 53 70 80 92 92 |
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23 160 35 40 46 46 |
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70 80 106 20 23 23 |
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35 40 53 10 70 70 |
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106 20 160 5 35 35 |
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53 10 80 16 106 106 |
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160 5 40 8 53 53 |
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80 16 20 4 160 160 |
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40 8 10 2 80 80 |
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20 4 5 1 40 40 |
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10 2 16 20 20 |
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5 1 8 10 10 |
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16 4 5 5 |
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8 2 16 16 |
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4 1 8 8 |
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2 4 4 |
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1 2 2 |
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1 1 |
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════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ |
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0 1 7 2 5 8 16 3 19 6 14 9 9 17 17 4 12 20 20 7 7 15 15 10 23 10 111 18 18 18 106 5 26 13 13 21 21 21 34 8 109 8 29 16 16 16 104 11 24 24 24 11 11 112 112 19 32 19 32 19 |
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</pre> |
</pre> |
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Revision as of 07:57, 17 November 2013
You are encouraged to solve this task according to the task description, using any language you may know.
According to Wikipedia, "In computing, a first-class object ... is an entity that can be constructed at run-time, passed as a parameter, returned from a subroutine, or assigned into a variable".
Often this term is used in the context of "first class functions". In an analogous way, a programming language may support "first class environments".
The environment is minimally, the set of variables accessable to a statement being executed. Change the environments and the same statement could produce different results when executed.
Often an environment is captured in a closure, which encapsulates a function together with an environment. That environment, however, is not first-class, as it cannot be created, passed etc. independently from the function's code.
Therefore, a first class environment is a set of variable bindings which can be constructed at run-time, passed as a parameter, returned from a subroutine, or assigned into a variable. It is like a closure without code. A statement must be able to be executed within a stored first class environment and act according to the environment variable values stored within.
The task: Build a dozen environments, and a single piece of code to be run repeatedly in each of these envionments.
Each environment contains the bindings for two variables: A value in the Hailstone sequence, and a count which is incremented until the value drops to 1. The initial hailstone values are 1 through 12, and the count in each environment is zero.
When the code runs, it calculates the next hailstone step in the current environment (unless the value is already 1) and counts the steps. Then it prints the current value in a tabular form.
When all hailstone values dropped to 1, processing stops, and the total number of hailstone steps for each environment is printed.
BBC BASIC
Here the 'environment' consists of all the dynamic variables; the static integer variables (A%-Z%) are not affected. <lang bbcbasic> DIM @environ$(12)
@% = 4 : REM Column width
REM Initialise:
FOR E% = 1 TO 12
PROCsetenvironment(@environ$(E%))
seq% = E%
cnt% = 0
@environ$(E%) = FNgetenvironment
NEXT
REM Run hailstone sequences:
REPEAT
T% = 0
FOR E% = 1 TO 12
PROCsetenvironment(@environ$(E%))
PRINT seq% ;
IF seq% <> 1 THEN
T% += 1
cnt% += 1
IF seq% AND 1 seq% = 3 * seq% + 1 ELSE seq% DIV= 2
ENDIF
@environ$(E%) = FNgetenvironment
NEXT
PRINT
UNTIL T% = 0
REM Print counts:
PRINT "Counts:"
FOR E% = 1 TO 12
PROCsetenvironment(@environ$(E%))
PRINT cnt% ;
@environ$(E%) = FNgetenvironment
NEXT
PRINT
END
DEF FNgetenvironment
LOCAL e$ : e$ = STRING$(216, CHR$0)
SYS "RtlMoveMemory", !^e$, ^@%+108, 216
= e$
DEF PROCsetenvironment(e$)
IF LEN(e$) < 216 e$ = STRING$(216, CHR$0)
SYS "RtlMoveMemory", ^@%+108, !^e$, 216
ENDPROC</lang>
Output:
1 2 3 4 5 6 7 8 9 10 11 12 1 1 10 2 16 3 22 4 28 5 34 6 1 1 5 1 8 10 11 2 14 16 17 3 1 1 16 1 4 5 34 1 7 8 52 10 1 1 8 1 2 16 17 1 22 4 26 5 1 1 4 1 1 8 52 1 11 2 13 16 1 1 2 1 1 4 26 1 34 1 40 8 1 1 1 1 1 2 13 1 17 1 20 4 1 1 1 1 1 1 40 1 52 1 10 2 1 1 1 1 1 1 20 1 26 1 5 1 1 1 1 1 1 1 10 1 13 1 16 1 1 1 1 1 1 1 5 1 40 1 8 1 1 1 1 1 1 1 16 1 20 1 4 1 1 1 1 1 1 1 8 1 10 1 2 1 1 1 1 1 1 1 4 1 5 1 1 1 1 1 1 1 1 1 2 1 16 1 1 1 1 1 1 1 1 1 1 1 8 1 1 1 1 1 1 1 1 1 1 1 4 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Counts: 0 1 7 2 5 8 16 3 19 6 14 9
Bracmat
<lang bracmat>( (environment=(cnt=0) (seq=)) & :?environments & 13:?seq & whl
' ( !seq+-1:>0:?seq & new$environment:?env & !seq:?(env..seq) & !env !environments:?environments )
& out$(Before !environments) & whl
' ( !environments:? (=? (seq=>1) ?) ?
& !environments:?envs
& whl
' ( !envs:(=?env) ?envs
& (
' ( $env
(
=
. put$(!(its.seq) \t)
& !(its.seq):1
| 1+!(its.cnt):?(its.cnt)
& 1/2*!(its.seq):~/?(its.seq)
| 3*!(its.seq)+1:?(its.seq)
)
)
.
)
$
)
& out$
)
& out$(After !environments) )</lang> Output:
Before (=(cnt=0) (seq=1)) (=(cnt=0) (seq=2)) (=(cnt=0) (seq=3)) (=(cnt=0) (seq=4)) (=(cnt=0) (seq=5)) (=(cnt=0) (seq=6)) (=(cnt=0) (seq=7)) (=(cnt=0) (seq=8)) (=(cnt=0) (seq=9)) (=(cnt=0) (seq=10)) (=(cnt=0) (seq=11)) (=(cnt=0) (seq=12)) 1 2 3 4 5 6 7 8 9 10 11 12 1 1 10 2 16 3 22 4 28 5 34 6 1 1 5 1 8 10 11 2 14 16 17 3 1 1 16 1 4 5 34 1 7 8 52 10 1 1 8 1 2 16 17 1 22 4 26 5 1 1 4 1 1 8 52 1 11 2 13 16 1 1 2 1 1 4 26 1 34 1 40 8 1 1 1 1 1 2 13 1 17 1 20 4 1 1 1 1 1 1 40 1 52 1 10 2 1 1 1 1 1 1 20 1 26 1 5 1 1 1 1 1 1 1 10 1 13 1 16 1 1 1 1 1 1 1 5 1 40 1 8 1 1 1 1 1 1 1 16 1 20 1 4 1 1 1 1 1 1 1 8 1 10 1 2 1 1 1 1 1 1 1 4 1 5 1 1 1 1 1 1 1 1 1 2 1 16 1 1 1 1 1 1 1 1 1 1 1 8 1 1 1 1 1 1 1 1 1 1 1 4 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 After (=(cnt=0) (seq=1)) (=(cnt=1) (seq=1)) (=(cnt=7) (seq=1)) (=(cnt=2) (seq=1)) (=(cnt=5) (seq=1)) (=(cnt=8) (seq=1)) (=(cnt=16) (seq=1)) (=(cnt=3) (seq=1)) (=(cnt=19) (seq=1)) (=(cnt=6) (seq=1)) (=(cnt=14) (seq=1)) (=(cnt=9) (seq=1))
C
Well, this fits the semantics, not sure about the spirit… <lang C>#include <stdio.h>
- define JOBS 12
- define jobs(a) for (switch_to(a = 0); a < JOBS || !printf("\n"); switch_to(++a))
typedef struct { int seq, cnt; } env_t;
env_t env[JOBS] = Template:0, 0; int *seq, *cnt;
void hail() { printf("% 4d", *seq); if (*seq == 1) return; ++*cnt; *seq = (*seq & 1) ? 3 * *seq + 1 : *seq / 2; }
void switch_to(int id) { seq = &env[id].seq; cnt = &env[id].cnt; }
int main() { int i; jobs(i) { env[i].seq = i + 1; }
again: jobs(i) { hail(); } jobs(i) { if (1 != *seq) goto again; }
printf("COUNTS:\n"); jobs(i) { printf("% 4d", *cnt); }
return 0; }</lang>
- Output:
1 2 3 4 5 6 7 8 9 10 11 12 1 1 10 2 16 3 22 4 28 5 34 6 1 1 5 1 8 10 11 2 14 16 17 3 1 1 16 1 4 5 34 1 7 8 52 10 1 1 8 1 2 16 17 1 22 4 26 5 1 1 4 1 1 8 52 1 11 2 13 16 1 1 2 1 1 4 26 1 34 1 40 8 1 1 1 1 1 2 13 1 17 1 20 4 1 1 1 1 1 1 40 1 52 1 10 2 1 1 1 1 1 1 20 1 26 1 5 1 1 1 1 1 1 1 10 1 13 1 16 1 1 1 1 1 1 1 5 1 40 1 8 1 1 1 1 1 1 1 16 1 20 1 4 1 1 1 1 1 1 1 8 1 10 1 2 1 1 1 1 1 1 1 4 1 5 1 1 1 1 1 1 1 1 1 2 1 16 1 1 1 1 1 1 1 1 1 1 1 8 1 1 1 1 1 1 1 1 1 1 1 4 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 COUNTS: 0 1 7 2 5 8 16 3 19 6 14 9
D
D doesn't have first class environments, this is an approximation.
<lang d>import std.stdio, std.algorithm, std.range, std.array;
struct Prop {
int[string] data;
ref opDispatch(string s)() pure nothrow {
return data[s];
}
}
immutable code = ` writef("% 4d", e.seq); if (e.seq != 1) {
e.cnt++; e.seq = (e.seq & 1) ? 3 * e.seq + 1 : e.seq / 2;
}`;
void main() {
auto envs = 12.iota.map!(i => Prop(["cnt": 0, "seq": i+1])).array;
while (envs.any!(env => env.seq > 1)) {
foreach (e; envs) {
mixin(code);
}
writeln;
}
writefln("Counts:\n%(% 4d%)", envs.map!(env => env.cnt));
}</lang>
- Output:
1 2 3 4 5 6 7 8 9 10 11 12 1 1 10 2 16 3 22 4 28 5 34 6 1 1 5 1 8 10 11 2 14 16 17 3 1 1 16 1 4 5 34 1 7 8 52 10 1 1 8 1 2 16 17 1 22 4 26 5 1 1 4 1 1 8 52 1 11 2 13 16 1 1 2 1 1 4 26 1 34 1 40 8 1 1 1 1 1 2 13 1 17 1 20 4 1 1 1 1 1 1 40 1 52 1 10 2 1 1 1 1 1 1 20 1 26 1 5 1 1 1 1 1 1 1 10 1 13 1 16 1 1 1 1 1 1 1 5 1 40 1 8 1 1 1 1 1 1 1 16 1 20 1 4 1 1 1 1 1 1 1 8 1 10 1 2 1 1 1 1 1 1 1 4 1 5 1 1 1 1 1 1 1 1 1 2 1 16 1 1 1 1 1 1 1 1 1 1 1 8 1 1 1 1 1 1 1 1 1 1 1 4 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 Counts: 0 1 7 2 5 8 16 3 19 6 14 9
Erlang
The Erlang modifiable environment, aka process dictionary, has the following warning in the documentation:
Note that using the Process Dictionary: Destroys referencial transparency Makes debugging difficult Survives Catch/Throw
There is a lot of code below to manage the tabular printout. Otherwise the task is simple. <lang Erlang> -module( first_class_environments ).
-export( [task/0] ).
task() -> Print_pid = erlang:spawn( fun() -> print_loop() end ), Environments = lists:seq( 1, 12 ), Print_pid ! "Environment: Sequence", Pids = [erlang:spawn(fun() -> hailstone_in_environment(Print_pid, X) end) || X <- Environments], Counts = counts( Pids ), Print_pid ! "{Environment, Step count}", Print_pid ! lists:flatten( io_lib:format("~p", [Counts]) ), ok.
counts( Pids ) -> My_pid = erlang:self(), [X ! {count, My_pid} || X <- Pids], counts( Pids, [] ).
counts( [], Acc ) -> Acc; counts( Pids, Acc ) -> receive {count, N, Count, Pid} -> counts( lists:delete(Pid, Pids), [{N, Count} | Acc] ) end.
hailstone_in_environment( Print_pid, N ) -> erlang:put( hailstone_value, N ), erlang:put( count, 0 ), hailstone_loop( hailstone_loop_done(N), Print_pid, N, [N] ).
hailstone_loop( stop, Print_pid, N, Acc ) -> Environment = lists:flatten( io_lib:format("~11B:", [N]) ), Sequence = lists:flatten( [io_lib:format("~4B", [X]) || X <- lists:reverse(Acc)] ), Print_pid ! Environment ++ Sequence, Count= erlang:get( count ), receive {count, Pid} -> Pid ! {count, N, Count, erlang:self()} end; hailstone_loop( keep_going, Print_pid, N, Acc ) -> Next = hailstone_next( erlang:get(hailstone_value) ), erlang:put( hailstone_value, Next ), Count = erlang:get( count ), erlang:put( count, Count + 1 ), hailstone_loop( hailstone_loop_done(Next), Print_pid, N, [Next | Acc] ).
hailstone_loop_done( 1 ) -> stop; hailstone_loop_done( _N ) -> keep_going.
hailstone_next( 1 ) -> 1; hailstone_next( Even ) when (Even rem 2) =:= 0 -> Even div 2; hailstone_next( Odd ) -> (3 * Odd) + 1.
print_loop() -> receive String -> io:fwrite("~s~n", [String] ) end, print_loop(). </lang>
- Output:
13> first_class_environments:task().
Environment: Sequence
1: 1
2: 2 1
3: 3 10 5 16 8 4 2 1
4: 4 2 1
5: 5 16 8 4 2 1
6: 6 3 10 5 16 8 4 2 1
7: 7 22 11 34 17 52 26 13 40 20 10 5 16 8 4 2 1
8: 8 4 2 1
9: 9 28 14 7 22 11 34 17 52 26 13 40 20 10 5 16 8 4 2 1
10: 10 5 16 8 4 2 1
11: 11 34 17 52 26 13 40 20 10 5 16 8 4 2 1
12: 12 6 3 10 5 16 8 4 2 1
{Environment, Step count}
[{12,9}, {11,14}, {10,6}, {9,19}, {8,3}, {7,16}, {6,8}, {5,5}, {4,2}, {3,7}, {2,1}, {1,0}]
Icon and Unicon
The simplest way to create an environment with variables isolated from code in Icon/Unicon is to create instances of records or class objects. <lang Icon>link printf
procedure main()
every put(environment := [], hailenv(1 to 12,0)) # setup environments
printf("Sequences:\n")
while (e := !environment).sequence > 1 do {
every hailstep(!environment)
printf("\n")
}
printf("\nCounts:\n")
every printf("%4d ",(!environment).count)
printf("\n")
end
record hailenv(sequence,count)
procedure hailstep(env)
printf("%4d ",env.sequence)
if env.sequence ~= 1 then {
env.count +:= 1
if env.sequence % 2 = 0 then env.sequence /:= 2
else env.sequence := 3 * env.sequence + 1
}
end</lang>
printf.icn provides formatting
- Output:
Sequences: 1 2 3 4 5 6 7 8 9 10 11 12 1 1 10 2 16 3 22 4 28 5 34 6 1 1 5 1 8 10 11 2 14 16 17 3 1 1 16 1 4 5 34 1 7 8 52 10 1 1 8 1 2 16 17 1 22 4 26 5 1 1 4 1 1 8 52 1 11 2 13 16 1 1 2 1 1 4 26 1 34 1 40 8 1 1 1 1 1 2 13 1 17 1 20 4 1 1 1 1 1 1 40 1 52 1 10 2 1 1 1 1 1 1 20 1 26 1 5 1 1 1 1 1 1 1 10 1 13 1 16 1 1 1 1 1 1 1 5 1 40 1 8 1 1 1 1 1 1 1 16 1 20 1 4 1 1 1 1 1 1 1 8 1 10 1 2 1 1 1 1 1 1 1 4 1 5 1 1 1 1 1 1 1 1 1 2 1 16 1 1 1 1 1 1 1 1 1 1 1 8 1 1 1 1 1 1 1 1 1 1 1 4 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 Counts: 0 1 7 2 5 8 16 3 19 6 14 9
J
I have tried to determine what makes this task interesting (see talk page), but I am still confused.
Here is my current interpretation of the task requirements: <lang j>coclass 'hailstone'
step=:3 :0
NB. and determine next element in hailstone sequence if.1=N do. N return.end. NB. count how many times this has run when N was not 1 STEP=:STEP+1 if.0=2|N do. N=: N%2 else. N=: 1 + 3*N end.
)
create=:3 :0
STEP=: 0 N=: y
)
current=:3 :0
N__y
)
run1=:3 :0
step__y STEP__y
)
run=:3 :0
old=: while. -. old -: state=: run1"0 y do. smoutput 4j0 ": current"0 y old=: state end.
)</lang>
- Example use:
<lang j> environments=: conew&'hailstone'"0 (1+i.12)
run_hailstone_ environments 1 1 10 2 16 3 22 4 28 5 34 6 1 1 5 1 8 10 11 2 14 16 17 3 1 1 16 1 4 5 34 1 7 8 52 10 1 1 8 1 2 16 17 1 22 4 26 5 1 1 4 1 1 8 52 1 11 2 13 16 1 1 2 1 1 4 26 1 34 1 40 8 1 1 1 1 1 2 13 1 17 1 20 4 1 1 1 1 1 1 40 1 52 1 10 2 1 1 1 1 1 1 20 1 26 1 5 1 1 1 1 1 1 1 10 1 13 1 16 1 1 1 1 1 1 1 5 1 40 1 8 1 1 1 1 1 1 1 16 1 20 1 4 1 1 1 1 1 1 1 8 1 10 1 2 1 1 1 1 1 1 1 4 1 5 1 1 1 1 1 1 1 1 1 2 1 16 1 1 1 1 1 1 1 1 1 1 1 8 1 1 1 1 1 1 1 1 1 1 1 4 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
0 1 7 2 5 8 16 3 19 6 14 9</lang>
In essence: run is a static method of the class hailstone which, given a list of objects of the class runs all of them until their hailstone sequence number stops changing. It also displays the hailstone sequence number from each of the objects at each step. Its result is the step count from each object.
Lua
In Lua, environments capture reads and writes to "global" variables (the environment for locals is static). Functions can have their own environments, or multiple functions can share an environment. Functions inherit the environment of their enclosing function when they are instantiated.
The way in which environments are manipulated depends on the Lua version:
- Lua 5.1 and before: the
setfenvfunction - Lua 5.2: an upvalue called
_ENV
<lang lua> local envs = { } for i = 1, 12 do
-- fallback to the global environment for io and math
envs[i] = setmetatable({ count = 0, n = i }, { __index = _G })
end
local code = [[ io.write(("% 4d"):format(n)) if n ~= 1 then
count = count + 1 n = (n % 2 == 1) and 3 * n + 1 or math.floor(n / 2)
end ]]
while true do
local finished = 0
for _, env in ipairs(envs) do
if env.n == 1 then finished = finished + 1 end
end
if finished == #envs then break end
for _, env in ipairs(envs) do
-- 5.1; in 5.2, use load(code, nil, nil, env)() instead
setfenv(loadstring(code), env)()
end
io.write "\n"
end
print "counts:" for _, env in ipairs(envs) do
io.write(("% 4d"):format(env.count))
end </lang>
- Output:
1 2 3 4 5 6 7 8 9 10 11 12 1 1 10 2 16 3 22 4 28 5 34 6 1 1 5 1 8 10 11 2 14 16 17 3 1 1 16 1 4 5 34 1 7 8 52 10 1 1 8 1 2 16 17 1 22 4 26 5 1 1 4 1 1 8 52 1 11 2 13 16 1 1 2 1 1 4 26 1 34 1 40 8 1 1 1 1 1 2 13 1 17 1 20 4 1 1 1 1 1 1 40 1 52 1 10 2 1 1 1 1 1 1 20 1 26 1 5 1 1 1 1 1 1 1 10 1 13 1 16 1 1 1 1 1 1 1 5 1 40 1 8 1 1 1 1 1 1 1 16 1 20 1 4 1 1 1 1 1 1 1 8 1 10 1 2 1 1 1 1 1 1 1 4 1 5 1 1 1 1 1 1 1 1 1 2 1 16 1 1 1 1 1 1 1 1 1 1 1 8 1 1 1 1 1 1 1 1 1 1 1 4 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 counts: 0 1 7 2 5 8 16 3 19 6 14 9
Order
Order supports environments as a first-class type, but since all values are immutable, updating a value means using one environment to update the next in a chain (nothing unusual for languages with immutable data structures): <lang c>#include <order/interpreter.h>
- define ORDER_PP_DEF_8hail ORDER_PP_FN( \
8fn(8N, 8cond((8equal(8N, 1), 1) \
(8is_0(8remainder(8N, 2)), 8quotient(8N, 2)) \
(8else, 8inc(8times(8N, 3))))) )
- define ORDER_PP_DEF_8h_loop ORDER_PP_FN( \
8fn(8S, \
8let((8F, 8fn(8E, 8env_ref(8(8H), 8E))), \
8do( \
8print(8seq_to_tuple(8seq_map(8F, 8S)) 8space), \
8let((8S, 8h_once(8S)), \
8if(8equal(1, \
8seq_fold(8times, 1, 8seq_map(8F, 8S))), \
8print_counts(8S), \
8h_loop(8S)))))) )
- define ORDER_PP_DEF_8h_once ORDER_PP_FN( \
8fn(8S, \
8seq_map( \
8fn(8E, \
8eval(8E, \
8quote( \
8env_bind(8(8C), \
8env_bind(8(8H), \
8env_bind(8(8E), 8E, 8E), \
8hail(8H)), \
8if(8equal(8H, 1), 8C, 8inc(8C))) ))), \
8S)) )
- define ORDER_PP_DEF_8print_counts ORDER_PP_FN( \
8fn(8S, \
8print(8space 8(Counts:) \
8seq_to_tuple(8seq_map(8fn(8E, 8env_ref(8(8C), 8E)), 8S)))) )
ORDER_PP(
8let((8S, // Build a list of environments
8seq_map(8fn(8N, 8seq_of_pairs_to_env(
8seq(8pair(8(8H), 8N), 8pair(8(8C), 0),
8pair(8(8E), 8env_nil)))),
8seq_iota(1, 13))),
8h_loop(8S))
)</lang>
- Output:
<lang>(1,2,3,4,5,6,7,8,9,10,11,12) (1,1,10,2,16,3,22,4,28,5,34,6) (1,1,5,1,8,10,11,2,14,16,17,3) (1,1,16,1,4,5,34,1,7,8,52,10) (1,1,8,1,2,16,17,1,22,4,26,5) (1,1,4,1,1,8,52,1,11,2,13,16) (1,1,2,1,1,4,26,1,34,1,40,8) (1,1,1,1,1,2,13,1,17,1,20,4) (1,1,1,1,1,1,40,1,52,1,10,2) (1,1,1,1,1,1,20,1,26,1,5,1) (1,1,1,1,1,1,10,1,13,1,16,1) (1,1,1,1,1,1,5,1,40,1,8,1) (1,1,1,1,1,1,16,1,20,1,4,1) (1,1,1,1,1,1,8,1,10,1,2,1) (1,1,1,1,1,1,4,1,5,1,1,1) (1,1,1,1,1,1,2,1,16,1,1,1) (1,1,1,1,1,1,1,1,8,1,1,1) (1,1,1,1,1,1,1,1,4,1,1,1) (1,1,1,1,1,1,1,1,2,1,1,1) Counts:(0,1,7,2,5,8,16,3,19,6,14,9)</lang> The C preprocessor cannot output newlines, so the output is all on one line, but easily parsable.
Perl
The Safe module (which is part of perl's standard distribution) is everything that one might want in a First Class Environment, and a bit more. The module's primary purpose is to provide a safe execution environment for untrustworthy code, and by doing so, it lends itself very well to this task's goal.
My use of the module is relatively straightforward.
Create a Safe object. Within that Safe, set up $value and $count variables, with appropriate initial values. Tell the Safe what "external" functions (from outside of the Safe object) it may run. Add a function, inside of the Safe, which will be run in the Safe, using the Safe's $value and $count variables. Add the Safe to an array. Repeat eleven more times.
Notice that to the function in the safe, $value and $count look like (and are!) perfectly ordinary variables.
Next, repeatedly perform the task, until the required conditions are met, and print the counts.
<lang perl> use strict; use warnings;
use Safe;
sub hail_next {
my $n = shift; return 1 if $n == 1; return $n * 3 + 1 if $n % 2; $n / 2;
};
my @enviornments; for my $initial ( 1..12 ) {
my $env = Safe->new;
${ $env->varglob('value') } = $initial;
${ $env->varglob('count') } = 0;
$env->share('&hail_next');
$env->reval(q{
sub task {
return if $value == 1;
$value = hail_next( $value );
++$count;
}
});
push @enviornments, $env;
}
my @value_refs = map $_->varglob('value'), @enviornments; my @tasks = map $_->varglob('task'), @enviornments; while( grep { $$_ != 1 } @value_refs ) {
printf "%4s", $$_ for @value_refs; print "\n"; $_->() for @tasks;
}
print "Counts\n";
printf "%4s", ${$_->varglob('count')} for @enviornments; print "\n"; </lang>
- Output:
1 2 3 4 5 6 7 8 9 10 11 12 1 1 10 2 16 3 22 4 28 5 34 6 1 1 5 1 8 10 11 2 14 16 17 3 1 1 16 1 4 5 34 1 7 8 52 10 1 1 8 1 2 16 17 1 22 4 26 5 1 1 4 1 1 8 52 1 11 2 13 16 1 1 2 1 1 4 26 1 34 1 40 8 1 1 1 1 1 2 13 1 17 1 20 4 1 1 1 1 1 1 40 1 52 1 10 2 1 1 1 1 1 1 20 1 26 1 5 1 1 1 1 1 1 1 10 1 13 1 16 1 1 1 1 1 1 1 5 1 40 1 8 1 1 1 1 1 1 1 16 1 20 1 4 1 1 1 1 1 1 1 8 1 10 1 2 1 1 1 1 1 1 1 4 1 5 1 1 1 1 1 1 1 1 1 2 1 16 1 1 1 1 1 1 1 1 1 1 1 8 1 1 1 1 1 1 1 1 1 1 1 4 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 Counts 0 1 7 2 5 8 16 3 19 6 14 9
Perl 6
Fairly straightforward. Set up an array of hashes containing the current values and iteration counts then pass each hash in turn with a code reference to a routine to calculate the next iteration.
<lang perl6>my $calculator = sub ($n is rw) {
return ($n == 1) ?? 1 !! $n %% 2 ?? $n div 2 !! $n * 3 + 1
};
sub next (%this is rw, &get_next) {
return %this if %this.<value> == 1; %this.<value>.=&get_next; %this.<count>++; return %this;
};
my @hailstones = map { $_ = %(value => $_, count => 0) }, 1 .. 12;
while not all( map { $_.<value> }, @hailstones ) == 1 {
say [~] map { $_.<value>.fmt("%4s") }, @hailstones;
@hailstones[$_].=&next($calculator) for ^@hailstones;
}
say 'Counts';
say [~] map { $_.<count>.fmt("%4s") }, @hailstones;</lang>
- Output:
1 2 3 4 5 6 7 8 9 10 11 12 1 1 10 2 16 3 22 4 28 5 34 6 1 1 5 1 8 10 11 2 14 16 17 3 1 1 16 1 4 5 34 1 7 8 52 10 1 1 8 1 2 16 17 1 22 4 26 5 1 1 4 1 1 8 52 1 11 2 13 16 1 1 2 1 1 4 26 1 34 1 40 8 1 1 1 1 1 2 13 1 17 1 20 4 1 1 1 1 1 1 40 1 52 1 10 2 1 1 1 1 1 1 20 1 26 1 5 1 1 1 1 1 1 1 10 1 13 1 16 1 1 1 1 1 1 1 5 1 40 1 8 1 1 1 1 1 1 1 16 1 20 1 4 1 1 1 1 1 1 1 8 1 10 1 2 1 1 1 1 1 1 1 4 1 5 1 1 1 1 1 1 1 1 1 2 1 16 1 1 1 1 1 1 1 1 1 1 1 8 1 1 1 1 1 1 1 1 1 1 1 4 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 Counts 0 1 7 2 5 8 16 3 19 6 14 9
PicoLisp
Runtime environments can be controlled with the 'job' function: <lang PicoLisp>(let Envs
(mapcar
'((N) (list (cons 'N N) (cons 'Cnt 0))) # Build environments
(range 1 12) )
(while (find '((E) (job E (> N 1))) Envs) # Until all values are 1:
(for E Envs
(job E # Use environment 'E'
(prin (align 4 N))
(unless (= 1 N)
(inc 'Cnt) # Increment step count
(setq N
(if (bit? 1 N) # Calculate next hailstone value
(inc (* N 3))
(/ N 2) ) ) ) ) )
(prinl) )
(prinl (need 48 '=))
(for E Envs # For each environment 'E'
(job E
(prin (align 4 Cnt)) ) ) # print the step count
(prinl) )</lang>
- Output:
1 2 3 4 5 6 7 8 9 10 11 12 1 1 10 2 16 3 22 4 28 5 34 6 1 1 5 1 8 10 11 2 14 16 17 3 1 1 16 1 4 5 34 1 7 8 52 10 1 1 8 1 2 16 17 1 22 4 26 5 1 1 4 1 1 8 52 1 11 2 13 16 1 1 2 1 1 4 26 1 34 1 40 8 1 1 1 1 1 2 13 1 17 1 20 4 1 1 1 1 1 1 40 1 52 1 10 2 1 1 1 1 1 1 20 1 26 1 5 1 1 1 1 1 1 1 10 1 13 1 16 1 1 1 1 1 1 1 5 1 40 1 8 1 1 1 1 1 1 1 16 1 20 1 4 1 1 1 1 1 1 1 8 1 10 1 2 1 1 1 1 1 1 1 4 1 5 1 1 1 1 1 1 1 1 1 2 1 16 1 1 1 1 1 1 1 1 1 1 1 8 1 1 1 1 1 1 1 1 1 1 1 4 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 ================================================ 0 1 7 2 5 8 16 3 19 6 14 9
Python
In Python, name bindings are held in dicts, one for global scope and another for local scope. When exec'ing code, you are allowed to give your own dictionaries for these scopes. In this example, two names are held in dictionaries that are used as the local scope for the evaluation of source. <lang python>environments = [{'cnt':0, 'seq':i+1} for i in range(12)]
code = print('% 4d' % seq, end=) if seq != 1:
cnt += 1 seq = 3 * seq + 1 if seq & 1 else seq // 2
while any(env['seq'] > 1 for env in environments):
for env in environments:
exec(code, globals(), env)
print()
print('Counts') for env in environments:
print('% 4d' % env['cnt'], end=)
print()</lang>
- Output:
1 2 3 4 5 6 7 8 9 10 11 12 1 1 10 2 16 3 22 4 28 5 34 6 1 1 5 1 8 10 11 2 14 16 17 3 1 1 16 1 4 5 34 1 7 8 52 10 1 1 8 1 2 16 17 1 22 4 26 5 1 1 4 1 1 8 52 1 11 2 13 16 1 1 2 1 1 4 26 1 34 1 40 8 1 1 1 1 1 2 13 1 17 1 20 4 1 1 1 1 1 1 40 1 52 1 10 2 1 1 1 1 1 1 20 1 26 1 5 1 1 1 1 1 1 1 10 1 13 1 16 1 1 1 1 1 1 1 5 1 40 1 8 1 1 1 1 1 1 1 16 1 20 1 4 1 1 1 1 1 1 1 8 1 10 1 2 1 1 1 1 1 1 1 4 1 5 1 1 1 1 1 1 1 1 1 2 1 16 1 1 1 1 1 1 1 1 1 1 1 8 1 1 1 1 1 1 1 1 1 1 1 4 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 Counts 0 1 7 2 5 8 16 3 19 6 14 9
R
<lang R>code <- quote(
if (n == 1) n else {
count <- count + 1;
n <- if (n %% 2 == 1) 3 * n + 1 else n/2
})
eprint <- function(envs, var="n")
cat(paste(sprintf("%4d", sapply(envs, `[[`, var)), collapse=" "), "\n")
envs <- mapply(function(...) list2env(list(...)), n=1:12, count=0)
while (any(sapply(envs, eval, expr=code) > 1)) {eprint(envs)} eprint(envs)
cat("\nCounts:\n") eprint(envs, "count")</lang>
- Output:
1 2 3 4 5 6 7 8 9 10 11 12 1 1 10 2 16 3 22 4 28 5 34 6 1 1 5 1 8 10 11 2 14 16 17 3 1 1 16 1 4 5 34 1 7 8 52 10 1 1 8 1 2 16 17 1 22 4 26 5 1 1 4 1 1 8 52 1 11 2 13 16 1 1 2 1 1 4 26 1 34 1 40 8 1 1 1 1 1 2 13 1 17 1 20 4 1 1 1 1 1 1 40 1 52 1 10 2 1 1 1 1 1 1 20 1 26 1 5 1 1 1 1 1 1 1 10 1 13 1 16 1 1 1 1 1 1 1 5 1 40 1 8 1 1 1 1 1 1 1 16 1 20 1 4 1 1 1 1 1 1 1 8 1 10 1 2 1 1 1 1 1 1 1 4 1 5 1 1 1 1 1 1 1 1 1 2 1 16 1 1 1 1 1 1 1 1 1 1 1 8 1 1 1 1 1 1 1 1 1 1 1 4 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 Counts: 0 1 7 2 5 8 16 3 19 6 14 9
Racket
<lang Racket>
- lang racket
(define namespaces
(for/list ([i (in-range 1 13)]) (define ns (make-base-namespace)) (eval `(begin (define N ,i) (define count 0)) ns) ns))
(define (get-var-values name)
(map (curry namespace-variable-value name #t #f) namespaces))
(define code
'(when (> N 1)
(set! N (if (even? N) (/ N 2) (+ 1 (* N 3))))
(set! count (add1 count))))
(define (show-nums nums)
(for ([n nums]) (display (~a n #:width 4 #:align 'right))) (newline))
(let loop ()
(define Ns (get-var-values 'N)) (show-nums Ns) (unless (andmap (λ(n) (= n 1)) Ns) (for ([ns namespaces]) (eval code ns)) (loop)))
(displayln (make-string (* 4 12) #\=)) (show-nums (get-var-values 'count)) </lang>
Output:
1 2 3 4 5 6 7 8 9 10 11 12 1 1 10 2 16 3 22 4 28 5 34 6 1 1 5 1 8 10 11 2 14 16 17 3 1 1 16 1 4 5 34 1 7 8 52 10 1 1 8 1 2 16 17 1 22 4 26 5 1 1 4 1 1 8 52 1 11 2 13 16 1 1 2 1 1 4 26 1 34 1 40 8 1 1 1 1 1 2 13 1 17 1 20 4 1 1 1 1 1 1 40 1 52 1 10 2 1 1 1 1 1 1 20 1 26 1 5 1 1 1 1 1 1 1 10 1 13 1 16 1 1 1 1 1 1 1 5 1 40 1 8 1 1 1 1 1 1 1 16 1 20 1 4 1 1 1 1 1 1 1 8 1 10 1 2 1 1 1 1 1 1 1 4 1 5 1 1 1 1 1 1 1 1 1 2 1 16 1 1 1 1 1 1 1 1 1 1 1 8 1 1 1 1 1 1 1 1 1 1 1 4 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ================================================ 0 1 7 2 5 8 16 3 19 6 14 9
REXX
The formatting is sensative to a terminating Collatz sequence and is shown as blanks.
Column widths are automatically adjusted for their width (maximum number displayed in a column).
<lang rexx>/*REXX program illustrates first-class environments (using hailstone #s)*/
parse arg N .; if N== then N=12 /*Was N defined? No, use default.*/
w=length(N) /*the width (so far) for columns.*/
@.=
do init=1 for N; @.init=init; end /*initialize all the environments*/
do forever until @.0; @.0=1 /* ◄─── process all environments.*/
do k=1 for N; x=hailstone(k); w=max(w,length(x))
@.k=@.k x /*where the rubber meets the road*/
end /*k*/
end /*forever*/
count=0 /* [↓] show tabular results. */
do lines=-1 until _==; _= /*process each line for each env.*/
do j=1 for N /*process each environment. */
select /*choose how to process the line.*/
when count== 1 then _=_ right(words(@.j)-1, w)
when lines==-1 then _=_ right(j, w) /*hdr.*/
when lines== 0 then _=_ right(, w, '─') /*sep.*/
otherwise _=_ right(word(@.j, lines), w)
end /*select*/
end /*j*/
if count==1 then count=2
_=strip(_,'T'); if _== then count=count+1 /*if null, bump*/
if count==1 then _=copies(" "left(, w, "═"), N) /*foot sep*/
if _\== then say substr(_,2) /*show the (foot) counts.*/
end /*lines*/
exit /*stick a fork in it, we're done.*/ /*─────────────────────────────────────HAILSTONE (Collatz) subroutine───*/ hailstone: procedure expose @.; parse arg y; _=word(@.y, words(@.y)) if _==1 then return ; @.0=0; if _//2==0 then return _%2; return _*3+1</lang> output using the default input:
1 2 3 4 5 6 7 8 9 10 11 12
─── ─── ─── ─── ─── ─── ─── ─── ─── ─── ─── ───
1 2 3 4 5 6 7 8 9 10 11 12
1 10 2 16 3 22 4 28 5 34 6
5 1 8 10 11 2 14 16 17 3
16 4 5 34 1 7 8 52 10
8 2 16 17 22 4 26 5
4 1 8 52 11 2 13 16
2 4 26 34 1 40 8
1 2 13 17 20 4
1 40 52 10 2
20 26 5 1
10 13 16
5 40 8
16 20 4
8 10 2
4 5 1
2 16
1 8
4
2
1
═══ ═══ ═══ ═══ ═══ ═══ ═══ ═══ ═══ ═══ ═══ ═══
0 1 7 2 5 8 16 3 19 6 14 9
output when using the input of: 60
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ────
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
1 10 2 16 3 22 4 28 5 34 6 40 7 46 8 52 9 58 10 64 11 70 12 76 13 82 14 88 15 94 16 100 17 106 18 112 19 118 20 124 21 130 22 136 23 142 24 148 25 154 26 160 27 166 28 172 29 178 30
5 1 8 10 11 2 14 16 17 3 20 22 23 4 26 28 29 5 32 34 35 6 38 40 41 7 44 46 47 8 50 52 53 9 56 58 59 10 62 64 65 11 68 70 71 12 74 76 77 13 80 82 83 14 86 88 89 15
16 4 5 34 1 7 8 52 10 10 11 70 2 13 14 88 16 16 17 106 3 19 20 124 22 22 23 142 4 25 26 160 28 28 29 178 5 31 32 196 34 34 35 214 6 37 38 232 40 40 41 250 7 43 44 268 46
8 2 16 17 22 4 26 5 5 34 35 1 40 7 44 8 8 52 53 10 58 10 62 11 11 70 71 2 76 13 80 14 14 88 89 16 94 16 98 17 17 106 107 3 112 19 116 20 20 124 125 22 130 22 134 23
4 1 8 52 11 2 13 16 16 17 106 20 22 22 4 4 26 160 5 29 5 31 34 34 35 214 1 38 40 40 7 7 44 268 8 47 8 49 52 52 53 322 10 56 58 58 10 10 62 376 11 65 11 67 70
2 4 26 34 1 40 8 8 52 53 10 11 11 2 2 13 80 16 88 16 94 17 17 106 107 19 20 20 22 22 22 134 4 142 4 148 26 26 160 161 5 28 29 29 5 5 31 188 34 196 34 202 35
1 2 13 17 20 4 4 26 160 5 34 34 1 1 40 40 8 44 8 47 52 52 53 322 58 10 10 11 11 11 67 2 71 2 74 13 13 80 484 16 14 88 88 16 16 94 94 17 98 17 101 106
1 40 52 10 2 2 13 80 16 17 17 20 20 4 22 4 142 26 26 160 161 29 5 5 34 34 34 202 1 214 1 37 40 40 40 242 8 7 44 44 8 8 47 47 52 49 52 304 53
20 26 5 1 1 40 40 8 52 52 10 10 2 11 2 71 13 13 80 484 88 16 16 17 17 17 101 107 112 20 20 20 121 4 22 22 22 4 4 142 142 26 148 26 152 160
10 13 16 20 20 4 26 26 5 5 1 34 1 214 40 40 40 242 44 8 8 52 52 52 304 322 56 10 10 10 364 2 11 11 11 2 2 71 71 13 74 13 76 80
5 40 8 10 10 2 13 13 16 16 17 107 20 20 20 121 22 4 4 26 26 26 152 161 28 5 5 5 182 1 34 34 34 1 1 214 214 40 37 40 38 40
16 20 4 5 5 1 40 40 8 8 52 322 10 10 10 364 11 2 2 13 13 13 76 484 14 16 16 16 91 17 17 17 107 107 20 112 20 19 20
8 10 2 16 16 20 20 4 4 26 161 5 5 5 182 34 1 1 40 40 40 38 242 7 8 8 8 274 52 52 52 322 322 10 56 10 58 10
4 5 1 8 8 10 10 2 2 13 484 16 16 16 91 17 20 20 20 19 121 22 4 4 4 137 26 26 26 161 161 5 28 5 29 5
2 16 4 4 5 5 1 1 40 242 8 8 8 274 52 10 10 10 58 364 11 2 2 2 412 13 13 13 484 484 16 14 16 88 16
1 8 2 2 16 16 20 121 4 4 4 137 26 5 5 5 29 182 34 1 1 1 206 40 40 40 242 242 8 7 8 44 8
4 1 1 8 8 10 364 2 2 2 412 13 16 16 16 88 91 17 103 20 20 20 121 121 4 22 4 22 4
2 4 4 5 182 1 1 1 206 40 8 8 8 44 274 52 310 10 10 10 364 364 2 11 2 11 2
1 2 2 16 91 103 20 4 4 4 22 137 26 155 5 5 5 182 182 1 34 1 34 1
1 1 8 274 310 10 2 2 2 11 412 13 466 16 16 16 91 91 17 17
4 137 155 5 1 1 1 34 206 40 233 8 8 8 274 274 52 52
2 412 466 16 17 103 20 700 4 4 4 137 137 26 26
1 206 233 8 52 310 10 350 2 2 2 412 412 13 13
103 700 4 26 155 5 175 1 1 1 206 206 40 40
310 350 2 13 466 16 526 103 103 20 20
155 175 1 40 233 8 263 310 310 10 10
466 526 20 700 4 790 155 155 5 5
233 263 10 350 2 395 466 466 16 16
700 790 5 175 1 1186 233 233 8 8
350 395 16 526 593 700 700 4 4
175 1186 8 263 1780 350 350 2 2
526 593 4 790 890 175 175 1 1
263 1780 2 395 445 526 526
790 890 1 1186 1336 263 263
395 445 593 668 790 790
1186 1336 1780 334 395 395
593 668 890 167 1186 1186
1780 334 445 502 593 593
890 167 1336 251 1780 1780
445 502 668 754 890 890
1336 251 334 377 445 445
668 754 167 1132 1336 1336
334 377 502 566 668 668
167 1132 251 283 334 334
502 566 754 850 167 167
251 283 377 425 502 502
754 850 1132 1276 251 251
377 425 566 638 754 754
1132 1276 283 319 377 377
566 638 850 958 1132 1132
283 319 425 479 566 566
850 958 1276 1438 283 283
425 479 638 719 850 850
1276 1438 319 2158 425 425
638 719 958 1079 1276 1276
319 2158 479 3238 638 638
958 1079 1438 1619 319 319
479 3238 719 4858 958 958
1438 1619 2158 2429 479 479
719 4858 1079 7288 1438 1438
2158 2429 3238 3644 719 719
1079 7288 1619 1822 2158 2158
3238 3644 4858 911 1079 1079
1619 1822 2429 2734 3238 3238
4858 911 7288 1367 1619 1619
2429 2734 3644 4102 4858 4858
7288 1367 1822 2051 2429 2429
3644 4102 911 6154 7288 7288
1822 2051 2734 3077 3644 3644
911 6154 1367 9232 1822 1822
2734 3077 4102 4616 911 911
1367 9232 2051 2308 2734 2734
4102 4616 6154 1154 1367 1367
2051 2308 3077 577 4102 4102
6154 1154 9232 1732 2051 2051
3077 577 4616 866 6154 6154
9232 1732 2308 433 3077 3077
4616 866 1154 1300 9232 9232
2308 433 577 650 4616 4616
1154 1300 1732 325 2308 2308
577 650 866 976 1154 1154
1732 325 433 488 577 577
866 976 1300 244 1732 1732
433 488 650 122 866 866
1300 244 325 61 433 433
650 122 976 184 1300 1300
325 61 488 92 650 650
976 184 244 46 325 325
488 92 122 23 976 976
244 46 61 70 488 488
122 23 184 35 244 244
61 70 92 106 122 122
184 35 46 53 61 61
92 106 23 160 184 184
46 53 70 80 92 92
23 160 35 40 46 46
70 80 106 20 23 23
35 40 53 10 70 70
106 20 160 5 35 35
53 10 80 16 106 106
160 5 40 8 53 53
80 16 20 4 160 160
40 8 10 2 80 80
20 4 5 1 40 40
10 2 16 20 20
5 1 8 10 10
16 4 5 5
8 2 16 16
4 1 8 8
2 4 4
1 2 2
1 1
════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════ ════
0 1 7 2 5 8 16 3 19 6 14 9 9 17 17 4 12 20 20 7 7 15 15 10 23 10 111 18 18 18 106 5 26 13 13 21 21 21 34 8 109 8 29 16 16 16 104 11 24 24 24 11 11 112 112 19 32 19 32 19
Ruby
The object is an environment for instance variables. These variables use the @ sigil. We create 12 objects, and put @n and @cnt inside these objects. We use Object#instance_eval to switch the current object and bring those instance variables into scope.
<lang ruby># Build environments
envs = (1..12).map do |n|
Object.new.instance_eval {@n = n; @cnt = 0; self}
end
- Until all values are 1:
until envs.all? {|e| e.instance_eval{@n} == 1}
envs.each do |e|
e.instance_eval do # Use environment _e_
printf "%4s", @n
if @n > 1
@cnt += 1 # Increment step count
@n = if @n.odd? # Calculate next hailstone value
@n * 3 + 1
else
@n / 2
end
end
end
end
puts
end puts '=' * 48 envs.each do |e| # For each environment _e_
e.instance_eval do printf "%4s", @cnt # print the step count end
end
puts</lang>
Ruby also provides the binding, an environment for local variables. The problem is that local variables have lexical scope. Ruby needs the lexical scope to parse Ruby code. So, the only way to use a binding is to evaluate a string of Ruby code. We use Kernel#binding to create the bindings, and Kernel#eval to evaluate strings in these bindings. The lines between <<-'eos' and eos are multi-line string literals.
<lang ruby># Build environments
envs = (1..12).map do |n|
e = class Object
# This is a new lexical scope with no local variables.
# Create a new binding here.
binding
end
eval(<<-EOS, e).call(n)
n, cnt = nil, 0
proc {|arg| n = arg}
EOS
e
end
- Until all values are 1:
until envs.all? {|e| eval('n == 1', e)}
envs.each do |e|
eval(<<-EOS, e) # Use environment _e_
printf "%4s", n
if n > 1
cnt += 1 # Increment step count
n = if n.odd? # Calculate next hailstone value
n * 3 + 1
else
n / 2
end
end
EOS
end
puts
end puts '=' * 48 envs.each do |e| # For each environment _e_
eval('printf "%4s", cnt', e) # print the step count
end puts</lang>
- Output:
1 2 3 4 5 6 7 8 9 10 11 12 1 1 10 2 16 3 22 4 28 5 34 6 1 1 5 1 8 10 11 2 14 16 17 3 1 1 16 1 4 5 34 1 7 8 52 10 1 1 8 1 2 16 17 1 22 4 26 5 1 1 4 1 1 8 52 1 11 2 13 16 1 1 2 1 1 4 26 1 34 1 40 8 1 1 1 1 1 2 13 1 17 1 20 4 1 1 1 1 1 1 40 1 52 1 10 2 1 1 1 1 1 1 20 1 26 1 5 1 1 1 1 1 1 1 10 1 13 1 16 1 1 1 1 1 1 1 5 1 40 1 8 1 1 1 1 1 1 1 16 1 20 1 4 1 1 1 1 1 1 1 8 1 10 1 2 1 1 1 1 1 1 1 4 1 5 1 1 1 1 1 1 1 1 1 2 1 16 1 1 1 1 1 1 1 1 1 1 1 8 1 1 1 1 1 1 1 1 1 1 1 4 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 ================================================ 0 1 7 2 5 8 16 3 19 6 14 9
Tcl
The simplest way to make a first-class environment in Tcl is to use a dictionary; the dict with command (and dict update; not shown here) will expand a dictionary and bind it to variables for the duration of its body script.
<lang tcl>package require Tcl 8.5
for {set i 1} {$i <= 12} {incr i} {
dict set hailenv hail$i [dict create num $i steps 0]
} while 1 {
set loopagain false
foreach k [dict keys $hailenv] {
dict with hailenv $k { puts -nonewline [format %4d $num] if {$num == 1} { continue } elseif {$num & 1} { set num [expr {3*$num + 1}] } else { set num [expr {$num / 2}] } set loopagain true incr steps }
}
puts ""
if {!$loopagain} break
} puts "Counts..." foreach k [dict keys $hailenv] {
dict with hailenv $k {
puts -nonewline [format %4d $steps]
}
} puts ""</lang>
- Output:
1 2 3 4 5 6 7 8 9 10 11 12 1 1 10 2 16 3 22 4 28 5 34 6 1 1 5 1 8 10 11 2 14 16 17 3 1 1 16 1 4 5 34 1 7 8 52 10 1 1 8 1 2 16 17 1 22 4 26 5 1 1 4 1 1 8 52 1 11 2 13 16 1 1 2 1 1 4 26 1 34 1 40 8 1 1 1 1 1 2 13 1 17 1 20 4 1 1 1 1 1 1 40 1 52 1 10 2 1 1 1 1 1 1 20 1 26 1 5 1 1 1 1 1 1 1 10 1 13 1 16 1 1 1 1 1 1 1 5 1 40 1 8 1 1 1 1 1 1 1 16 1 20 1 4 1 1 1 1 1 1 1 8 1 10 1 2 1 1 1 1 1 1 1 4 1 5 1 1 1 1 1 1 1 1 1 2 1 16 1 1 1 1 1 1 1 1 1 1 1 8 1 1 1 1 1 1 1 1 1 1 1 4 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Counts... 0 1 7 2 5 8 16 3 19 6 14 9