First class environments: Difference between revisions
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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
Often an environment is captured in a [[wp:Closure_(computer_science)|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.
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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.
;Task:
Build a dozen environments, and a single piece of code to be run repeatedly in each of these environments.
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.
<br><br>
=={{header|BBC BASIC}}==
{{works with|BBC BASIC for Windows}}
Here the 'environment' consists of all the dynamic variables; the static integer variables (A%-Z%) are not affected.
<
@% = 4 : REM Column width
Line 65 ⟶ 74:
IF LEN(e$) < 216 e$ = STRING$(216, CHR$0)
SYS "RtlMoveMemory", ^@%+108, !^e$, 216
ENDPROC</
'''Output:'''
<pre>
Line 93 ⟶ 102:
=={{header|Bracmat}}==
<
& :?environments
& 13:?seq
Line 126 ⟶ 135:
)
& out$(After !environments)
)</
Output:
<pre> Before
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=={{header|C}}==
Well, this fits the semantics, not sure about the spirit…
<
#define JOBS 12
Line 211 ⟶ 220:
return 0;
}</
{{out}}
<pre>
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COUNTS:
0 1 7 2 5 8 16 3 19 6 14 9
</pre>
=={{header|Clojure}}==
<syntaxhighlight lang="clojure">
(def hailstone-src
"(defn hailstone-step [env]
(let [{:keys[n cnt]} env]
(cond
(= n 1) {:n 1 :cnt cnt}
(even? n) {:n (/ n 2) :cnt (inc cnt)}
:else {:n (inc (* n 3)) :cnt (inc cnt)})))")
(defn create-hailstone-table [f-src]
(let [done? (fn [e] (= (:n e) 1))
print-step (fn [envs] (println (map #(format "%4d" (:n %)) envs)))
print-counts (fn [envs] (println "Counts:\n"
(map #(format "%4d" (:cnt %)) envs)))]
(loop [f (eval (read-string f-src))
envs (for [n (range 12)]
{:n (inc n) :cnt 0})]
(if (every? done? envs)
(print-counts envs)
(do
(print-step envs)
(recur f (map f envs)))))))
</syntaxhighlight>
{{out}}
<pre>
( 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)
</pre>
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D doesn't have first class environments, this is an approximation.
{{trans|Python}}
<
struct Prop {
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writefln("Counts:\n%(% 4d%)", envs.map!(env => env.cnt));
}</
{{out}}
<pre> 1 2 3 4 5 6 7 8 9 10 11 12
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=={{header|EchoLisp}}==
'''(environment-new ((name value) ..) ''' is used to create a new envrionment. '''(eval form env)''' is used to evaluate a form in a specified environment.
<
(define (bump-value)
(when (> value 1)
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(env-show 'value envs))
(env-show 'count envs))
</syntaxhighlight>
{{out}}
<pre>
Line 349 ⟶ 409:
</pre>
There is a lot of code below to manage the tabular printout. Otherwise the task is simple.
<syntaxhighlight lang="erlang">
-module( first_class_environments ).
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end,
print_loop().
</syntaxhighlight>
{{out}}
<pre>
Line 432 ⟶ 492:
=={{header|Factor}}==
Factor is a stack language without the need for variable bindings. Values are variables through and through. This simplifies matters somewhat. It means we can use data stacks (sequences) for our first class environments. The <code>with-datastack</code> combinator takes a data stack (sequence) and quotation as input, and inside the quotation, it is as though one is operating on a new data stack populated with values from the sequence. The resultant data stack is then once again stored as a sequence for safe keeping.
<
math.ranges sequences ;
Line 452 ⟶ 512:
[ dup done? ] [ step ] until nl
"Counts:" print
[ [ drop "%4d " printf ] with-datastack drop ] each nl</
{{out}}
<pre>
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0 1 7 2 5 8 16 3 19 6 14 9
</pre>
=={{header|FreeBASIC}}==
{{trans|Wren}}
<syntaxhighlight lang="vbnet">Type E
As Integer _valor, _contar
Public:
Declare Sub Constructor_(value As Integer, count As Integer)
Declare Function Valor() As Integer
Declare Function Contar() As Integer
Declare Sub Hailstone()
End Type
Sub E.Constructor_(value As Integer, count As Integer)
This._valor = value
This._contar = count
End Sub
Function E.Valor() As Integer
Return This._valor
End Function
Function E.Contar() As Integer
Return This._contar
End Function
Sub E.Hailstone()
Print Using "####"; This._valor;
If (This._valor = 1) Then Exit Sub
This._contar = This._contar + 1
This._valor = Iif(This._valor Mod 2 = 0, This._valor \ 2, 3 * This._valor + 1)
End Sub
Dim As Integer jobs = 12
Dim As E envs(jobs)
For i As Integer = 0 To jobs - 1
envs(i).Constructor_(i + 1, 0)
Next i
Print "Sequences:"
Dim As Integer done = 0
While done = 0
For i As Integer = 0 To jobs - 1
envs(i).Hailstone()
Next i
Print
done = 1
For i As Integer = 0 To jobs - 1
If envs(i).Valor() <> 1 Then
done = 0
Exit For
End If
Next i
Wend
Print "Counts:"
For i As Integer = 0 To jobs - 1
Print Using "####"; envs(i).Contar();
Next i
Print
Sleep</syntaxhighlight>
{{out}}
<pre>Same as Wren entry.</pre>
=={{header|Go}}==
{{trans|C}}
<
import "fmt"
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}
fmt.Println()
}</
{{out}}
Line 566 ⟶ 692:
0 1 7 2 5 8 16 3 19 6 14 9
</pre>
=={{header|Haskell}}==
First let's implement the algorithm of calculating Hailstone series:
<
| n == 1 = 1
| even n = n `div` 2
| odd n = 3*n + 1</
and a data structure representing the environment
<
deriving Eq</
In Haskell operations with first class environments could be implemented using several approaches:
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Let's define a collection of environments:
<
and a <code>process</code>, which changes an environment according to a task.
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Approach 1.
<
process (Environment c n) = Environment (c+1) (hailstone n)</
Approach 3. (needs <code>import Control.Monad.State</code>)
<
n <- gets value
c <- gets count
when (n > 1) $ modify $ \env -> env { count = c + 1 }
modify $ \env -> env { value = hailstone n }</
Repetitive batch processing of a collection we implement as following:
<
| fx == x = [x]
| otherwise = x : fixedPoint f fx
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mapM_ (prettyPrint value) result
putStrLn (replicate 36 '-')
prettyPrint count (last result)</
{{Out}}
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Or in "transposed" way
<
let result = map (fixedPoint process) environments
mapM_ (prettyPrint value) result
putStrLn (replicate 36 '-')
putStrLn "Counts: "
prettyPrint (count . last) result</
{{Out}}
Line 728 ⟶ 801:
0 1 7 2 5 8 16 3 19 6 14 9 </pre>
=={{header|Icon}} and {{header|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.
<syntaxhighlight 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</syntaxhighlight>
{{libheader|Icon Programming Library}}
[http://www.cs.arizona.edu/icon/library/src/procs/printf.icn printf.icn provides formatting]
{{out}}
<pre>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 </pre>
=={{header|J}}==
Line 733 ⟶ 858:
Here is my current interpretation of the task requirements:
<
step=:3 :0
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old=: state
end.
)</
{{out|Example use}}
<
run_hailstone_ environments
1 1 10 2 16 3 22 4 28 5 34 6
Line 790 ⟶ 915:
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</
In essence: run is a static method of the class <code>hailstone</code> 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.
=={{header|Java}}==
<syntaxhighlight lang="java">
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
public final class FirstClassEnvironments {
public static void main(String[] aArgs) {
code();
}
private static void code() {
do {
for ( int job = 0; job < JOBS; job++ ) {
switchTo(job);
hailstone();
}
System.out.println();
} while ( ! allDone() );
System.out.println(System.lineSeparator() + "Counts:");
for ( int job = 0; job < JOBS; job++ ) {
switchTo(job);
System.out.print(String.format("%4d", count));
}
System.out.println();
}
private static boolean allDone() {
for ( int job = 0; job < JOBS; job++ ) {
switchTo(job);
if ( sequence > 1 ) {
return false;
}
}
return true;
}
private static void hailstone() {
System.out.print(String.format("%4d", sequence));
if ( sequence == 1 ) {
return;
}
count += 1;
sequence = ( sequence % 2 == 1 ) ? 3 * sequence + 1 : sequence / 2;
}
private static void switchTo(int aID) {
if ( aID != currentId ) {
environments.get(currentId).seq = sequence;
environments.get(currentId).count = count;
currentId = aID;
}
sequence = environments.get(aID).seq;
count = environments.get(aID).count;
}
private static class Environment {
public Environment(int aSeq, int aCount) {
seq = aSeq; count = aCount;
}
private int seq, count;
}
private static int sequence, count, currentId;
private static List<Environment> environments =
IntStream.rangeClosed(1, 12).mapToObj( i -> new Environment(i, 0 ) ).collect(Collectors.toList());
private static final int JOBS = 12;
}
</syntaxhighlight>
{{ out }}
<pre>
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
</pre>
=={{header|jq}}==
Line 812 ⟶ 1,042:
Let us therefore define a function named "code" accordingly:
<
# Given an integer as input, compute the corresponding hailstone value:
def hail: if . % 2 == 0 then ./2|floor else 3*. + 1 end;
if .value > 1 then (.value |= hail) | .count += 1 else . end;
</syntaxhighlight>
To generate the n-th environment, it is useful to define a function:
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Putting it all together:
<
map(.value) | @tsv;
"", "Counts:", (map(.count) | @tsv ))</
Line 880 ⟶ 1,110:
=={{header|Julia}}==
{{trans|C}}
<
mutable struct Environment
Line 935 ⟶ 1,165:
runtest()
</
1 2 3 4 5 6 7 8 9 10 11 12
1 1 10 2 16 3 22 4 28 5 34 6
Line 959 ⟶ 1,189:
0 1 7 2 5 8 16 3 19 6 14 9
</pre>
=={{header|Kotlin}}==
This is based on the C entry except that, instead of using object references (Kotlin/JVM doesn't support explicit pointers) to switch between environments, it saves and restores the actual values of the two variables on each job switch. I see no reason why objects shouldn't be used to represent the environments as long as they have no member functions.
<
class Environment(var seq: Int, var count: Int)
Line 1,018 ⟶ 1,247:
fun main(args: Array<String>) {
code()
}</
{{out}}
Line 1,053 ⟶ 1,282:
* Lua 5.2: an upvalue called <code>_ENV</code>
<
local envs = { }
for i = 1, 12 do
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io.write(("% 4d"):format(env.count))
end
</syntaxhighlight>
{{out}}
Line 1,113 ⟶ 1,342:
0 1 7 2 5 8 16 3 19 6 14 9
</pre>
=={{header|Nim}}==
{{trans|C}}
<syntaxhighlight lang="nim">import strformat
const Jobs = 12
type Environment = object
sequence: int
count: int
var
env: array[Jobs, Environment]
sequence, count: ptr int
#---------------------------------------------------------------------------------------------------
proc hail() =
stdout.write fmt"{sequence[]: 4d}"
if sequence[] == 1: return
inc count[]
sequence[] = if (sequence[] and 1) != 0: 3 * sequence[] + 1
else: sequence[] div 2
#---------------------------------------------------------------------------------------------------
proc switchTo(id: int) =
sequence = addr(env[id].sequence)
count = addr(env[id].count)
#---------------------------------------------------------------------------------------------------
template forAllJobs(statements: untyped): untyped =
for i in 0..<Jobs:
switchTo(i)
statements
#———————————————————————————————————————————————————————————————————————————————————————————————————
for i in 0..<Jobs:
switchTo(i)
env[i].sequence = i + 1
var terminated = false
while not terminated:
forAllJobs:
hail()
echo ""
terminated = true
forAllJobs:
if sequence[] != 1:
terminated = false
break
echo ""
echo "Counts:"
forAllJobs:
stdout.write fmt"{count[]: 4d}"
echo ""</syntaxhighlight>
{{out}}
<pre> 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</pre>
=={{header|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):
<
#define ORDER_PP_DEF_8hail ORDER_PP_FN( \
Line 1,159 ⟶ 1,473:
8seq_iota(1, 13))),
8h_loop(8S))
)</
{{out}}
<syntaxhighlight lang="text">(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)</
The C preprocessor cannot output newlines, so the output is all on one line, but easily parsable.
Line 1,175 ⟶ 1,489:
Next, repeatedly perform the task, until the required conditions are met, and print the counts.
<
use strict;
use warnings;
Line 1,216 ⟶ 1,530:
printf "%4s", ${$_->varglob('count')} for @enviornments;
print "\n";
</syntaxhighlight>
{{out}}
<pre>
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
Line 1,293 ⟶ 1,557:
=={{header|Phix}}==
Emulation using edx as an "enviroment index" into static sequences. (You could of course nest the three sequences inside a single "environments" sequence, if you prefer.)<br>
See also [[Nested_function#Phix]]
<!--<syntaxhighlight lang="phix">(phixonline)-->
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">hail</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span> <span style="color: #000000;">n</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">if</span> <span style="color: #7060A8;">remainder</span><span style="color: #0000FF;">(</span><span style="color: #000000;">n</span><span style="color: #0000FF;">,</span><span style="color: #000000;">2</span><span style="color: #0000FF;">)=</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">n</span> <span style="color: #0000FF;">/=</span> <span style="color: #000000;">2</span>
<span style="color: #008080;">else</span>
<span style="color: #000000;">n</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">3</span><span style="color: #0000FF;">*</span><span style="color: #000000;">n</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">return</span> <span style="color: #000000;">n</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">hails</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">tagset</span><span style="color: #0000FF;">(</span><span style="color: #000000;">12</span><span style="color: #0000FF;">),</span>
<span style="color: #000000;">counts</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">12</span><span style="color: #0000FF;">),</span>
<span style="color: #000000;">results</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">columnize</span><span style="color: #0000FF;">({</span><span style="color: #000000;">hails</span><span style="color: #0000FF;">})</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">step</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span> <span style="color: #000000;">edx</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">n</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">hails</span><span style="color: #0000FF;">[</span><span style="color: #000000;">edx</span><span style="color: #0000FF;">]</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">n</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">then</span> <span style="color: #008080;">return</span> <span style="color: #000000;">0</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #000000;">n</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">hail</span><span style="color: #0000FF;">(</span><span style="color: #000000;">n</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">hails</span><span style="color: #0000FF;">[</span><span style="color: #000000;">edx</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">n</span>
<span style="color: #000000;">counts</span><span style="color: #0000FF;">[</span><span style="color: #000000;">edx</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1</span>
<span style="color: #000000;">results</span><span style="color: #0000FF;">[</span><span style="color: #000000;">edx</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">deep_copy</span><span style="color: #0000FF;">(</span><span style="color: #000000;">results</span><span style="color: #0000FF;">[</span><span style="color: #000000;">edx</span><span style="color: #0000FF;">])</span> <span style="color: #0000FF;">&</span> <span style="color: #000000;">n</span>
<span style="color: #008080;">return</span> <span style="color: #000000;">1</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
<span style="color: #008080;">procedure</span> <span style="color: #000000;">main</span><span style="color: #0000FF;">()</span>
<span style="color: #004080;">bool</span> <span style="color: #000000;">done</span> <span style="color: #0000FF;">=</span> <span style="color: #004600;">false</span>
<span style="color: #008080;">while</span> <span style="color: #008080;">not</span> <span style="color: #000000;">done</span> <span style="color: #008080;">do</span>
<span style="color: #000000;">done</span> <span style="color: #0000FF;">=</span> <span style="color: #004600;">true</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #000000;">12</span> <span style="color: #008080;">do</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">step</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">done</span> <span style="color: #0000FF;">=</span> <span style="color: #004600;">false</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #7060A8;">max</span><span style="color: #0000FF;">(</span><span style="color: #000000;">counts</span><span style="color: #0000FF;">)+</span><span style="color: #000000;">1</span> <span style="color: #008080;">do</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">j</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #000000;">12</span> <span style="color: #008080;">do</span>
<span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;"><=</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">results</span><span style="color: #0000FF;">[</span><span style="color: #000000;">j</span><span style="color: #0000FF;">])?</span><span style="color: #7060A8;">sprintf</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"%4d"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">results</span><span style="color: #0000FF;">[</span><span style="color: #000000;">j</span><span style="color: #0000FF;">][</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]}):</span><span style="color: #008000;">" "</span><span style="color: #0000FF;">))</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"\n"</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">" %s\n"</span><span style="color: #0000FF;">,{</span><span style="color: #7060A8;">join</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"==="</span><span style="color: #0000FF;">,</span><span style="color: #000000;">12</span><span style="color: #0000FF;">))})</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">j</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #000000;">12</span> <span style="color: #008080;">do</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%4d"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">counts</span><span style="color: #0000FF;">[</span><span style="color: #000000;">j</span><span style="color: #0000FF;">]})</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"\n"</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
<span style="color: #000000;">main</span><span style="color: #0000FF;">()</span>
<!--</syntaxhighlight>-->
Emulation using edx as a dictionary_id (creating a separate dictionary for each environment):
<!--<syntaxhighlight lang="phix">(phixonline)-->
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">hail</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span> <span style="color: #000000;">n</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">if</span> <span style="color: #7060A8;">remainder</span><span style="color: #0000FF;">(</span><span style="color: #000000;">n</span><span style="color: #0000FF;">,</span><span style="color: #000000;">2</span><span style="color: #0000FF;">)=</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">n</span> <span style="color: #0000FF;">/=</span> <span style="color: #000000;">2</span>
<span style="color: #008080;">else</span>
<span style="color: #000000;">n</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">3</span><span style="color: #0000FF;">*</span><span style="color: #000000;">n</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">return</span> <span style="color: #000000;">n</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">step</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span> <span style="color: #000000;">edx</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">n</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">getd</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"hail"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">edx</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">n</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">then</span> <span style="color: #008080;">return</span> <span style="color: #000000;">0</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #000000;">n</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">hail</span><span style="color: #0000FF;">(</span><span style="color: #000000;">n</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">setd</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"hail"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">n</span><span style="color: #0000FF;">,</span><span style="color: #000000;">edx</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">setd</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"count"</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">getd</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"count"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">edx</span><span style="color: #0000FF;">)+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">edx</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">setd</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"results"</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">deep_copy</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">getd</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"results"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">edx</span><span style="color: #0000FF;">))&</span><span style="color: #000000;">n</span><span style="color: #0000FF;">,</span><span style="color: #000000;">edx</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">return</span> <span style="color: #000000;">1</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">dicts</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{}</span>
<span style="color: #008080;">procedure</span> <span style="color: #000000;">main</span><span style="color: #0000FF;">()</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #000000;">12</span> <span style="color: #008080;">do</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">d</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">new_dict</span><span style="color: #0000FF;">()</span>
<span style="color: #7060A8;">setd</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"hail"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">i</span><span style="color: #0000FF;">,</span><span style="color: #000000;">d</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">setd</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"count"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">d</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">setd</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"results"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">i</span><span style="color: #0000FF;">},</span><span style="color: #000000;">d</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">dicts</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">d</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #004080;">bool</span> <span style="color: #000000;">done</span> <span style="color: #0000FF;">=</span> <span style="color: #004600;">false</span>
<span style="color: #008080;">while</span> <span style="color: #008080;">not</span> <span style="color: #000000;">done</span> <span style="color: #008080;">do</span>
<span style="color: #000000;">done</span> <span style="color: #0000FF;">=</span> <span style="color: #004600;">true</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #000000;">12</span> <span style="color: #008080;">do</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">step</span><span style="color: #0000FF;">(</span><span style="color: #000000;">dicts</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">])</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">done</span> <span style="color: #0000FF;">=</span> <span style="color: #004600;">false</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
<span style="color: #000000;">done</span> <span style="color: #0000FF;">=</span> <span style="color: #004600;">false</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">i</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">1</span>
<span style="color: #008080;">while</span> <span style="color: #008080;">not</span> <span style="color: #000000;">done</span> <span style="color: #008080;">do</span>
<span style="color: #000000;">done</span> <span style="color: #0000FF;">=</span> <span style="color: #004600;">true</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">j</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #000000;">12</span> <span style="color: #008080;">do</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">res</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">getd</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"results"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">dicts</span><span style="color: #0000FF;">[</span><span style="color: #000000;">j</span><span style="color: #0000FF;">])</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">i</span><span style="color: #0000FF;"><</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">res</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">then</span> <span style="color: #000000;">done</span> <span style="color: #0000FF;">=</span> <span style="color: #004600;">false</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;"><=</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">res</span><span style="color: #0000FF;">)?</span><span style="color: #7060A8;">sprintf</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"%4d"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">res</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]}):</span><span style="color: #008000;">" "</span><span style="color: #0000FF;">))</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"\n"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">i</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">" %s\n"</span><span style="color: #0000FF;">,{</span><span style="color: #7060A8;">join</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"==="</span><span style="color: #0000FF;">,</span><span style="color: #000000;">12</span><span style="color: #0000FF;">))})</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">j</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #000000;">12</span> <span style="color: #008080;">do</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">count</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">getd</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"count"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">dicts</span><span style="color: #0000FF;">[</span><span style="color: #000000;">j</span><span style="color: #0000FF;">])</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%4d"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">count</span><span style="color: #0000FF;">})</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"\n"</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
<span style="color: #000000;">main</span><span style="color: #0000FF;">()</span>
<!--</syntaxhighlight>-->
{{out}}
(same for both)
Line 1,433 ⟶ 1,704:
=={{header|PicoLisp}}==
Runtime environments can be controlled with the '[http://software-lab.de/doc/refJ.html#job job]' function:
<
(mapcar
'((N) (list (cons 'N N) (cons 'Cnt 0))) # Build environments
Line 1,452 ⟶ 1,723:
(job E
(prin (align 4 Cnt)) ) ) # print the step count
(prinl) )</
{{out}}
<pre> 1 2 3 4 5 6 7 8 9 10 11 12
Line 1,478 ⟶ 1,749:
=={{header|Python}}==
In Python, name bindings are held in dicts, one for global scope and another for local scope. When [http://docs.python.org/release/3.1.3/library/functions.html#exec 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.
<
code = '''
Line 1,495 ⟶ 1,766:
for env in environments:
print('% 4d' % env['cnt'], end='')
print()</
{{out}}
<pre> 1 2 3 4 5 6 7 8 9 10 11 12
Line 1,522 ⟶ 1,793:
=={{header|R}}==
<
if (n == 1) n else {
count <- count + 1;
Line 1,537 ⟶ 1,808:
cat("\nCounts:\n")
eprint(envs, "count")</
{{out}}
Line 1,565 ⟶ 1,836:
=={{header|Racket}}==
<syntaxhighlight lang="racket">
#lang racket
Line 1,594 ⟶ 1,865:
(displayln (make-string (* 4 12) #\=))
(show-nums (get-var-values 'count))
</syntaxhighlight>
Output:
Line 1,621 ⟶ 1,892:
0 1 7 2 5 8 16 3 19 6 14 9
</pre>
=={{header|Raku}}==
(formerly Perl 6)
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.
<syntaxhighlight lang="raku" line>my $calculator = sub ($n is rw) {
$n == 1 ?? 1 !! $n %% 2 ?? $n div 2 !! $n * 3 + 1
}
sub next (%this, &get_next) {
return %this if %this.<value> == 1;
%this.<value> .= &get_next;
%this.<count>++;
%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 "\nCounts\n" ~ [~] map { $_.<count>.fmt: '%4s' }, @hailstones;</syntaxhighlight>
{{out}}
<pre> 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</pre>
=={{header|REXX}}==
Line 1,626 ⟶ 1,945:
<br>once a '''1''' (unity) is found, no more numbers are displayed in that column).
Column widths are automatically adjusted for their width (the maximum decimal digits displayed in a column).
The '''hailstone''' function (subroutine) could be coded
<br>the solution have a ''single piece of code to be run repeatedly in each of these environments''.
<
parse arg
if
do i=1 for n; @.i= i /* " environments to an index. */
w= length(n) /*width (so far) for columnar output.*/
do forever until @.0;
do k=1 for
w= max(w, length(x)
@.k= @.k x
end /*k*/
#=
do lines=-1 until _=''; _= /*process a line for each environment. */
do j=1 for
select /*determine how to process the line. */
when #== 1 then _= _ right(words(@.j) - 1, w) /*environment count.*/
when lines==-1 then _= _ right(j, w)
when lines== 0 then _= _ right('', w, "─")
otherwise _= _ right(word(@.j, lines), w)
end /*select*/
end /*j*/
if
if
if
if _\='' then say strip( substr(_, 2), "T") /*display the counts*/
end /*lines*/
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
hailstone:
{{out|output|text= when using the default input:}}
(Shown at three─fourths size.)
<pre style="font-size:75%>
1 2 3 4 5 6 7 8 9 10 11 12
── ── ── ── ── ── ── ── ── ── ── ──
Line 1,691 ⟶ 2,014:
{{out|output|text= when using the input of: <tt> 60 </tt>}}
(Shown at
<pre style="font-size:
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
──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ──── ────
Line 1,815 ⟶ 2,138:
{{trans|PicoLisp}}
The ''object'' is an environment for instance variables. These variables use the <code>@</code> sigil. We create 12 objects, and put <code>@n</code> and <code>@cnt</code> inside these objects. We use <code>Object#instance_eval</code> to switch the current object and bring those instance variables into scope.
<
envs = (1..12).map do |n|
Object.new.instance_eval {@n = n; @cnt = 0; self}
Line 1,843 ⟶ 2,166:
end
end
puts</
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 <code>Kernel#binding</code> to create the bindings, and <code>Kernel#eval</code> to evaluate strings in these bindings. The lines between <code><<-'eos'</code> and <code>eos</code> are multi-line string literals.
<
envs = (1..12).map do |n|
e = class Object
Line 1,880 ⟶ 2,203:
eval('printf "%4s", cnt', e) # print the step count
end
puts</
{{out}}
<pre>
Line 1,907 ⟶ 2,230:
=={{header|Sidef}}==
{{trans|
<
func calculator(n {.is_even}) { n / 2 }
func calculator(n ) { 3*n + 1 }
Line 1,932 ⟶ 2,255:
say 'Counts';
say enviornments.map{ |h| "%4s" % h{:count} }.join;</
{{out}}
<pre>
Line 1,960 ⟶ 2,283:
=={{header|Tcl}}==
The simplest way to make a first-class environment in Tcl is to use a dictionary; the <code>dict with</code> command (and <code>dict update</code>; not shown here) will expand a dictionary and bind it to variables for the duration of its body script.
<
for {set i 1} {$i <= 12} {incr i} {
Line 1,990 ⟶ 2,313:
}
}
puts ""</
{{out}}
<pre>
Line 2,014 ⟶ 2,337:
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
</pre>
=={{header|Wren}}==
{{libheader|Wren-fmt}}
In Wren classes satisfy the definition of first-class objects in that: "they can be constructed at run-time, passed as a parameter, returned from a subroutine, or assigned into a variable."
It also appears that they can represent first-class environments in that they can encapsulate a set of variables (the class's fields) and code (the class's methods) which acts on those variables.
So that's what we use here. However, to create a dynamic class you have to wrap it in a function which then returns a reference to the class object.
<syntaxhighlight lang="wren">import "./fmt" for Fmt
var environment = Fn.new {
class E {
construct new(value, count) {
_value = value
_count = count
}
value { _value }
count { _count }
hailstone() {
Fmt.write("$4d", _value)
if (_value == 1) return
_count = _count + 1
_value = (_value%2 == 0) ? _value/2 : 3*_value + 1
}
}
return E
}
// create and initialize the environments
var jobs = 12
var envs = List.filled(jobs, null)
for (i in 0...jobs) envs[i] = environment.call().new(i+1, 0)
System.print("Sequences:")
var done = false
while (!done) {
for (env in envs) env.hailstone()
System.print()
done = true
for (env in envs) {
if (env.value != 1) {
done = false
break
}
}
}
System.print("Counts:")
for (env in envs) Fmt.write("$4d", env.count)
System.print()</syntaxhighlight>
{{out}}
<pre>
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
</pre>
Line 2,019 ⟶ 2,418:
=={{header|zkl}}==
In zkl, classes wrap state. All instances of a class share code but each instance binds code to itself. In this task, class creation, instead of returning a new class instance, it returns a bound function. Calling this function calculates the next hailstone in the environment the function is bound to. To get the counts from the class/environment, we ask the function for its container and then pull the count.
<
var n,cnt=0;
fcn init(_n){n=_n; returnClass(self.f)}
Line 2,029 ⟶ 2,428:
n
}
}</
<
while(1){
ns:=es.run(True);
Line 2,037 ⟶ 2,436:
}
println("Counts:");
es.pump(String,fcn(e){"%4d".fmt(e.container.cnt)}).println();</
{{out}}
<pre>
|