Source code in the clu programming language

% This program uses the 'bigint' cluster from PCLU's 'misc.lib'

% Remove leading and trailing whitespace (bigint$unparse adds a lot)
strip = proc (s: string) returns (string)
    ac = array[char]
    sc = sequence[char]
    cs: ac := string$s2ac(s)
    while ~ac$empty(cs) cand ac$bottom(cs)=' ' do ac$reml(cs) end
    while ~ac$empty(cs) cand ac$top(cs)=' ' do ac$remh(cs) end
    % There's a bug in ac2s that makes it not return all elements
    % This is a workaround
    return(string$sc2s(sc$a2s(cs)))
end strip 

divisor_sum = proc (n: bigint) returns (bigint)
    own zero: bigint := bigint$i2bi(0)
    own one: bigint := bigint$i2bi(1)
    own two: bigint := bigint$i2bi(2)
    own three: bigint := bigint$i2bi(3)
    
    total: bigint := one
    power: bigint := two
    while n//two=zero do 
        total := total + power
        power := power * two
        n := n / two
    end
    p: bigint := three
    while p*p <= n do   
        sum: bigint := one
        power := p
        while n//p = zero do
            sum := sum + power
            power := power * p
            n := n/p
        end
        total := total * sum
        p := p + two
    end
    if n>one then total := total * (n+one) end
    return(total)
end divisor_sum

classify_aliquot_sequence = proc (n: bigint)
    LIMIT = 16
    abi = array[bigint] 
    own zero: bigint := bigint$i2bi(0)
    po: stream := stream$primary_output()
    
    terms: array[bigint] := abi$predict(0,LIMIT)
    abi$addh(terms, n)
    
    classification: string := "non-terminating"
    for i: int in int$from_to(1, limit-1) do
        abi$addh(terms, divisor_sum(abi$top(terms)) - abi$top(terms))
        if abi$top(terms) = n then
            if i=1 then classification := "perfect"
            elseif i=2 then classification := "amicable"
            else classification := "sociable"
            end
            break
        end
        j: int := 1
        while j
        if j
            if j=1 then classification := "aspiring"
            else classification := "cyclic"
            end
            break
        end
        if abi$top(terms) = zero then
            classification := "terminating"
            break
        end
    end
    
    stream$puts(po, strip(bigint$unparse(n)) || ": " || classification || ", sequence: "
                 || strip(bigint$unparse(terms[0])))
    for i: int in int$from_to(1, abi$high(terms)) do
        if terms[i] = terms[i-1] then break end
        stream$puts(po, " " || strip(bigint$unparse(terms[i])))
    end
    stream$putl(po, "")
end classify_aliquot_sequence

start_up = proc ()
    for i: int in int$from_to(1, 10) do 
        classify_aliquot_sequence(bigint$i2bi(i)) 
    end
    for i: int in array[int]$elements(array[int]$
        [11,12,28,496,220,1184,12496,1264460,790,909,562,1064,1488]) do
        classify_aliquot_sequence(bigint$i2bi(i))
    end
    classify_aliquot_sequence(bigint$parse("15355717786080"))
    classify_aliquot_sequence(bigint$parse("153557177860800"))
end start_up