RosettaCodeData/Task/Execute-a-Markov-algorithm/Jq/execute-a-markov-algorithm-...

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def parseRules($rules):
"^ *(?<period>[.]?) *(?<rule>.*)" as $pattern
| reduce $rules[] as $rule ([];
if $rule | (startswith("#") or (test(" -> ")|not)) then .
else ($rule|split2(" -> ")) as $splits
| ($splits[1] | capture($pattern)) as $re
| . + [[($splits[0]|trim|deregex), $re.period, ($re.rule | trim)]]
end );
# applyRules applies $rules to . recursively,
# where $rules is the set of applicable rules in the form of an array-of-triples.
# Input and output: a string
def applyRules($rules):
# The inner function has arity-0 for efficiency
# input and output: {stop, string}
def apply:
if .stop then .
else .string as $copy
| first( foreach $rules[] as $c (.;
.string |= sub($c[0]; $c[2])
| if $c[1] == "."
then .stop=true
elif .string != $copy
then (apply | .stop = true)
else .
end;
if .stop then . else empty end))
// .
end;
{stop: false, string: .} | apply | .string;
def proceed:
rules as $rules
| tests as $tests
| range(0; $tests|length) as $ix
| $tests[$ix]
| " \(.)\n=>\(applyRules( parseRules( $rules[$ix] ) ))\n" ;
proceed