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September 2017 Update

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Ingy döt Net 2017-09-23 10:01:46 +02:00
parent bba7bfd280
commit ba8067c3b7
14570 changed files with 153136 additions and 63871 deletions
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40
Task/Parsing-Shunting-yard-algorithm/Sidef/parsing-shunting-yard-algorithm.sidef
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@ -5,7 +5,7 @@ var prec = Hash(
'+' => 2,
'-' => 2,
'(' => 1,
);
)
var assoc = Hash(
'^' => 'right',
@ -13,38 +13,46 @@ var assoc = Hash(
'/' => 'left',
'+' => 'left',
'-' => 'left',
);
)
func shunting_yard(prog) {
var inp = prog.words;
var ops = [];
var res = [];
var inp = prog.words
var ops = []
var res = []
 
func report (op) {
printf("%25s  %-7s %10s %s\n",
res.join(' '), ops.join(' '), op, inp.join(' '))
}
func report (op) { printf("%25s %-7s %10s %s\n", res.join(' '), ops.join(' '), op, inp.join(' ')) }
func shift (t) { report( "shift #{t}"); ops << t }
func reduce (t) { report("reduce #{t}"); res << t }
 
while (inp) {
given(var t = inp.shift) {
when (/\d/) { reduce(t) }
when ('(') { shift(t) }
when (')') { var x; while (ops && (x = ops.pop) && (x != '(')) { reduce(x) } }
when (')') {
while (ops) {
(var x = ops.pop) == '(' ? break : reduce(x)
}
}
default {
var newprec = prec{t};
var newprec = prec{t}
while (ops) {
var oldprec = prec{ops[-1]};
var oldprec = prec{ops[-1]}
 
break if (newprec > oldprec)
break if ((newprec == oldprec) && (assoc{t} == 'right'))
reduce(ops.pop);
 
reduce(ops.pop)
}
shift(t);
shift(t)
}
}
}
while (ops) { reduce(ops.pop) }
return res
}
say shunting_yard('3 + 4 * 2 / ( 1 - 5 ) ^ 2 ^ 3').join(' ');
 
say shunting_yard('3 + 4 * 2 / ( 1 - 5 ) ^ 2 ^ 3').join(' ')