Parsing/RPN to infix conversion: Difference between revisions
Added Wren
SqrtNegInf (talk | contribs) m (→{{header|Sidef}}: Fix link: Perl 6 --> Raku) |
(Added Wren) |
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Line 3,940:
^ -> [((1 + 2) ^ (3 + 4)) ^ (5 + 6)]
Infix : ((1 + 2) ^ (3 + 4)) ^ (5 + 6)</pre>
=={{header|Wren}}==
{{trans|Kotlin}}
{{libheader|Wren-seq}}
{{libheader|Wren-pattern}}
<lang ecmascript>import "/seq" for Stack
import "/pattern" for Pattern
class Expression {
static ops { "-+/*^" }
construct new(ex, op, prec) {
_ex = ex
_op = op
_prec = prec
}
static build(e1, e2, o) { new("%(e1) %(o) %(e2)", o, (ops.indexOf(o)/2).floor) }
ex { _ex }
ex=(other) { _ex = other }
prec { _prec }
toString { _ex }
}
var postfixToInfix = Fn.new { |postfix|
var expr = Stack.new()
var p = Pattern.new("+1/s")
for (token in p.splitAll(postfix)) {
var c = token[0]
var idx = Expression.ops.indexOf(c)
if (idx != -1 && token.count == 1) {
var r = expr.pop()
var l = expr.pop()
var opPrec = (idx/2).floor
if (l.prec < opPrec || (l.prec == opPrec && c == "^")) {
l.ex = "(%(l.ex))"
}
if (r.prec < opPrec || (r.prec == opPrec && c != "^")) {
r.ex = "(%(r.ex))"
}
expr.push(Expression.build(l.ex, r.ex, token))
} else {
expr.push(Expression.new(token, "", 3))
}
System.print("%(token) -> %(expr)")
}
return expr.peek().ex
}
var es = [
"3 4 2 * 1 5 - 2 3 ^ ^ / +",
"1 2 + 3 4 + ^ 5 6 + ^"
]
for (e in es) {
System.print("Postfix : %(e)")
System.print("Infix : %(postfixToInfix.call(e))\n")
}</lang>
{{out}}
<pre>
Postfix : 3 4 2 * 1 5 - 2 3 ^ ^ / +
3 -> [3]
4 -> [3, 4]
2 -> [3, 4, 2]
* -> [3, 4 * 2]
1 -> [3, 4 * 2, 1]
5 -> [3, 4 * 2, 1, 5]
- -> [3, 4 * 2, 1 - 5]
2 -> [3, 4 * 2, 1 - 5, 2]
3 -> [3, 4 * 2, 1 - 5, 2, 3]
^ -> [3, 4 * 2, 1 - 5, 2 ^ 3]
^ -> [3, 4 * 2, (1 - 5) ^ 2 ^ 3]
/ -> [3, 4 * 2 / (1 - 5) ^ 2 ^ 3]
+ -> [3 + 4 * 2 / (1 - 5) ^ 2 ^ 3]
Infix : 3 + 4 * 2 / (1 - 5) ^ 2 ^ 3
Postfix : 1 2 + 3 4 + ^ 5 6 + ^
1 -> [1]
2 -> [1, 2]
+ -> [1 + 2]
3 -> [1 + 2, 3]
4 -> [1 + 2, 3, 4]
+ -> [1 + 2, 3 + 4]
^ -> [(1 + 2) ^ (3 + 4)]
5 -> [(1 + 2) ^ (3 + 4), 5]
6 -> [(1 + 2) ^ (3 + 4), 5, 6]
+ -> [(1 + 2) ^ (3 + 4), 5 + 6]
^ -> [((1 + 2) ^ (3 + 4)) ^ (5 + 6)]
Infix : ((1 + 2) ^ (3 + 4)) ^ (5 + 6)
</pre>
=={{header|zkl}}==
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