CalcRPN - calculate reverse polish notation [1032662]

< > BotCompany Repo | #1032662 // CalcRPN - calculate reverse polish notation

JavaX fragment (include) [tags: use-pretranspiled]

// sequence can contain operators (+, -, *, /), Doubles or string-encoded doubles
srecord CalcRPN(L sequence) is Steppable {
  int i;
  new DoubleList stack;
  
  run { stepAll(this); }
  
  bool done() { ret i >= l(sequence); }
  
  public bool step() {
    if (done()) false;
    O o = sequence.get(i++);
    if (eq(o, "*")) perform((a, b) -> a * b);
    else if (eq(o, "/")) perform((a, b) -> doubleRatio(a, b));
    else if (eq(o, "+")) perform((a, b) -> a + b);
    else if (eq(o, "-")) perform((a, b) -> a - b);
    else if (eq(o, "u-")) perform(a -> -a);
    else if (o cast S)
      handleUnknownString(o);
    else
      stack.add(toDouble(o));
    true;
  }

  void handleUnknownString(S s) {
    stack.add(toDouble(trim(s)));
  }
    
  void perform(IF2<Double> f) {
    var arg2 = popLast(stack);
    var arg1 = popLast(stack);
    stack.add(f.get(arg1, arg2));
  }
  
  void perform(IF1<Double> f) {
    stack.add(f.get(popLast(stack)));
  }
  
  double get() {
    run();
    assertEquals(1, l(stack));
    ret last(stack);
  }
}

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Snippet ID:

#1032662

Snippet name:

CalcRPN - calculate reverse polish notation

Eternal ID of this version:

#1032662/11

Text MD5:

31a1f3dcb1533e50eec3b0a7c56bc552

Transpilation MD5:

6a7f98cb8ba0ad4c001c0ba19215e329

Author:

stefan

Category:

javax

Type:

JavaX fragment (include)

Public (visible to everyone):

Yes

Archived (hidden from active list):

Created/modified:

2021-10-02 00:58:25

Source code size:

1086 bytes / 44 lines

Pitched / IR pitched:

No / No

Views / Downloads:

410 / 602

Version history:

10 change(s)

Referenced in:

[show references]

1	// sequence can contain operators (+, -, *, /), Doubles or string-encoded doubles
2	srecord CalcRPN(L sequence) is Steppable {
3	int i;
4	new DoubleList stack;
5
6	run { stepAll(this); }
7
8	bool done() { ret i >= l(sequence); }
9
10	public bool step() {
11	if (done()) false;
12	O o = sequence.get(i++);
13	if (eq(o, "")) perform((a, b) -> a b);
14	else if (eq(o, "/")) perform((a, b) -> doubleRatio(a, b));
15	else if (eq(o, "+")) perform((a, b) -> a + b);
16	else if (eq(o, "-")) perform((a, b) -> a - b);
17	else if (eq(o, "u-")) perform(a -> -a);
18	else if (o cast S)
19	handleUnknownString(o);
20	else
21	stack.add(toDouble(o));
22	true;
23	}
24
25	void handleUnknownString(S s) {
26	stack.add(toDouble(trim(s)));
27	}
28
29	void perform(IF2<Double> f) {
30	var arg2 = popLast(stack);
31	var arg1 = popLast(stack);
32	stack.add(f.get(arg1, arg2));
33	}
34
35	void perform(IF1<Double> f) {
36	stack.add(f.get(popLast(stack)));
37	}
38
39	double get() {
40	run();
41	assertEquals(1, l(stack));
42	ret last(stack);
43	}
44	}