57 lines
1.3 KiB
Plaintext
57 lines
1.3 KiB
Plaintext
func evalArithmeticExp(s) {
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func evalExp(s) {
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func operate(s, op) {
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s.split(op).map{|c| c.to_num }.reduce(op);
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}
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func add(s) {
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operate(s.sub(/^\+/,'').sub(/\++/,'+'), '+');
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}
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func subtract(s) {
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s.gsub!(/(\+-|-\+)/,'-');
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if (s ~~ /--/) {
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return(add(s.sub(/--/,'+')));
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}
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var b = s.split('-');
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b.len == 3 ? (-1*b[1].to_num - b[2].to_num)
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: operate(s, '-');
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}
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s.gsub!(/[()]/,'').gsub!(/-\+/, '-');
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var reM = /\*/;
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var reMD = %r"(\d+\.?\d*\s*[*/]\s*[+-]?\d+\.?\d*)";
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var reA = /\d\+/;
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var reAS = /(-?\d+\.?\d*\s*[+-]\s*[+-]?\d+\.?\d*)/;
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while (var match = reMD.match(s)) {
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match[0] ~~ reM
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? s.sub!(reMD, operate(match[0], '*').to_s)
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: s.sub!(reMD, operate(match[0], '/').to_s);
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}
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while (var match = reAS.match(s)) {
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match[0] ~~ reA
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? s.sub!(reAS, add(match[0]).to_s)
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: s.sub!(reAS, subtract(match[0]).to_s);
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}
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return s;
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}
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var rePara = /(\([^\(\)]*\))/;
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s.split!.join!('').sub!(/^\+/,'');
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while (var match = s.match(rePara)) {
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s.sub!(rePara, evalExp(match[0]));
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}
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return evalExp(s).to_num;
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}
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