Arithmetic evaluation: Difference between revisions
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? arithEvaluate("(1 + 2 / 2) * (5 + 5)") |
? arithEvaluate("(1 + 2 / 2) * (5 + 5)") |
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# value: 20.0</lang> |
# value: 20.0</lang> |
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=={{header|Elena}}== |
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<lang elena>#define basic'* = std'basic'*. |
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#define ctrl'* = std'patterns'*. |
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#define io'* = ext'io'*. |
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#subject parse_order. |
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#class Token |
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{ |
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#field theValue. |
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#method parse_order'get = 0. |
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#method += aChar |
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[ |
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theValue += aChar. |
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] |
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#method + aNode |
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[ |
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^ aNode += self. |
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] |
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#method new |
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[ |
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theValue := basic'String. |
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] |
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#method real'get = basic'RealType evaluate:theValue. |
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} |
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#class Node |
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{ |
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#field theLeft. |
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#field theRight. |
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#role Empty |
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{ |
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#method += aNode |
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[ |
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theLeft := aNode. |
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$self $setLeftAssigned. |
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] |
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} |
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#role LeftAssigned |
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{ |
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#method += aNode |
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[ |
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theRight := aNode. |
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#shift. |
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] |
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} |
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#method $setLeftAssigned |
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[ |
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#shift LeftAssigned. |
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] |
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#method + aNode |
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[ |
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#if (self parse_order > aNode parse_order)? |
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[ |
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self += aNode. |
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] |
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| [ |
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aNode += self. |
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^ aNode. |
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]. |
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] |
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#method += aNode |
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[ |
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#if (theRight parse_order > aNode parse_order)? |
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[ |
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theRight += aNode. |
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] |
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| [ |
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theRight := aNode += theRight. |
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]. |
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] |
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#method new |
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[ |
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#shift Empty. |
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] |
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} |
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#class SummaryNode (Node) |
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{ |
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#method parse_order'get = 2. |
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#method real'get = theLeft real'get + theRight real'get. |
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} |
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#class DifferenceNode (Node) |
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{ |
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#method parse_order'get = 2. |
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#method real'get = theLeft real'get - theRight real'get. |
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} |
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#class ProductNode (Node) |
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{ |
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#method parse_order'get = 1. |
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#method real'get = theLeft real'get * theRight real'get. |
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} |
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#class FractionNode (Node) |
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{ |
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#method parse_order'get = 1. |
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#method real'get = theLeft real'get / theRight real'get. |
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} |
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#class SubExpression |
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{ |
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#field theParser. |
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#field theCounter. |
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#role EOF |
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{ |
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#method eof'is [] |
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#method += aChar [ $self fail. ] |
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} |
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#method parse_order'get = 0. |
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#method + aNode |
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[ |
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^ aNode += self. |
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] |
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#method += aChar |
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[ |
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#if ctrl'Control if:(aChar == 41) |
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[ |
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theCounter -= 1. |
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] |
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| if:(aChar == 40) |
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[ |
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theCounter += 1. |
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]. |
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#if(theCounter == 0)? |
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[ #shift EOF. ^ $self. ]. |
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theParser evaluate:aChar. |
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] |
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#method real'get = theParser real. |
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#method new |
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[ |
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theParser := arithmeval'Parser. |
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theCounter := basic'Integer << 1. |
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] |
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} |
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#class Parser |
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{ |
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#field theToken. |
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#field theTopNode. |
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#role Start |
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{ |
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#method evaluate : aChar |
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[ |
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#if (aChar == 40)? |
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[ |
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theToken := SubExpression. |
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theTopNode := theToken. |
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$self $setBrackets. |
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] |
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| [ |
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theToken := Token. |
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theTopNode := theToken. |
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theToken += aChar. |
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#shift. |
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]. |
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] |
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} |
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#role Operator |
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{ |
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#method evaluate : aChar |
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[ |
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#if ctrl'Control if:(aChar > 48) if:(aChar < 58) |
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[ |
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theToken := (Token += aChar). |
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theTopNode += theToken. |
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] |
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| [ $self fail. ]. |
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#shift. |
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] |
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} |
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#role Brackets |
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{ |
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#method evaluate : aChar |
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[ |
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theToken += aChar. |
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#if theToken eof'is |
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[ |
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#shift. |
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]. |
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] |
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} |
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#method real'get = theTopNode real. |
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#method evaluate : aChar |
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[ |
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#if ctrl'Control if:(aChar > 48) if:(aChar < 58) |
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[ |
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theToken += aChar. |
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] |
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| if:(aChar == 42) // * |
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[ |
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theTopNode := theTopNode + ProductNode. |
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#shift Operator. |
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] |
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| if:(aChar == 47) // / |
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[ |
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theTopNode := theTopNode + FractionNode. |
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#shift Operator. |
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] |
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| if:(aChar == 43) // + |
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[ |
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theTopNode := theTopNode + SummaryNode. |
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#shift Operator. |
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] |
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| if:(aChar == 45) // - |
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[ |
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theTopNode := theTopNode + DifferenceNode. |
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#shift Operator. |
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] |
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| if:(aChar == 40) |
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[ |
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theToken := SubExpression. |
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theTopNode := theToken. |
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#shift Brackets. |
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] |
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| [ $self fail. ]. |
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] |
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#method new |
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[ |
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#shift Start. |
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] |
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#method $setBrackets |
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[ |
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#shift Brackets. |
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] |
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} |
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#symbol Program => |
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[ |
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#var aText := basic'String. |
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#loop ((io'Console >> aText) length > 0)? |
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[ |
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#var aParser := Parser. |
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io'Console << "=" << ctrl'Control do: => |
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[ |
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ctrl'Control run &literal:aText &foreach: aParser. |
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^ aParser real. |
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] |
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| back:"Invalid Expression". |
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io'Console << "%n". |
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]. |
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]. |
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</lang> |
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=={{header|Factor}}== |
=={{header|Factor}}== |