Computer Science Canada String to Command? |
| Author: | The_Bean [ Wed Sep 17, 2008 9:14 pm ] |
| Post subject: | String to Command? |
Is there anyway to convert a string to a command? example: for a drawing program the user inputs "Draw.FillOval(...)" then have turing converts the string to a command and actually draws the circle I actually need it for a graphing calculator, but that example is a bit easier to understand |
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| Author: | [Gandalf] [ Wed Sep 17, 2008 9:28 pm ] |
| Post subject: | RE:String to Command? |
Mostly you would just use conditional statements for something like this, unless you're planning to create your own Turing interpreter in Turing. If your goal is to create a graphing calculator, though, why do you need this at all? Just get the function (say) that you want to graph and use the appropriate drawing commands accordingly. |
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| Author: | Tony [ Wed Sep 17, 2008 9:44 pm ] |
| Post subject: | RE:String to Command? |
Though the function would still have to be interpreted. Which is more involving than simply conditional statements. |
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| Author: | The_Bean [ Wed Sep 17, 2008 9:48 pm ] |
| Post subject: | Re: String to Command? |
when the user inputs: y=(x-4)(x-3)^2(x+2) and then somehow get from a string into for x : -25..25 y:=(x-4)*(x-3)**2*(x+2) Draw.Dot(x,y,7) end for |
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| Author: | Tony [ Wed Sep 17, 2008 11:31 pm ] |
| Post subject: | RE:String to Command? |
you're going to need a scanner -- fairly easy since there are very few symbols. you're going to need a parser build a parse tree of the expression you're going to need a way to evaluate that tree (should also be easy -- recursion + eval of basic algebra operations) |
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