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POSpecifying settings for Options
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copied!<p>How do you explicitly state the valid settings for an option? Take this example for instance</p> <pre><code>Options[myFunc] = {opt1 -> "SomeString"}; myFunc[OptionsPattern[]] := Print[OptionValue[opt1]]; </code></pre> <p><code>myFunc</code> prints the value of the option. If we evaluate <code>myFunc[opt1 -> {1, 2}]</code> then it prints <code>{1, 2}</code>. This function will essentially print anything that you set to <code>opt1</code>. My question is, how can I make sure that my function only accept a given number of values for <code>opt1</code>. We can start with something simple like a <code>String</code> and an <code>Integer</code>.</p> <p>To have a better idea of the behavior that we would except when given the wrong values for <code>opt1</code> we can take a look at what happens when we give the wrong values for <code>PlotRange</code> in the function <code>Plot</code>.</p> <p><img src="https://i.stack.imgur.com/as16Y.png" alt="enter image description here"></p> <p>In the example given in the picture I purposely gave wrong values to the <code>PlotRange</code> options and gave me a message specifying the correct type of values for that particular options. It seems that it <code>PlotRange</code> ended up taking its default value and thus it return the <code>Graphics</code> object.</p> <p>In the simple example what we would like to obtain is something like:</p> <pre><code>myFunc::sometag : Value of option opt1 -> `1` is not a string or interger. </code></pre> <p>Does anyone know how to achieve this?</p>

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