Peter + AI

Posted on Nov 2

🧮 Understanding the $tan Function in Uniface 10.4

#tutorial #learning #programming

⚠️ This blog post was created with AI assistance to help developers understand Uniface functionality better.

📝 What is $tan?

The $tan function in Uniface 10.4 is a mathematical function that calculates the tangent of an angle. If you remember your math classes, the tangent is one of the basic trigonometric functions, alongside sine and cosine. 📐

In Uniface, you can use this function to perform trigonometric calculations directly in your ProcScript code.

🔧 How Does It Work?

The syntax is very simple:

$tan(X)

Where X is an angle measured in radians (not degrees!). This is important to remember. ⚡

The parameter X can be:

A direct numeric value
A field reference
A variable
An expression that evaluates to a number

💡 Basic Example

Here's a simple example from the documentation:

vTangent = $tan($pi() * RADIANS)

This code calculates the tangent by multiplying π (pi) with a value stored in RADIANS. The result is stored in the variable vTangent. 🎯

🎓 Understanding Radians

If you're used to working with degrees, remember that you need to convert them first:

180 degrees = π radians
90 degrees = π/2 radians
45 degrees = π/4 radians

To convert degrees to radians, use this formula:

radians = degrees * ($pi() / 180)

🛠️ Practical Use Cases

When would you use $tan in your Uniface applications? Here are some real-world scenarios:

Engineering calculations: When building applications for construction or engineering firms that need to calculate angles and slopes 📏
Gaming applications: For calculating trajectories and movement paths 🎮
Scientific applications: Any application that requires trigonometric calculations 🔬
Financial applications: Some financial models use trigonometric functions for cyclical patterns 📊

⚠️ Error Handling

Like all Uniface functions, $tan can encounter errors. The most common error is overflow, which happens when the calculation result is too large to handle.

After calling $tan, you should check $procerror:

vResult = $tan(vAngle)
if ($procerror < 0)
   ; Handle error
   if ($procerror = -1208)
      ; Overflow occurred
   endif
endif

The error code -1208 (UPROCERR_OVERFLOW) specifically indicates an overflow error. 🚨

✨ Complete Example

Here's a more complete example showing how to use $tan safely:

; Convert 45 degrees to radians
vDegrees = 45
vRadians = vDegrees * ($pi() / 180)

; Calculate tangent
vResult = $tan(vRadians)

; Check for errors
if ($procerror < 0)
   $putmess "Error calculating tangent!"
else
   ; The tangent of 45 degrees is approximately 1
   $putmess "Tangent result: %%vResult%%"
endif

🔗 Related Functions

Uniface also provides other trigonometric functions that work together with $tan:

$sin: Calculates the sine of an angle
$cos: Calculates the cosine of an angle
$atan: Calculates the arc tangent (inverse of $tan)
$pi: Returns the value of π

📍 Where Can You Use It?

The good news is that $tan is allowed in all component types in Uniface. Whether you're working with forms, services, or reports, you can use this function wherever you need trigonometric calculations. ✅

💭 Tips and Best Practices

Always work in radians: Remember that $tan expects radians, not degrees. Convert your values first! 🔄
Check for errors: Always verify $procerror after the calculation to catch potential problems early 🔍
Avoid extreme values: The tangent function has discontinuities at π/2, 3π/2, etc. Be careful with values near these points ⚡
Use constants: Use $pi() instead of hardcoding 3.14159 for better accuracy 🎯

🎉 Conclusion

The $tan function in Uniface 10.4 is a straightforward way to perform trigonometric calculations in your applications. While it's simple to use, remember to work in radians and always check for errors to build robust applications.

Whether you're building engineering tools, games, or scientific applications, having access to mathematical functions like $tan makes Uniface a powerful platform for development. Happy coding! 💻

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