hyTags
Fibonacci Numbers
Overview
This example demonstrates recursive function definitions in hyTags. Enter a number and calculate its Fibonacci value.
The example shows how to define functions with parameters and return types, use variables, and handle form submissions.
<form>
<input type="text" name="n" value="20">
<button>Calculate</button>
</form>
<on submit>
<form-get-value name="n">
<number-from-string>
<function-call name="fib"></function-call>
<selection-scope next-sibling=".result">
<number-to-string>
<selection-set-text>
</selection-scope>
</on>
<div class="result"></div>
<function name="fib" params="n: number" return="number">
<number-is-equal other="0">
<if-true>
<function-return value="0">
</if-true>
<number-is-equal other="1">
<if-true>
<function-return value="1">
</if-true>
<var-set name="first">
<number-subtract $self="n" value="1">
<function-call name="fib"></function-call>
</var-set>
<var-set name="second">
<number-subtract $self="n" value="2">
<function-call name="fib"></function-call>
</var-set>
<number-add $self="first" $value="second">
</function>
Explanation
- on submit: Attaches a submit event handler to the form. Runs when the form is submitted.
- form-get-value: Gets the value of a form field by name. Pushes the value as a
stringonto the stack. - number-from-string: Converts the
stringon the stack to anumber. - function-call: Calls a function by name. Arguments are taken from the stack based on the function's parameter types.
- selection-scope: Temporarily changes the selection to execute commands on a different element (the result div).
- number-to-string: Converts the
numberon the stack to astring. - selection-set-text: Sets the text content of the current selection to the
stringon the stack. - function: Defines a reusable function with typed parameters and return type. The function body contains the implementation.
- var-set: Creates or updates a variable with the result of the code block inside.
- function-return: Exits the current function and returns a value to the caller.
