Macros Overview

Macros are built-in functions that handle common operations in question writing — math formatting, string manipulation, array processing, conditional logic, and feedback generation.

Macro Categories

Category	Purpose	Key Functions
Math	Numeric computations, rounding	round(), gcd(), lcm(), mod()
String	Text processing and formatting	stringlen(), stringclean(), stringpos()
Array	Array creation and manipulation	array(), sortarray(), sumarray()
Format	Display formatting	prettyreal(), makereducedfraction(), makescinot()
Conditional	Branching and logic	if/else, comparison operators, in_array()
Feedback	Adaptive hints and messages	getfeedbackbasic(), getfeedbacktxt()

Using Macros

Macros are called in the question's code, in the Common Control box. They look like function calls:

$formatted = prettyreal($ans, 2);             // format $ans to 2 decimal places
$simplified = makereducedfraction($num, $den); // reduce a fraction to lowest terms

You can chain macro calls and use their return values in variable assignments, conditional checks, or directly in the question text.

Macros vs. PHP Functions

Many macros parallel standard PHP or math library functions, but are adapted for educational math contexts — for example, makereducedfraction() returns a fraction in lowest terms (makereducedfraction(6, 8) gives 3/4), and prettyreal() rounds a value to a fixed number of decimal places and adds thousands separators (prettyreal(1234.5, 2) gives 1,234.50).

The engine exposes a deliberate subset of native PHP — count(), in_array(), substr(), str_replace(), explode(), sprintf(), array_keys(), array_values(), array_reverse(), array_unique() and a few more. Anything outside that subset, including strlen(), sort() and implode(), is a hard error. Use the engine's own stringlen(), sortarray() and joinarray() instead.

Quick Reference

See each category page for the full list of available macros with examples.