Preset variables

You can preset variables before compilation by using the replaceVariables($vars) or addVariables($vars) methods of the Compiler. Compiler::getVariables allows to get the list of registered variables. Compiler::unsetVariable($name) allows to unset a variable (the exact name used for the registration must be passed).

Presetting variables is semantically equivalent to prepending variable declarations at the beginning of the input. If the variable is also defined in your scss source, use the !default flag in the source to prevent your preset variables from being overridden.

Variable names can optionally include the leading $ and can use dashes or underscores interchangeably. If multiple preset variables have the same normalized name, the last one wins (as they are declared in order). The recommendation is to stick with normalized names (no leading $ and dashes rather than underscores) to avoid confusion.

Variable values must be converted to the internal representation of Sass values using the \ScssPhp\ScssPhp\ValueConverter API. This API exposes 2 helpers:

ValueConverter::parseValue parses a string containing a SCSS representation of a value.
ValueConverter::fromPhp converts a PHP scalar (or null) to the equivalent SCSS value. Note that not all Sass values can be represented as a PHP scalar (numbers with units or colors for instance).

use ScssPhp\ScssPhp\Compiler;
use ScssPhp\ScssPhp\ValueConverter;

$compiler = new Compiler();
$compiler->replaceVariables(array(
    'var' => ValueConverter::parseValue('false'),
    'size' => ValueConverter::parseValue('25px'),
));

echo $compiler->compileString('$var: true !default; @debug $var;')->getCss();

scssphp

Preset variables