cables_dev/cables/src/core/cg/preproc.js

export function preproc(str, vars)
{
    const lines = str.split("\n");
    const outLines = [];
    let stack = [];

    for (let i = 0; i < lines.length; i++)
    {
        let line = lines[i].trim();
        let parts = line.split(" ");

        if (line.startsWith("#ifdef "))
        {
            const s = vars[parts[1]];
            stack.push({ "state": s });
            continue;
        }
        if (line.startsWith("#ifndef "))
        {
            const s = vars[parts[1]];
            stack.push({ "state": !s });
            continue;
        }
        if (line.startsWith("#endif"))
        {
            stack.pop();
            continue;
        }
        const state = stack[stack.length - 1];

        if (line.startsWith("#else"))
        {
            state.state = !state.state;
            continue;
        }

        if (!state || state.state)
        {
            outLines.push(lines[i]);
        }
    }

    return outLines.join("\n");
}