less.js/lib/less/tree/mixin-definition.js

module.exports = function (tree) {

var Definition = function (name, params, rules, condition, variadic, frames) {
    this.name = name;
    this.selectors = [new(tree.Selector)([new(tree.Element)(null, name, this.index, this.currentFileInfo)])];
    this.params = params;
    this.condition = condition;
    this.variadic = variadic;
    this.arity = params.length;
    this.rules = rules;
    this._lookups = {};
    this.required = params.reduce(function (count, p) {
        if (!p.name || (p.name && !p.value)) { return count + 1; }
        else                                 { return count; }
    }, 0);
    this.parent = tree.Ruleset.prototype;
    this.frames = frames;
};
Definition.prototype = {
    type: "MixinDefinition",
    accept: function (visitor) {
        if (this.params && this.params.length) {
            this.params = visitor.visitArray(this.params);
        }
        this.rules = visitor.visitArray(this.rules);
        if (this.condition) {
            this.condition = visitor.visit(this.condition);
        }
    },
    variable:  function (name) { return this.parent.variable.call(this, name); },
    variables: function ()     { return this.parent.variables.call(this); },
    find:      function ()     { return this.parent.find.apply(this, arguments); },
    rulesets:  function ()     { return this.parent.rulesets.apply(this); },

    evalParams: function (env, mixinEnv, args, evaldArguments) {
        /*jshint boss:true */
        var frame = new(tree.Ruleset)(null, null),
            varargs, arg,
            params = this.params.slice(0),
            i, j, val, name, isNamedFound, argIndex, argsLength = 0;

        mixinEnv = new tree.evalEnv(mixinEnv, [frame].concat(mixinEnv.frames));

        if (args) {
            args = args.slice(0);
            argsLength = args.length;

            for(i = 0; i < argsLength; i++) {
                arg = args[i];
                if (name = (arg && arg.name)) {
                    isNamedFound = false;
                    for(j = 0; j < params.length; j++) {
                        if (!evaldArguments[j] && name === params[j].name) {
                            evaldArguments[j] = arg.value.eval(env);
                            frame.prependRule(new(tree.Rule)(name, arg.value.eval(env)));
                            isNamedFound = true;
                            break;
                        }
                    }
                    if (isNamedFound) {
                        args.splice(i, 1);
                        i--;
                        continue;
                    } else {
                        throw { type: 'Runtime', message: "Named argument for " + this.name +
                            ' ' + args[i].name + ' not found' };
                    }
                }
            }
        }
        argIndex = 0;
        for (i = 0; i < params.length; i++) {
            if (evaldArguments[i]) { continue; }

            arg = args && args[argIndex];

            if (name = params[i].name) {
                if (params[i].variadic) {
                    varargs = [];
                    for (j = argIndex; j < argsLength; j++) {
                        varargs.push(args[j].value.eval(env));
                    }
                    frame.prependRule(new(tree.Rule)(name, new(tree.Expression)(varargs).eval(env)));
                } else {
                    val = arg && arg.value;
                    if (val) {
                        val = val.eval(env);
                    } else if (params[i].value) {
                        val = params[i].value.eval(mixinEnv);
                        frame.resetCache();
                    } else {
                        throw { type: 'Runtime', message: "wrong number of arguments for " + this.name +
                            ' (' + argsLength + ' for ' + this.arity + ')' };
                    }

                    frame.prependRule(new(tree.Rule)(name, val));
                    evaldArguments[i] = val;
                }
            }

            if (params[i].variadic && args) {
                for (j = argIndex; j < argsLength; j++) {
                    evaldArguments[j] = args[j].value.eval(env);
                }
            }
            argIndex++;
        }

        return frame;
    },
    eval: function (env) {
        return new tree.mixin.Definition(this.name, this.params, this.rules, this.condition, this.variadic, this.frames || env.frames.slice(0));
    },
    evalCall: function (env, args, important) {
        var _arguments = [],
            mixinFrames = this.frames ? this.frames.concat(env.frames) : env.frames,
            frame = this.evalParams(env, new(tree.evalEnv)(env, mixinFrames), args, _arguments),
            rules, ruleset;

        frame.prependRule(new(tree.Rule)('@arguments', new(tree.Expression)(_arguments).eval(env)));

        rules = this.rules.slice(0);

        ruleset = new(tree.Ruleset)(null, rules);
        ruleset.originalRuleset = this;
        ruleset = ruleset.eval(new(tree.evalEnv)(env, [this, frame].concat(mixinFrames)));
        if (important) {
            ruleset = this.parent.makeImportant.apply(ruleset);
        }
        return ruleset;
    },
    matchCondition: function (args, env) {
        if (this.condition && !this.condition.eval(
            new(tree.evalEnv)(env,
                [this.evalParams(env, new(tree.evalEnv)(env, this.frames ? this.frames.concat(env.frames) : env.frames), args, [])] // the parameter variables
                    .concat(this.frames) // the parent namespace/mixin frames
                    .concat(env.frames)))) { // the current environment frames
            return false;
        }
        return true;
    },
    matchArgs: function (args, env) {
        var argsLength = (args && args.length) || 0, len;

        if (! this.variadic) {
            if (argsLength < this.required)                               { return false; }
            if (argsLength > this.params.length)                          { return false; }
        } else {
            if (argsLength < (this.required - 1))                         { return false; }
        }

        len = Math.min(argsLength, this.arity);

        for (var i = 0; i < len; i++) {
            if (!this.params[i].name && !this.params[i].variadic) {
                if (args[i].value.eval(env).toCSS() != this.params[i].value.eval(env).toCSS()) {
                    return false;
                }
            }
        }
        return true;
    }
};
return Definition;
};