Add get-string and get-type functions

[Denis535]

        function getString(expr) {{
            expr = Stylus.utils.unwrap(expr);
            if (expr.nodes.length == 0) {{
                return new Stylus.nodes.Null();
            }}
            if (expr.nodes.length == 1) {{
                const value = expr.nodes[0];
                if (value.constructor.name == 'String')   return new Stylus.nodes.String( value.string ?? value.toString() );
                if (value.constructor.name == 'Literal')  return new Stylus.nodes.String( value.string ?? value.toString() );
                if (value.constructor.name == 'Ident')    return new Stylus.nodes.String( value.string ?? value.toString() );
                if (value.constructor.name == 'Unit')     return new Stylus.nodes.String( value.string ?? value.toString() );
                if (value.constructor.name == 'RGBA')     return new Stylus.nodes.String( value.name                       );
                if (value.constructor.name == 'Function') return new Stylus.nodes.String( value.name                       );
                if (value.constructor.name == 'Null')     return new Stylus.nodes.Null();
                throw new Error( ""Argument is invalid: "" + value );
            }}
            throw new Error( ""Argument is invalid: "" + expr );
        }}

        function getType(expr) {{
            expr = Stylus.utils.unwrap(expr);
            if (expr.nodes.length == 0) {{
                return new Stylus.nodes.Null();
            }}
            if (expr.nodes.length == 1) {{
                const value = expr.nodes[0];
                return new Stylus.nodes.String( value.constructor.name );
            }}
            {{
                return new Stylus.nodes.String( expr.constructor.name );
            }}
        }}

[Denis535]

Also those functions would be useful.

        function define(name, expr, global) {{
            name = Stylus.utils.unwrap(name).nodes[0].string;
            expr = Stylus.utils.unwrap(expr);
            global = global && global.toBoolean().isTrue;
            if (global === true) {{
                const node = new Stylus.nodes.Ident(name, expr);
                this.global.scope.add(node);
                return;
            }}
            if (global === false || global === undefined) {{
                const node = new Stylus.nodes.Ident(name, expr);
                this.currentScope.add(node);
                return;
            }}
        }}
        
        function isDefined(name, global) {{
            name = Stylus.utils.unwrap(name).nodes[0].string;
            global = global && global.toBoolean().isTrue;
            if (global === true) {{
                return new Stylus.nodes.Boolean(this.global.scope.locals[name]);
            }}
            if (global === false) {{
                return new Stylus.nodes.Boolean(this.currentScope.locals[name]);
            }}
            return new Stylus.nodes.Boolean(this.lookup(name));
        }}
        
        function getDefinition(name, global) {{
            name = Stylus.utils.unwrap(name).nodes[0].string;
            global = global && global.toBoolean().isTrue;
            if (global === true) {{
                return this.global.scope.locals[name];
            }}
            if (global === false) {{
                return this.currentScope.locals[name];
            }}
            return this.lookup(name);
        }}
        
        function getDefinitions(global) {{
            global = global && global.toBoolean().isTrue;
            if (global === true) {{
                const result = new Stylus.nodes.Object();
                for (const [key, value] of Object.entries(this.global.scope.locals)) {{
                    result.setValue(key, value);
                }}
                return result;
            }}
            if (global === false) {{
                const result = new Stylus.nodes.Object();
                for (const [key, value] of Object.entries(this.currentScope.locals)) {{
                    result.setValue(key, value);
                }}
                return result;
            }}
            console.error('Not implemented');
        }}

[slightlyfaulty]

There's already a typeof() function and an is defined binary operator.

You can also cast values to string with the join() function, e.g. join('', red) => '#ff0'.

[Denis535]

is defined binary operator.

It doesn't work with variables. That is, it takes variable's name but not variable's value.

The typeof() also works badly.

[slightlyfaulty]

You don't define values, you define variables. It makes no sense to check if a "value" is defined. If you want to check if a variable is defined by a string name, you can just use lookup().

In future it would be a good idea to give clear examples of why you think your custom functions are useful. Nothing is useful without a use-case.

[Denis535]

I mean next:

my-variable = null
name = "my-variable"
name is defined // It checks "name" is defined or not. But I need to check  "my-variable".

I can not use lookup() because defined variable can also have null value.

[Denis535]

Also define function can not define variable with array value. It can define variable only with one value.

[slightlyfaulty]

If you're using dynamic variables that much you should probably re-think your code design. For example by using hashes which make working with string keys a lot simpler.

[Denis535]

I use dynamic variables because I can change dynamically name of variable. For example: theme--color----------light I change on theme--color--light. When there are a lot of variables, this makes a lot of sense.