code: function (path, loc) {
            // TODO resolve relative to curr path
            path = normalizePath(base, path)
  
            if (!modules[path]) {
              return {type: 'Error', loc: loc, message: 'Module not found: ' + path}
            }
  
            var moduleId = nextModuleId()
            myModules[moduleId] = path
  
            return {
              type: 'Ok',
              value: {
                id: moduleId,
                module: modules[path]
              }
            }
          }
docs: TODO use src + path