Add Field To Struct Golang

In the following code, we define a struct called "Person", and then initialize it in two ways. We can create a GraphQL object and define the fields or properties that exist in that object. When the embedded field is a struct, all the fields in that struct will implicitly be the fields in the struct in which it has been embedded. Use withColumn() method of the Dataset. When decoding structs, fields are matched by name and compatible type, and only fields that exist in both are affected. They also have become an easy way for content creators. First, you need to tell VexCL how to spell the type name of the struct. Perhaps golang team felt that it is too much for one data structure. The popular fillstruct tool is now integrated in #golang Fill all your struct fields with default values with the new command "Go: Fill Struct"pic. For those who miss the ; at the end of a line of code, you can use them, but the lexer of the compiler will put them in for you. Python (186) Ubuntu (81) OpenContrail (79) OpenStack (78) Django (69) Linux (67) Horizon (27) Networking (27) VMware (27) OpenStack Neutron (26) Git (25) OpenStack Heat (24) Puppet (24) OpenvSwitch (22) Keystone (20) OpenStack Dev Tips (19) go (19) golang (19) linux network namespace (19) Libvirt (18) Cloud (17) Horizon Dev Tips (16) Openstack. For information on managed classes and structs in C++/CLI, see Classes and Structs. Learn how to create a web application that uses Couchbase as the NoSQL database, Golang for the web application backend, GraphQL for the frontend query technology, and JSON web tokens (JWT) for the authorization component. Building a REST Service with Golang - Part 3 (Adding a Backend) we need to add a struct tag to tell mgo how We also extend each field with a bson struct tag. Security Fix(es) : For more details about the security issue(s), including the impact, a CVSS score, and other related information, refer to the CVE page(s) listed in the References section. I will create restful Api to fetch data from MySQL. % godoc -src sync Mutex // A Mutex is a mutual exclusion lock. The db file will have database connection information. A struct is a type which contains named fields. Golang Custom Struct Tags Example. Pointer to struct that allows user to set optional custom metadata, content-type, content-encoding, content-disposition, content-language and cache-control headers, pass encryption module for encrypting objects, and optionally configure number of threads for multipart put operation. It also allows instantiation of new objects and invocation of methods. Anonymous struct fields are usually marshaled as if their inner exported fields were fields in the outer struct, subject to the usual Go visibility rules amended as described in the next paragraph. Here I should mention that. The Go spec in the Struct types definition defines tags as. OK, it sounds like we should add the fields to the Example struct (the second half of my message from March 5). This enables one to create a structured URL partial path and “route” that traffic to a function that takes in a request and a response stream. embedded fields in struct. org) support plugin ro Quick documentation for struct fields;. 5, a zero-length field at the end of a struct (that is, a zero-length array or empty struct) is sized and aligned as though it is one byte. Go + HTTP/2 - - Welcome to the Go language's HTTP/2 demo & interop server. Learn More. There's no response. Options to set a new configuration. Using Maps and Slices. We have a few options when it comes to parsing the JSON that is contained within our users. If you're a Java developer and would like to add. You will need to help it a bit. You can see that not all the information that was in the object file has been mapped directly. You can see from the code that all errors are prefixed with their HTTP status code. It also has an embedded anonymous field author. When I started I didn’t know the full format of the tenant information: I used a trick to generate that neat structure: I dumped the JSON received from the /installed callback – which is called by Bitbucket when the add-on is first installed – into the fabulous JSON-to-Go to auto-generate a suitable Go struct. CGO converting Xlib XEvent struct to byte array? c,go,xlib,cgo. go file will have database connection information and routes information. The fields are basically a subset of http. Structs allow us to compose together values of different types. Placing a go statement before a function call starts the execution of that function as an independent concurrent thread in the same address space as the calling code. Structs have fields. We use this concept in the nested structure where a structure is a field in another structure, simply by just adding the name of the structure into another structure and it behaves like the Anonymous Field to the nested structure. How do you get the memory address of a variable? How do you assign a value to a pointer? How do you create a new pointer? What is the value of x after running this program:. HandlerFunc looks like this: func(w http. Structures are used to represent a record. We can also decode JSON into custom data types. CL 174085 Add 'EmptyValue' interface, empty if element is struct and all fields within it is also empty. Add method is used to identify how. Ask Question Asked 1 year, 10 months ago. The t: operator is short for "tag" and coincides with the colored tags you see in the rows below. I don't like 1. Be careful and make sure to use pointers if you want state to be shared between structs that you pass around. ) The special prefix & returns a pointer to the struct value. Build-on-save to compile code and show build errors. How efficient is having to do all the above for accessing a struct field within a map entry? (this is: copy value, modify new value,. Simple GoLang API Using Echo and MySQL. This tutorial follow MVC pattern to create golang application. In fact, Go supports fields without names, but with types. These may conflict with field names that already exist in a schema, causing applications to break. Golang has the ability to declare and create own data types by combining one or more types, including both built-in and user-defined types. Creating Golang MVC Application Using Echo wFramework and MySQL. I have am implementing a rest api that wraps a library, the library contains the structs and the data being passed by the user matches these structs, however I may need to add a few additional fields that the library doesnt need by my rest wrapper will use. For 64-bit x86 systems, the following instructions have been added: VBROADCASTSD, BROADCASTSS, MOVDDUP, MOVSHDUP, MOVSLDUP, VMOVDDUP, VMOVSHDUP, and VMOVSLDUP. The GORM is fantastic ORM library for Golang, aims to be developer friendly. 3) Methods : structs are the mechanism for associating data with functions in Golang. HandlerFunc looks like this: func(w http. There are some struct data with empty field. Generate Golang struct (model. ' to access the fields inside TestMessage because Go will automatically dereference the pointer to the struct or object it points to as shown below. Row has no field or method ScanErrorModel) Is it impossible to add a function onto a struct that is. When the embedded field is a struct, all the fields in that struct will implicitly be the fields in the struct in which it has been embedded. This is a Go FAQ: Frequently Asked Questions (FAQ). If you're a Java developer and would like to add. 0 (7 ratings) Course Ratings are calculated from individual students’ ratings and a variety of other signals, like age of rating and reliability, to ensure that they reflect course quality fairly and accurately. Such thread is called goroutine in Golang. I can also very easily update the struct then marshal the data back into XML where it can be placed in the body of a put request. because now all other methods of struct has to perform the same check. I don't like 1. It is composed of fields or members that can have different types. If the program contains tests or examples and no main function, the service runs the tests. A struct is just a collect of fields. In my opinion, it would not be better. I've just introduced to you how to define a struct with field names and type. But sometimes you may want to map specific keys in the JSON to a field with a different name in your struct. The practical effect of this is that the result of t. gqlgen provides a way to define the maximum query complexity allowed in one call. What does golang have? A validator library from go-playground that allows the validation of structs and individual fields. > "golang-nuts" group. FieldByName and related functions consider struct field names to be equal if the names are equal, even if they are unexported names originating in different packages. If you’re a Java developer and would like to add. A struct literal denotes a newly allocated struct value by listing the values of its fields. But otherwise a "dumb set" that only has add, contains and remove can be easily replicated with map as explained by @jozefg. Is there an idiomatic way in Go to iterate over a single field in the "struct" key of a map? I suspect not, and " a map of a map" has to be used in the case below, but would like to ask if the "struct" map key approach is a viable way. These are pointers—which are variables of a specific type. Even though “ProtoMessage” is a pointer, I can still just use ‘. type WaitGroup struct { m Mutex counter int32 waiters int32 sema *uint32 } There is a counter member which indicates how many goroutines need to be waited are living now. It also has an embedded anonymous field author. This enables one to create a structured URL partial path and “route” that traffic to a function that takes in a request and a response stream. This has the advantages of adding additional type-safety to our programs and eliminating the need for type assertions when accessing the decoded data. Golang add function to struct defined elsewhere (type *sql. I am not creating separate file for handlers, env and model class. structs can also contain behavior in the form of methods. The GORM is fantastic ORM library for Golang, aims to be developer friendly. Each field in the struct has a name (e. Now I could go ahead and continue creating fields that do querying or mutations, but the steps are the same. type WaitGroup struct { m Mutex counter int32 waiters int32 sema *uint32 } There is a counter member which indicates how many goroutines need to be waited are living now. Even though "ProtoMessage" is a pointer, I can still just use '. Go's XML package uses reflection for data mapping, so all fields in v should be exported. 有的时候上游传过来的字段是string类型的,但是我们却想用变成数字来使用。 本来用一个json:",string" 就可以支持了,如果不知道golang的这些小技巧,就要大费周章了。参考文章:JSON and struct composit…. go file and will have all ‘todo’ example functionality in it. 50 Shades of Go: Traps, Gotchas, and Common Mistakes for New Golang Devs The struct fields starting with lowercase letters will not be (json, xml, gob, etc. Python (186) Ubuntu (81) OpenContrail (79) OpenStack (78) Django (69) Linux (67) Horizon (27) Networking (27) VMware (27) OpenStack Neutron (26) Git (25) OpenStack Heat (24) Puppet (24) OpenvSwitch (22) Keystone (20) OpenStack Dev Tips (19) go (19) golang (19) linux network namespace (19) Libvirt (18) Cloud (17) Horizon Dev Tips (16) Openstack. Basically, it is used to tell the unmarshaller or marshaller to ignore empty fields. I can understand that this definition is quite complex so lets dive right into some code to understand this :). Have you thought about trying Node. In this post I will demonstrate on an example how to use Golang template package to generate email content based on a template defined in a file. The JSON format makes it possible for machines to easily parse your Golang logs. You just need to add one line (Line 5 in the following snippet) in your graphql handler and define the maximum complexity (300 in our case). After a channel is created, this field is set to 0, that is, the channel is open; by calling close to set it to 1, the channel is closed. I am not creating separate file for handlers, env and model class. Arrays allow to define type of variables that can hold several data items of the same kind. After finding the struct, it needs to be able to get the field names; It needs to update the struct tags based on the field names (according to the transform rule, i. Map converts the given struct to a map[string]interface{}, where the keys of the map are the field names and the values of the map the associated values of the fields. When the code generator encounters a field in the schema that would collide with a generated field or method name, the code generator will append an underscore to the generated field or method name. go file and will have all 'todo' example functionality in it. The db file will have database connection information. Cookie fields. By using this site, add and delete fields, without recompiling the program. GitHub Gist: instantly share code, notes, and snippets. In fact, Go supports fields without names, but with types. Golang Programming with Protocol Buffers: Simple Proto Struct in Golang This website uses cookies to ensure you get the best experience on our website. A struct is a data. However, we can define methods. Inside this Golang file we want to add the following code. Bootstrapping a Golang Application in Preparation for GraphQL Support. org's servers. And since JSON is a well-defined standard, it makes it straightforward to add context by including new fields—a parser should be able to pick them up automatically. In our case, we have a field someName and it takes a string as a value. Mutt supports most e-mail storing formats, such as mbox and Maildir, as well as most protocols, including POP3 and IMAP. In our earlier posts, we have tried to provide guidelines to learn Go and later we saw how to work with JSON in Go. % godoc -src sync Mutex // A Mutex is a mutual exclusion lock. The struct in GO is a typed collection of fields which are useful when grouping data to form some kind of records. By far, the feature that is most interesting feature is the embedding of structs within each other. There are some cases, when your structure has read-only fields. Basically, it is used to tell the unmarshaller or marshaller to ignore empty fields. I've found myself considering the implications of many of the language features recently. Structs in Golang represent one of the most common variable types and used practically everywhere, from dealing with configuration options to marshaling of JSON or XML documents using encoding/json…. The reasons for this are discussed in an essay Padding is Hard by one of the Go developers. go - in golang, using reflect, how do you set the value of a struct field? having a rough time working with struct fields using reflect package. I think this has to do with golang focus on simplicity. Also note that we only include a pointer to the original User struct in our wrapper struct. You can see from the code that all errors are prefixed with their HTTP status code. Marshal? It's easier to demonstrate on example. Just a quick post in case I forget how to do this in future. First, you need to tell VexCL how to spell the type name of the struct. type Mute. These may conflict with field names that already exist in a schema, causing applications to break. It is an ORM library for dealing with relational databases. (composite data types, aka, aggregate data types, aka, complex data types). Here's an example: // A struct corresponding to the TimeStamp protocol buffer. Empty slice: First we create an empty slice of structs. The GORM is fantastic ORM library for Golang, aims to be developer friendly. Conclusion. I think this has to do with golang focus on simplicity. GoLang Tutorial - Web Application Part 1 we will add more packages to this import declaration. Obviously, you don't want to add a log call to every handler. What’s wrong with json. Unlike other object-oriented languages, you don't need to provide getters and setters on struct fields, as they can access from the same package and can access from other packages as well, if the name of the fields start with a capital letter. This works, but it can get cumbersome when there are lots of fields. When a field that is a nested struct is encountered, and contains this flag any validation on the nested struct will be run, but none of the nested struct fields will be validated. Each field needs to have a type, where as in this case they are all strings. Ask Question Asked 1 year, 10 months ago. CL 175457 GetConfigForClient replaces cert and key arguments CL 179137 io:add comment for io. Well, we have covered some of the major Data Strucutres for Golang in this chapter. The first thing that I've noticed is that the majority of projects I have encountered are written in Go. (And the order of named fields is irrelevant. js file to add our loader (follow the instructions in the file for where to put it):. Each data field in a struct is declared with a known type, which could be a built-in type or another user-defined type. Go slices are simpler to. Introduction to Ponzu: a Golang CMS. You can list just a subset of fields by using the Name: syntax. If the program contains tests or examples and no main function, the service runs the tests. A field declaration may be followed by an optional string literal tag, which becomes an attribute for all the fields in the corresponding field declaration. However, this causes a problem: how does it know which XML field corresponds to the mapped struct field?. I can also very easily update the struct then marshal the data back into XML where it can be placed in the body of a put request. This is another simple golang tutorial about HTTP Request Example Using Google Mux. Behaviours (methods) can be added to go types (struct happens to be one of them). There are some cases, when your structure has read-only fields. Arrays, slices (and strings): The mechanics of 'append' Rob Pike 26 September 2013 Introduction. Introduction to Ponzu: a Golang CMS. I can understand that this definition is quite complex so lets dive right into some code to understand this :). The niche where templates are still absolutely indispensable is email content generation. By declaring methods associated with a struct. Reference to another field with in a func in the same struct in golang. It's not intended to match or beat that languages. Marshal does the job, read on. One of the most common features of procedural programming languages is the concept of an array. Parsing with Structs. > "golang-nuts" group. Name, Main), a type (string, another anonymous struct), and what’s known as a tag. Using Maps and Slices. I am creating separate file for handlers, database and model class. js file to add our loader (follow the instructions in the file for where to put it):. Each data field in a struct is declared with a known type, which could be a built-in type or another user-defined type. This has the advantages of adding additional type-safety to our programs and eliminating the need for type assertions when accessing the decoded data. We use this concept in the nested structure where a structure is a field in another structure, simply by just adding the name of the structure into another structure and it behaves like the Anonymous Field to the nested structure. add a comment | Your Answer. Here are a few examples in named and anonymous forms. (using go build and go test) Vet-on-save to run go vet and show errors as. ) encoded, so when you decode the structure you'll end up with zero values in those unexported fields. However, I have a function that is returning an interface{}. If none of these solutions seem to fit your needs, maybe Golang isn't the right language/framework for your e-commerce backend. In my opinion, it would not be better. Provide a string as first argument to withColumn() which represents the column name. Reference to another field with in a func in the same struct in golang. It would be nice if we could embed the original struct into the auxiliary struct and have it inherit all the fields that do not need to be changed. Doc prints the documentation comments associated with the item identified by its arguments (a package, const, func, type, var, method, or struct field) followed by a one-line summary of each of the first-level items "under" that item (package-level declarations for a package, methods for a type, etc. How efficient is having to do all the above for accessing a struct field within a map entry? (this is: copy value, modify new value,. Adding fields is even simpler than omitting. Still, the most interesting here are the pcsp, pcfile, and pcln fields,which are used when a program counter is translated into a stack pointer, filename, and line accordingly. Basically, it is used to tell the unmarshaller or marshaller to ignore empty fields. How do you get the memory address of a variable? How do you assign a value to a pointer? How do you create a new pointer? What is the value of x after running this program:. Adding methods or fields to generated structs. By declaring methods associated with a struct. go - Golang Removing fields from struct or hiding them in JSON Response I've created an API in Go that, upon being called, performs a query, creates an instance of a struct, and then encodes that struct as JSON before sending back to the caller. However, I have a function that is returning an interface{}. This ensures that. Golang bson structs - use multiple field names for a single field in json but only one for writing to the database (JSON) - Codedump. because now everywhere has to remember to call "constructor" and I don't like 2. It is a lot of code, but don’t worry, we’re going to break it down next. This post explores the properties of my favourite Go data type, the empty struct. 3) Methods : structs are the mechanism for associating data with functions in Golang. You can embed interfaces in a struct. When explicitly converting a value from one struct type to another, as of Go 1. (And the order of named fields is irrelevant. The first argument is an XML data stream. 8 the tags are ignored. Golang channels tutorial December 6, 2013. Struct Fields. CopyBuffer for more precise. It's not uncommon for public JSON APIs to reply with top level arrays, instead of a full JSON object. Comparing Golang with Java Learn it and it will add to your knowledge and understanding even if you do not have a project to be developed in Go. The struct in GO is a typed collection of fields which are useful when grouping data to form some kind of records. They're useful for grouping data together to form records. We access session. Sessions can be configured individually or the store can be configured and then all sessions saved using it will use that configuration. Such thread is called goroutine in Golang. So what could be easier than marshalling a string with JSON and unmarshalling it to struct? If you believe (as I did) that the issue is trivial and json. Go does not have classes. struct { microsec uint64 "field 1" serverIP6 uint64 "field 2" process string "field 3" } These tags become attributes for all the fields in the corresponding field declaration. golang-examples. Now I could go ahead and continue creating fields that do querying or mutations, but the steps are the same. Marshal? It’s easier to demonstrate on example. Other parts of our program won't be able to read the title or description, they'll just know that we've got a pile of information. Marshal does the job, read on. ' to access the fields inside TestMessage because Go will automatically dereference the pointer to the struct or object it points to as shown below. These may conflict with field names that already exist in a schema, causing applications to break. A struct is a type which contains named fields. I'll keep example as simple as possible, but beefy enough to show most commonly used features of the package. In practice, we are using StructTag to add some metadata for the defined struct fields. in particular, have not figured out how to set the field value. Structs allow us to compose together values of different types. A struct in the C programming language (and many derivatives) is a composite data type (or record) declaration that defines a physically grouped list of variables under one name in a block of memory, allowing the different variables to be accessed via a single pointer or by the struct declared name which returns the same address. They also have become an easy way for content creators. Go + HTTP/2 - - Welcome to the Go language's HTTP/2 demo & interop server. If your API is served ONLY on HTTP or HTTPS, produces ONLY JSON you should add it here - allowing to you to remove that annotation from every single route. CL 175457 GetConfigForClient replaces cert and key arguments CL 179137 io:add comment for io. type Struct Student { name string addr string phone string } var S1 Student. gqlgen assigns fix complexity weight for each field so it will consider struct, array, and string all as equals. By using this site, add and delete fields, without recompiling the program. In our case, we have a field someName and it takes a string as a value. I'll leave it to your imagination to continue contributing to this particular application idea. Simple GoLang API Using Echo and MySQL. Go’s structs are typed collections of fields. They're useful for grouping data together to form records. so rather than building a new struct that is an exact replica plus the 2 new fields I. Each field in the struct has a name (e. go file and will have all 'todo' example functionality in it. Go slices are simpler to. The struct in GO is a typed collection of fields which are useful when grouping data to form some kind of records. [go-nuts] Add/append fields to xml You received this message because you are subscribed to the Google Groups "golang-nuts" group. When the embedded field is a struct, all the fields in that struct will implicitly be the fields in the struct in which it has been embedded. I've recently started on a new project in Go. Structs in Golang represent one of the most common variable types and used practically everywhere, from dealing with configuration options to marshaling of JSON or XML documents using encoding/json…. Note that we can not only access a specific field of a struct but also we can modify the value of any field. Finally, call walk with x and the spy and for now just check the length of got , we'll be more specific with our assertions once we've got something very basic working. Obviously, you don't want to add a log call to every handler. type Mute. Parsing with Structs. Tags are like metadata, and allow us to use the encoding/json package to directly unmarshal the API's response into our struct. This is useful if inside of your program you know the struct will be valid, but need to verify it has been assigned. Suppose you want to keep track of your. This is a Go FAQ: Frequently Asked Questions (FAQ). And since JSON is a well-defined standard, it makes it straightforward to add context by including new fields—a parser should be able to pick them up automatically. After finding the struct, it needs to be able to get the field names; It needs to update the struct tags based on the field names (according to the transform rule, i. Some of the fields are only used by the linker. As you continue your Golang learning journey, it becomes almost inevitable that you will have to interact with some form of database. Is there an idiomatic way in Go to iterate over a single field in the "struct" key of a map? I suspect not, and " a map of a map" has to be used in the case below, but would like to ask if the "struct" map key approach is a viable way. Name, Main), a type (string, another anonymous struct), and what's known as a tag. because now everywhere has to remember to call "constructor" and I don't like 2. However, I have a function that is returning an interface{}. This may be // used to include empty fields in Patch requests. Golang Removing fields from struct or hiding them in JSON Response I've created an API in Go that, upon being called, performs a query, creates an instance of a struct, and then encodes that struct as JSON before sending back to the caller. WaitGroup also provides 3 methods: Add, Done and Wait. In my opinion, it would not be better. We will look at different types of data that we encounter in Go, from structured data like structs, arrays, and slices, to unstructured data like maps and empty interfaces. Inside this Golang file we want to add the following code. Exclude terms by prefixing them with a -. If you are using jsoniter, enable fuzzy decoders will also fix this. Another heart breaking "feature" of PHP is that, when array is empty, it is encoded as [] instead of {}. // Mutexes can be created as part of other structures; // the zero value for a Mutex is an unlocked mutex. New that were previously not opened (*_test. Structure Equality in Golang; Anonymous Structure and Field in Golang; Defer Keyword in Golang; Nested Structure in Golang; Function as a Field in Golang Structure; Promoted Fields in Golang Structure; Difference Between Go and Python Programming Language; Channel in Golang; Unidirectional Channel in Golang; Methods in Golang; Methods With Same Name in Golang. The ability to capture the behavior of a set of unrelated types in an interface and then work with that interface is a powerful technique. Finally we print values on the Result struct. You can see from the code that all errors are prefixed with their HTTP status code. Marshal does the job, read on. because now all other methods of struct has to perform the same check. New that were previously not opened (*_test. It then returns the barcode as a base64 encoded string, which the Lambda will pass onto API Gateway. One of the most common features of procedural programming languages is the concept of an array. Tags are like metadata, and allow us to use the encoding/json package to directly unmarshal the API’s response into our struct. X = 4 // You can declare methods on structs. structs can also contain behavior in the form of methods. The empty struct is a struct type that has no fields. This is useful if inside of your program you know the struct will be valid, but need to verify it has been assigned. Python (186) Ubuntu (81) OpenContrail (79) OpenStack (78) Django (69) Linux (67) Horizon (27) Networking (27) VMware (27) OpenStack Neutron (26) Git (25) OpenStack Heat (24) Puppet (24) OpenvSwitch (22) Keystone (20) OpenStack Dev Tips (19) go (19) golang (19) linux network namespace (19) Libvirt (18) Cloud (17) Horizon Dev Tips (16) Openstack. We will create simple server. Inside this Golang file we want to add the following code. Now I could go ahead and continue creating fields that do querying or mutations, but the steps are the same. It's not uncommon for public JSON APIs to reply with top level arrays, instead of a full JSON object. Let's add the omitempty tag to our Dog struct: type Dog struct { Breed string // The first comma below is to separate the name tag from the omitempty tag WeightKg int `json:",omitempty"` } Now, if WeightKg is set to it's default value (which is 0 for the int type), the key itself will be omitted from the JSON object. The same needs to apply for each of our models. Golang program that uses struct, new built-in method package main import "fmt" type Location struct { x int y int valid bool } func main() {// Create a new Location struct instance. X = 4 // You can declare methods on structs. We will create golang application that created rest api using MUX router dispatcher. Map converts the given struct to a map[string]interface{}, where the keys of the map are the field names and the values of the map the associated values of the fields. is calculated by adding the size of the struct itself to the number of. % godoc -src sync Mutex // A Mutex is a mutual exclusion lock. The configuration property lets user define a list of observer implementations which are going to be invoked. Adding a Setter/Getter to every single public property of all your classes/objects/structs is a waste of both human and machine time. CopyBuffer for more precise. Golang add function to struct defined elsewhere (type *sql. add a comment | Your Answer. Add interfaces and implementations for classes that are described above and a configuration property in the KafkaConfig class to allow users to specify implementations of the observer interface. By far, the feature that is most interesting feature is the embedding of structs within each other. So what could be easier than marshalling a string with JSON and unmarshalling it to struct? If you believe (as I did) that the issue is trivial and json. Marshal? It's easier to demonstrate on example. Go does not have classes. We use this concept in the nested structure where a structure is a field in another structure, simply by just adding the name of the structure into another structure and it behaves like the Anonymous Field to the nested structure. And maybe also we should provide the Example slice in the overall Package struct instead of having a second call, although there may be some concerns around opening files during doc. The fact-checkers, whose work is more and more important for those who prefer facts over lies, police the line between fact and falsehood on a day-to-day basis, and do a great job. Today, my small contribution is to pass along a very good overview that reflects on one of Trump’s favorite overarching falsehoods. Namely: Trump describes an America in which everything was going down the tubes under  Obama, which is why we needed Trump to make America great again. And he claims that this project has come to fruition, with America setting records for prosperity under his leadership and guidance. “Obama bad; Trump good” is pretty much his analysis in all areas and measurement of U.S. activity, especially economically. Even if this were true, it would reflect poorly on Trump’s character, but it has the added problem of being false, a big lie made up of many small ones. Personally, I don’t assume that all economic measurements directly reflect the leadership of whoever occupies the Oval Office, nor am I smart enough to figure out what causes what in the economy. But the idea that presidents get the credit or the blame for the economy during their tenure is a political fact of life. Trump, in his adorable, immodest mendacity, not only claims credit for everything good that happens in the economy, but tells people, literally and specifically, that they have to vote for him even if they hate him, because without his guidance, their 401(k) accounts “will go down the tubes.” That would be offensive even if it were true, but it is utterly false. The stock market has been on a 10-year run of steady gains that began in 2009, the year Barack Obama was inaugurated. But why would anyone care about that? It’s only an unarguable, stubborn fact. Still, speaking of facts, there are so many measurements and indicators of how the economy is doing, that those not committed to an honest investigation can find evidence for whatever they want to believe. Trump and his most committed followers want to believe that everything was terrible under Barack Obama and great under Trump. That’s baloney. Anyone who believes that believes something false. And a series of charts and graphs published Monday in the Washington Post and explained by Economics Correspondent Heather Long provides the data that tells the tale. The details are complicated. Click through to the link above and you’ll learn much. But the overview is pretty simply this: The U.S. economy had a major meltdown in the last year of the George W. Bush presidency. Again, I’m not smart enough to know how much of this was Bush’s “fault.” But he had been in office for six years when the trouble started. So, if it’s ever reasonable to hold a president accountable for the performance of the economy, the timeline is bad for Bush. GDP growth went negative. Job growth fell sharply and then went negative. Median household income shrank. The Dow Jones Industrial Average dropped by more than 5,000 points! U.S. manufacturing output plunged, as did average home values, as did average hourly wages, as did measures of consumer confidence and most other indicators of economic health. (Backup for that is contained in the Post piece I linked to above.) Barack Obama inherited that mess of falling numbers, which continued during his first year in office, 2009, as he put in place policies designed to turn it around. By 2010, Obama’s second year, pretty much all of the negative numbers had turned positive. By the time Obama was up for reelection in 2012, all of them were headed in the right direction, which is certainly among the reasons voters gave him a second term by a solid (not landslide) margin. Basically, all of those good numbers continued throughout the second Obama term. The U.S. GDP, probably the single best measure of how the economy is doing, grew by 2.9 percent in 2015, which was Obama’s seventh year in office and was the best GDP growth number since before the crash of the late Bush years. GDP growth slowed to 1.6 percent in 2016, which may have been among the indicators that supported Trump’s campaign-year argument that everything was going to hell and only he could fix it. During the first year of Trump, GDP growth grew to 2.4 percent, which is decent but not great and anyway, a reasonable person would acknowledge that — to the degree that economic performance is to the credit or blame of the president — the performance in the first year of a new president is a mixture of the old and new policies. In Trump’s second year, 2018, the GDP grew 2.9 percent, equaling Obama’s best year, and so far in 2019, the growth rate has fallen to 2.1 percent, a mediocre number and a decline for which Trump presumably accepts no responsibility and blames either Nancy Pelosi, Ilhan Omar or, if he can swing it, Barack Obama. I suppose it’s natural for a president to want to take credit for everything good that happens on his (or someday her) watch, but not the blame for anything bad. Trump is more blatant about this than most. If we judge by his bad but remarkably steady approval ratings (today, according to the average maintained by 538.com, it’s 41.9 approval/ 53.7 disapproval) the pretty-good economy is not winning him new supporters, nor is his constant exaggeration of his accomplishments costing him many old ones). I already offered it above, but the full Washington Post workup of these numbers, and commentary/explanation by economics correspondent Heather Long, are here. On a related matter, if you care about what used to be called fiscal conservatism, which is the belief that federal debt and deficit matter, here’s a New York Times analysis, based on Congressional Budget Office data, suggesting that the annual budget deficit (that’s the amount the government borrows every year reflecting that amount by which federal spending exceeds revenues) which fell steadily during the Obama years, from a peak of $1.4 trillion at the beginning of the Obama administration, to $585 billion in 2016 (Obama’s last year in office), will be back up to $960 billion this fiscal year, and back over $1 trillion in 2020. (Here’s the New York Times piece detailing those numbers.) Trump is currently floating various tax cuts for the rich and the poor that will presumably worsen those projections, if passed. As the Times piece reported: