423 lines
13 KiB
Smarty
423 lines
13 KiB
Smarty
|
[](https://travis-ci.org/dave/jennifer) [](https://goreportcard.com/report/github.com/dave/jennifer) [](https://codecov.io/gh/dave/jennifer)  [](https://sourcegraph.com/github.com/dave/jennifer?badge) <a href="https://patreon.com/davebrophy" title="Help with my hosting bills using Patreon"><img src="https://img.shields.io/badge/patreon-donate-yellow.svg" style="max-width:100%;"></a>
|
||
|
|
|
||
|
|
# Jennifer
|
||
|
|
Jennifer is a code generator for Go.
|
||
|
|
|
||
|
|
```go
|
||
|
|
package main
|
||
|
|
|
||
|
|
import (
|
||
|
|
"fmt"
|
||
|
|
|
||
|
|
. "github.com/dave/jennifer/jen"
|
||
|
|
)
|
||
|
|
|
||
|
|
func main() {{ "ExampleNewFile" | code }}
|
||
|
|
```
|
||
|
|
Output:
|
||
|
|
```go
|
||
|
|
{{ "ExampleNewFile" | output }}
|
||
|
|
```
|
||
|
|
|
||
|
|
### Install
|
||
|
|
```
|
||
|
|
go get -u github.com/dave/jennifer/jen
|
||
|
|
```
|
||
|
|
|
||
|
|
### Need help?
|
||
|
|
If you get stuck, have a question, would like a code review, or just want a
|
||
|
|
chat: I'm happy to help! Feel free to open an issue, email me or mention @dave
|
||
|
|
in your PR.
|
||
|
|
|
||
|
|
### Examples
|
||
|
|
Jennifer has a comprehensive suite of examples - see [godoc](https://godoc.org/github.com/dave/jennifer/jen#pkg-examples) for an index. Here's some examples of jennifer being used in the real-world:
|
||
|
|
|
||
|
|
* [genjen](genjen/render.go) (which generates much of jennifer, using data in [data.go](genjen/data.go))
|
||
|
|
* [zerogen](https://github.com/mrsinham/zerogen/blob/master/generator.go)
|
||
|
|
* [go-contentful-generator](https://github.com/nicolai86/go-contentful-generator)
|
||
|
|
|
||
|
|
### Rendering
|
||
|
|
For testing, a File or Statement can be rendered with the fmt package
|
||
|
|
using the %#v verb.
|
||
|
|
|
||
|
|
{{ "ExampleCall_fmt" | example }}
|
||
|
|
|
||
|
|
This is not recommended for use in production because any error will cause a
|
||
|
|
panic. For production use, [File.Render](#render) or [File.Save](#save) are
|
||
|
|
preferred.
|
||
|
|
|
||
|
|
# Identifiers
|
||
|
|
**Identifiers** [Keywords](#keywords) [Operators](#operators) [Braces](#braces) [Parentheses](#parentheses) [Control flow](#control-flow) [Collections](#collections) [Literals](#literals) [Comments](#comments) [Helpers](#helpers) [Misc](#misc) [File](#file)
|
||
|
|
|
||
|
|
### Id
|
||
|
|
{{ "Id" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleId" | example }}
|
||
|
|
|
||
|
|
### Dot
|
||
|
|
{{ "Dot" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleDot" | example }}
|
||
|
|
|
||
|
|
### Qual
|
||
|
|
{{ "Qual[0]" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleQual" | example }}
|
||
|
|
|
||
|
|
{{ "Qual[1:4]" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleQual_file" | example }}
|
||
|
|
|
||
|
|
{{ "Qual[4:]" | doc }}
|
||
|
|
|
||
|
|
### List
|
||
|
|
{{ "List" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleList" | example }}
|
||
|
|
|
||
|
|
# Keywords
|
||
|
|
[Identifiers](#identifiers) **Keywords** [Operators](#operators) [Braces](#braces) [Parentheses](#parentheses) [Control flow](#control-flow) [Collections](#collections) [Literals](#literals) [Comments](#comments) [Helpers](#helpers) [Misc](#misc) [File](#file)
|
||
|
|
|
||
|
|
Simple keywords, predeclared identifiers and built-in functions are self
|
||
|
|
explanatory:
|
||
|
|
|
||
|
|
| Construct | Name |
|
||
|
|
| ---------------- | ---- |
|
||
|
|
| Keywords | Break, Chan, Const, Continue, Default, Defer, Else, Fallthrough, Func, Go, Goto, Range, Select, Type, Var |
|
||
|
|
| Functions | Append, Cap, Close, Complex, Copy, Delete, Imag, Len, Make, New, Panic, Print, Println, Real, Recover |
|
||
|
|
| Types | Bool, Byte, Complex64, Complex128, Error, Float32, Float64, Int, Int8, Int16, Int32, Int64, Rune, String, Uint, Uint8, Uint16, Uint32, Uint64, Uintptr |
|
||
|
|
| Constants | True, False, Iota, Nil |
|
||
|
|
| Helpers | Err |
|
||
|
|
|
||
|
|
Built-in functions take a list of parameters and render them appropriately:
|
||
|
|
|
||
|
|
{{ "ExampleAppend_more" | example }}
|
||
|
|
|
||
|
|
Special cases for [If, For](#if-for), [Interface, Struct](#interface-struct), [Switch, Case](#switch-select), [Return](#return) and [Map](#map) are explained below.
|
||
|
|
|
||
|
|
# Operators
|
||
|
|
[Identifiers](#identifiers) [Keywords](#keywords) **Operators** [Braces](#braces) [Parentheses](#parentheses) [Control flow](#control-flow) [Collections](#collections) [Literals](#literals) [Comments](#comments) [Helpers](#helpers) [Misc](#misc) [File](#file)
|
||
|
|
|
||
|
|
{{ "Op" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleOp" | example }}
|
||
|
|
|
||
|
|
{{ "ExampleOp_star" | example }}
|
||
|
|
|
||
|
|
{{ "ExampleOp_variadic" | example }}
|
||
|
|
|
||
|
|
{{ "ExampleOp_complex_conditions" | example }}
|
||
|
|
|
||
|
|
# Braces
|
||
|
|
[Identifiers](#identifiers) [Keywords](#keywords) [Operators](#operators) **Braces** [Parentheses](#parentheses) [Control flow](#control-flow) [Collections](#collections) [Literals](#literals) [Comments](#comments) [Helpers](#helpers) [Misc](#misc) [File](#file)
|
||
|
|
|
||
|
|
Several methods render curly braces, summarized below:
|
||
|
|
|
||
|
|
| Name | Prefix | Separator | Example |
|
||
|
|
| ------------------------------ | ------------ | --------- | -------------------------------------|
|
||
|
|
| [Block](#block) | | `\n` | `func a() { ... }` or `if a { ... }` |
|
||
|
|
| [Interface](#interface-struct) | `interface` | `\n` | `interface { ... }` |
|
||
|
|
| [Struct](#interface-struct) | `struct` | `\n` | `struct { ... }` |
|
||
|
|
| [Values](#values) | | `,` | `[]int{1, 2}` or `A{B: "c"}` |
|
||
|
|
|
||
|
|
### Block
|
||
|
|
{{ "Block[:2]" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleBlock" | example }}
|
||
|
|
|
||
|
|
{{ "ExampleBlock_if" | example }}
|
||
|
|
|
||
|
|
{{ "Block[2:]" | doc }} [See example](#switch-select).
|
||
|
|
|
||
|
|
### Interface, Struct
|
||
|
|
Interface and Struct render the keyword followed by a statement list enclosed
|
||
|
|
by curly braces.
|
||
|
|
|
||
|
|
{{ "ExampleInterface_empty" | example }}
|
||
|
|
|
||
|
|
{{ "ExampleInterface" | example }}
|
||
|
|
|
||
|
|
{{ "ExampleStruct_empty" | example }}
|
||
|
|
|
||
|
|
{{ "ExampleStruct" | example }}
|
||
|
|
|
||
|
|
# Parentheses
|
||
|
|
[Identifiers](#identifiers) [Keywords](#keywords) [Operators](#operators) [Braces](#braces) **Parentheses** [Control flow](#control-flow) [Collections](#collections) [Literals](#literals) [Comments](#comments) [Helpers](#helpers) [Misc](#misc) [File](#file)
|
||
|
|
|
||
|
|
Several methods output parenthesis, summarized below:
|
||
|
|
|
||
|
|
| Name | Prefix | Separator | Example |
|
||
|
|
| ----------------- | ------ | --------- | --------------------------------- |
|
||
|
|
| [Call](#call) | | `,` | `fmt.Println(b, c)` |
|
||
|
|
| [Params](#params) | | `,` | `func (a *A) Foo(i int) { ... }` |
|
||
|
|
| [Defs](#defs) | | `\n` | `const ( ... )` |
|
||
|
|
| [Parens](#parens) | | | `[]byte(s)` or `a / (b + c)` |
|
||
|
|
| [Assert](#assert) | `.` | | `s, ok := i.(string)` |
|
||
|
|
|
||
|
|
### Call
|
||
|
|
{{ "Call" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleCall" | example }}
|
||
|
|
|
||
|
|
### Params
|
||
|
|
{{ "Params" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleParams" | example }}
|
||
|
|
|
||
|
|
### Defs
|
||
|
|
{{ "Defs" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleDefs" | example }}
|
||
|
|
|
||
|
|
### Parens
|
||
|
|
{{ "Parens" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleParens" | example }}
|
||
|
|
|
||
|
|
{{ "ExampleParens_order" | example }}
|
||
|
|
|
||
|
|
### Assert
|
||
|
|
{{ "Assert" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleAssert" | example }}
|
||
|
|
|
||
|
|
# Control flow
|
||
|
|
[Identifiers](#identifiers) [Keywords](#keywords) [Operators](#operators) [Braces](#braces) [Parentheses](#parentheses) **Control flow** [Collections](#collections) [Literals](#literals) [Comments](#comments) [Helpers](#helpers) [Misc](#misc) [File](#file)
|
||
|
|
|
||
|
|
### If, For
|
||
|
|
If and For render the keyword followed by a semicolon separated list.
|
||
|
|
|
||
|
|
{{ "ExampleIf" | example }}
|
||
|
|
|
||
|
|
{{ "ExampleFor" | example }}
|
||
|
|
|
||
|
|
### Switch, Select
|
||
|
|
Switch, Select, Case and Block are used to build switch or select statements:
|
||
|
|
|
||
|
|
{{ "ExampleSwitch" | example }}
|
||
|
|
|
||
|
|
### Return
|
||
|
|
{{ "Return" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleReturn" | example }}
|
||
|
|
|
||
|
|
# Collections
|
||
|
|
[Identifiers](#identifiers) [Keywords](#keywords) [Operators](#operators) [Braces](#braces) [Parentheses](#parentheses) [Control flow](#control-flow) **Collections** [Literals](#literals) [Comments](#comments) [Helpers](#helpers) [Misc](#misc) [File](#file)
|
||
|
|
|
||
|
|
### Map
|
||
|
|
{{ "Map" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleMap" | example }}
|
||
|
|
|
||
|
|
### Index
|
||
|
|
{{ "Index" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleIndex" | example }}
|
||
|
|
|
||
|
|
{{ "ExampleIndex_index" | example }}
|
||
|
|
|
||
|
|
{{ "ExampleIndex_empty" | example }}
|
||
|
|
|
||
|
|
### Values
|
||
|
|
{{ "Values" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleValues" | example }}
|
||
|
|
|
||
|
|
{{ "Dict" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleValues_dict_multiple" | example }}
|
||
|
|
|
||
|
|
{{ "ExampleValues_dict_composite" | example }}
|
||
|
|
|
||
|
|
{{ "DictFunc[0]" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleDictFunc" | example }}
|
||
|
|
|
||
|
|
Note: the items are ordered by key when rendered to ensure repeatable code.
|
||
|
|
|
||
|
|
# Literals
|
||
|
|
[Identifiers](#identifiers) [Keywords](#keywords) [Operators](#operators) [Braces](#braces) [Parentheses](#parentheses) [Control flow](#control-flow) [Collections](#collections) **Literals** [Comments](#comments) [Helpers](#helpers) [Misc](#misc) [File](#file)
|
||
|
|
|
||
|
|
### Lit
|
||
|
|
{{ "Lit" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleLit" | example }}
|
||
|
|
|
||
|
|
{{ "ExampleLit_float" | example }}
|
||
|
|
|
||
|
|
{{ "LitFunc[1:2]" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleLitFunc" | example }}
|
||
|
|
|
||
|
|
For the default constant types (bool, int, float64, string, complex128), Lit
|
||
|
|
will render the untyped constant.
|
||
|
|
|
||
|
|
| Code | Output |
|
||
|
|
| ------------- | ---------- |
|
||
|
|
| `Lit(true)` | `true` |
|
||
|
|
| `Lit(1)` | `1` |
|
||
|
|
| `Lit(1.0)` | `1.0` |
|
||
|
|
| `Lit("foo")` | `"foo"` |
|
||
|
|
| `Lit(0 + 1i)` | `(0 + 1i)` |
|
||
|
|
|
||
|
|
For all other built-in types (float32, int8, int16, int32, int64, uint, uint8,
|
||
|
|
uint16, uint32, uint64, uintptr, complex64), Lit will also render the type.
|
||
|
|
|
||
|
|
| Code | Output |
|
||
|
|
| ------------------------ | ------------------- |
|
||
|
|
| `Lit(float32(1))` | `float32(1)` |
|
||
|
|
| `Lit(int16(1))` | `int16(1)` |
|
||
|
|
| `Lit(uint8(0x1))` | `uint8(0x1)` |
|
||
|
|
| `Lit(complex64(0 + 1i))` | `complex64(0 + 1i)` |
|
||
|
|
|
||
|
|
The built-in alias types byte and rune need a special case. LitRune and LitByte
|
||
|
|
render rune and byte literals.
|
||
|
|
|
||
|
|
| Code | Output |
|
||
|
|
| ------------------------ | ----------- |
|
||
|
|
| `LitRune('x')` | `'x'` |
|
||
|
|
| `LitByte(byte(0x1))` | `byte(0x1)` |
|
||
|
|
|
||
|
|
# Comments
|
||
|
|
[Identifiers](#identifiers) [Keywords](#keywords) [Operators](#operators) [Braces](#braces) [Parentheses](#parentheses) [Control flow](#control-flow) [Collections](#collections) [Literals](#literals) **Comments** [Helpers](#helpers) [Misc](#misc) [File](#file)
|
||
|
|
|
||
|
|
### Comment
|
||
|
|
{{ "Comment[:2]" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleComment" | example }}
|
||
|
|
|
||
|
|
{{ "ExampleComment_multiline" | example }}
|
||
|
|
|
||
|
|
{{ "Comment[2:]" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleComment_formatting_disabled" | example }}
|
||
|
|
|
||
|
|
### Commentf
|
||
|
|
{{ "Commentf[0]" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleCommentf" | example }}
|
||
|
|
|
||
|
|
# Helpers
|
||
|
|
[Identifiers](#identifiers) [Keywords](#keywords) [Operators](#operators) [Braces](#braces) [Parentheses](#parentheses) [Control flow](#control-flow) [Collections](#collections) [Literals](#literals) [Comments](#comments) **Helpers** [Misc](#misc) [File](#file)
|
||
|
|
|
||
|
|
### Func methods
|
||
|
|
All constructs that accept a variadic list of items are paired with GroupFunc
|
||
|
|
functions that accept a func(*Group). Use for embedding logic.
|
||
|
|
|
||
|
|
{{ "ExampleValuesFunc" | example }}
|
||
|
|
|
||
|
|
{{ "ExampleBlockFunc" | example }}
|
||
|
|
|
||
|
|
### Add
|
||
|
|
{{ "Add" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleAdd" | example }}
|
||
|
|
|
||
|
|
{{ "ExampleAdd_var" | example }}
|
||
|
|
|
||
|
|
### Do
|
||
|
|
{{ "Do" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleDo" | example }}
|
||
|
|
|
||
|
|
# Misc
|
||
|
|
[Identifiers](#identifiers) [Keywords](#keywords) [Operators](#operators) [Braces](#braces) [Parentheses](#parentheses) [Control flow](#control-flow) [Collections](#collections) [Literals](#literals) [Comments](#comments) [Helpers](#helpers) **Misc** [File](#file)
|
||
|
|
|
||
|
|
### Tag
|
||
|
|
{{ "Tag" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleTag" | example }}
|
||
|
|
|
||
|
|
Note: the items are ordered by key when rendered to ensure repeatable code.
|
||
|
|
|
||
|
|
### Null
|
||
|
|
{{ "Null" | doc }}
|
||
|
|
|
||
|
|
In lists, nil will produce the same effect.
|
||
|
|
|
||
|
|
{{ "ExampleNull_and_nil" | example }}
|
||
|
|
|
||
|
|
### Empty
|
||
|
|
{{ "Empty" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleEmpty" | example }}
|
||
|
|
|
||
|
|
### Line
|
||
|
|
{{ "Line" | doc }}
|
||
|
|
|
||
|
|
### Clone
|
||
|
|
Be careful when passing *Statement. Consider the following...
|
||
|
|
|
||
|
|
{{ "ExampleStatement_Clone_broken" | example }}
|
||
|
|
|
||
|
|
Id("a") returns a *Statement, which the Call() method appends to twice. To
|
||
|
|
avoid this, use Clone. {{ "Statement.Clone" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleStatement_Clone_fixed" | example }}
|
||
|
|
|
||
|
|
### Cgo
|
||
|
|
The cgo "C" pseudo-package is a special case, and always renders without a package alias. The
|
||
|
|
import can be added with `Qual`, `Anon` or by supplying a preamble. The preamble is added with
|
||
|
|
`File.CgoPreamble` which has the same semantics as [Comment](#comments). If a preamble is provided,
|
||
|
|
the import is separated, and preceded by the preamble.
|
||
|
|
|
||
|
|
{{ "ExampleFile_CgoPreamble" | example }}
|
||
|
|
|
||
|
|
# File
|
||
|
|
[Identifiers](#identifiers) [Keywords](#keywords) [Operators](#operators) [Braces](#braces) [Parentheses](#parentheses) [Control flow](#control-flow) [Collections](#collections) [Literals](#literals) [Comments](#comments) [Helpers](#helpers) [Misc](#misc) **File**
|
||
|
|
|
||
|
|
{{ "File" | doc }}
|
||
|
|
|
||
|
|
### NewFile
|
||
|
|
{{ "NewFile" | doc }}
|
||
|
|
|
||
|
|
### NewFilePath
|
||
|
|
{{ "NewFilePath" | doc }}
|
||
|
|
|
||
|
|
### NewFilePathName
|
||
|
|
{{ "NewFilePathName" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleNewFilePathName" | example }}
|
||
|
|
|
||
|
|
### Save
|
||
|
|
{{ "File.Save" | doc }}
|
||
|
|
|
||
|
|
### Render
|
||
|
|
{{ "File.Render" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleFile_Render" | example }}
|
||
|
|
|
||
|
|
### Anon
|
||
|
|
{{ "File.Anon" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleFile_Anon" | example }}
|
||
|
|
|
||
|
|
### ImportName
|
||
|
|
{{ "File.ImportName" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleFile_ImportName" | example }}
|
||
|
|
|
||
|
|
### ImportNames
|
||
|
|
{{ "File.ImportNames" | doc }}
|
||
|
|
|
||
|
|
### ImportAlias
|
||
|
|
{{ "File.ImportAlias" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleFile_ImportAlias" | example }}
|
||
|
|
|
||
|
|
### Comments
|
||
|
|
{{ "File.PackageComment" | doc }}
|
||
|
|
|
||
|
|
{{ "File.HeaderComment" | doc }}
|
||
|
|
|
||
|
|
{{ "File.CanonicalPath" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleFile_HeaderAndPackageComments" | example }}
|
||
|
|
|
||
|
|
{{ "File.CgoPreamble" | doc }}
|
||
|
|
|
||
|
|
### PackagePrefix
|
||
|
|
{{ "File.PackagePrefix" | doc }}
|
||
|
|
|
||
|
|
{{ "ExampleFile_PackagePrefix" | example }}
|