gen

Documentation

Overview

Package gen implements code generation functionality that work on interface specifications from the parse package. Code is generated using the package "github.com/dave/jennifer/jen".

Index

• func AddDefaultPackageComment(f *jen.File)
• func LowercaseFirst(s string) string
• func UppercaseFirst(s string) string
• type GenResult
• type GeneratedFile
  • func MergeResults(results []GenResult) []GeneratedFile
• type Generator
• type SimpleGenerator
  • func NewSimpleGenerator() *SimpleGenerator
  • func (s *SimpleGenerator) GenFunction(receiver jen.Code, name string, params jen.Code, returns jen.Code, ...) jen.Code
  • func (s *SimpleGenerator) GenFunctionParams(params []parse.Param) jen.Code
  • func (s *SimpleGenerator) GenParamNames(params []parse.Param) []string
  • func (s *SimpleGenerator) GenParamType(p parse.ParamType) jen.Code
  • func (s *SimpleGenerator) GenParamTypes(params []parse.Param) []jen.Code
  • func (s *SimpleGenerator) GenReturnParams(params []parse.Param) jen.Code
  • func (s *SimpleGenerator) GenStructType(name string, fields []jen.Code) jen.Code

Functions

func AddDefaultPackageComment

func AddDefaultPackageComment(f *jen.File)

Adds the following package comment to the given code file: "generated code, do not edit"

func LowercaseFirst

func LowercaseFirst(s string) string

Lowercase first letter of string, useful for generating e.g. parameter or variable names.

func UppercaseFirst

func UppercaseFirst(s string) string

Uppercase first letter of string, userful for generating e.g. exported struct or function names.

Types

type GenResult

type GenResult struct {
	// Piece of code, that does not include any package or import statements.
	Code *jen.Group
	// Full path of package this code belongs to, e.g. "example.com/abc/xyz".
	PackagePath string
	// Package name of package this code belongs to, usually the last section of the package path, e.g. "xyz".
	PackageName string
	// Define explicit aliases for imports used by this code.
	// Maps from package path to alias, e.g. "example.com/abc/xyz":"x"
	Imports map[string]string
	// Path of the file the code should ultimately be written to.
	OutputFile string
}

A piece of code returned by a code generator, that is assigned to a particular output package/file. Multiple instances of GenResult can be merged into a single code file, since different code generators might provide parts of it.

type GeneratedFile

type GeneratedFile struct {
	File *jen.File
	Path string
}

func MergeResults

func MergeResults(results []GenResult) []GeneratedFile

Generates a list of GeneratedFile values by merging together all the code pieces for the same output file path into a single code file.

type Generator

type Generator interface {
	Generate() ([]GenResult, error)
}

The interface all code generators should implement. A code generator should be created with a specification that defines what exactly needs to be generated. Calling the Generate() method should then always yield the same result.

A code generator should not actually write any files, instead the Generate() method should return a list of GenResult values that each define a piece of code belonging to an output file.

type SimpleGenerator

type SimpleGenerator struct{}

SimpleGenerator provides functions to make it easier to generate common code elements like parameters, struct types and functions.

func NewSimpleGenerator

func NewSimpleGenerator() *SimpleGenerator

func (*SimpleGenerator) GenFunction

func (s *SimpleGenerator) GenFunction(receiver jen.Code, name string, params jen.Code, returns jen.Code, body []jen.Code) jen.Code

Generates a function with the given receiver, name, parameters, return values and statements in the body.

func (*SimpleGenerator) GenFunctionParams

func (s *SimpleGenerator) GenFunctionParams(params []parse.Param) jen.Code

Generatesa parameter list for the given parameter specification. E.g. (ctx context.Context, p1 string, p2 int) If parameter specifications do not contain a name, consecutive integers will be used, e.g. "p0", "p1", "p2".

func (*SimpleGenerator) GenParamNames

func (s *SimpleGenerator) GenParamNames(params []parse.Param) []string

Returns a list of parameter names for the given parameter specification. If a parameter specification contains a name, that name will be used, otherwise a name is generated by using consecutive integers, i.e. "p0", "p1", "p2". The underscore in the generated param names is used to avoid any naming conflicts with existing code elements.

func (*SimpleGenerator) GenParamType

func (s *SimpleGenerator) GenParamType(p parse.ParamType) jen.Code

Generates a type e.g. for a function parameter or return value.

func (*SimpleGenerator) GenParamTypes

func (s *SimpleGenerator) GenParamTypes(params []parse.Param) []jen.Code

func (*SimpleGenerator) GenReturnParams

func (s *SimpleGenerator) GenReturnParams(params []parse.Param) jen.Code

func (*SimpleGenerator) GenStructType

func (s *SimpleGenerator) GenStructType(name string, fields []jen.Code) jen.Code

Generates a struct type with the given name and fields.