goastwriter 👻 ✍️
goastwriter is a library that offers abstractions for defining and writing Go source files
programmatically. It is effectively a convenience wrapper for the structs and functions defined in
the go/ast package. However, by providing higher-level abstractions, convenience functions and
tests, goastwriter makes writing Go code programatically much simpler for simple use cases.
goastwriter processes its generated code using gofmt, so its output is gofmt-compliant.
Usage
goastwriter.Write is the primary function exported by the package and generates the code for a
single Go file. It is provided with the package name that should be used for the file and the
components that make up the file.
Example
Code for generating a Go source file:
out, _ := goastwriter.Write("testpkg",
decl.NewImports(map[string]string{
"fmt": "",
"go/format": "gofmt",
}),
&decl.Struct{
Name: "Foo",
Comment: "Foo is a struct",
Fields: []decl.StructField{
{
Name: "Bar",
Type: expression.StringType,
Comment: "Bar is a field",
},
{
Name: "baz",
Type: expression.BoolType.Pointer(),
Comment: "Baz is a field",
},
},
},
&decl.Function{
Name: "Bar",
Params: []*decl.FuncParam{
decl.NewFuncParam("input", expression.Type("Foo").Pointer()),
},
ReturnTypes: []expression.Type{
expression.Type("Foo").Pointer(),
expression.ErrorType,
},
Body: []astgen.ASTStmt{
&statement.Expression{
Expr: expression.NewCallFunction("fmt", "Println"),
},
&statement.Expression{
Expr: expression.NewCallFunction("gofmt", "Source", expression.Nil),
},
&statement.Return{
Values: []astgen.ASTExpr{
expression.VariableVal("input"),
expression.Nil,
},
},
},
},
)
fmt.Println(string(out))Output:
package testpkg
import (
"fmt"
gofmt "go/format"
)
// Foo is a struct
type Foo struct {
// Bar is a field
Bar string
// Baz is a field
baz *bool
}
func Bar(input *Foo) (*Foo, error) {
fmt.Println()
gofmt.Source(nil)
return input, nil
}