I don't know.
Here is what ChatGPT 4o mini suggested, accessed at https://chatgpt.com/;
with some minor corrections to make it build.
It seems to suggest there is no shortcut crosslink.
The code below does demonstrate how to use the more up-to-date
"golang.org/x/tools/go/packages"
which handles modern modules (versus the older "golang.org/x/tools/go/loader
", pointed to/demonstrated above, which does not).
Q: In golang, How do you make the jump from a go/type.TypeName to ast.Decl ?
Answer:
In Go, if you want to convert a type or a type name (go/types.TypeName) to
an ast.Decl, you're essentially looking to map a type information structure
from the go/types package to its corresponding declaration in the go/token
package.
The go/types.TypeName represents a type name in the Go type system, while
ast.Decl is part of the abstract syntax tree (AST) and represents a
declaration in Go source code.
Here's a general approach you can take to achieve this:
1.
*Locate the Source Position:* Use the go/types package to get the
position of the type declaration. The go/types.TypeName object should have
information about its position in the source code, but this might be a bit
indirect since go/types does not provide direct mapping to ast.Decl.
2.
*Read the Source File:* Once you have the position, you can use the
go/parser package to read and parse the source file to find the specific
declaration.
3.
*Map the Position to the AST Declaration:* Using the source file content
and the position, you can find the corresponding declaration in the AST.
Here’s a step-by-step outline of how you might implement this:
Example Code
package main
import (
"fmt"
//"go/parser"
"go/token"
//"go/types"
"log"
"golang.org/x/tools/go/packages"
)
func findDecl(pkgPath string, typeName string) (*token.Position, string) {
// Load the package
cfg := &packages.Config{Mode: packages.NeedTypes | packages.NeedFiles |
packages.NeedSyntax}
pkgs, err := packages.Load(cfg, pkgPath)
if err != nil {
log.Fatalf("failed to load package: %v", err)
}
// Find the type name
var typePos token.Position
for _, pkg := range pkgs {
for _, file := range pkg.Syntax {
for _, decl := range file.Decls {
if genDecl, ok := decl.(*ast.GenDecl); ok && genDecl.Tok == token.TYPE {
for _, spec := range genDecl.Specs {
if typeSpec, ok := spec.(*ast.TypeSpec); ok && typeSpec.Name.Name ==
typeName {
// Found the type declaration
typePos = pkg.Fset.Position(typeSpec.Pos())
return &typePos, pkg.Fset.File(typeSpec.Pos()).Name()
}
}
}
}
}
}
return nil, ""
}
func main() {
// Example usage
pos, file := findDecl("your_package_path", "YourTypeName")
if pos != nil {
fmt.Printf("Type declaration found in file %s at position %v\n", file, *pos)
} else {
fmt.Println("Type declaration not found")
}
}
Explanation
1.
*Load Package:* Use golang.org/x/tools/go/packages to load the Go
package you’re interested in. This will give you access to the syntax trees
and type information.
2.
*Search for Type Declaration:* Iterate through the syntax trees to find
the type declaration that matches your typeName. This is done by checking
each declaration in the file to see if it matches the type you're looking
for.
3.
*Get Position:* Once you find the type declaration, get its position
using pkg.Fset.Position(). This gives you the line and column information
of the declaration.
4.
*Return Results:* Return the position and filename where the type
declaration was found.
Notes
- This approach assumes that you have access to the source code files
and that you can load them using the packages package.
- The go/types package itself does not directly provide a way to get an
ast.Decl, so this indirect approach through positions and source file
parsing is necessary.
- Make sure to adjust pkgPath and YourTypeName according to your
specific use case.
This method is useful for tooling and analysis where you need to connect
type information with its corresponding code in the source file.
end Answer.
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