Created
July 24, 2022 13:45
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io.Writer.Writeに定義されている関数の方と名前を参照するスクリプト
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package main | |
import ( | |
"fmt" | |
"go/types" | |
"log" | |
"golang.org/x/tools/go/loader" | |
) | |
func main() { | |
c := loader.Config{} | |
c.Import("io") | |
prog, err := c.Load() | |
if err != nil { | |
log.Fatal(err) | |
} | |
info := prog.Package("io") | |
ob := info.Pkg.Scope().Lookup("Writer") | |
fmt.Println("io pkg is loaded and look up Writer interface") | |
if typ, _ := ob.Type().Underlying().(*types.Interface); typ != nil { | |
errTyp := types.Universe.Lookup("error").Type().Underlying().(*types.Interface) | |
byteType := types.Typ[types.Byte] | |
intType := types.Typ[types.Int] | |
sig := typ.Method(0).Type().(*types.Signature) | |
pElem := sig.Params().At(0).Type().(*types.Slice).Elem() | |
fmt.Printf("method name %#v\n", typ.Method(0).Name()) | |
fmt.Printf("param 0 name %#v\n", sig.Params().At(0).Name()) | |
if types.Identical(pElem, byteType) { | |
fmt.Println("is type of byte") | |
} | |
fmt.Printf("res0 name %#v\n", sig.Results().At(0).Name()) | |
r0Type := sig.Results().At(0).Type() | |
if types.Identical(r0Type, intType) { | |
fmt.Println("is type of int") | |
} | |
fmt.Printf("res1 name %#v\n", sig.Results().At(1).Name()) | |
r1Type := sig.Results().At(1).Type() | |
if types.Implements(r1Type, errTyp) { | |
fmt.Println("implementes error type") | |
} | |
} | |
} |
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