80 lines
2.7 KiB
Go
80 lines
2.7 KiB
Go
// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// MakeFunc implementation.
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package reflect
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import (
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"unsafe"
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)
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// makeFuncImpl is the closure value implementing the function
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// returned by MakeFunc.
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type makeFuncImpl struct {
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code uintptr
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typ *funcType
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fn func([]Value) []Value
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}
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// MakeFunc returns a new function of the given Type
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// that wraps the function fn. When called, that new function
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// does the following:
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//
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// - converts its arguments to a list of Values args.
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// - runs results := fn(args).
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// - returns the results as a slice of Values, one per formal result.
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//
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// The implementation fn can assume that the argument Value slice
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// has the number and type of arguments given by typ.
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// If typ describes a variadic function, the final Value is itself
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// a slice representing the variadic arguments, as in the
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// body of a variadic function. The result Value slice returned by fn
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// must have the number and type of results given by typ.
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//
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// The Value.Call method allows the caller to invoke a typed function
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// in terms of Values; in contrast, MakeFunc allows the caller to implement
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// a typed function in terms of Values.
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//
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// The Examples section of the documentation includes an illustration
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// of how to use MakeFunc to build a swap function for different types.
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//
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func MakeFunc(typ Type, fn func(args []Value) (results []Value)) Value {
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if typ.Kind() != Func {
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panic("reflect: call of MakeFunc with non-Func type")
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}
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t := typ.common()
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ftyp := (*funcType)(unsafe.Pointer(t))
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_, _ = t, ftyp
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panic("reflect MakeFunc not implemented")
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}
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// makeMethodValue converts v from the rcvr+method index representation
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// of a method value to an actual method func value, which is
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// basically the receiver value with a special bit set, into a true
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// func value - a value holding an actual func. The output is
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// semantically equivalent to the input as far as the user of package
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// reflect can tell, but the true func representation can be handled
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// by code like Convert and Interface and Assign.
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func makeMethodValue(op string, v Value) Value {
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if v.flag&flagMethod == 0 {
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panic("reflect: internal error: invalid use of makePartialFunc")
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}
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// Ignoring the flagMethod bit, v describes the receiver, not the method type.
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fl := v.flag & (flagRO | flagAddr | flagIndir)
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fl |= flag(v.typ.Kind()) << flagKindShift
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rcvr := Value{v.typ, v.val, fl}
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// Cause panic if method is not appropriate.
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// The panic would still happen during the call if we omit this,
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// but we want Interface() and other operations to fail early.
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methodReceiver(op, rcvr, int(v.flag)>>flagMethodShift)
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panic("reflect makeMethodValue not implemented")
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}
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