1 files changed, 70 insertions, 0 deletions
diff --git a/libgo/go/exp/eval/func.go b/libgo/go/exp/eval/func.go
new file mode 100644
index 000000000..cb1b579e4
--- /dev/null
+++ b/libgo/go/exp/eval/func.go
@@ -0,0 +1,70 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package eval
+
+import "os"
+
+/*
+ * Virtual machine
+ */
+
+type Thread struct {
+	abort chan os.Error
+	pc    uint
+	// The execution frame of this function.  This remains the
+	// same throughout a function invocation.
+	f *Frame
+}
+
+type code []func(*Thread)
+
+func (i code) exec(t *Thread) {
+	opc := t.pc
+	t.pc = 0
+	l := uint(len(i))
+	for t.pc < l {
+		pc := t.pc
+		t.pc++
+		i[pc](t)
+	}
+	t.pc = opc
+}
+
+/*
+ * Code buffer
+ */
+
+type codeBuf struct {
+	instrs code
+}
+
+func newCodeBuf() *codeBuf { return &codeBuf{make(code, 0, 16)} }
+
+func (b *codeBuf) push(instr func(*Thread)) {
+	b.instrs = append(b.instrs, instr)
+}
+
+func (b *codeBuf) nextPC() uint { return uint(len(b.instrs)) }
+
+func (b *codeBuf) get() code {
+	// Freeze this buffer into an array of exactly the right size
+	a := make(code, len(b.instrs))
+	copy(a, b.instrs)
+	return code(a)
+}
+
+/*
+ * User-defined functions
+ */
+
+type evalFunc struct {
+	outer     *Frame
+	frameSize int
+	code      code
+}
+
+func (f *evalFunc) NewFrame() *Frame { return f.outer.child(f.frameSize) }
+
+func (f *evalFunc) Call(t *Thread) { f.code.exec(t) }