134 lines
2.3 KiB
Go
134 lines
2.3 KiB
Go
// Package forge implements sort of a stack-based interpreter.
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package forge
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import (
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"git.sr.ht/~cco/go-scopes/common/ptr"
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"git.sr.ht/~cco/go-scopes/common/stack"
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"git.sr.ht/~cco/go-scopes/common/voc"
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)
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type fitem interface{}
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type fptr = ptr.Ptr[fitem]
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type fstack = stack.Stack[fitem]
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type fvoc = voc.Vocabulary[fitem]
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type Callable func(*forgeEnv, XT)
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type forgeEnv struct {
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ds, rs fstack
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cp, ip, dp fptr
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voc *fvoc
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}
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type FE = *forgeEnv
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func NewFE() *forgeEnv {
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return newFE(newVoc(nil))
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}
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func (f *forgeEnv) ChildFE() *forgeEnv {
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return newFE(newVoc(f.voc))
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}
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func newFE(voc *fvoc) *forgeEnv {
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return &forgeEnv{
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ds: stack.NewStack[fitem](),
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rs: stack.NewStack[fitem](),
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ip: ptr.NewSlice[fitem](),
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voc: voc,
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}
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}
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var newVoc = voc.NewVoc[fitem]
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var newScalar = ptr.NewScalar[fitem]
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var newPtr = ptr.NewSlice[fitem]
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// xitem (executable item) / XT (execution token)
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type xitem struct {
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name string
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fct Callable
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body fptr
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}
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type XT = *xitem
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func Register(voc *fvoc, name string, fct Callable) *xitem {
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it := xitem{
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name: name,
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fct: fct,
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}
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voc.Register(name, &it)
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return &it
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}
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func (it *xitem) Name() string {
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return it.name
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}
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// forgeEnv methods
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func (f *forgeEnv) Code(items ...fitem) fptr {
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code := newPtr(items...)
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// ... pre-process (compile) code ...
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return code
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}
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func (f *forgeEnv) Call(code fptr) {
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f.rs.Push(f.ip)
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f.ip = code.Clone()
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for f.ip.Next() != nil {
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xt := f.ip.Value().(XT)
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xt.fct(f, xt)
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}
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f.ip = f.rs.Pop().(fptr)
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}
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func (f *forgeEnv) Exec(items ...fitem) {
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f.Call(f.Code(items...))
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}
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func (f *forgeEnv) Def(name string, items ...fitem) XT {
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xt := Register(f.voc, name, doDef)
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xt.body = newPtr(f.Code(items...)).Next()
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return xt
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}
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func (f *forgeEnv) Const(name string, value fitem) XT {
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xt := Register(f.voc, name, doData)
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xt.body = newScalar()
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xt.body.Append(value)
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return xt
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}
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func (f *forgeEnv) Literal() {
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f.Push(f.ip.Next().Value())
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}
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func (f *forgeEnv) Voc() *fvoc {
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return f.voc
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}
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func (f *forgeEnv) Push(it fitem) {
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f.ds.Push(it)
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}
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func (f *forgeEnv) Pop() fitem {
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return f.ds.Pop()
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}
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func (f *forgeEnv) Peek(d int) fitem {
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return f.ds.Peek(d)
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}
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// basic functions for executable items
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func doDef(f *forgeEnv, xt XT) {
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f.Call(xt.body.Value().(fptr))
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}
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func doData(f *forgeEnv, xt XT) {
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f.Push(xt.body.Value())
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}
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