refactor a lot, got recursive statement eval kind of working

expr/build.go

@@ -2,27 +2,78 @@ package expr
 
 import "llvm.org/llvm/bindings/go/llvm"
 
-type LLVMCtx struct {
+type BuildCtx struct {
+	C *Ctx
 	B llvm.Builder
 	M llvm.Module
 }
 
-func Build(ctx *Ctx, lctx LLVMCtx, stmts []Expr) {
+func (bctx BuildCtx) Build(stmts ...Statement) llvm.Value {
+	var lastVal llvm.Value
 	for _, stmt := range stmts {
-		BuildStmt(ctx, lctx, stmt)
+		if e := bctx.BuildStmt(stmt); e != nil {
+			lastVal = bctx.buildVal(e)
+		}
 	}
+	if (lastVal == llvm.Value{}) {
+		lastVal = bctx.B.CreateRetVoid()
+	}
+	return lastVal
 }
 
-func BuildStmt(ctx *Ctx, lctx LLVMCtx, stmtE Expr) {
-	s := stmtE.Actual.(Statement)
-	m := s.Op.Actual.(Macro)
+func (bctx BuildCtx) BuildStmt(s Statement) Expr {
+	m := s.Op.(Macro)
 
-	fn := ctx.GetMacro(m)
+	fn := bctx.C.GetMacro(m)
 	if fn == nil {
 		panicf("unknown macro: %q", m)
 	}
-	lv, ok := fn(ctx, lctx, s.Arg)
-	if ok {
-		ctx.LastVal = lv
-	}
+
+	return fn(bctx, bctx.buildExpr(s.Arg))
+}
+
+// may return nil if e is a Statement which has no return
+func (bctx BuildCtx) buildExpr(e Expr) Expr {
+	switch ea := e.(type) {
+	case llvmVal:
+		return e
+	case Int:
+		return llvmVal(llvm.ConstInt(llvm.Int64Type(), uint64(ea), false))
+	case Identifier:
+		return bctx.buildExpr(bctx.C.GetIdentifier(ea))
+	case Statement:
+		return bctx.BuildStmt(ea)
+	case Tuple:
+		for i := range ea {
+			ea[i] = bctx.buildExpr(ea[i])
+		}
+		return ea
+	default:
+		panicf("type %T can't express a value", ea)
+	}
+	panic("go is dumb")
+}
+
+func (bctx BuildCtx) buildVal(e Expr) llvm.Value {
+	return llvm.Value(bctx.buildExpr(e).(llvmVal))
+}
+
+// globalCtx describes what's available to *all* contexts, and is what all
+// contexts should have as the root parent in the tree
+var globalCtx = &Ctx{
+	macros: map[Macro]MacroFn{
+		"add": func(bctx BuildCtx, e Expr) Expr {
+			tup := e.(Tuple)
+			a := bctx.buildVal(tup[0])
+			b := bctx.buildVal(tup[1])
+			return llvmVal(bctx.B.CreateAdd(a, b, ""))
+		},
+
+		"bind": func(bctx BuildCtx, e Expr) Expr {
+			tup := e.(Tuple)
+			id := bctx.buildExpr(tup[0]).(Identifier)
+			bctx.C.idents[id] = bctx.buildVal(tup[1])
+			return nil
+		},
+	},
 }

expr/ctx.go

@@ -2,29 +2,64 @@ package expr
 
 import "llvm.org/llvm/bindings/go/llvm"
 
-type MacroFn func(*Ctx, LLVMCtx, Expr) (llvm.Value, bool)
+// MacroFn is a compiler function which takes in an existing Expr and returns
+// the llvm Value for it
+type MacroFn func(BuildCtx, Expr) Expr
 
-// Ctx contains all the Macros and Identifiers available. A Ctx is based on the
-// parent it was created from. If the current Ctx doesn't have a particular key
-// being looked up, the parent is called instead, and so on. A consequence of
-// this is that keys in the children take precedence over the parent's
+// Ctx contains all the Macros and Identifiers available. A Ctx also keeps a
+// reference to the global context, which has a number of macros available for
+// all contexts to use.
 type Ctx struct {
-	Parent *Ctx
-	Macros map[Macro]MacroFn
-
-	LastVal llvm.Value
+	global *Ctx
+	macros map[Macro]MacroFn
+	idents map[Identifier]llvm.Value
 }
 
-// GetMacro returns the first instance of the given of the given Macro found. If
-// not found nil is returned.
+// NewCtx returns a blank context instance
+func NewCtx() *Ctx {
+	return &Ctx{
+		global: globalCtx,
+		macros: map[Macro]MacroFn{},
+		idents: map[Identifier]llvm.Value{},
+	}
+}
+
+// GetMacro returns the MacroFn associated with the given identifier, or panics
+// if the macro isn't found
 func (c *Ctx) GetMacro(m Macro) MacroFn {
-	if c.Macros != nil {
-		if fn, ok := c.Macros[m]; ok {
-			return fn
-		}
+	if fn := c.macros[m]; fn != nil {
+		return fn
 	}
-	if c.Parent != nil {
-		return c.Parent.GetMacro(m)
+	if fn := c.global.macros[m]; fn != nil {
+		return fn
 	}
+	panicf("macro %q not found in context", m)
 	return nil
 }
+
+// GetIdentifier returns the llvm.Value for the Identifier, or panics
+func (c *Ctx) GetIdentifier(i Identifier) llvm.Value {
+	if v, ok := c.idents[i]; ok {
+		return v
+	}
+	// The global context doesn't have any identifiers, so don't bother checking
+	panicf("identifier %q not found in context", i)
+	return llvm.Value{}
+}
+
+// NewWith returns a new Ctx instance which imports the given macros from the
+// parent
+//func (c *Ctx) NewWith(mm ...Macro) *Ctx {
+//	nc := &Ctx{
+//		global: c.global,
+//		macros: map[Macro]MacroFn{},
+//	}
+//	for _, m := range mm {
+//		fn := c.macros[m]
+//		if fn == nil {
+//			panicf("no macro %q found in context", m)
+//		}
+//		nc.macros[m] = fn
+//	}
+//	return nc
+//}

expr/expr.go

@@ -4,20 +4,10 @@ import (
 	"fmt"
 
 	"llvm.org/llvm/bindings/go/llvm"
-
-	"github.com/mediocregopher/ginger/lexer"
 )
 
-// TODO empty blocks?
-// TODO empty parenthesis
-// TODO need to figure out how to test LLVMVal stuff
-// TODO once we're a bit more confident, make ActualFunc
-
-// Actual represents the actual expression in question. It is wrapped by Expr
-// which also holds onto contextual information, like the token to which Actual
-// was originally parsed from
-type Actual interface {
-}
+// Expr represents the actual expression in question.
+type Expr interface{}
 
 // equaler is used to compare two expressions. The comparison should not take
 // into account Token values, only the actual value being represented
@@ -25,30 +15,30 @@ type equaler interface {
 	equal(equaler) bool
 }
 
-// Expr contains the actual expression as well as some contextual information
-// wrapping it. Most interactions will be with this and not with the Actual
-// directly.
-type Expr struct {
-	Actual Actual
-
-	// Token is a nice-to-have, nothing will break if it's not there
-	Token lexer.Token
-
-	val *llvm.Value
-}
-
-// will panic if either Expr's Actual doesn't implement equaler
-func (e Expr) equal(e2 Expr) bool {
-	eq1, ok1 := e.Actual.(equaler)
-	eq2, ok2 := e2.Actual.(equaler)
+// will panic if either Expr doesn't implement equaler
+func exprEqual(e1, e2 Expr) bool {
+	eq1, ok1 := e1.(equaler)
+	eq2, ok2 := e2.(equaler)
 	if !ok1 || !ok2 {
-		panic(fmt.Sprintf("can't compare %T and %T", e.Actual, e2.Actual))
+		panic(fmt.Sprintf("can't compare %T and %T", e1, e2))
 	}
 	return eq1.equal(eq2)
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 
+// an Expr which simply wraps an existing llvm.Value
+type llvmVal llvm.Value
+
+/*
+func voidVal(lctx LLVMCtx) llvmVal {
+	return llvmVal{lctx.B.CreateRetVoid()}
+}
+*/
+
+////////////////////////////////////////////////////////////////////////////////
+
+/*
 // Void represents no data (size = 0)
 type Void struct{}
 
@@ -56,6 +46,7 @@ func (v Void) equal(e equaler) bool {
 	_, ok := e.(Void)
 	return ok
 }
+*/
 
 ////////////////////////////////////////////////////////////////////////////////
 /*
@@ -75,12 +66,6 @@ func (b Bool) equal(e equaler) bool {
 // Int represents an integer value
 type Int int64
 
-func (i Int) build(lctx LLVMCtx) llvm.Value {
-	v := lctx.B.CreateAlloca(llvm.Int64Type(), "")
-	lctx.B.CreateStore(llvm.ConstInt(llvm.Int64Type(), uint64(i), false), v)
-	return v
-}
-
 func (i Int) equal(e equaler) bool {
 	ii, ok := e.(Int)
 	return ok && ii == i
@@ -133,6 +118,11 @@ func (m Macro) equal(e equaler) bool {
 // they were a single value
 type Tuple []Expr
 
+// NewTuple returns a Tuple around the given list of Exprs
+func NewTuple(ee ...Expr) Tuple {
+	return Tuple(ee)
+}
+
 func (tup Tuple) String() string {
 	return "(" + exprsJoin(tup) + ")"
 }
@@ -152,12 +142,12 @@ type Statement struct {
 }
 
 func (s Statement) String() string {
-	return fmt.Sprintf("(%v %s)", s.Op.Actual, s.Arg.Actual)
+	return fmt.Sprintf("(%v %s)", s.Op, s.Arg)
 }
 
 func (s Statement) equal(e equaler) bool {
 	ss, ok := e.(Statement)
-	return ok && s.Op.equal(ss.Op) && s.Arg.equal(ss.Arg)
+	return ok && exprEqual(s.Op, ss.Op) && exprEqual(s.Arg, ss.Arg)
 }
 
 ////////////////////////////////////////////////////////////////////////////////

expr/macros.go

@@ -1,23 +0,0 @@
-package expr
-
-import "llvm.org/llvm/bindings/go/llvm"
-
-// RootCtx describes what's available to *all* contexts, and is what all
-// contexts should have as the root parent in the tree
-var RootCtx = &Ctx{
-	Macros: map[Macro]MacroFn{
-		"add": func(ctx *Ctx, lctx LLVMCtx, e Expr) (llvm.Value, bool) {
-			tup := e.Actual.(Tuple)
-			buildInt := func(e Expr) llvm.Value {
-				return lctx.B.CreateLoad(e.Actual.(Int).build(lctx), "")
-			}
-
-			a := buildInt(tup[0])
-			for i := range tup[1:] {
-				b := buildInt(tup[i+1])
-				a = lctx.B.CreateAdd(a, b, "")
-			}
-			return a, true
-		},
-	},
-}

expr/util.go

@@ -18,7 +18,7 @@ func randStr() string {
 func exprsJoin(ee []Expr) string {
 	strs := make([]string, len(ee))
 	for i := range ee {
-		strs[i] = fmt.Sprint(ee[i].Actual)
+		strs[i] = fmt.Sprint(ee[i])
 	}
 	return strings.Join(strs, ", ")
 }
@@ -28,7 +28,7 @@ func exprsEqual(ee1, ee2 []Expr) bool {
 		return false
 	}
 	for i := range ee1 {
-		if !ee1[i].equal(ee2[i]) {
+		if !exprEqual(ee1[i], ee2[i]) {
 			return false
 		}
 	}

main.go

@@ -21,53 +21,52 @@ func main() {
 	llvm.InitializeNativeTarget()
 	llvm.InitializeNativeAsmPrinter()
 
-	// setup our builder and module
-	lctx := expr.LLVMCtx{
+	// setup our context, builder, and module
+	bctx := expr.BuildCtx{
+		C: expr.NewCtx(),
 		B: llvm.NewBuilder(),
 		M: llvm.NewModule("my_module"),
 	}
 
 	// do the work in the function
-	a := expr.Expr{Actual: expr.Int(1)}
-	b := expr.Expr{Actual: expr.Int(2)}
-	c := expr.Expr{Actual: expr.Int(3)}
-	tup := expr.Expr{Actual: expr.Tuple([]expr.Expr{a, b, c})}
-	addMacro := expr.Expr{Actual: expr.Macro("add")}
-	stmt := expr.Expr{Actual: expr.Statement{Op: addMacro, Arg: tup}}
+	tup := expr.NewTuple(expr.Int(1), expr.Int(2))
+	addMacro := expr.Macro("add")
+	stmt := expr.Statement{Op: addMacro, Arg: tup}
+	stmt = expr.Statement{Op: addMacro, Arg: expr.NewTuple(stmt, expr.Int(3))}
 
 	//block := expr.Block([]expr.Expr{stmt})
 	//fn := block.LLVMVal(expr.RootCtx, lctx)
 
 	// create main and call our function
-	mainFn := llvm.AddFunction(lctx.M, "main", llvm.FunctionType(llvm.Int64Type(), []llvm.Type{}, false))
+	mainFn := llvm.AddFunction(bctx.M, "main", llvm.FunctionType(llvm.Int64Type(), []llvm.Type{}, false))
 	mainBlock := llvm.AddBasicBlock(mainFn, "entry")
-	lctx.B.SetInsertPoint(mainBlock, mainBlock.FirstInstruction())
-	expr.BuildStmt(expr.RootCtx, lctx, stmt)
-	lctx.B.CreateRet(expr.RootCtx.LastVal)
+	bctx.B.SetInsertPoint(mainBlock, mainBlock.FirstInstruction())
+	v := bctx.Build(stmt)
+	bctx.B.CreateRet(v)
 
 	//ret := lctx.B.CreateCall(fn, []llvm.Value{}, "")
 	//lctx.B.CreateRet(ret)
 
 	// verify it's all good
-	if err := llvm.VerifyModule(lctx.M, llvm.ReturnStatusAction); err != nil {
+	if err := llvm.VerifyModule(bctx.M, llvm.ReturnStatusAction); err != nil {
 		panic(err)
 	}
 	fmt.Println("# verified")
 
 	// Dump the IR
 	fmt.Println("# dumping IR")
-	lctx.M.Dump()
+	bctx.M.Dump()
 	fmt.Println("# done dumping IR")
 
 	// create our exe engine
 	fmt.Println("# creating new execution engine")
-	engine, err := llvm.NewExecutionEngine(lctx.M)
+	engine, err := llvm.NewExecutionEngine(bctx.M)
 	if err != nil {
 		panic(err)
 	}
 
 	// run the function!
 	fmt.Println("# running the function main")
-	funcResult := engine.RunFunction(lctx.M.NamedFunction("main"), []llvm.GenericValue{})
+	funcResult := engine.RunFunction(bctx.M.NamedFunction("main"), []llvm.GenericValue{})
 	fmt.Printf("%d\n", funcResult.Int(false))
 }