Fix declared and not used errors and unused import errors in

the interpreter and update code to use ast.BasicDecl and
multi-type switch.  There are still a lot of "switch _ :=
x.(type)" that should make use of the new type switch syntax,
but those will be a different CL.

R=rsc
APPROVED=rsc
DELTA=58  (16 added, 23 deleted, 19 changed)
OCL=34853
CL=34963

8 files changed, 35 insertions, 42 deletions

diff --git a/usr/austin/eval/compiler.go b/usr/austin/eval/compiler.go
index 12cace9e0..f3c962c2b 100644
--- a/usr/austin/eval/compiler.go
+++ b/usr/austin/eval/compiler.go
@@ -6,7 +6,6 @@ package eval
 
 import (
 	"fmt";
-	"go/ast";
 	"go/scanner";
 	"go/token";
 )
diff --git a/usr/austin/eval/expr.go b/usr/austin/eval/expr.go
index 472db83c1..5c4e79249 100644
--- a/usr/austin/eval/expr.go
+++ b/usr/austin/eval/expr.go
@@ -7,10 +7,8 @@ package eval
 import (
 	"bignum";
 	"go/ast";
-	"go/scanner";
 	"go/token";
 	"log";
-	"os";
 	"strconv";
 	"strings";
 )
@@ -191,7 +189,7 @@ func (a *expr) convertToInt(max int64, negErr string, errOp string) *expr {
 // expression.
 func (a *expr) derefArray() *expr {
 	if pt, ok := a.t.lit().(*PtrType); ok {
-		if at, ok := pt.Elem.lit().(*ArrayType); ok {
+		if _, ok := pt.Elem.lit().(*ArrayType); ok {
 			deref := a.compileStarExpr(a);
 			if deref == nil {
 				log.Crashf("failed to dereference *array");
@@ -481,15 +479,23 @@ func (a *exprCompiler) compile(x ast.Expr, callCtx bool) *expr {
 
 	switch x := x.(type) {
 	// Literals
-	case *ast.CharLit:
-		return ei.compileCharLit(string(x.Value));
+	case *ast.BasicLit:
+		switch x.Kind {
+		case token.INT:
+			return ei.compileIntLit(string(x.Value));
+		case token.FLOAT:
+			return ei.compileFloatLit(string(x.Value));
+		case token.CHAR:
+			return ei.compileCharLit(string(x.Value));
+		case token.STRING:
+			return ei.compileStringLit(string(x.Value));
+		default:
+			log.Crashf("unexpected basic literal type %v", x.Kind);
+		}
 
 	case *ast.CompositeLit:
 		goto notimpl;
 
-	case *ast.FloatLit:
-		return ei.compileFloatLit(string(x.Value));
-
 	case *ast.FuncLit:
 		decl := ei.compileFuncType(a.block, x.Type);
 		if decl == nil {
@@ -507,12 +513,6 @@ func (a *exprCompiler) compile(x ast.Expr, callCtx bool) *expr {
 		}
 		return ei.compileFuncLit(decl, fn);
 
-	case *ast.IntLit:
-		return ei.compileIntLit(string(x.Value));
-
-	case *ast.StringLit:
-		return ei.compileStringLit(string(x.Value));
-
 	// Types
 	case *ast.ArrayType:
 		// TODO(austin) Use a multi-type case
@@ -744,7 +744,7 @@ func (a *exprInfo) compileIdealInt(i *bignum.Integer, desc string) *expr {
 }
 
 func (a *exprInfo) compileIntLit(lit string) *expr {
-	i, _, _2 := bignum.IntFromString(lit, 0);
+	i, _, _ := bignum.IntFromString(lit, 0);
 	return a.compileIdealInt(i, "integer literal");
 }
 
@@ -754,7 +754,7 @@ func (a *exprInfo) compileCharLit(lit string) *expr {
 		a.silentErrors++;
 		return nil;
 	}
-	v, mb, tail, err := strconv.UnquoteChar(lit[1:len(lit)], '\'');
+	v, _, tail, err := strconv.UnquoteChar(lit[1:len(lit)], '\'');
 	if err != nil || tail != "'" {
 		// Caught by parser
 		a.silentErrors++;
@@ -863,7 +863,7 @@ func (a *exprInfo) compileSelectorExpr(v *expr, name string) *expr {
 
 		// If it's a named type, look for methods
 		if ti, ok := t.(*NamedType); ok {
-			method, ok := ti.methods[name];
+			_, ok := ti.methods[name];
 			if ok {
 				mark(depth, pathName + "." + name);
 				log.Crash("Methods not implemented");
@@ -1638,12 +1638,8 @@ func (a *exprInfo) compileBinaryExpr(op token.Token, l, r *expr) *expr {
 			return nil;
 		}
 		// Arrays and structs may not be compared to anything.
-		// TODO(austin) Use a multi-type switch
-		if _, ok := l.t.(*ArrayType); ok {
-			a.diagOpTypes(op, origlt, origrt);
-			return nil;
-		}
-		if _, ok := l.t.(*StructType); ok {
+		switch l.t.(type) {
+		case *ArrayType, *StructType:
 			a.diagOpTypes(op, origlt, origrt);
 			return nil;
 		}
diff --git a/usr/austin/eval/scope.go b/usr/austin/eval/scope.go
index 7e10293d5..7ee4a8915 100644
--- a/usr/austin/eval/scope.go
+++ b/usr/austin/eval/scope.go
@@ -5,7 +5,6 @@
 package eval
 
 import (
-	"fmt";
 	"go/token";
 	"log";
 )
diff --git a/usr/austin/eval/stmt.go b/usr/austin/eval/stmt.go
index 758157827..9ec6fb83d 100644
--- a/usr/austin/eval/stmt.go
+++ b/usr/austin/eval/stmt.go
@@ -7,11 +7,8 @@ package eval
 import (
 	"bignum";
 	"log";
-	"os";
 	"go/ast";
-	"go/scanner";
 	"go/token";
-	"strconv";
 )
 
 const (
@@ -1018,7 +1015,7 @@ func (a *stmtCompiler) compileSwitchStmt(s *ast.SwitchStmt) {
 	// Count cases
 	ncases := 0;
 	hasDefault := false;
-	for i, c := range s.Body.List {
+	for _, c := range s.Body.List {
 		clause, ok := c.(*ast.CaseClause);
 		if !ok {
 			a.diagAt(clause, "switch statement must contain case clauses");
@@ -1090,7 +1087,7 @@ func (a *stmtCompiler) compileSwitchStmt(s *ast.SwitchStmt) {
 		// Save jump PC's
 		pc := a.nextPC();
 		if clause.Values != nil {
-			for _, v := range clause.Values {
+			for _ = range clause.Values {
 				casePCs[i] = &pc;
 				i++;
 			}
@@ -1215,7 +1212,7 @@ func (a *blockCompiler) compileStmt(s ast.Stmt) {
 }
 
 func (a *blockCompiler) compileStmts(block *ast.BlockStmt) {
-	for i, sub := range block.List {
+	for _, sub := range block.List {
 		a.compileStmt(sub);
 	}
 }
diff --git a/usr/austin/eval/type.go b/usr/austin/eval/type.go
index 656108445..b73f92163 100644
--- a/usr/austin/eval/type.go
+++ b/usr/austin/eval/type.go
@@ -165,7 +165,7 @@ type boolType struct {
 var BoolType = universe.DefineType("bool", universePos, &boolType{})
 
 func (t *boolType) compat(o Type, conv bool) bool {
-	t2, ok := o.lit().(*boolType);
+	_, ok := o.lit().(*boolType);
 	return ok;
 }
 
@@ -364,7 +364,7 @@ type idealIntType struct {
 var IdealIntType Type = &idealIntType{}
 
 func (t *idealIntType) compat(o Type, conv bool) bool {
-	t2, ok := o.lit().(*idealIntType);
+	_, ok := o.lit().(*idealIntType);
 	return ok;
 }
 
@@ -485,7 +485,7 @@ type idealFloatType struct {
 var IdealFloatType Type = &idealFloatType{};
 
 func (t *idealFloatType) compat(o Type, conv bool) bool {
-	t2, ok := o.lit().(*idealFloatType);
+	_, ok := o.lit().(*idealFloatType);
 	return ok;
 }
 
@@ -520,7 +520,7 @@ type stringType struct {
 var StringType = universe.DefineType("string", universePos, &stringType{})
 
 func (t *stringType) compat(o Type, conv bool) bool {
-	t2, ok := o.lit().(*stringType);
+	_, ok := o.lit().(*stringType);
 	return ok;
 }
 
diff --git a/usr/austin/eval/typec.go b/usr/austin/eval/typec.go
index a4d055fb5..dcff93ccb 100644
--- a/usr/austin/eval/typec.go
+++ b/usr/austin/eval/typec.go
@@ -26,7 +26,7 @@ type typeCompiler struct {
 }
 
 func (a *typeCompiler) compileIdent(x *ast.Ident, allowRec bool) Type {
-	_bl, _index, def := a.block.Lookup(x.Value);
+	_, _, def := a.block.Lookup(x.Value);
 	if def == nil {
 		a.diagAt(x, "%s: undefined", x.Value);
 		return nil;
@@ -106,7 +106,7 @@ func (a *typeCompiler) compileFields(fs []*ast.Field, allowRec bool) ([]Type, []
 
 	bad := false;
 	i := 0;
-	for fi, f := range fs {
+	for _, f := range fs {
 		t := a.compileType(f.Type, allowRec);
 		if t == nil {
 			bad = true;
diff --git a/usr/austin/eval/util.go b/usr/austin/eval/util.go
index 68f58842d..9cdf23722 100644
--- a/usr/austin/eval/util.go
+++ b/usr/austin/eval/util.go
@@ -6,8 +6,6 @@ package eval
 
 import (
 	"bignum";
-	"fmt";
-	"go/token";
 )
 
 // TODO(austin): Maybe add to bignum in more general form
diff --git a/usr/austin/eval/world.go b/usr/austin/eval/world.go
index 6738f6b50..4eba216bb 100644
--- a/usr/austin/eval/world.go
+++ b/usr/austin/eval/world.go
@@ -5,7 +5,6 @@
 package eval
 
 import (
-	"fmt";
 	"go/ast";
 	"go/parser";
 	"go/scanner";
@@ -64,7 +63,7 @@ func (w *World) compileStmts(stmts []ast.Stmt) (Code, os.Error) {
 		block: w.scope.block,
 	};
 	nerr := cc.numError();
-	for i, stmt := range stmts {
+	for _, stmt := range stmts {
 		bc.compileStmt(stmt);
 	}
 	fc.checkLabels();
@@ -107,11 +106,16 @@ func (w *World) compileExpr(e ast.Expr) (Code, os.Error) {
 		return nil, errors.GetError(scanner.Sorted);
 	}
 	var eval func(Value, *Thread);
-	switch _ := ec.t.(type) {
+	switch t := ec.t.(type) {
 	case *idealIntType:
 		// nothing
 	case *idealFloatType:
 		// nothing
+	case *MultiType:
+		if len(t.Elems) == 0 {
+			return &stmtCode{w, code{ec.exec}}, nil;
+		}
+		fallthrough;
 	default:
 		eval = genAssign(ec.t, ec);
 	}