Better ecc

checker/checker.go

@@ -93,6 +93,9 @@ func (v *visitor) NilNode(node *ast.NilNode) reflect.Type {
 }
 
 func (v *visitor) IdentifierNode(node *ast.IdentifierNode) reflect.Type {
+	if v.types == nil {
+		return interfaceType
+	}
 	if t, ok := v.types[node.Value]; ok {
 		return t.Type
 	}

cmd/ecc/main.go

@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"flag"
 	"fmt"
+	"github.com/antonmedv/expr/checker"
 	"github.com/antonmedv/expr/compiler"
 	"github.com/antonmedv/expr/parser"
 	"github.com/antonmedv/expr/vm"
@@ -85,10 +86,13 @@ func printAst() {
 }
 
 func printDisassemble() {
-	node, err := parser.Parse(input())
+	tree, err := parser.Parse(input())
 	check(err)
 
-	program, err := compiler.Compile(node)
+	_, err = checker.Check(tree, nil)
+	check(err)
+
+	program, err := compiler.Compile(tree)
 	check(err)
 
 	_, _ = fmt.Fprintf(os.Stdout, program.Disassemble())
@@ -98,6 +102,9 @@ func runProgram() {
 	tree, err := parser.Parse(input())
 	check(err)
 
+	_, err = checker.Check(tree, nil)
+	check(err)
+
 	program, err := compiler.Compile(tree)
 	check(err)
 
@@ -127,6 +134,12 @@ func startRepl() {
 			goto prompt
 		}
 
+		_, err = checker.Check(tree, nil)
+		if err != nil {
+			fmt.Printf("%v\n", err)
+			goto prompt
+		}
+
 		program, err = compiler.Compile(tree)
 		if err != nil {
 			fmt.Printf("%v\n", err)