idl: replace internal.Position with ast.Position (#505)

With idl.Position moved to ast.Position, there's no need for a separate
internal.Position type.

idl/error.go

@@ -45,7 +45,7 @@ func newParseError(errors []internal.ParseError) error {
 	errs := make([]Error, len(errors))
 	for i, err := range errors {
 		errs[i] = Error{
-			Pos: ast.Position{Line: err.Pos.Line},
+			Pos: err.Pos,
 			Err: err.Err,
 		}
 	}

idl/info_test.go

@@ -31,7 +31,7 @@ import (
 func TestPos(t *testing.T) {
 	tests := []struct {
 		node ast.Node
-		pos  *internal.Position
+		pos  *ast.Position
 		want ast.Position
 	}{
 		{
@@ -44,7 +44,7 @@ func TestPos(t *testing.T) {
 		},
 		{
 			node: ast.ConstantString("s"),
-			pos:  &internal.Position{Line: 1},
+			pos:  &ast.Position{Line: 1},
 			want: ast.Position{Line: 1},
 		},
 	}

idl/internal/error.go

@@ -20,8 +20,10 @@
 
 package internal
 
+import "go.uber.org/thriftrw/ast"
+
 // ParseError holds a parse error and the position that caused it.
 type ParseError struct {
-	Pos Position
+	Pos ast.Position
 	Err error
 }

idl/internal/lex.go

@@ -16607,11 +16607,11 @@ func (lex *lexer) Error(e string) {
 
 func (lex *lexer) AppendError(err error) {
 	lex.parseFailed = true
-	lex.errors = append(lex.errors, ParseError{Pos: Position{Line: lex.line}, Err: err})
+	lex.errors = append(lex.errors, ParseError{Pos: ast.Position{Line: lex.line}, Err: err})
 }
 
 func (lex *lexer) RecordPosition(n ast.Node) {
-	lex.nodePositions[n] = Position{Line: lex.line}
+	lex.nodePositions[n] = ast.Position{Line: lex.line}
 }
 
 func (lex *lexer) LastDocstring() string {

idl/internal/lex.rl

@@ -351,11 +351,11 @@ func (lex *lexer) Error(e string) {
 
 func (lex *lexer) AppendError(err error)  {
   lex.parseFailed = true
-  lex.errors = append(lex.errors, ParseError{Pos: Position{Line: lex.line}, Err: err})
+  lex.errors = append(lex.errors, ParseError{Pos: ast.Position{Line: lex.line}, Err: err})
 }
 
 func (lex* lexer) RecordPosition(n ast.Node) {
-    lex.nodePositions[n] = Position{Line: lex.line}
+    lex.nodePositions[n] = ast.Position{Line: lex.line}
 }
 
 func (lex *lexer) LastDocstring() string {

idl/internal/parser.go

@@ -26,6 +26,9 @@ func init() {
 	yyErrorVerbose = true
 }
 
+// NodePositions maps (hashable) nodes to their document positions.
+type NodePositions map[ast.Node]ast.Position
+
 // ParseResult holds the result of a successful Parse.
 type ParseResult struct {
 	Program       *ast.Program