fix: positions of expressions (#505)

Fix Idx1 of ConditionalExpression so that it points to the next character after alternate expression.
Fix Idx1 of SequenceExpression to return Idx1 of the last sequence element, not first.
Fix Idx0 of unary expression to point to the start of operand in case of a postfix operator.
Fix Idx1 of VariableExpression so that it points to the character right after the name literal if the
expression does not have an initializer.

ast/node.go

@@ -178,7 +178,7 @@ func (ce *ConditionalExpression) Idx0() file.Idx {
 
 // Idx1 implements Node.
 func (ce *ConditionalExpression) Idx1() file.Idx {
-	return ce.Test.Idx1()
+	return ce.Alternate.Idx1()
 }
 
 // expression implements Expression.
@@ -397,7 +397,7 @@ func (se *SequenceExpression) Idx0() file.Idx {
 
 // Idx1 implements Node.
 func (se *SequenceExpression) Idx1() file.Idx {
-	return se.Sequence[0].Idx1()
+	return se.Sequence[len(se.Sequence)-1].Idx1()
 }
 
 // expression implements Expression.
@@ -451,6 +451,9 @@ type UnaryExpression struct {
 
 // Idx0 implements Node.
 func (ue *UnaryExpression) Idx0() file.Idx {
+	if ue.Postfix {
+		return ue.Operand.Idx0()
+	}
 	return ue.Idx
 }
 
@@ -480,7 +483,7 @@ func (ve *VariableExpression) Idx0() file.Idx {
 // Idx1 implements Node.
 func (ve *VariableExpression) Idx1() file.Idx {
 	if ve.Initializer == nil {
-		return file.Idx(int(ve.Idx) + len(ve.Name) + 1)
+		return file.Idx(int(ve.Idx) + len(ve.Name))
 	}
 	return ve.Initializer.Idx1()
 }

parser/expression.go

@@ -884,7 +884,7 @@ func (p *parser) parseLogicalOrExpression() ast.Expression {
 	return left
 }
 
-func (p *parser) parseConditionlExpression() ast.Expression {
+func (p *parser) parseConditionalExpression() ast.Expression {
 	left := p.parseLogicalOrExpression()
 
 	if p.token == token.QUESTION_MARK {
@@ -911,7 +911,7 @@ func (p *parser) parseConditionlExpression() ast.Expression {
 }
 
 func (p *parser) parseAssignmentExpression() ast.Expression {
-	left := p.parseConditionlExpression()
+	left := p.parseConditionalExpression()
 	var operator token.Token
 	switch p.token {
 	case token.ASSIGN:

parser/parser_test.go

@@ -1056,6 +1056,50 @@ func TestPosition(t *testing.T) {
 		node = program.Body[0].(*ast.ExpressionStatement).Expression.(*ast.AssignExpression).Right.(*ast.ArrayLiteral)
 		is(node.Idx0(), 5)
 		is(parser.slice(node.Idx0(), node.Idx1()), "[1, 2]")
+
+		parser = newParser("", "x = true ? 1 : 2", 1, nil)
+		program, err = parser.parse()
+		is(err, nil)
+		node = program.Body[0].(*ast.ExpressionStatement).Expression.(*ast.AssignExpression).Right.(*ast.ConditionalExpression)
+		is(node.Idx0(), 5)
+		is(parser.slice(node.Idx0(), node.Idx1()), "true ? 1 : 2")
+
+		parser = newParser("", "(function(){ x = 1, y = 2; })", 1, nil)
+		program, err = parser.parse()
+		is(err, nil)
+		block = program.Body[0].(*ast.ExpressionStatement).Expression.(*ast.FunctionLiteral).Body.(*ast.BlockStatement)
+		node = block.List[0].(*ast.ExpressionStatement).Expression.(*ast.SequenceExpression)
+		is(node.Idx0(), 14)
+		is(parser.slice(node.Idx0(), node.Idx1()), "x = 1, y = 2")
+
+		parser = newParser("", "x = ~x", 1, nil)
+		program, err = parser.parse()
+		is(err, nil)
+		node = program.Body[0].(*ast.ExpressionStatement).Expression.(*ast.AssignExpression).Right.(*ast.UnaryExpression)
+		is(node.Idx0(), 5)
+		is(parser.slice(node.Idx0(), node.Idx1()), "~x")
+
+		parser = newParser("", "(function(){ xyz++; })", 1, nil)
+		program, err = parser.parse()
+		is(err, nil)
+		block = program.Body[0].(*ast.ExpressionStatement).Expression.(*ast.FunctionLiteral).Body.(*ast.BlockStatement)
+		node = block.List[0].(*ast.ExpressionStatement).Expression.(*ast.UnaryExpression)
+		is(node.Idx0(), 14)
+		is(parser.slice(node.Idx0(), node.Idx1()), "xyz++")
+
+		parser = newParser("", "(function(){ var abc, xyz = 1; })", 1, nil)
+		program, err = parser.parse()
+		is(err, nil)
+		block = program.Body[0].(*ast.ExpressionStatement).Expression.(*ast.FunctionLiteral).Body.(*ast.BlockStatement)
+		node = block.List[0].(*ast.VariableStatement)
+		is(node.Idx0(), 14)
+		is(parser.slice(node.Idx0(), node.Idx1()), "var abc, xyz = 1")
+		node = block.List[0].(*ast.VariableStatement).List[0].(*ast.VariableExpression)
+		is(node.Idx0(), 18)
+		is(parser.slice(node.Idx0(), node.Idx1()), "abc")
+		node = block.List[0].(*ast.VariableStatement).List[1].(*ast.VariableExpression)
+		is(node.Idx0(), 23)
+		is(parser.slice(node.Idx0(), node.Idx1()), "xyz = 1")
 	})
 }