Merge pull request #246 from NeowayLabs/addIndexingToStrings

Add indexing to strings

Author: i4ki

internal/sh/builtin/len.go

@@ -10,7 +10,7 @@ import (
 
 type (
 	lenFn struct {
-		arg sh.Obj
+		arg sh.Collection
 	}
 )
 
@@ -29,12 +29,7 @@ func lenresult(res int) []sh.Obj {
 }
 
 func (l *lenFn) Run(in io.Reader, out io.Writer, err io.Writer) ([]sh.Obj, error) {
-	if l.arg.Type() == sh.ListType {
-		arglist := l.arg.(*sh.ListObj)
-		return lenresult(len(arglist.List())), nil
-	}
-	argstr := l.arg.(*sh.StrObj)
-	return lenresult(len(argstr.Str())), nil
+	return lenresult(l.arg.Len()), nil
 }
 
 func (l *lenFn) SetArgs(args []sh.Obj) error {
@@ -43,11 +38,11 @@ func (l *lenFn) SetArgs(args []sh.Obj) error {
 	}
 
 	obj := args[0]
-
-	if obj.Type() != sh.ListType && obj.Type() != sh.StringType {
-		return errors.NewError("lenfn expects a list or a string, but a %s was provided", obj.Type())
+	col, err := sh.NewCollection(obj)
+	if err != nil {
+		return errors.NewError("len:error[%s]", err)
 	}
 
-	l.arg = obj
+	l.arg = col
 	return nil
 }

internal/sh/shell.go

@@ -529,41 +529,37 @@ func (shell *Shell) ExecFile(path string) error {
 }
 
 func (shell *Shell) setvar(name *ast.NameNode, value sh.Obj) error {
-	finalObj := value
 
-	if name.Index != nil {
-		if list, ok := shell.Getvar(name.Ident); ok {
-			index, err := shell.evalIndex(name.Index)
-
-			if err != nil {
-				return err
-			}
-
-			if list.Type() != sh.ListType {
-				return errors.NewEvalError(shell.filename,
-					name, "Indexed assigment on non-list type: Variable %s is %s",
-					name.Ident,
-					list.Type())
-			}
+	if name.Index == nil {
+		shell.Setvar(name.Ident, value)
+		return nil
+	}
 
-			lobj := list.(*sh.ListObj)
-			lvalues := lobj.List()
+	obj, ok := shell.Getvar(name.Ident)
+	if !ok {
+		return errors.NewEvalError(shell.filename,
+			name, "Variable %s not found", name.Ident)
+	}
 
-			if index >= len(lvalues) {
-				return errors.NewEvalError(shell.filename,
-					name, "List out of bounds error. List has %d elements, but trying to access index %d",
-					len(lvalues), index)
-			}
+	index, err := shell.evalIndex(name.Index)
+	if err != nil {
+		return err
+	}
 
-			lvalues[index] = value
-			finalObj = sh.NewListObj(lvalues)
-		} else {
-			return errors.NewEvalError(shell.filename,
-				name, "Variable %s not found", name.Ident)
-		}
+	col, err := sh.NewWriteableCollection(obj)
+	if err != nil {
+		return errors.NewEvalError(shell.filename, name, err.Error())
 	}
 
-	shell.Setvar(name.Ident, finalObj)
+	err = col.Set(index, value)
+	if err != nil {
+		return errors.NewEvalError(
+			shell.filename,
+			name,
+			"error[%s] setting var",
+			err,
+		)
+	}
 	return nil
 }
 
@@ -1486,27 +1482,21 @@ func (shell *Shell) evalIndexedVar(indexVar *ast.IndexExpr) (sh.Obj, error) {
 		return nil, err
 	}
 
-	if v.Type() != sh.ListType {
-		return nil, errors.NewEvalError(shell.filename, indexVar.Var,
-			"Invalid indexing of non-list variable: %s (%+v)", v.Type(), v)
+	col, err := sh.NewCollection(v)
+	if err != nil {
+		return nil, errors.NewEvalError(shell.filename, indexVar.Var, err.Error())
 	}
 
 	indexNum, err := shell.evalIndex(indexVar.Index)
 	if err != nil {
 		return nil, err
 	}
 
-	vlist := v.(*sh.ListObj)
-	values := vlist.List()
-
-	if indexNum < 0 || indexNum >= len(values) {
-		return nil, errors.NewEvalError(shell.filename,
-			indexVar.Var,
-			"Index out of bounds. len(%s) == %d, but given %d", indexVar.Var.Name,
-			len(values), indexNum)
+	val, err := col.Get(indexNum)
+	if err != nil {
+		return nil, errors.NewEvalError(shell.filename, indexVar.Var, err.Error())
 	}
-
-	return values[indexNum], nil
+	return val, nil
 }
 
 func (shell *Shell) evalArgIndexedVar(indexVar *ast.IndexExpr) ([]sh.Obj, error) {
@@ -1515,28 +1505,21 @@ func (shell *Shell) evalArgIndexedVar(indexVar *ast.IndexExpr) ([]sh.Obj, error)
 		return nil, err
 	}
 
-	if v.Type() != sh.ListType {
-		return nil, errors.NewEvalError(shell.filename, indexVar.Var,
-			"Invalid indexing of non-list variable: %s (%+v)", v.Type(), v)
+	col, err := sh.NewCollection(v)
+	if err != nil {
+		return nil, errors.NewEvalError(shell.filename, indexVar.Var, err.Error())
 	}
 
 	indexNum, err := shell.evalIndex(indexVar.Index)
 	if err != nil {
 		return nil, err
 	}
 
-	vlist := v.(*sh.ListObj)
-	values := vlist.List()
-
-	if indexNum < 0 || indexNum >= len(values) {
-		return nil, errors.NewEvalError(shell.filename,
-			indexVar.Var,
-			"Index out of bounds. len(%s) == %d, but given %d", indexVar.Var.Name,
-			len(values), indexNum)
+	retval, err := col.Get(indexNum)
+	if err != nil {
+		return nil, errors.NewEvalError(shell.filename, indexVar.Var, err.Error())
 	}
 
-	retval := values[indexNum]
-
 	if indexVar.IsVariadic {
 		if retval.Type() != sh.ListType {
 			return nil, errors.NewEvalError(shell.filename,
@@ -1545,7 +1528,7 @@ func (shell *Shell) evalArgIndexedVar(indexVar *ast.IndexExpr) ([]sh.Obj, error)
 		retlist := retval.(*sh.ListObj)
 		return retlist.List(), nil
 	}
-	return []sh.Obj{values[indexNum]}, nil
+	return []sh.Obj{retval}, nil
 }
 
 func (shell *Shell) evalVariable(a ast.Expr) (sh.Obj, error) {
@@ -2213,14 +2196,18 @@ func (shell *Shell) executeFor(n *ast.ForNode) ([]sh.Obj, error) {
 		return nil, err
 	}
 
-	if obj.Type() != sh.ListType {
+	col, err := sh.NewCollection(obj)
+	if err != nil {
 		return nil, errors.NewEvalError(shell.filename,
-			inExpr, "Invalid variable type in for range: %s", obj.Type())
+			inExpr, "error[%s] trying to iterate", err)
 	}
 
-	objlist := obj.(*sh.ListObj)
-
-	for _, val := range objlist.List() {
+	for i := 0; i < col.Len(); i++ {
+		val, err := col.Get(i)
+		if err != nil {
+			return nil, errors.NewEvalError(shell.filename,
+				inExpr, "unexpected error[%s] during iteration", err)
+		}
 		shell.Setvar(id, val)
 
 		objs, err := shell.executeTree(n.Tree(), false)

internal/sh/shell_test.go

@@ -524,59 +524,6 @@ func TestExecuteCmdMultipleAssignment(t *testing.T) {
 	}
 }
 
-// IFS *DO NOT* exists anymore.
-// This tests only assure things works as expected (IFS has no power)
-func TestExecuteCmdAssignmentIFSDontWork(t *testing.T) {
-	for _, test := range []execTestCase{
-		{
-			"ifs",
-			`IFS = (" ")
-range <= echo 1 2 3 4 5 6 7 8 9 10
-
-for i in $range {
-    echo "i = " + $i
-}`,
-			"", "",
-			"<interactive>:4:9: Invalid variable type in for range: StringType",
-		},
-		{
-			"ifs",
-			`IFS = (";")
-range <= echo "1;2;3;4;5;6;7;8;9;10"
-
-for i in $range {
-    echo "i = " + $i
-}`,
-			"", "",
-			"<interactive>:4:9: Invalid variable type in for range: StringType",
-		},
-		{
-			"ifs",
-			`IFS = (" " ";")
-range <= echo "1;2;3;4;5;6 7;8;9;10"
-
-for i in $range {
-    echo "i = " + $i
-}`,
-			"", "",
-			"<interactive>:4:9: Invalid variable type in for range: StringType",
-		},
-		{
-			"ifs",
-			`IFS = (" " "-")
-range <= echo "1;2;3;4;5;6;7-8;9;10"
-
-for i in $range {
-    echo "i = " + $i
-}`,
-			"", "",
-			"<interactive>:4:9: Invalid variable type in for range: StringType",
-		},
-	} {
-		testExec(t, test)
-	}
-}
-
 func TestExecuteRedirection(t *testing.T) {
 	f, teardown := setup(t)
 	defer teardown()

sh/obj.go

@@ -29,25 +29,72 @@ type (
 
 	StrObj struct {
 		objType
-		str string
+		runes []rune
+	}
+
+	Collection interface {
+		Len() int
+		Get(index int) (Obj, error)
+	}
+
+	WriteableCollection interface {
+		Set(index int, val Obj) error
 	}
 )
 
+func NewCollection(o Obj) (Collection, error) {
+	sizer, ok := o.(Collection)
+	if !ok {
+		return nil, fmt.Errorf(
+			"SizeError: trying to get size from type %s which is not a collection",
+			o.Type(),
+		)
+	}
+	return sizer, nil
+}
+
+func NewWriteableCollection(o Obj) (WriteableCollection, error) {
+	indexer, ok := o.(WriteableCollection)
+	if !ok {
+		return nil, fmt.Errorf(
+			"IndexError: trying to use a non write/indexable type %s to write on index: ",
+			o.Type(),
+		)
+	}
+	return indexer, nil
+}
+
 func (o objType) Type() objType {
 	return o
 }
 
 func NewStrObj(val string) *StrObj {
 	return &StrObj{
-		str:     val,
+		runes:   []rune(val),
 		objType: StringType,
 	}
 }
 
-func (o *StrObj) Str() string { return o.str }
+func (o *StrObj) Str() string { return string(o.runes) }
 
 func (o *StrObj) String() string { return o.Str() }
 
+func (o *StrObj) Get(index int) (Obj, error) {
+	if index >= o.Len() {
+		return nil, fmt.Errorf(
+			"IndexError: Index[%d] out of range, string size[%d]",
+			index,
+			o.Len(),
+		)
+	}
+
+	return NewStrObj(string(o.runes[index])), nil
+}
+
+func (o *StrObj) Len() int {
+	return len(o.runes)
+}
+
 func NewFnObj(val FnDef) *FnObj {
 	return &FnObj{
 		fn:      val,
@@ -66,6 +113,33 @@ func NewListObj(val []Obj) *ListObj {
 	}
 }
 
+func (o *ListObj) Len() int {
+	return len(o.list)
+}
+
+func (o *ListObj) Set(index int, value Obj) error {
+	if index >= len(o.list) {
+		return fmt.Errorf(
+			"IndexError: Index[%d] out of range, list size[%d]",
+			index,
+			len(o.list),
+		)
+	}
+	o.list[index] = value
+	return nil
+}
+
+func (o *ListObj) Get(index int) (Obj, error) {
+	if index >= len(o.list) {
+		return nil, fmt.Errorf(
+			"IndexError: Index out of bounds, index[%d] but list size[%d]",
+			index,
+			len(o.list),
+		)
+	}
+	return o.list[index], nil
+}
+
 func (o *ListObj) List() []Obj { return o.list }
 
 func (o *ListObj) String() string {

tests/cfg.go

@@ -0,0 +1,3 @@
+package tests
+
+const nashcmd = "../cmd/nash/nash"