add import

Examples/import/a.lox

@@ -0,0 +1,3 @@
+print "a.lox";
+
+import "b";

Examples/import/b.lox

@@ -0,0 +1,3 @@
+import "a";
+
+print "b.lox";

Lox/Ast/IStmtVisitor.rbbas

@@ -42,6 +42,12 @@ Protected Interface IStmtVisitor
 		End Function
 	#tag EndMethod
 
+	#tag Method, Flags = &h0
+		Function VisitImport(stmt As Lox.Ast.Import) As Variant
+
+		End Function
+	#tag EndMethod
+
 	#tag Method, Flags = &h0
 		Function VisitModuleStmt(stmt As Lox.Ast.ModuleStmt) As Variant
 

Lox/Ast/Import.rbbas

@@ -0,0 +1,58 @@
+#tag Class
+Protected Class Import
+Inherits Lox.Ast.Stmt
+	#tag Method, Flags = &h0
+		Function Accept(visitor As IStmtVisitor) As Variant
+		  Return visitor.VisitImport(Self)
+		End Function
+	#tag EndMethod
+
+	#tag Method, Flags = &h1000
+		Sub Constructor(name As Token)
+		  Self.Name= name
+		End Sub
+	#tag EndMethod
+
+
+	#tag Property, Flags = &h0
+		Name As Token
+	#tag EndProperty
+
+
+	#tag ViewBehavior
+		#tag ViewProperty
+			Name="Index"
+			Visible=true
+			Group="ID"
+			InitialValue="-2147483648"
+			InheritedFrom="Object"
+		#tag EndViewProperty
+		#tag ViewProperty
+			Name="Left"
+			Visible=true
+			Group="Position"
+			InitialValue="0"
+			InheritedFrom="Object"
+		#tag EndViewProperty
+		#tag ViewProperty
+			Name="Name"
+			Visible=true
+			Group="ID"
+			InheritedFrom="Object"
+		#tag EndViewProperty
+		#tag ViewProperty
+			Name="Super"
+			Visible=true
+			Group="ID"
+			InheritedFrom="Object"
+		#tag EndViewProperty
+		#tag ViewProperty
+			Name="Top"
+			Visible=true
+			Group="Position"
+			InitialValue="0"
+			InheritedFrom="Object"
+		#tag EndViewProperty
+	#tag EndViewBehavior
+End Class
+#tag EndClass

Lox/Inter/Interpreter.rbbas

@@ -52,7 +52,7 @@ Implements Lox.Ast.IExprVisitor,Lox.Ast.IStmtVisitor
 		  Catch exp As StackOverflowException
 		    HadRuntimeError= True
 		    #pragma BreakOnExceptions Off
-		    Raise New RuntimeError(New Token(Lox.TokenType.EOF, "",Nil,  -1), _
+		    Raise New RuntimeError(New Token(Lox.TokenType.NIL_, "",Nil,  -1), _
 		    "StackOverflowException")
 		  Finally
 		    mEnvironment= previous
@@ -161,6 +161,8 @@ Implements Lox.Ast.IExprVisitor,Lox.Ast.IStmtVisitor
 		  mEnvironment= mGlobals
 
 		  mLocals= New Lox.Misc.CSDictionary
+
+		  mImportFiles= New Dictionary
 		End Sub
 	#tag EndMethod
 
@@ -764,6 +766,30 @@ Implements Lox.Ast.IExprVisitor,Lox.Ast.IStmtVisitor
 		End Function
 	#tag EndMethod
 
+	#tag Method, Flags = &h0
+		Function VisitImport(stmt As Lox.Ast.Import) As Variant
+		  Dim file As FolderItem= Findfile(stmt.Name.Literal.StringValue)
+		  If file Is Nil Or Not file.Exists Then
+		    HadRuntimeError= True
+		    #pragma BreakOnExceptions Off
+		    Raise New RuntimeError(stmt.Name, "Couldn't find a module on "+ _
+		    file.AbsoluteNativePathLox+ ".")
+		  End If
+
+		  If mImportFiles.HasKey(file.AbsoluteNativePathLox) Then Return Nil
+
+		  Dim statements() As Lox.Ast.Stmt= ResolveFile(file, stmt.Name, Self)
+
+		  mImportFiles.Value(file.AbsoluteNativePathLox)= True
+
+		  For Each statement As Lox.Ast.Stmt In statements
+		    execute statement
+		  Next
+
+		  Return Nil
+		End Function
+	#tag EndMethod
+
 	#tag Method, Flags = &h0
 		Function VisitInterpolatedStr(expr As Lox.Ast.InterpolatedStr) As Variant
 		  Dim sb() As String
@@ -1035,6 +1061,10 @@ Implements Lox.Ast.IExprVisitor,Lox.Ast.IStmtVisitor
 		Private mGlobals As Environment
 	#tag EndProperty
 
+	#tag Property, Flags = &h21
+		Private mImportFiles As Dictionary
+	#tag EndProperty
+
 	#tag Property, Flags = &h21
 		Private mLocals As Lox.Misc.CSDictionary
 	#tag EndProperty

Lox/Inter/Resolver.rbbas

@@ -312,6 +312,12 @@ Implements Lox.Ast.IExprVisitor,Lox.Ast.IStmtVisitor
 		End Function
 	#tag EndMethod
 
+	#tag Method, Flags = &h0
+		Function VisitImport(stmt As Lox.Ast.Import) As Variant
+
+		End Function
+	#tag EndMethod
+
 	#tag Method, Flags = &h0
 		Function VisitInterpolatedStr(expr As Lox.Ast.InterpolatedStr) As Variant
 		  For Each part As Lox.Ast.Expr In expr.Parts

Lox/Lox.rbbas

@@ -1,5 +1,34 @@
 #tag Module
 Protected Module Lox
+	#tag Method, Flags = &h0
+		Function AbsoluteNativePathLox(Extends obj As FolderItem) As String
+		  #if RBVersion< 2013
+		    Return obj.AbsolutePath
+		  #else
+		    Return obj.NativePath
+		  #endif
+		End Function
+	#tag EndMethod
+
+	#tag Method, Flags = &h0
+		Sub AddSearchPath(path As String)
+		  Dim folder As FolderItem
+
+		  Try
+		    #pragma BreakOnExceptions Off
+		    folder= New FolderItem(path)
+		  Catch exc
+		    Return
+		  End Try
+
+		  If Not folder.Directory Then Return
+
+		  ChkSearchPaths
+
+		  mSearchPaths.Append folder
+		End Sub
+	#tag EndMethod
+
 	#tag Method, Flags = &h21
 		Private Function AreEqual(expected As Double, actual As Double, tolerance As Double = 0.000001) As Boolean
 		  Dim diff As Double= Abs(expected- actual)
@@ -24,6 +53,14 @@ Protected Module Lox
 		End Sub
 	#tag EndMethod
 
+	#tag Method, Flags = &h21
+		Private Sub ChkSearchPaths()
+		  If mSearchPaths.Ubound= -1 Then
+		    mSearchPaths.Append app.ExecutableFile.Parent
+		  End If
+		End Sub
+	#tag EndMethod
+
 	#tag Method, Flags = &h0
 		Function Count(Extends obj() As Token) As Integer
 		  Return obj.Ubound+ 1
@@ -72,6 +109,24 @@ Protected Module Lox
 		End Function
 	#tag EndMethod
 
+	#tag Method, Flags = &h21
+		Private Function FindFile(name As String) As FolderItem
+		  ChkSearchPaths
+
+		  If name.InStr(".lox")= 0 Then name= name+ ".lox"
+
+		  Dim file As New FolderItem(name) // full path
+		  If Not (file Is Nil) And file.Exists Then Return file
+
+		  For Each path As FolderItem In mSearchPaths // search paths
+		    file= path.Child(name)
+		    If Not (file Is Nil) And file.Exists Then Return file
+		  Next
+
+		  Return file
+		End Function
+	#tag EndMethod
+
 	#tag Method, Flags = &h21
 		Private Function IIf(stmt As Boolean, ifTrue As TokenType, ifFalse As TokenType) As TokenType
 		  If stmt Then Return ifTrue Else Return ifFalse
@@ -139,6 +194,38 @@ Protected Module Lox
 		End Sub
 	#tag EndMethod
 
+	#tag Method, Flags = &h21
+		Private Function ResolveFile(file As FolderItem, tok As Token, interp As Lox.Inter.Interpreter) As Lox.Ast.Stmt()
+		  Dim ti As TextInputStream= TextInputStream.Open(file)
+
+		  Dim scanner As New Lox.Scanner(ti.ReadAll)
+		  Dim tokens() As Lox.Token= scanner.Scan
+		  If scanner.HadError Then
+		    interp.HadRuntimeError= True
+		    #pragma BreakOnExceptions Off
+		    Raise New RuntimeError(tok, "scanner.HadError.")
+		  End If
+
+		  Dim parser As New Lox.Parser(tokens)
+		  Dim statements() As Lox.Ast.Stmt= parser.Parse
+		  If parser.HadError Then
+		    interp.HadRuntimeError= True
+		    #pragma BreakOnExceptions Off
+		    Raise New RuntimeError(tok, "parser.HadError.")
+		  End If
+
+		  Dim resolver As New Lox.Inter.Resolver(Lox.Interpreter)
+		  resolver.Resolve(statements)
+		  If resolver.HadError Then
+		    interp.HadRuntimeError= True
+		    #pragma BreakOnExceptions Off
+		    Raise New RuntimeError(tok, "resolver.HadError.")
+		  End If
+
+		  Return statements
+		End Function
+	#tag EndMethod
+
 	#tag Method, Flags = &h1
 		Protected Sub RuntimeError(error As RuntimeError)
 		  Dim msg As String= error.Message+ EndOfLine+ "[line "+ _
@@ -274,8 +361,6 @@ Protected Module Lox
 		    Return "ELVIS"
 		  Case TokenType.ELVIS_DOT
 		    Return "ELVIS_DOT"
-		  Case TokenType.USING_
-		    Return "USING"
 		  Case TokenType.LEFT_BRACKET
 		    Return "LEFT_BRACKET"
 		  Case TokenType.RIGHT_BRACKET
@@ -286,6 +371,8 @@ Protected Module Lox
 		    Return "HASHTAG_BRACE"
 		  Case TokenType.STRING_INTERPOLATION
 		    Return "STRING_INTERPOLATION"
+		  Case TokenType.IMPORT
+		    Return "IMPORT"
 
 		  Case Else
 		    Return "STRINGIFY->"
@@ -434,6 +521,10 @@ Protected Module Lox
 		Private mPrintOut As Writeable
 	#tag EndProperty
 
+	#tag Property, Flags = &h21
+		Private mSearchPaths() As FolderItem
+	#tag EndProperty
+
 	#tag ComputedProperty, Flags = &h0
 		#tag Getter
 			Get
@@ -453,7 +544,7 @@ Protected Module Lox
 	#tag EndComputedProperty
 
 
-	#tag Constant, Name = Version, Type = String, Dynamic = False, Default = \"0.0.240913", Scope = Public
+	#tag Constant, Name = Version, Type = String, Dynamic = False, Default = \"0.0.240915", Scope = Public
 	#tag EndConstant
 
 
@@ -514,12 +605,12 @@ Protected Module Lox
 		  GREATER_GREATER
 		  ELVIS
 		  ELVIS_DOT
-		  USING_
 		  LEFT_BRACKET
 		  RIGHT_BRACKET
 		  FAT_ARROW
 		  HASHTAG_BRACE
-		STRING_INTERPOLATION
+		  STRING_INTERPOLATION
+		IMPORT
 	#tag EndEnum
 
 

Lox/Misc/AstPrinter.rbbas

@@ -280,9 +280,25 @@ Implements Lox.Ast.IExprVisitor,Lox.Ast.IStmtVisitor
 		End Function
 	#tag EndMethod
 
+	#tag Method, Flags = &h0
+		Function VisitImport(stmt As Lox.Ast.Import) As Variant
+		  Return Parenthesize2("import", stmt.Name)
+		End Function
+	#tag EndMethod
+
 	#tag Method, Flags = &h0
 		Function VisitInterpolatedStr(expr As Lox.Ast.InterpolatedStr) As Variant
+		  Dim sb() As String
+
+		  sb.Append "(interpolated str "
 
+		  For Each part As Lox.Ast.Expr In expr.Parts
+		    sb.Append part.Accept(Self)
+		  Next
+
+		  sb.Append ")"
+
+		  Return Join(sb, "")
 		End Function
 	#tag EndMethod
 
@@ -324,7 +340,7 @@ Implements Lox.Ast.IExprVisitor,Lox.Ast.IStmtVisitor
 
 	#tag Method, Flags = &h0
 		Function VisitPostfix(expr As Lox.Ast.Postfix) As Variant
-
+		  Return Parenthesize2("postfix", expr.Name, expr.Operator, expr.Left)
 		End Function
 	#tag EndMethod