EOI: Lecture 10 & 11 complete.

App/EoI/EoI_Viewer.tscn

@@ -42,17 +42,27 @@ margin_bottom = -2.0
 
 [node name="Eva_Interpret_Btn" type="Button" parent="VBox"]
 margin_right = 203.0
-margin_bottom = 30.0
+margin_bottom = 27.0
 rect_pivot_offset = Vector2( -123, -302 )
 size_flags_vertical = 3
 size_flags_stretch_ratio = 0.08
 theme = ExtResource( 1 )
 text = "Eva: Interpret"
 
-[node name="ClearOutput_Btn" type="Button" parent="VBox"]
+[node name="Eva_ResetEnv_Btn" type="Button" parent="VBox"]
-margin_top = 34.0
+margin_top = 31.0
 margin_right = 203.0
-margin_bottom = 64.0
+margin_bottom = 59.0
+rect_pivot_offset = Vector2( -123, -302 )
+size_flags_vertical = 3
+size_flags_stretch_ratio = 0.08
+theme = ExtResource( 1 )
+text = "Eva: Reset Enviornment"
+
+[node name="ClearOutput_Btn" type="Button" parent="VBox"]
+margin_top = 63.0
+margin_right = 203.0
+margin_bottom = 91.0
 rect_pivot_offset = Vector2( -123, -302 )
 size_flags_vertical = 3
 size_flags_stretch_ratio = 0.08
@@ -61,14 +71,14 @@ text = "Clear Output"
 
 [node name="Separator" type="HSeparator" parent="VBox"]
 modulate = Color( 0.145098, 0.145098, 0.164706, 0 )
-margin_top = 68.0
+margin_top = 95.0
 margin_right = 203.0
-margin_bottom = 443.0
+margin_bottom = 445.0
 size_flags_vertical = 15
 theme = ExtResource( 5 )
 
 [node name="Back_Btn" type="Button" parent="VBox"]
-margin_top = 447.0
+margin_top = 449.0
 margin_right = 203.0
 margin_bottom = 478.0
 rect_pivot_offset = Vector2( -123, -302 )

App/EoI/Scripts/EoI_Viewer.gd

@@ -13,18 +13,18 @@ var   Eva : SEva
 
 
 # UX --------------------------------------------------------
-onready var Editor    = get_node("Editor_TEdit")
+onready var Editor        = get_node("Editor_TEdit")
-onready var Output    = get_node("Output_TEdit")
+onready var Output        = get_node("Output_TEdit")
-onready var Debug     = get_node("Debug_TEdit")
+onready var Debug         = get_node("Debug_TEdit")
-onready var Eva_Btn   = get_node("VBox/Eva_Interpret_Btn")
+onready var Eva_Btn       = get_node("VBox/Eva_Interpret_Btn")
-onready var Clear_Btn = get_node("VBox/ClearOutput_Btn")
+onready var Eva_Reset_Btn = get_node("VBox/Eva_ResetEnv_Btn")
-onready var Back_Btn  = get_node("VBox/Back_Btn")
+onready var Clear_Btn     = get_node("VBox/ClearOutput_Btn")
+onready var Back_Btn      = get_node("VBox/Back_Btn")
 
 
 func evaBtn_pressed():
 	Lexer  = SLexer.new(Editor.text, Output)
 	Parser = SParser.new(Lexer, Output)
-	Eva    = SEva.new(null, Output)
 
 	var ast    = Parser.parse()
 	var result = Eva.eval(ast)
@@ -34,6 +34,10 @@ func evaBtn_pressed():
 	
 	Debug.text = JSON.print( Eva.get_EnvSnapshot(), "\t" )
 	
+func evaResetBtn_pressed():
+	Eva        = SEva.new(null, Output)
+	Debug.text = JSON.print( Eva.get_EnvSnapshot(), "\t" )
+	
 func clearBtn_pressed():
 	Output.text = ""
  
@@ -42,6 +46,10 @@ func backBtn_pressed():
 	
 
 func _ready():
+	Eva        = SEva.new(null, Output)
+	Debug.text = JSON.print( Eva.get_EnvSnapshot(), "\t" )
+	
 	Eva_Btn.connect("pressed", self, "evaBtn_pressed")
+	Eva_Reset_Btn.connect("pressed", self, "evaResetBtn_pressed")
 	Clear_Btn.connect("pressed", self, "clearBtn_pressed")
 	Back_Btn.connect("pressed", self, "backBtn_pressed")

App/EoI/Scripts/Eva.gd

@@ -25,11 +25,17 @@ var   Env    : EvaEnv
 var Parent
 # ---------------------------------------------------------- GLOBALS END
 
+func get_class():
+	return "Eva"
+
 func _init(parent, evalOut):
 	EvalOut = evalOut
 	Env     = EvaEnv.new(EvalOut)
 	Parent  = parent
 	
+	if Parent == null:
+		Env.setup_Globals()
+
 func eval( ast ):
 	match ast.type():
 		NType.program :
@@ -47,7 +53,7 @@ func eval( ast ):
 		NType.block :
 			return eval_Block( ast )
 
-		NType.conditional:
+		NType.conditional :
 			var condition = eval( ast.arg(1) )
 
 			if condition:
@@ -58,7 +64,7 @@ func eval( ast ):
 			if ast.num_args() > 2:
 				return eval( ast.arg(3))
 				
-		NType.expr_While:
+		NType.expr_While :
 			var result
 			
 			while eval( ast.arg(1) ):
@@ -66,32 +72,33 @@ func eval( ast ):
 				
 			return result
 			
+		NType.fn_User :
+			var symbol = ast.arg(1)
+			var fnDef  = \
+			[ 
+				ast.arg(2), # Parameters
+				ast.arg(3), # Body
+				self        # Closure (Environment capture)
+			]
+			
+			Env.define(symbol, fnDef)
+			return Env.lookup(symbol)
+	
 		NType.identifier :
-			var identifier = ast.arg(1)
+			return eval_Lookup( ast )
-		
-			if Parent != null && !Env.has( identifier):
-				return Parent.Env.lookup( identifier )
-		
-			return Env.lookup( identifier )
 		
 		NType.op_Assign :
-			var symbol = ast.arg(1)
+			return eval_Assign( ast )
-			var value  = eval( ast.arg(2) )
 			
-			if Parent != null && !Env.has( symbol):
+		NType.op_Fn:
-				return Parent.Env.set( symbol, value )
+			return eval_Func( ast )
-			
-			return Env.set( symbol, value )
 
 		NType.op_Greater:
 			return eval( ast.arg(1) ) > eval( ast.arg(2) )
-
 		NType.op_Lesser:
 			return eval( ast.arg(1) ) < eval( ast.arg(2) )
-
 		NType.op_GreaterEqual:
 			return eval( ast.arg(1) ) >= eval( ast.arg(2) )
-
 		NType.op_LesserEqual:
 			return eval( ast.arg(1) ) <= eval( ast.arg(2) )
 			
@@ -100,10 +107,14 @@ func eval( ast ):
 	
 		NType.variable :
 			var symbol = ast.arg(1)
-			var value  = eval( ast.arg(2) )
+			var value
 			
-			Env.define_Var(symbol, value)
+			if ast.num_args() == 2:
-			return value
+				value = eval( ast.arg(2) )
+				
+			Env.define(symbol, value)
+			
+			return Env.lookup(symbol)
 	
 	if ast.is_Number() : 	
 		return float( ast.arg(1) )		
@@ -125,6 +136,44 @@ func eval_Block( ast ):
 
 	return result
 
+func eval_Lookup( ast ) :
+	var identifier = ast.arg(1)
+		
+	if Parent != null && !Env.has( identifier):
+		return Parent.eval_Lookup( ast )
+		
+	return Env.lookup( identifier )
+	
+func eval_Assign( ast, oriEva = null ) :
+	var symbol = ast.arg(1)
+	
+	if Parent != null && !Env.has( symbol):
+		return Parent.eval_Assign( ast, self )
+	
+	var value
+	
+	if oriEva != null :
+		value = oriEva.eval( ast.arg(2) )
+	else :
+		value = eval( ast.arg(2) )
+	
+	return Env.set( symbol, value )
+	
+func eval_Func( ast ):
+	var fn     = eval_Lookup( ast )
+	var params = fn[0]
+	var body   = fn[1]
+	var fnEva  = get_script().new( fn[2], EvalOut )
+	
+	if params.type() != NType.empty:
+		var index = 1
+		while index <= params.num_args():
+			var paramVal = eval( ast.arg(index + 1) )
+			fnEva.Env.define(params.arg(index), paramVal )
+			index += 1
+			
+	return fnEva.eval( body )
+
 func eval_Numeric( ast ):
 	if ast.type() == NType.op_Add:
 		var result  = 0.0; var index = 1
@@ -136,6 +185,9 @@ func eval_Numeric( ast ):
 		return result
 		
 	if ast.type() == NType.op_Sub:
+		if ast.num_args() == 2:
+			return -eval( ast.arg(1) )
+		
 		var result = 0.0; var index = 1
 		
 		while index <= ast.num_args():
@@ -171,9 +223,11 @@ func eval_Print( ast ):
 	return null
 	
 func get_EnvSnapshot():
-	var snapshot = Env.Records.duplicate(true)
+	var \
+	snapshot         = EvaEnv.new(EvalOut)
+	snapshot.Records = Env.Records.duplicate(true)
 	
 	if Parent != null:
-		snapshot[Parent] = Parent.Env.Records.duplicate(true)
+		snapshot[Parent] = Parent.get_EnvSnapshot()
 		
-	return snapshot
+	return snapshot.to_Dictionary()

App/EoI/Scripts/EvaEnv.gd

@@ -19,15 +19,17 @@ class_name EvaEnv
 var Records : Dictionary
 
 
-func _init(errorOut):
+func define(symbol : String, value) :
-	ErrorOut = errorOut
-	
-func define_Var(symbol : String, value) :
 	Records[symbol] = value
 
 func has(symbol : String) :
 	return Records.has(symbol)
 	
+func lookup(symbol : String) :
+	check(Records.has(symbol), String("Symbol not found in environment records"))
+
+	return Records[symbol]
+	
 func set(symbol : String, value) :
 	check(Records.has(symbol), String("Symbol not found in environment records"))
 	
@@ -35,7 +37,83 @@ func set(symbol : String, value) :
 	
 	return Records[symbol]
 
-func lookup(symbol : String) :
+func setup_Globals():
-	check(Records.has(symbol), String("Symbol not found in environment records"))
+	Records["null"]  = null
+	Records["true"]  = true
+	Records["false"] = false
 	
-	return Records[symbol]
+	
+func _init(errorOut):
+	ErrorOut = errorOut
+	
+	
+# Serialization ----------------------------------------------------
+var SEva
+
+func array_Serialize(array, fn_objSerializer) :
+	var result = []
+
+	for entry in array :
+		if typeof(entry) == TYPE_ARRAY :
+			result.append( array_Serialize( entry, fn_objSerializer ))
+
+		elif typeof(entry) == TYPE_OBJECT :
+			if entry.get_class() ==  "Eva":
+				result.append(entry)
+			else:
+				fn_objSerializer.set_instance(entry)
+				result.append( fn_objSerializer.call_func() )
+		else :
+			result.append( entry )
+			
+	return result
+
+func to_SExpression():
+	var expression = []
+	
+	for key in Records.keys() :
+		var entry = [key]
+		var Value = Records[key]
+		
+		if typeof( Value ) == TYPE_ARRAY :
+			var \
+			to_SExpression_Fn = FuncRef.new()
+			to_SExpression_Fn.set_function("to_SExpression")
+			
+			var array = array_Serialize( Value, to_SExpression_Fn )
+			
+			entry.append(array)
+			
+		elif typeof( Value ) == TYPE_OBJECT :
+			entry.append( Value.to_SExpression() )
+			
+		else :
+			entry.append(Value)
+			
+		expression.append(entry)
+		
+	return expression
+
+func to_Dictionary():
+	var result = {}
+
+	for key in Records.keys() :
+		var Value = Records[key]
+		
+		if typeof(Value) == TYPE_ARRAY :
+			var \
+			to_SExpression_Fn = FuncRef.new()
+			to_SExpression_Fn.set_function("to_SExpression")
+			
+			var array = array_Serialize( Value, to_SExpression_Fn )
+			
+			result[key] = array
+
+		elif typeof(Value) == TYPE_OBJECT :
+			result[key] = Value.to_SExpression()
+			
+		else :
+			result[key] = Value
+			
+	return result
+# Serialization END -------------------------------------------------

App/EoI/Scripts/Lexer.gd

@@ -24,12 +24,13 @@ const TType : Dictionary = \
 	cmt_SL = "Comment Single-Line",
 	cmt_ML = "Comment Multi-Line",
 	
-	def_Block = "Expression Block Start",
 	def_Start = "Expression Start",
 	def_End   = "Expression End",
+	def_Block = "Expression Block Start",
 	def_Cond  = "Expression Conditional",
 	def_While = "Expression While",
 	def_Var   = "Variable Declaration",
+	def_Func  = "Function Declaration",
 	
 	literal_Number = "Literal: Number",
 	literal_String = "Literal: String",
@@ -50,12 +51,13 @@ const Spec : Dictionary = \
 	
 	TType.fmt_S : "start whitespace.repeat(1-).lazy",
 
-	TType.def_Block : "start \"begin\"",
 	TType.def_Start : "start \\(",
 	TType.def_End   : "start \\)",
+	TType.def_Block : "start \"begin\"",
 	TType.def_Cond  : "start \"if\"",
 	TType.def_While : "start \"while\"",
 	TType.def_Var   : "start \"var\"",
+	TType.def_Func  : "start \"def\"",
 	
 	TType.literal_Number : \
 	"""start 

App/EoI/Scripts/Parser.gd

@@ -21,6 +21,8 @@ const NType = \
 {
 	program = "Program",
 	
+	empty = "Empty",
+	
 	block = "Scope Block",
 
 	conditional = "Conditional",
@@ -30,6 +32,7 @@ const NType = \
 	literal_String = "Literal: String",
 	
 	op_Assign = "Assignment",
+	op_Fn     = "Function Call",
 	
 	op_Add     = "+",
 	op_Sub     = "-",
@@ -42,9 +45,11 @@ const NType = \
 	op_LesserEqual  = "<=",
 	
 	fn_Print = "Print",
+	fn_User  = "User Function",
+	fn_Params = "Function Parameters",
 
 	identifier = "Identifier",
-	variable = "Variable"
+	variable   = "Variable"
 }
 
 class ASTNode:
@@ -163,6 +168,8 @@ func parse_Expression():
 			node = parse_While()
 		TType.def_Var:
 			node = parse_Variable()
+		TType.def_Func:
+			node = parse_fn_User()
 		TType.fn_Print:
 			node = parse_fn_Print()
 		TType.op_Assgin:
@@ -171,7 +178,8 @@ func parse_Expression():
 			node = parse_op_Numeric()
 		TType.op_Relational:
 			node = parse_op_Relational()
-
+		TType.identifier:
+			node = parse_op_Fn()
 	
 	var arg = 1
 	while NextToken.Type != TType.def_End:
@@ -184,6 +192,10 @@ func parse_Expression():
 		
 	eat(TType.def_End)
 	
+	if node == null:
+		node = ASTNode.new()
+		node.set_Type(NType.empty)
+	
 	return node
 
 func parse_Block():
@@ -222,11 +234,40 @@ func parse_Variable():
 	node.add_TokenValue( NextToken )
 	eat(TType.identifier)
 		
-	if NextToken.Type == TType.def_Start :
+	return node
-		node.add_Expr( parse_Expression() )
 	
-	else :
+func parse_fn_User():
-		node.add_Expr( parse_Literal() )
+	var \
+	node = ASTNode.new()
+	node.set_Type(NType.fn_User)
+	eat(TType.def_Func)
+	
+	check( NextToken.Type == TType.identifier,
+		String("Parser - parse_op_Assign: NextToken should have been identifier, Type: {type} Value: {value}") \
+		.format({"type" : NextToken.Type, "value" : NextToken.Value })
+	)
+	
+	node.add_TokenValue( NextToken )
+	eat(TType.identifier)
+	
+	# Parameters
+	var \
+	pNode = ASTNode.new()
+	pNode.set_Type(NType.fn_Params)
+	eat(TType.def_Start)
+	
+	while NextToken.Type != TType.def_End:
+		check( NextToken.Type == TType.identifier,
+			String("Parser - parse_op_Assign: NextToken should have been identifier, Type: {type} Value: {value}") \
+			.format({"type" : NextToken.Type, "value" : NextToken.Value })
+		)
+		
+		pNode.add_TokenValue(NextToken)
+		eat(TType.identifier)
+		
+	eat(TType.def_End)
+	
+	node.add_Expr( pNode )
 		
 	return node
 	
@@ -306,6 +347,15 @@ func parse_op_Relational():
 
 	return node
 	
+func parse_op_Fn():
+	var \
+	node = ASTNode.new()
+	node.set_Type(NType.op_Fn)
+	node.add_TokenValue( NextToken )
+	eat(TType.identifier)
+	
+	return node
+
 func parse_Literal():
 	var node = ASTNode.new()