rasp interpreter

RASP_support/Environment.py

@@ -0,0 +1,77 @@
+from Sugar import tokens_asis, tokens_str, tokens_int, tokens_bool, tokens_float, indices, length
+from FunctionalSupport import Unfinished, RASPTypeError
+from Evaluator import RASPFunction
+from copy import deepcopy
+
+class UndefinedVariable(Exception):
+	def __init__(self,varname):
+		super().__init__("Error: Undefined variable: "+varname)
+
+class ReservedName(Exception):
+	def __init__(self,varname):
+		super().__init__("Error: Cannot set reserved name: "+varname)
+
+class Environment:
+	def __init__(self,parent_env=None,name=None,stealing_env=None):
+		self.variables = {}
+		self.name = name
+		self.parent_env = parent_env
+		self.stealing_env = stealing_env
+		self.base_setup() # nested envs can have them too. makes life simpler,
+		# instead of checking if they have the constant_variables etc in get. bit heavier on memory
+		# but no one's going to use this language for big nested stuff anyway
+
+	def base_setup(self):
+		self.constant_variables = {"tokens_asis":tokens_asis,
+						 "tokens_str":tokens_str,
+						 "tokens_int":tokens_int,
+						 "tokens_bool":tokens_bool,
+						 "tokens_float":tokens_float,
+						 "indices":indices,
+						 "length":length,
+						 "True":True,
+						 "False":False}
+		self.reserved_words=["if","else","not","and","or","out","def","return","range","for","in","zip","len","get"] +\
+										list(self.constant_variables.keys())
+
+	def snapshot(self):
+		res = Environment(parent_env=self.parent_env,name=self.name,stealing_env=self.stealing_env)
+		def carefulcopy(val):
+			if isinstance(val,Unfinished) or isinstance(val,RASPFunction):
+				return val # non mutable, at least not through rasp commands
+			elif isinstance(val,float) or isinstance(val,int) or isinstance(val,str) or isinstance(val,bool):
+				return val # non mutable
+			elif isinstance(val,list):
+				return [carefulcopy(v) for v in val]
+			else:
+				raise RASPTypeError("environment contains element that is not unfinished,",
+									"rasp function, float, int, string, bool, or list? :",val)
+		res.variables = {d:carefulcopy(self.variables[d]) for d in self.variables}
+		return res
+
+	def make_nested(self,names_vars=[]):
+		res = Environment(self,name=str(self.name)+"'")
+		for n,v in names_vars:
+			res.set_variable(n,v)
+		return res
+
+	def get_variable(self,name):
+		if name in self.constant_variables:
+			return self.constant_variables[name]
+		if name in self.variables:
+			return self.variables[name]
+		if not None is self.parent_env:
+			return self.parent_env.get_variable(name)
+		raise UndefinedVariable(name)
+
+	def set_variable(self,name,val):
+		if name in self.reserved_words:
+			raise ReservedName(name)
+		self.variables[name] = val
+		if not None is self.stealing_env:
+			if name.startswith("_") or name=="out": # things we don't want to steal
+				return
+			self.stealing_env.set_variable(name,val)
+
+	def set_out(self,val):
+		self.variables["out"] = val