initial

s_basic/code_segments/abc.py

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+"""
+This module provides abstract code segment classes.
+"""
+
+
+from abc import ABC, abstractmethod
+
+class AbstractCodeSegment(ABC):
+	@abstractmethod
+	def parse(self):
+		pass
+
+class AbstractNestingCodeSegment(AbstractCodeSegment):
+	@abstractmethod
+	def parse_children(self):
+		pass
+	@abstractmethod
+	def parse_child(self):
+		pass

s_basic/code_segments/statements.py

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+"""
+This module provides statement classes.
+"""
+
+from .abc import AbstractCodeSegment
+
+class VariableDefinitionStatement(AbstractCodeSegment):
+	def __init__(self, parsing_context):
+		self.parsing_context = parsing_context
+
+	def parse(self):
+

s_basic/context/context.py

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+"""
+This module provides the parsing context classes.
+"""
+from ..util import CharacterDevice
+
+class ParsingContext(object):
+	def __init__(self, file_, static_context):
+		self._file = CharacterDevice(file_)
+		self._static = static_context
+		self._line = 0
+		self._column = 0
+		self._last_column = 0
+
+	def getc(self):
+		res = self._file.getc()
+		if(res == "\n"):
+			self._line += 1
+			self._last_column = self._column
+			self._column = 0
+		else:
+			self._column += 1
+		return res
+	def ungetc(self, c):
+		if(c == "\n"):
+			self._column = self._last_column
+			self._line -= 1
+		else:
+			self._column -= 1
+		return self._file.ungetc(c)
+	def ungets(self, s):
+		for c in s:
+			self.ungetc(c)
+
+
+class StaticParsingContext(object):
+	def __init__(self, custom_kwd_code_segments, custom_ctx_code_segments):
+		self._kwd_code_segments = {
+			(["int", "str", "chr"], ["statement"]):  "variable_definition_segment",
+			(["STOP"], ["statement"]): "stop_command_segment",
+			(["CALL"], ["statement"]): "routine_call_segment",
+			(["("], ["expression", "int"]): "arithmetic_segment",
+			(["ROUTINE"], ["statement"]): "routine_segment",
+			(["WHILE"], ["statement"]): "while_segment",
+			(["IF"], ["statement"]): "if_segment",
+			(["\"", "`"], ["expression", "str"]): "string_definition_segment",
+			(["'"], ["expression", "chr"]): "character_definition_segment"
+
+		}
+
+		self._kwd_code_segments.update(custom_kwd_code_segments)
+
+		self._ctx_code_segments = {
+			["statement"]: "assignment_segment",
+			["expression", "int"]: "arithmetic_segment",
+
+

s_basic/util/io.py

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+"""
+This module provides utility functions and classed for I/O.
+"""
+
+
+class CharacterDevice(object):
+	def __init__(self, file_):
+		self._file = file_
+
+	def getc(self):
+		return self._file.read(1)
+	def ungetc(self, c):
+		self._file.seek(-1, 1)
+	def ungets(self, s):
+		self._file.seel(-len(s), 1)
+	def close(self):
+		return self._file.close()
+