"""
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",