add LineStream class

PyTeX/format/tex_formatter.py

@@ -1,5 +1,63 @@
+from typing import List, TextIO
+from pathlib import Path
 from .pytex_formatter import PyTeXFormatter
+from .macros import Macro
+
+
+class LineStream:
+    def __init__(self, filename: Path):
+        self._file = filename
+        self._handle = open(filename, 'r')
+        self._cached_lines: List[str] = []
+
+    def current_line(self):
+        return self.future_line(0)
+
+    def set_line(self, line):
+        self.set_future_line(0, line)
+
+    def pop_line(self) -> str:
+        self.reserve_lines(1)
+        line = self._cached_lines[0]
+        self._cached_lines = self._cached_lines[1:]
+        return line
+
+    def push_line(self, line):
+        self.push_lines([line])
+
+    def push_lines(self, lines: List[str]):
+        self._cached_lines = lines + self._cached_lines
+
+    def future_line(self, pos: int):
+        self.reserve_lines(pos + 1)
+        return self._cached_lines[pos]
+
+    def set_future_line(self, line, pos):
+        self.reserve_lines(pos + 1)
+        self._cached_lines[pos] = line
+
+    def reserve_lines(self, num_lines):
+        for i in range(0, num_lines - len(self._cached_lines) -1):
+            self._cached_lines.append(
+                self._handle.readline()
+            )
+        if self._cached_lines[-1] == '':
+            self._handle.close()
+
 
 
 class TexFormatter(PyTeXFormatter):
-    pass
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self._macros: List[Macro] = []
+        self._output_file: TextIO = None
+
+    def _handle_macro(self, macro: Macro):
+        self._current_line = macro.apply(self._current_line, self)
+
+    def _shipout_line(self):
+        self.write_line(self._current_line.rstrip())
+
+    def write_line(self, line: str):
+        self._output_file.writelines([line])
+