implement config parsing of pytex files in pytex formatter class

PyTeX/format/formatting_config.py

@@ -32,6 +32,10 @@ class FormattingConfig(Config):
 
         self._escape_character: Optional[str] = None
 
+    @classmethod
+    def from_yaml(cls, yaml):
+        pass
+
     def merge_with(self, other, strict: bool = False):
         """
         Merges the other config into this one

PyTeX/format/pytex_formatter.py

@@ -4,6 +4,9 @@ from .formatting_config import FormattingConfig
 from .enums import TeXType, TeXFlavour
 from .formatterif import FormatterIF
 from .generic_text import GenericText
+import re
+from .constants import *
+from ..logger import logger
 
 
 class PyTeXFormatter(FormatterIF):
@@ -12,17 +15,74 @@ class PyTeXFormatter(FormatterIF):
             input_file: Optional[Path] = None,
             config: Optional[FormattingConfig] = None,
             tex_type: Optional[TeXType] = None,
-            tex_flavour: Optional[TeXFlavour] = None
+            tex_flavour: Optional[TeXFlavour] = None,
+            locate_file_config: bool = True,
+            allow_infile_config: bool = True
     ):
         super().__init__(
             input_file=input_file,
             config=config
         )
-        self._config: Optional[FormattingConfig] = self._config
+        self._config: Optional[FormattingConfig] = self._config  # for type-hinting
         self._tex_type: Optional[TeXType] = tex_type
         self._tex_flavour: Optional[TeXFlavour] = tex_flavour
+        self._allow_infile_config = allow_infile_config
         self._header: Optional[GenericText] = None
-        self._formatted_header: Optional[str] = None
+        if locate_file_config:
+            file_config = self.parse_file_config()
+            if allow_infile_config:
+                infile_config = self.parse_infile_config()
+                self._config = \
+                    file_config.merge_with(
+                        infile_config,
+                        strict=True
+                    ).merge_with(self._config, strict=False)
+            else:
+                self._config = file_config.merge_with(self._config)
+        else:
+            if allow_infile_config:
+                infile_config = self.parse_infile_config()
+                self._config = infile_config.merge_with(self._config)
+
+    def parse_file_config(self) -> Optional[FormattingConfig]:
+        config_file = self.input_file.with_name(self.input_file.name + PYTEX_CONFIG_FILE_EXTENSION)
+        if config_file.exists():
+            with open(config_file, 'r') as file:
+                config = file.readlines()
+            try:
+                return FormattingConfig.from_yaml(config)
+            except:
+                raise NotImplementedError  # Invalid yaml file format
+        else:
+            return None
+
+    def parse_infile_config(self) -> Optional[FormattingConfig]:
+        with open(self._input_file, "r") as file:
+            line = file.readline()
+            if re.match(self.config.escape_character + INFILE_CONFIG_BEGIN_CONFIG, line):
+                if not line.strip().lstrip('%').strip() == self.config.escape_character + INFILE_CONFIG_BEGIN_CONFIG:
+                    logger.warning(
+                        "File {file}: Start of infile config invalid."
+                    )
+                config = []
+                while True:
+                    line = file.readline()
+                    if re.match(self.config.escape_character + INFILE_CONFIG_END_CONFIG, line):
+                        if not line.strip().lstrip(
+                                '%').strip() == self.config.escape_character + INFILE_CONFIG_END_CONFIG:
+                            logger.warning(
+                                "File {file}: End of infile config invalid."
+                            )
+                        break
+                    if line == '':
+                        raise NotImplementedError  # No matching end block
+                    config.append(line.lstrip('%').rstrip())
+                try:
+                    return FormattingConfig.from_yaml(config)
+                except:
+                    raise NotImplementedError  # Invalid yaml file format
+            else:
+                return None
 
     @property
     def config(self) -> FormattingConfig: