add

ccxt/static_dependencies/lark/parsers/lalr_parser.py

@@ -0,0 +1,122 @@
+"""This module implements a LALR(1) Parser
+"""
+# Author: Erez Shinan (2017)
+# Email : erezshin@gmail.com
+from typing import Dict, Any, Optional
+from ..lexer import Token, LexerThread
+from ..utils import Serialize
+from ..common import ParserConf, ParserCallbacks
+
+from .lalr_analysis import LALR_Analyzer, IntParseTable, ParseTableBase
+from .lalr_interactive_parser import InteractiveParser
+from ..exceptions import UnexpectedCharacters, UnexpectedInput, UnexpectedToken
+from .lalr_parser_state import ParserState, ParseConf
+
+###{standalone
+
+class LALR_Parser(Serialize):
+    def __init__(self, parser_conf: ParserConf, debug: bool=False, strict: bool=False):
+        analysis = LALR_Analyzer(parser_conf, debug=debug, strict=strict)
+        analysis.compute_lalr()
+        callbacks = parser_conf.callbacks
+
+        self._parse_table = analysis.parse_table
+        self.parser_conf = parser_conf
+        self.parser = _Parser(analysis.parse_table, callbacks, debug)
+
+    @classmethod
+    def deserialize(cls, data, memo, callbacks, debug=False):
+        inst = cls.__new__(cls)
+        inst._parse_table = IntParseTable.deserialize(data, memo)
+        inst.parser = _Parser(inst._parse_table, callbacks, debug)
+        return inst
+
+    def serialize(self, memo: Any = None) -> Dict[str, Any]:
+        return self._parse_table.serialize(memo)
+
+    def parse_interactive(self, lexer: LexerThread, start: str):
+        return self.parser.parse(lexer, start, start_interactive=True)
+
+    def parse(self, lexer, start, on_error=None):
+        try:
+            return self.parser.parse(lexer, start)
+        except UnexpectedInput as e:
+            if on_error is None:
+                raise
+
+            while True:
+                if isinstance(e, UnexpectedCharacters):
+                    s = e.interactive_parser.lexer_thread.state
+                    p = s.line_ctr.char_pos
+
+                if not on_error(e):
+                    raise e
+
+                if isinstance(e, UnexpectedCharacters):
+                    # If user didn't change the character position, then we should
+                    if p == s.line_ctr.char_pos:
+                        s.line_ctr.feed(s.text[p:p+1])
+
+                try:
+                    return e.interactive_parser.resume_parse()
+                except UnexpectedToken as e2:
+                    if (isinstance(e, UnexpectedToken)
+                        and e.token.type == e2.token.type == '$END'
+                        and e.interactive_parser == e2.interactive_parser):
+                        # Prevent infinite loop
+                        raise e2
+                    e = e2
+                except UnexpectedCharacters as e2:
+                    e = e2
+
+
+class _Parser:
+    parse_table: ParseTableBase
+    callbacks: ParserCallbacks
+    debug: bool
+
+    def __init__(self, parse_table: ParseTableBase, callbacks: ParserCallbacks, debug: bool=False):
+        self.parse_table = parse_table
+        self.callbacks = callbacks
+        self.debug = debug
+
+    def parse(self, lexer: LexerThread, start: str, value_stack=None, state_stack=None, start_interactive=False):
+        parse_conf = ParseConf(self.parse_table, self.callbacks, start)
+        parser_state = ParserState(parse_conf, lexer, state_stack, value_stack)
+        if start_interactive:
+            return InteractiveParser(self, parser_state, parser_state.lexer)
+        return self.parse_from_state(parser_state)
+
+
+    def parse_from_state(self, state: ParserState, last_token: Optional[Token]=None):
+        """Run the main LALR parser loop
+
+        Parameters:
+            state - the initial state. Changed in-place.
+            last_token - Used only for line information in case of an empty lexer.
+        """
+        try:
+            token = last_token
+            for token in state.lexer.lex(state):
+                assert token is not None
+                state.feed_token(token)
+
+            end_token = Token.new_borrow_pos('$END', '', token) if token else Token('$END', '', 0, 1, 1)
+            return state.feed_token(end_token, True)
+        except UnexpectedInput as e:
+            try:
+                e.interactive_parser = InteractiveParser(self, state, state.lexer)
+            except NameError:
+                pass
+            raise e
+        except Exception as e:
+            if self.debug:
+                print("")
+                print("STATE STACK DUMP")
+                print("----------------")
+                for i, s in enumerate(state.state_stack):
+                    print('%d)' % i , s)
+                print("")
+
+            raise
+###}