Files
Sheerka/src/parsers/SyaConceptsParser.py
T

112 lines
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Python

from core.concept import DefinitionType
from parsers.state_machine import ConceptToRecognize, End, ManageUnrecognized, PrepareReadTokens, ReadConcept, \
ReadTokens, Start, \
StateMachine, StateMachineContext
from parsers.tokenizer import Token, TokenKind, Tokenizer
class SyaConceptsParser:
""""
This class is to parse concepts with parameter
ex : def concept a plus b as a + b
It parses a sequence of concepts
"""
def __init__(self):
tokens_wkf = {
Start("start", next_states=["prepare read tokens"]),
PrepareReadTokens("prepare read tokens", next_states=["read tokens"]),
ReadTokens("read tokens", next_states=["read tokens", "eof", "concepts found"]),
ManageUnrecognized("eof", next_states=["end"]),
ManageUnrecognized("concepts found", next_states=["#concept_wkf"]),
End("end", next_states=None)
}
concept_wkf = {
Start("start", next_states=["read concept"]),
ReadConcept("read concept", next_states=["#tokens_wkf"]),
}
self.workflows = {
"#tokens_wkf": {t.name: t for t in tokens_wkf},
"#concept_wkf": {t.name: t for t in concept_wkf},
}
self.error_sink = []
@staticmethod
def _get_expected_tokens(concept_key):
"""
Return of list of pairs of (expected token, number of expected variable before this token)
ex:
'if x y then z end' => ('if', 0), ('then', 2), ('end', 1)
:param concept_key:
:type concept_key:
:return:
:rtype:
"""
# def custom_strip_tokens(_tokens):
# return _tokens
def custom_strip_tokens(_tokens):
"""
Removes consecutive whitespace tokens
Returns empy list if only whitespace tokens
:param _tokens:
:type _tokens:
:return:
:rtype:
"""
res = []
buffer = None
for t in _tokens:
if t.type == TokenKind.WHITESPACE:
buffer = t
else:
if buffer:
res.append(buffer)
buffer = None
res.append(t)
if res and buffer: # add the buffer only is the result is not empty
res.append(buffer)
return res
expected = [] # tuple of expected token and number of expected variables before this token
tokens = []
nb_variables = 0
parsing_tokens = None # True if we are parsing tokens (and not VAR_DEF)
for token in Tokenizer(concept_key, yield_eof=False):
if token.type == TokenKind.WHITESPACE:
tokens.append(token)
elif token.type == TokenKind.VAR_DEF:
if parsing_tokens is not None and parsing_tokens:
expected.append((custom_strip_tokens(tokens), nb_variables))
nb_variables = 1
tokens = []
parsing_tokens = False
else:
nb_variables += 1
else:
tokens.append(token)
parsing_tokens = True
# do not forget the remaining ones
if tokens or nb_variables:
expected.append((custom_strip_tokens(tokens), nb_variables))
return expected
def get_metadata_from_first_token(self, context, token: Token):
return [ConceptToRecognize(m, self._get_expected_tokens(m.key), "key")
for m in context.sheerka.get_metadatas_from_first_token("key", token.value)
if m.definition_type == DefinitionType.DEFAULT and len(m.parameters) > 0]
def parse(self, context, parser_input):
sm = StateMachine(self.workflows)
sm_context = StateMachineContext(context, parser_input, self.get_metadata_from_first_token)
sm.run("#tokens_wkf", "start", sm_context)
pass