Syntax 如何解决这种转变/减少冲突？
我的代码中有以下语法Syntax 如何解决这种转变/减少冲突？,syntax,grammar,conflict,ply,Syntax,Grammar,Conflict,Ply,我的代码中有以下语法 Rule 0 S' -> program Rule 1 write -> WRITE LPAREN expression_list RPAREN SEMICOLON Rule 2 read -> READ LPAREN expression_list RPAREN SEMICOLON Rule 3 program -> function Rule 4 function -> identifier iden
Rule 0 S' -> program
Rule 1 write -> WRITE LPAREN expression_list RPAREN SEMICOLON
Rule 2 read -> READ LPAREN expression_list RPAREN SEMICOLON
Rule 3 program -> function
Rule 4 function -> identifier identifier formal_parameters block
Rule 5 function -> VOID identifier formal_parameters block
Rule 6 formal_parameters -> LPAREN formal_parameter formal_parameters_list RPAREN
Rule 7 formal_parameters -> LPAREN empty RPAREN
Rule 8 formal_parameters_list -> SEMICOLON formal_parameter formal_parameters_list
Rule 9 formal_parameters_list -> empty
Rule 10 empty -> <empty>
Rule 11 formal_parameter -> expression_parameter
Rule 12 formal_parameter -> function_parameter
Rule 13 function_parameter -> VOID identifier formal_parameters
Rule 14 function_parameter -> INTEGER identifier formal_parameters
Rule 15 function_parameter -> identifier identifier formal_parameters
Rule 16 expression_parameter -> identifier_list COLON INTEGER
Rule 17 expression_parameter -> VAR identifier_list COLON INTEGER
Rule 18 identifier_list -> identifier
Rule 19 identifier_list -> identifier_list COMMA identifier
Rule 20 block -> body
Rule 21 block -> labels body
Rule 22 block -> labels variables body
Rule 23 block -> labels variables functions body
Rule 24 block -> labels functions body
Rule 25 block -> variables body
Rule 26 block -> variables functions body
Rule 27 block -> functions body
Rule 28 functions -> FUNCTIONS function_list
Rule 29 function_list -> function
Rule 30 function_list -> function function_list
Rule 31 variables -> VARS identifier_list COLON type SEMICOLON
Rule 32 type -> INTEGER
Rule 33 labels -> LABELS identifier_list SEMICOLON
Rule 34 body -> LBRACES stamement_list RBRACES
Rule 35 stamement_list -> statement stamement_list
Rule 36 stamement_list -> empty
Rule 37 statement -> unlabeled_statement
Rule 38 statement -> compound
Rule 39 unlabeled_statement -> assignment
Rule 40 unlabeled_statement -> function_call_statement
Rule 41 unlabeled_statement -> goto
Rule 42 unlabeled_statement -> return
Rule 43 unlabeled_statement -> conditional
Rule 44 unlabeled_statement -> repetitive
Rule 45 unlabeled_statement -> empty_statement
Rule 46 unlabeled_statement -> write
Rule 47 unlabeled_statement -> read
Rule 48 goto -> GOTO identifier SEMICOLON
Rule 49 return -> RETURN return_optional
Rule 50 return_optional -> expression
Rule 51 return_optional -> empty
Rule 52 function_call_statement -> function_call SEMICOLON
Rule 53 function_call -> IDENTIFIER LPAREN expression_list_and_empty RPAREN
Rule 54 expression_list_and_empty -> empty
Rule 55 expression_list_and_empty -> expression_list
Rule 56 expression_list -> expression
Rule 57 expression_list -> expression_list COMMA expression
Rule 58 repetitive -> WHILE LPAREN expression RPAREN compound
Rule 59 compound -> LBRACES compound_list RBRACES
Rule 60 compound_list -> unlabeled_statement
Rule 61 compound_list -> compound_list unlabeled_statement
Rule 62 empty_statement -> SEMICOLON
Rule 63 assignment -> identifier EQUALS expression SEMICOLON
Rule 64 variable -> identifier
Rule 65 variable -> identifier LBRACKETS expression_list RBRACKETS
Rule 66 expression -> simple_expression expression_optional
Rule 67 expression_optional -> relational_operator simple_expression
Rule 68 expression_optional -> empty
Rule 69 relational_operator -> COMPAREEQUAL
Rule 70 relational_operator -> NOTEQQUAL
Rule 71 relational_operator -> LESS
Rule 72 relational_operator -> LESSEQUAL
Rule 73 relational_operator -> GREATQUAL
Rule 74 relational_operator -> GREAT
Rule 75 conditional -> IF LPAREN expression RPAREN compound
Rule 76 conditional -> IF LPAREN expression RPAREN compound ELSE compound
Rule 77 simple_expression -> term simple_expression_list
Rule 78 simple_expression_list -> additive_operator term simple_expression_list
Rule 79 simple_expression_list -> empty
Rule 80 additive_operator -> PLUS
Rule 81 additive_operator -> MINUS
Rule 82 term -> factor multiplicative_operator_list
Rule 83 multiplicative_operator -> TIMES
Rule 84 multiplicative_operator -> DIVIDE
Rule 85 multiplicative_operator_list -> multiplicative_operator factor multiplicative_operator_list
Rule 86 multiplicative_operator_list -> empty
Rule 87 factor -> NUMBER
Rule 88 factor -> variable
Rule 89 factor -> LPAREN expression RPAREN
Rule 90 factor -> function_call
Rule 91 identifier -> IDENTIFIER
### Write Function ###
def p_write(p):
'''write : WRITE LPAREN expression_list RPAREN SEMICOLON'''
p[0] = ('write', p[3])
### Read Function ###
def p_read(p):
'''read : READ LPAREN expression_list RPAREN SEMICOLON'''
p[0] = ('read', p[3])
def p_program(p):
'''program : function'''
p[0] = p[1]
def p_function(p):
'''function : identifier identifier formal_parameters block
| VOID identifier formal_parameters block'''
p[0] = [p[1], p[2], p[3], p[4]]
def p_formal_parameters(p):
'''formal_parameters : LPAREN formal_parameter formal_parameters_list RPAREN
| LPAREN empty RPAREN'''
p[0] = p[2]
def p_formal_parameters_list(p):
'''formal_parameters_list : SEMICOLON formal_parameter formal_parameters_list
| empty'''
if len(p) == 4:
p[0] = p[3]
p[0].append(p[2])
elif len(p) == 2:
p[0] = [p[1]]
def p_empty(p):
'empty :'
pass
def p_formal_parameter(p):
'''formal_parameter : expression_parameter
| function_parameter'''
p[0] = p[1]
def p_function_parameter(p):
'''function_parameter : VOID identifier formal_parameters
| INTEGER identifier formal_parameters
| identifier identifier formal_parameters'''
p[0] = (p[1], p[2], p[3])
# Mudei um detalhe aqui
def p_expression_parameter(p):
'''expression_parameter : identifier_list COLON INTEGER
| VAR identifier_list COLON INTEGER'''
if len(p) == 4:
p[0] = (p[1], p[3])
elif len(p) == 5:
p[0] = (p[2], p[4])
def p_identifier_list(p):
'''identifier_list : identifier
| identifier_list COMMA identifier'''
if len(p) == 4:
p[0] = p[1]
p[0].append(p[3])
elif len(p) == 2:
p[0] = [p[1]]
def p_block(p):
'''block : body
| labels body
| labels variables body
| labels variables functions body
| labels functions body
| variables body
| variables functions body
| functions body'''
# body
if len(p) == 2:
p[0] = p[1]
# labels body
# variables body
# functions body
elif len(p) == 3:
p[0] = (p[1], p[2])
# labels variable body
# labels functions body
# variables functions body
elif len(p) == 4:
p[0] = (p[1], p[2], p[3])
#labels variables functions body
elif len(p) == 5:
p[0] = (p[1], p[2], p[3], p[4])
def p_functions(p):
'''functions : FUNCTIONS function_list'''
p[0] = p[2]
def p_functions_list(p):
'''function_list : function
| function function_list'''
if len(p) == 3:
p[0] = p[2]
p[0].append(p[1])
elif len(p) == 2:
p[0] = [p[1]]
def p_variables(p):
'''variables : VARS identifier_list COLON type SEMICOLON'''
p[0] = (p[2], p[4])
def p_type(p):
'''type : INTEGER'''
p[0] = p[1]
def p_labels(p):
'''labels : LABELS identifier_list SEMICOLON'''
p[0] = ('labels', p[2])
def p_body(p):
'''body : LBRACES stamement_list RBRACES '''
p[0] = p[2]
def p_stamement_list(p):
'''stamement_list : statement stamement_list
| empty'''
if len(p) == 3:
p[0] = p[2]
p[0].append(p[1])
elif len(p) == 2:
p[0] = [None]
def p_statement(p):
'''statement : unlabeled_statement
| compound'''
p[0] = p[1]
def p_unlabeled_statement(p):
'''unlabeled_statement : assignment
| function_call_statement
| goto
| return
| conditional
| repetitive
| empty_statement
| write
| read'''
p[0] = p[1]
def p_goto(p):
'''goto : GOTO identifier SEMICOLON'''
p[0] = ('goto', p[2])
def p_return(p):
'''return : RETURN return_optional'''
p[0] = (p[2])
def p_return_optional(p):
'''return_optional : expression
| empty'''
p[0] = (p[1])
def p_function_call_statement(p):
'''function_call_statement : function_call SEMICOLON'''
p[0] = p[1]
def p_function_call(p):
'''function_call : IDENTIFIER LPAREN expression_list_and_empty RPAREN'''
p[0] = (p[1], [p[3]])
def p_expression_list_and_empty(p):
'''expression_list_and_empty : empty
| expression_list'''
p[0] = p[1]
def p_expression_list(p):
'''expression_list : expression
| expression_list COMMA expression'''
if len(p) == 4:
p[0] = p[1]
p[0].append(p[3])
elif len(p) == 2:
p[0] = [p[1]]
def p_repetitive(p):
'''repetitive : WHILE LPAREN expression RPAREN compound'''
p[0] = (p[3], p[5])
def p_compound(p):
'''compound : LBRACES compound_list RBRACES'''
p[0] = ('{', p[2], '}')
def p_compound_list(p):
'''compound_list : unlabeled_statement
| compound_list unlabeled_statement'''
if len(p) == 3:
p[0] = p[1]
p[0].append(p[2])
elif len(p) == 2:
p[0] = [p[1]]
def p_empty_statement(p):
'''empty_statement : SEMICOLON'''
p[0] = None
def p_assignment(p):
'''assignment : identifier EQUALS expression SEMICOLON'''
p[0] = p[1]
def p_variable(p):
'''variable : identifier
| identifier LBRACKETS expression_list RBRACKETS'''
p[0] = p[1]
def p_expression(p):
'''expression : simple_expression expression_optional'''
p[0] = (p[1], p[2])
def p_expression_optional(p):
'''expression_optional : relational_operator simple_expression
| empty'''
if len(p) == 3:
p[0] = (p[1], p[2])
if len(p) == 2:
p[0] = None
def p_relational_operator(p):
'''relational_operator : COMPAREEQUAL
| NOTEQQUAL
| LESS
| LESSEQUAL
| GREATQUAL
| GREAT'''
p[0] = p[1]
def p_conditional(p):
'''conditional : IF LPAREN expression RPAREN compound
| IF LPAREN expression RPAREN compound ELSE compound'''
if len(p) == 6:
p[0] = ('IF', p[3], p[5])
if len(p) == 8:
p[0] = ('IF', p[3], p[5], 'ELSE', p[7])
def p_simple_expression(p):
'''simple_expression : term simple_expression_list'''
p[0] = (p[1], p[2])
def p_simple_expression_list(p):
'''simple_expression_list : additive_operator term simple_expression_list
| empty '''
if len(p) == 4:
p[0] = p[3]
p[0].append( (p[1], p[2]) )
elif len(p) == 2:
p[0] = [None]
def p_additive_operator(p):
'''additive_operator : PLUS
| MINUS'''
p[0] = p[1]
def p_term(p):
'''term : factor multiplicative_operator_list'''
p[0] = p[1]
def p_multiplicative_operator(p):
'''multiplicative_operator : TIMES
| DIVIDE'''
p[0] = p[1]
def p_multiplicative_operator_list(p):
'''multiplicative_operator_list : multiplicative_operator factor multiplicative_operator_list
| empty'''
if len(p) == 4:
p[0] = p[3]
p[0].append( (p[1], p[2]) )
elif len(p) == 2:
p[0] = [None]
def p_factor(p):
'''factor : NUMBER
| variable
| LPAREN expression RPAREN
| function_call'''
p[0] = p[1]
def p_identifier(p):
'''identifier : IDENTIFIER'''
p[0] = p[1]
def p_error(p):
print("Error", p)
您忘记用分号终止return语句。由于return语句采用可选表达式，并且后面可能跟有表达式语句，因此表达式后面的
return有什么意义？另外，我建议您将形式参数列表
更改为与其他列表相同的左递归形式。但我认为这与冲突无关。@riciempty
是一个epsilon产品。@Xilpex当然。我会更新我的问题。@miriade\ux：这是一个epsilon产品，当然，我在你的语法列表中看到了。但为什么会在那里？既然您已经发布了源代码，很明显（正如我所怀疑的）归约函数没有任何作用。所以你可以删除它，删除对它的引用，除了语法更紧凑，解析器执行速度更快之外，什么都不会改变。你完全正确！成功了。非常感谢你！
### Write Function ###
def p_write(p):
'''write : WRITE LPAREN expression_list RPAREN SEMICOLON'''
p[0] = ('write', p[3])
### Read Function ###
def p_read(p):
'''read : READ LPAREN expression_list RPAREN SEMICOLON'''
p[0] = ('read', p[3])
def p_program(p):
'''program : function'''
p[0] = p[1]
def p_function(p):
'''function : identifier identifier formal_parameters block
| VOID identifier formal_parameters block'''
p[0] = [p[1], p[2], p[3], p[4]]
def p_formal_parameters(p):
'''formal_parameters : LPAREN formal_parameter formal_parameters_list RPAREN
| LPAREN empty RPAREN'''
p[0] = p[2]
def p_formal_parameters_list(p):
'''formal_parameters_list : SEMICOLON formal_parameter formal_parameters_list
| empty'''
if len(p) == 4:
p[0] = p[3]
p[0].append(p[2])
elif len(p) == 2:
p[0] = [p[1]]
def p_empty(p):
'empty :'
pass
def p_formal_parameter(p):
'''formal_parameter : expression_parameter
| function_parameter'''
p[0] = p[1]
def p_function_parameter(p):
'''function_parameter : VOID identifier formal_parameters
| INTEGER identifier formal_parameters
| identifier identifier formal_parameters'''
p[0] = (p[1], p[2], p[3])
# Mudei um detalhe aqui
def p_expression_parameter(p):
'''expression_parameter : identifier_list COLON INTEGER
| VAR identifier_list COLON INTEGER'''
if len(p) == 4:
p[0] = (p[1], p[3])
elif len(p) == 5:
p[0] = (p[2], p[4])
def p_identifier_list(p):
'''identifier_list : identifier
| identifier_list COMMA identifier'''
if len(p) == 4:
p[0] = p[1]
p[0].append(p[3])
elif len(p) == 2:
p[0] = [p[1]]
def p_block(p):
'''block : body
| labels body
| labels variables body
| labels variables functions body
| labels functions body
| variables body
| variables functions body
| functions body'''
# body
if len(p) == 2:
p[0] = p[1]
# labels body
# variables body
# functions body
elif len(p) == 3:
p[0] = (p[1], p[2])
# labels variable body
# labels functions body
# variables functions body
elif len(p) == 4:
p[0] = (p[1], p[2], p[3])
#labels variables functions body
elif len(p) == 5:
p[0] = (p[1], p[2], p[3], p[4])
def p_functions(p):
'''functions : FUNCTIONS function_list'''
p[0] = p[2]
def p_functions_list(p):
'''function_list : function
| function function_list'''
if len(p) == 3:
p[0] = p[2]
p[0].append(p[1])
elif len(p) == 2:
p[0] = [p[1]]
def p_variables(p):
'''variables : VARS identifier_list COLON type SEMICOLON'''
p[0] = (p[2], p[4])
def p_type(p):
'''type : INTEGER'''
p[0] = p[1]
def p_labels(p):
'''labels : LABELS identifier_list SEMICOLON'''
p[0] = ('labels', p[2])
def p_body(p):
'''body : LBRACES stamement_list RBRACES '''
p[0] = p[2]
def p_stamement_list(p):
'''stamement_list : statement stamement_list
| empty'''
if len(p) == 3:
p[0] = p[2]
p[0].append(p[1])
elif len(p) == 2:
p[0] = [None]
def p_statement(p):
'''statement : unlabeled_statement
| compound'''
p[0] = p[1]
def p_unlabeled_statement(p):
'''unlabeled_statement : assignment
| function_call_statement
| goto
| return
| conditional
| repetitive
| empty_statement
| write
| read'''
p[0] = p[1]
def p_goto(p):
'''goto : GOTO identifier SEMICOLON'''
p[0] = ('goto', p[2])
def p_return(p):
'''return : RETURN return_optional'''
p[0] = (p[2])
def p_return_optional(p):
'''return_optional : expression
| empty'''
p[0] = (p[1])
def p_function_call_statement(p):
'''function_call_statement : function_call SEMICOLON'''
p[0] = p[1]
def p_function_call(p):
'''function_call : IDENTIFIER LPAREN expression_list_and_empty RPAREN'''
p[0] = (p[1], [p[3]])
def p_expression_list_and_empty(p):
'''expression_list_and_empty : empty
| expression_list'''
p[0] = p[1]
def p_expression_list(p):
'''expression_list : expression
| expression_list COMMA expression'''
if len(p) == 4:
p[0] = p[1]
p[0].append(p[3])
elif len(p) == 2:
p[0] = [p[1]]
def p_repetitive(p):
'''repetitive : WHILE LPAREN expression RPAREN compound'''
p[0] = (p[3], p[5])
def p_compound(p):
'''compound : LBRACES compound_list RBRACES'''
p[0] = ('{', p[2], '}')
def p_compound_list(p):
'''compound_list : unlabeled_statement
| compound_list unlabeled_statement'''
if len(p) == 3:
p[0] = p[1]
p[0].append(p[2])
elif len(p) == 2:
p[0] = [p[1]]
def p_empty_statement(p):
'''empty_statement : SEMICOLON'''
p[0] = None
def p_assignment(p):
'''assignment : identifier EQUALS expression SEMICOLON'''
p[0] = p[1]
def p_variable(p):
'''variable : identifier
| identifier LBRACKETS expression_list RBRACKETS'''
p[0] = p[1]
def p_expression(p):
'''expression : simple_expression expression_optional'''
p[0] = (p[1], p[2])
def p_expression_optional(p):
'''expression_optional : relational_operator simple_expression
| empty'''
if len(p) == 3:
p[0] = (p[1], p[2])
if len(p) == 2:
p[0] = None
def p_relational_operator(p):
'''relational_operator : COMPAREEQUAL
| NOTEQQUAL
| LESS
| LESSEQUAL
| GREATQUAL
| GREAT'''
p[0] = p[1]
def p_conditional(p):
'''conditional : IF LPAREN expression RPAREN compound
| IF LPAREN expression RPAREN compound ELSE compound'''
if len(p) == 6:
p[0] = ('IF', p[3], p[5])
if len(p) == 8:
p[0] = ('IF', p[3], p[5], 'ELSE', p[7])
def p_simple_expression(p):
'''simple_expression : term simple_expression_list'''
p[0] = (p[1], p[2])
def p_simple_expression_list(p):
'''simple_expression_list : additive_operator term simple_expression_list
| empty '''
if len(p) == 4:
p[0] = p[3]
p[0].append( (p[1], p[2]) )
elif len(p) == 2:
p[0] = [None]
def p_additive_operator(p):
'''additive_operator : PLUS
| MINUS'''
p[0] = p[1]
def p_term(p):
'''term : factor multiplicative_operator_list'''
p[0] = p[1]
def p_multiplicative_operator(p):
'''multiplicative_operator : TIMES
| DIVIDE'''
p[0] = p[1]
def p_multiplicative_operator_list(p):
'''multiplicative_operator_list : multiplicative_operator factor multiplicative_operator_list
| empty'''
if len(p) == 4:
p[0] = p[3]
p[0].append( (p[1], p[2]) )
elif len(p) == 2:
p[0] = [None]
def p_factor(p):
'''factor : NUMBER
| variable
| LPAREN expression RPAREN
| function_call'''
p[0] = p[1]
def p_identifier(p):
'''identifier : IDENTIFIER'''
p[0] = p[1]
def p_error(p):
print("Error", p)