Why scanf in bison grammatical rule not working?

I have this gramatical rule in my .y file

...

    listaIdentificadores  :listaIdentificadores ',' ID {leer($3);}

                          |ID {leer($1);}

    ;

...

and this is definition of leer()

void leer(char* identificador) {

    int valor;

    scanf("%d",&valor);

    cargarTS(identificador, valor);

}

but when scanf() should be executed it does not ask for the keyboard input and it simply continues with the execution of the following code line.

edited Nov 14 '18 at 14:49

Cœur

17.6k9105145

asked Nov 14 '18 at 14:37

Cosmonauta

1

I am not familar with Bison, but are you leaving any newlines (n or pressing Enter) or any other characters in the input stream before the scanf() from other scanf()s, reads, et cetera?

– Tau
Nov 14 '18 at 14:42

1

You are going to have to provide more code than that. Where is the lexer getting its input from? If it is also coming from standard input, it's very hard to see how that can "work" (although it's also not clear to me what you are trying to do).

– rici
Nov 14 '18 at 15:14

I'm using 'flex', getting the characters from the standard input. maybe later I can upload all the code

– Cosmonauta
Nov 14 '18 at 17:25

1

"getting the characters from the standard input". So when you call scanf, do you expect that to read from the file that you're piping into stdin? So does that mean that after the ID token there will be a number in the source and you want scanf to read that number? If that's the case, you should just add an integer token to your grammar rule instead of scanf. If you're trying to read user input independently from reading the source code, you can't read both from stdin.

– sepp2k
Nov 14 '18 at 17:32

1

@Cosmonauta First of all, you can't read input from stdin as the same type as you're reading the source from stdin? How should that work? Do you want the user to enter the source code, followed by some terminator and then the input? If so, that won't work because your actions are going to be evaluated while the source is being read, not after. Secondly, trying to run the program while parsing it, isn't going to work anyway. As soon as you try to implement ifs or loops that way, you're going run into trouble. You'll want to make your parser generate an AST or bytecode and then ...

– sepp2k
Nov 15 '18 at 17:52

|
show 3 more comments

I have this gramatical rule in my .y file

...

    listaIdentificadores  :listaIdentificadores ',' ID {leer($3);}

                          |ID {leer($1);}

    ;

...

and this is definition of leer()

void leer(char* identificador) {

    int valor;

    scanf("%d",&valor);

    cargarTS(identificador, valor);

}

but when scanf() should be executed it does not ask for the keyboard input and it simply continues with the execution of the following code line.

edited Nov 14 '18 at 14:49

Cœur

17.6k9105145

asked Nov 14 '18 at 14:37

Cosmonauta

1

I am not familar with Bison, but are you leaving any newlines (n or pressing Enter) or any other characters in the input stream before the scanf() from other scanf()s, reads, et cetera?

– Tau
Nov 14 '18 at 14:42

1

You are going to have to provide more code than that. Where is the lexer getting its input from? If it is also coming from standard input, it's very hard to see how that can "work" (although it's also not clear to me what you are trying to do).

– rici
Nov 14 '18 at 15:14

I'm using 'flex', getting the characters from the standard input. maybe later I can upload all the code

– Cosmonauta
Nov 14 '18 at 17:25

1

"getting the characters from the standard input". So when you call scanf, do you expect that to read from the file that you're piping into stdin? So does that mean that after the ID token there will be a number in the source and you want scanf to read that number? If that's the case, you should just add an integer token to your grammar rule instead of scanf. If you're trying to read user input independently from reading the source code, you can't read both from stdin.

– sepp2k
Nov 14 '18 at 17:32

1

@Cosmonauta First of all, you can't read input from stdin as the same type as you're reading the source from stdin? How should that work? Do you want the user to enter the source code, followed by some terminator and then the input? If so, that won't work because your actions are going to be evaluated while the source is being read, not after. Secondly, trying to run the program while parsing it, isn't going to work anyway. As soon as you try to implement ifs or loops that way, you're going run into trouble. You'll want to make your parser generate an AST or bytecode and then ...

– sepp2k
Nov 15 '18 at 17:52

|
show 3 more comments

I have this gramatical rule in my .y file

...

    listaIdentificadores  :listaIdentificadores ',' ID {leer($3);}

                          |ID {leer($1);}

    ;

...

and this is definition of leer()

void leer(char* identificador) {

    int valor;

    scanf("%d",&valor);

    cargarTS(identificador, valor);

}

but when scanf() should be executed it does not ask for the keyboard input and it simply continues with the execution of the following code line.

edited Nov 14 '18 at 14:49

Cœur

17.6k9105145

asked Nov 14 '18 at 14:37

Cosmonauta

I have this gramatical rule in my .y file

...

    listaIdentificadores  :listaIdentificadores ',' ID {leer($3);}

                          |ID {leer($1);}

    ;

...

and this is definition of leer()

void leer(char* identificador) {

    int valor;

    scanf("%d",&valor);

    cargarTS(identificador, valor);

}

but when scanf() should be executed it does not ask for the keyboard input and it simply continues with the execution of the following code line.

scanf bison

edited Nov 14 '18 at 14:49

Cœur

17.6k9105145

asked Nov 14 '18 at 14:37

Cosmonauta

edited Nov 14 '18 at 14:49

Cœur

17.6k9105145

asked Nov 14 '18 at 14:37

Cosmonauta

edited Nov 14 '18 at 14:49

Cœur

17.6k9105145

edited Nov 14 '18 at 14:49

Cœur

17.6k9105145

edited Nov 14 '18 at 14:49

Cœur

17.6k9105145

asked Nov 14 '18 at 14:37

Cosmonauta

asked Nov 14 '18 at 14:37

Cosmonauta

asked Nov 14 '18 at 14:37

Cosmonauta

1

I am not familar with Bison, but are you leaving any newlines (n or pressing Enter) or any other characters in the input stream before the scanf() from other scanf()s, reads, et cetera?

– Tau
Nov 14 '18 at 14:42

1

You are going to have to provide more code than that. Where is the lexer getting its input from? If it is also coming from standard input, it's very hard to see how that can "work" (although it's also not clear to me what you are trying to do).

– rici
Nov 14 '18 at 15:14

I'm using 'flex', getting the characters from the standard input. maybe later I can upload all the code

– Cosmonauta
Nov 14 '18 at 17:25

1

"getting the characters from the standard input". So when you call scanf, do you expect that to read from the file that you're piping into stdin? So does that mean that after the ID token there will be a number in the source and you want scanf to read that number? If that's the case, you should just add an integer token to your grammar rule instead of scanf. If you're trying to read user input independently from reading the source code, you can't read both from stdin.

– sepp2k
Nov 14 '18 at 17:32

1

@Cosmonauta First of all, you can't read input from stdin as the same type as you're reading the source from stdin? How should that work? Do you want the user to enter the source code, followed by some terminator and then the input? If so, that won't work because your actions are going to be evaluated while the source is being read, not after. Secondly, trying to run the program while parsing it, isn't going to work anyway. As soon as you try to implement ifs or loops that way, you're going run into trouble. You'll want to make your parser generate an AST or bytecode and then ...

– sepp2k
Nov 15 '18 at 17:52

|
show 3 more comments

1

I am not familar with Bison, but are you leaving any newlines (n or pressing Enter) or any other characters in the input stream before the scanf() from other scanf()s, reads, et cetera?

– Tau
Nov 14 '18 at 14:42

1

You are going to have to provide more code than that. Where is the lexer getting its input from? If it is also coming from standard input, it's very hard to see how that can "work" (although it's also not clear to me what you are trying to do).

– rici
Nov 14 '18 at 15:14

I'm using 'flex', getting the characters from the standard input. maybe later I can upload all the code

– Cosmonauta
Nov 14 '18 at 17:25

1

"getting the characters from the standard input". So when you call scanf, do you expect that to read from the file that you're piping into stdin? So does that mean that after the ID token there will be a number in the source and you want scanf to read that number? If that's the case, you should just add an integer token to your grammar rule instead of scanf. If you're trying to read user input independently from reading the source code, you can't read both from stdin.

– sepp2k
Nov 14 '18 at 17:32

1

@Cosmonauta First of all, you can't read input from stdin as the same type as you're reading the source from stdin? How should that work? Do you want the user to enter the source code, followed by some terminator and then the input? If so, that won't work because your actions are going to be evaluated while the source is being read, not after. Secondly, trying to run the program while parsing it, isn't going to work anyway. As soon as you try to implement ifs or loops that way, you're going run into trouble. You'll want to make your parser generate an AST or bytecode and then ...

– sepp2k
Nov 15 '18 at 17:52

I am not familar with Bison, but are you leaving any newlines (n or pressing Enter) or any other characters in the input stream before the scanf() from other scanf()s, reads, et cetera?

– Tau
Nov 14 '18 at 14:42

You are going to have to provide more code than that. Where is the lexer getting its input from? If it is also coming from standard input, it's very hard to see how that can "work" (although it's also not clear to me what you are trying to do).

– rici
Nov 14 '18 at 15:14

I'm using 'flex', getting the characters from the standard input. maybe later I can upload all the code

– Cosmonauta
Nov 14 '18 at 17:25

"getting the characters from the standard input". So when you call scanf, do you expect that to read from the file that you're piping into stdin? So does that mean that after the ID token there will be a number in the source and you want scanf to read that number? If that's the case, you should just add an integer token to your grammar rule instead of scanf. If you're trying to read user input independently from reading the source code, you can't read both from stdin.

– sepp2k
Nov 14 '18 at 17:32

@Cosmonauta First of all, you can't read input from stdin as the same type as you're reading the source from stdin? How should that work? Do you want the user to enter the source code, followed by some terminator and then the input? If so, that won't work because your actions are going to be evaluated while the source is being read, not after. Secondly, trying to run the program while parsing it, isn't going to work anyway. As soon as you try to implement ifs or loops that way, you're going run into trouble. You'll want to make your parser generate an AST or bytecode and then ...

– sepp2k
Nov 15 '18 at 17:52

|
show 3 more comments

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